Author: jayendrapatil

Amazon DynamoDB Global Tables

~ Last updated on : ~ jayendrapatil

Amazon DynamoDB Global Tables

  • DynamoDB Global Tables is a fully managed, serverless, multi-master, active-active database.
  • Global tables provide 99.999% availability, increased application resiliency, and improved business continuity.
  • Global table’s automatic cross-region replication capability helps achieve fast, local read and write performance and regional fault tolerance for database workloads.
  • Applications can now perform reads and writes to DynamoDB in AWS regions around the world, with changes in any region propagated to every region where a table is replicated.
  • Global Tables help in building applications to advantage of data locality to reduce overall latency.
  • Global Tables supports eventual consistency & strong consistency for same region reads, but only eventual consistency for cross-region reads.
  • Global Tables replicates data among regions within a single AWS account and currently does not support cross-account access.
  • Global Tables uses the Last Write Wins approach for conflict resolution.

Global Tables Working

  • Global Table is a collection of one or more replica tables, all owned by a single AWS account.
  • A single Amazon DynamoDB global table can only have one replica table per AWS Region.
  • Each replica table stores the same set of data items, has the same table name, and the same primary key schema.
  • When an application writes data to a replica table in one Region, DynamoDB automatically replicates the writes to other replica tables in the other AWS Regions.
  • Global Tables requires DynamoDB streams enabled with New and Old image settings.

DynamoDB Global Tables vs. Aurora Global Databases

AWS Aurora Global Database vs DynamoDB Global Tables

AWS Certification Exam Practice Questions

  • Questions are collected from Internet and the answers are marked as per my knowledge and understanding (which might differ with yours).
  • AWS services are updated everyday and both the answers and questions might be outdated soon, so research accordingly.
  • AWS exam questions are not updated to keep up the pace with AWS updates, so even if the underlying feature has changed the question might not be updated
  • Open to further feedback, discussion and correction.
  1. A company is building a web application on AWS. The application requires the database to support read and write operations in multiple AWS Regions simultaneously. The database also needs to propagate data changes between Regions as the changes occur. The application must be highly available and must provide a latency of single-digit milliseconds. Which solution meets these requirements?
    1. Amazon DynamoDB global tables
    2. Amazon DynamoDB streams with AWS Lambda to replicate the data
    3. An Amazon ElastiCache for Redis cluster with cluster mode enabled and multiple shards
    4. An Amazon Aurora global database

References

Amazon_DynamoDB_Global_Tables

Amazon DynamoDB Streams

~ Last updated on : ~ jayendrapatil ~ 2 Comments

Amazon DynamoDB Streams

  • DynamoDB Streams provides a time-ordered sequence of item-level changes made to data in a table.
  • DynamoDB Streams stores the data for the last 24 hours, after which they are erased.
  • DynamoDB Streams maintains an ordered sequence of the events per item however, sequence across items is not maintained.
  • Example
    • For e.g., suppose that you have a DynamoDB table tracking high scores for a game and that each item in the table represents an individual player. If you make the following three updates in this order:
      • Update 1: Change Player 1’s high score to 100 points
      • Update 2: Change Player 2’s high score to 50 points
      • Update 3: Change Player 1’s high score to 125 points
    • DynamoDB Streams will maintain the order for Player 1 score events. However, it would not maintain order across the players. So Player 2 score event is not guaranteed between the 2 Player 1 events
  • Applications can access this log and view the data items as they appeared before and after they were modified, in near-real time.
  • DynamoDB Streams APIs help developers consume updates and receive the item-level data before and after items are changed.
  • Streams allow reads at up to twice the rate of the provisioned write capacity of the DynamoDB table.
  • Streams have to be enabled on a per-table basis. When enabled on a table, DynamoDB captures information about every modification to data items in the table.
  • Streams support Encryption at rest to encrypt the data.
  • Streams are designed for No Duplicates so that every update made to the table will be represented exactly once in the stream.
  • Streams write stream records in near-real time so that applications can consume these streams and take action based on the contents.
  • Streams can be used for multi-region replication to keep other data stores up-to-date with the latest changes to DynamoDB or to take actions based on the changes made to the table
  • Stream records can be processed using Kinesis Data Streams, Lambda, or KCL application.

AWS Certification Exam Practice Questions

  • Questions are collected from Internet and the answers are marked as per my knowledge and understanding (which might differ with yours).
  • AWS services are updated everyday and both the answers and questions might be outdated soon, so research accordingly.
  • AWS exam questions are not updated to keep up the pace with AWS updates, so even if the underlying feature has changed the question might not be updated
  • Open to further feedback, discussion and correction.
  1. An application currently writes a large number of records to a DynamoDB table in one region. There is a requirement for a secondary application to retrieve new records written to the DynamoDB table every 2 hours and process the updates accordingly. Which of the following is an ideal way to ensure that the secondary application gets the relevant changes from the DynamoDB table?
    1. Insert a timestamp for each record and then scan the entire table for the timestamp as per the last 2 hours.
    2. Create another DynamoDB table with the records modified in the last 2 hours.
    3. Use DynamoDB Streams to monitor the changes in the DynamoDB table.
    4. Transfer records to S3 which were modified in the last 2 hours.

References

DynamoDB_Streams

Amazon DynamoDB Consistency

~ Last updated on : ~ jayendrapatil

DynamoDB Consistency

  • AWS has a Region, which is a physical location around the world where we cluster data centers, with one or more Availability Zones which are discrete data centers with redundant power, networking, and connectivity in an AWS Region.
  • Amazon automatically stores each DynamoDB table in the three geographically distributed locations or AZs for durability.
  • DynamoDB consistency represents the manner and timing in which the successful write or update of a data item is reflected in a subsequent read operation of that same item.

DynamoDB Consistency Modes

Eventually Consistent Reads (Default)

  • Eventual consistency option maximizes the read throughput.
  • Consistency across all copies is usually reached within a second
  • However, an eventually consistent read might not reflect the results of a recently completed write.
  • Repeating a read after a short time should return the updated data.
  • DynamoDB uses eventually consistent reads, by default.

Strongly Consistent Reads

  • Strongly consistent read returns a result that reflects all writes that received a successful response prior to the read
  • Strongly consistent reads are 2x the cost of Eventually consistent reads
  • Strongly Consistent Reads come with disadvantages
    • A strongly consistent read might not be available if there is a network delay or outage. In this case, DynamoDB may return a server error (HTTP 500).
    • Strongly consistent reads may have higher latency than eventually consistent reads.
    • Strongly consistent reads are not supported on global secondary indexes.
    • Strongly consistent reads use more throughput capacity than eventually consistent reads.
  • DynamoDB allows the user to specify whether the read should be eventually consistent or strongly consistent at the time of the request
  • Read operations (such as GetItem, Query, and Scan) provide a ConsistentRead parameter, if set to true, DynamoDB uses strongly consistent reads during the operation.
  • Query, GetItem, and BatchGetItem operations perform eventually consistent reads by default.
    • Query and GetItem operations can be forced to be strongly consistent
    • Query operations cannot perform strongly consistent reads on Global Secondary Indexes
    • BatchGetItem operations can be forced to be strongly consistent on a per-table basis

AWS Certification Exam Practice Questions

  • Questions are collected from Internet and the answers are marked as per my knowledge and understanding (which might differ with yours).
  • AWS services are updated everyday and both the answers and questions might be outdated soon, so research accordingly.
  • AWS exam questions are not updated to keep up the pace with AWS updates, so even if the underlying feature has changed the question might not be updated
  • Open to further feedback, discussion and correction.
  1. Which of the following statements is true about DynamoDB?
    1. Requests are eventually consistent unless otherwise specified.
    2. Requests are strongly consistent.
    3. Tables do not contain primary keys.
    4. None of the above
  2. How is provisioned throughput affected by the chosen consistency model when reading data from a DynamoDB table?
    1. Strongly consistent reads use the same amount of throughput as eventually consistent reads
    2. Strongly consistent reads use variable throughput depending on read activity
    3. Strongly consistent reads use more throughput than eventually consistent reads.
    4. Strongly consistent reads use less throughput than eventually consistent reads

References

DynamoDB_Read_Consistency

Amazon DynamoDB Auto Scaling

DynamoDB Auto Scaling
~ Last updated on : ~ jayendrapatil ~ 1 Comment

DynamoDB Auto Scaling

  • DynamoDB Auto Scaling uses the AWS Application Auto Scaling service to dynamically adjust provisioned throughput capacity on your behalf, in response to actual traffic patterns.
  • Application Auto Scaling enables a DynamoDB table or a global secondary index to increase its provisioned read and write capacity to handle sudden increases in traffic, without throttling.
  • When the workload decreases, Application Auto Scaling decreases the throughput so that you don’t pay for unused provisioned capacity.

DynamoDB Auto Scaling Process

DynamoDB Auto Scaling

  1. Application Auto Scaling policy can be created on the DynamoDB table.
  2. DynamoDB publishes consumed capacity metrics to CloudWatch.
  3. If the table’s consumed capacity exceeds the target utilization (or falls below the target) for a specific length of time, CloudWatch triggers an alarm. You can view the alarm on the console and receive notifications using Simple Notification Service – SNS.
    1. The upper threshold alarm is triggered when consumed reads or writes breach the target utilization percent for two consecutive minutes.
    2. The lower threshold alarm is triggered after traffic falls below the target utilization minus 20 percent for 15 consecutive minutes.
  4. CloudWatch alarm invokes Application Auto Scaling to evaluate the scaling policy.
  5. Application Auto Scaling issues an UpdateTable request to adjust the table’s provisioned throughput.
  6. DynamoDB processes the UpdateTable request, dynamically increasing (or decreasing) the table’s provisioned throughput capacity so that it approaches your target utilization.

AWS Certification Exam Practice Questions

  • Questions are collected from Internet and the answers are marked as per my knowledge and understanding (which might differ with yours).
  • AWS services are updated everyday and both the answers and questions might be outdated soon, so research accordingly.
  • AWS exam questions are not updated to keep up the pace with AWS updates, so even if the underlying feature has changed the question might not be updated
  • Open to further feedback, discussion and correction.
  1. An application running on Amazon EC2 instances writes data synchronously to an Amazon DynamoDB table configured for 60 write capacity units. During normal operation, the application writes 50KB/s to the table but can scale up to 500 KB/s during peak hours. The application is currently getting throttling errors from the DynamoDB table during peak hours. What is the MOST cost-effective change to support the increased traffic with minimal changes to the application?
    1. Use Amazon SNS to manage the write operations to the DynamoDB table
    2. Change DynamoDB table configuration to 600 write capacity units
    3. Increase the number of Amazon EC2 instances to support the traffic
    4. Configure Amazon DynamoDB Auto Scaling to handle the extra demand

References

DynamoDB_Auto_Scaling

AWS Certified Security – Specialty (SCS-C02) Exam Learning Path

AWS Security - Specialty SCS-C02 Certificate
~ Last updated on : ~ jayendrapatil ~ 1 Comment

AWS Certified Security – Specialty (SCS-C02) Exam Learning Path

I recently re-certified the updated AWS Certified Security – Specialty (SCS-C02) certification exam. The format and domains are pretty much the same as SCS-C01, however it has been enhanced to cover all the latest services.

AWS Certified Security – Specialty (SCS-C02) Exam Content

  • AWS Certified Security – Specialty (SCS-C02) exam focuses on the AWS Security and Compliance concepts. It basically validates
    • An understanding of specialized data classifications and AWS data protection mechanisms.
    • An understanding of data-encryption methods and AWS mechanisms to implement them.
    • An understanding of secure Internet protocols and AWS mechanisms to implement them.
    • The ability to make tradeoff decisions with regard to cost, security, and deployment complexity to meet a set of application requirements.
    • An understanding of security operations and risks

Refer to AWS Certified Security – Speciality Exam Guide

AWS Security - Specialty SCS-C02 Domains
  • SCS-C02 has added a new domain
    • Domain 6: Management and Security Governance with 14% coverage.
  • SCS-C02 has reduced the % of domains
    • Domain 3: Infrastructure Security (⬇︎ 6%),
    • Domain 4: Identity and Access Management (⬇︎ 2%),
    • Domain 5: Data Protection (⬇︎ 6%)

AWS Certified Security – Specialty (SCS-C02) Exam Summary

  • Specialty exams are tough, lengthy, and tiresome. Most of the questions and answers options have a lot of prose and a lot of reading that needs to be done, so be sure you are prepared and manage your time well.
  • SCS-C02 exam has 65 questions to be solved in 170 minutes which gives you roughly 2 1/2 minutes to attempt each question.
  • SCS-C02 exam includes two types of questions, multiple-choice and multiple-response.
  • SCS-C02 has a scaled score between 100 and 1,000. The scaled score needed to pass the exam is 750.
  • Associate exams currently cost $ 300 + tax.
  • You can get an additional 30 minutes if English is your second language by requesting Exam Accommodations. It might not be needed for Associate exams but is helpful for Professional and Specialty ones.
  • As always, mark the questions for review, move on, and come back to them after you are done with all.
  • As always, having a rough architecture or mental picture of the setup helps focus on the areas that you need to improve. Trust me, you will be able to eliminate 2 answers for sure and then need to focus on only the other two. Read the other 2 answers to check the difference area and that would help you reach the right answer or at least have a 50% chance of getting it right.
  • AWS exams can be taken either remotely or online, I prefer to take them online as it provides a lot of flexibility. Just make sure you have a proper place to take the exam with no disturbance and nothing around you.
  • Also, if you are taking the AWS Online exam for the first time try to join at least 30 minutes before the actual time as I have had issues with both PSI and Pearson with long wait times.

AWS Certified Security – Specialty (SCS-C02) Exam Resources

AWS Certified Security – Specialty (SCS-C02) Exam Topics

  • AWS Certified Security – Specialty (SCS-C02) exam focuses a lot on Security and compliance concepts involving Data Encryption at rest or in transit, Data protection, Auditing, Compliance and regulatory requirements, and automated remediation.

Security, Identity & Compliance

  • Identity and Access Management (IAM)
    • IAM Roles to grant the service, users temporary access to AWS services.
      • IAM Role can be used to give cross-account access and usually involves creating a role within the trusting account with a trust and permission policy and granting the user in the trusted account permissions to assume the trusting account role.
    • Identity Providers & Federation to grant external user identity (SAML or Open ID compatible IdPs) permissions to AWS resources without having to be created within the AWS account.
    • IAM Policies help define who has access & what actions can they perform.
  • Deep dive into Key Management Service (KMS). There would be quite a few questions on this.
    • is a managed encryption service that allows the creation and control of encryption keys to enable data encryption.
    • uses Envelope Encryption which uses a master key to encrypt the data key, which is then used to encrypt the data.
    • Understand how KMS works
    • Understand IAM Policies, Key Policies, Grants to grant access.
      • Key policies are the primary way to control access to KMS keys. Unless the key policy explicitly allows it, you cannot use IAM policies to allow access to a KMS key.
    • are regional, however, supports multi-region keys, which are KMS keys in different AWS Regions that can be used interchangeably – as though you had the same key in multiple Regions.
    • KMS Multi-region keys
      • are AWS KMS keys in different AWS Regions that can be used interchangeably – as though having the same key in multiple Regions.
      • are not global and each multi-region key needs to be replicated and managed independently.
    • Understand the difference between CMK with generated and imported key material esp. in rotating keys
    • KMS usage with VPC Endpoint which ensures the communication between the VPC and KMS is conducted entirely within the AWS network.
    • KMS ViaService condition
  • Cloud HSM
    • is a cloud-based hardware security module (HSM) that enables you to easily generate and use your own encryption keys on the AWS Cloud
  • AWS Certificate Manager (ACM)
    • helps provision, manage, and deploy public and private SSL/TLS certificates for use with AWS services
    • to use an ACM Certificate with CloudFront, the certificate must be imported into the US East (N. Virginia) region.
    • is regional and you need to request certificates in all regions and associate individually in all regions.
    • does not support EC2 instances and private keys cannot be exported.
  • AWS Secrets Manager
    • protects secrets needed to access applications, services, etc.
    • enables you to easily rotate, manage, and retrieve database credentials, API keys, and other secrets throughout their lifecycle
    • supports automatic rotation of credentials for RDS, DocumentDB, etc.
  • Secrets Manager vs. Systems Manager Parameter Store
    • Secrets Manager supports automatic rotation while SSM Parameter Store does not
    • Parameter Store is cost-effective as compared to Secrets Manager.
  • AWS GuardDuty
    • is a threat detection service that continuously monitors the AWS accounts and workloads for malicious activity and delivers detailed security findings for visibility and remediation.
    • supports CloudTrail S3 data events and management event logs, DNS logs, EKS audit logs, and VPC flow logs.
  • AWS Inspector
    • is an automated security assessment service that helps improve the security and compliance of applications deployed on AWS.
  • Amazon Macie
    • is a security service that uses machine learning to automatically discover, classify, and protect sensitive data in S3.
  • AWS Artifact is a central resource for compliance-related information that provides on-demand access to AWS’ security and compliance reports and select online agreements
  • AWS Shield & Shield Advanced
    • for DDoS protection and integrates with Route 53, CloudFront, ALB, and Global Accelerator.
  • AWS WAF
    • protects from common attack techniques like SQL injection and XSS, Conditions based include IP addresses, HTTP headers, HTTP body, and URI strings.
    • integrates with CloudFront, ALB, and API Gateway.
    • supports Web ACLs and can block traffic based on IPs, Rate limits, and specific countries as well
    • allows IP match set rules to allow/deny specific IP addresses and rate-based rules to limit the number of requests.
    • logs can be sent to the CloudWatch Logs log group, an S3 bucket, or Kinesis Data Firehose.
  • AWS Security Hub is a cloud security posture management service that performs security best practice checks, aggregates alerts, and enables automated remediation.
  • AWS Network Firewall is a stateful, fully managed, network firewall and intrusion detection and prevention service (IDS/IPS) for VPCs.
  • AWS Resource Access Manager helps you securely share your resources across AWS accounts, within your organization or organizational units (OUs), and with IAM roles and users for supported resource types.
  • AWS Signer is a fully managed code-signing service to ensure the trust and integrity of your code.
  • AWS Audit Manager to map your compliance requirements to AWS usage data with prebuilt and custom frameworks and automated evidence collection.
  • AWS Cognito esp. User Pools
  • Firewall Manager helps centrally configure and manage firewall rules across the accounts and applications in AWS Organizations which includes a variety of protections, including WAF, Shield Advanced, VPC security groups, Network Firewall, and Route 53 Resolver DNS Firewall.

Networking & Content Delivery

  • Virtual Private Connect – VPC
    • Security Groups, NACLs
      • NACLs are stateless, Security groups are stateful
      • NACLs at the subnet level, Security groups at the instance level
      • NACLs need to open ephemeral ports for response traffic.
    • VPC Gateway Endpoints to provide access to S3 and DynamoDB
    • VPC Interface Endpoints or PrivateLink provide access to a variety of services like SQS, Kinesis, or Private APIs exposed through NLB.
    • VPC Peering
      • to enable communication between VPCs within the same or different regions.
      • Route tables need to be configured on either VPC for them to be able to communicate.
      • does not allow cross-region security group reference.
    • VPC Flow Logs help capture information about the IP traffic going to and from network interfaces in the VPC
    • NAT Gateway provides managed NAT service that provides better availability, higher bandwidth and requires less administrative effort.
  • Virtual Private Network – VPN & Direct Connect to establish connectivity a secured, low latency access between an on-premises data center and VPC.
    • IPSec VPN over Direct Connect to provide secure connectivity.
  • CloudFront
    • integrates with S3 to improve latency and performance.
    • provides multiple security features
    • supports encryption at rest and end-to-end encryption
      • Viewer Protocol Policy and Origin Protocol Policy to enforce HTTPS – can be configured to require that viewers use HTTPS to request the files so that connections are encrypted when CloudFront communicates with viewers.
      • Integrates with ACM and requires certs to be in the us-east-1 region
      • Underlying origin can be applied certs from ACM or issued by a third party.
    • CloudFront Origin Shield
      • helps improve the cache hit ratio and reduce the load on the origin.
      • requests from other regional caches would hit the Origin shield rather than the Origin.
      • should be placed in the regional cache and not in the edge cache
      • should be deployed to the region closer to the origin server
    • CloudFront provides Encryption at Rest
      • uses SSDs which are encrypted for edge location points of presence (POPs), and encrypted EBS volumes for Regional Edge Caches (RECs).
      • Function code and configuration are always stored in an encrypted format on the encrypted SSDs on the edge location POPs, and in other storage locations used by CloudFront.
    • Restricting access to content
  • Route 53
    • is a highly available and scalable DNS web service.
    • Resolver Query logging
      • logs the queries that originate in specified VPCs, on-premises resources that use inbound resolver or ones using outbound resolver as well as the responses to those DNS queries.
      • can be logged to CloudWatch logs, S3, and Kinesis Data Firehose
    • Route 53 DNSSEC secures DNS traffic, and helps protect a domain from DNS spoofing man-in-the-middle attacks.
  • Elastic Load Balancer
    • End to End encryption
      • can be done NLB with TCP listener as pass through and terminating SSL on the EC2 instances
      • can be done with ALB with SSL termination and using HTTPS between ALB and EC2 instances
  • Gateway Load Balancer – GWLB
    • helps deploy, scale, and manage virtual appliances, such as firewalls, IDS/IPS systems, and deep packet inspection systems.

Management & Governance Tools

  • CloudWatch
  • CloudTrail for audit and governance
    • CloudTrail can be enabled for all regions at one go and supports log file integrity validation
    • With Organizations, the trail can be configured to log CloudTrail from all accounts to a central account.
  • AWS Config
    • AWS Config rules can be used to alert for any changes and Config can be used to check the history of changes. AWS Config can also help check approved AMIs compliance
    • allows you to remediate noncompliant resources using AWS Systems Manager Automation documents.
    • AWS Config -> EventBridge -> Lambda/SNS
  • CloudTrail vs Config
    • CloudTrail provides the WHO and Config provides the WHAT.
  • Systems Manager
    • Parameter Store provides secure, scalable, centralized, hierarchical storage for configuration data and secret management. Does not support secrets rotation. Use Secrets Manager instead
    • Systems Manager Patch Manager helps select and deploy the operating system and software patches automatically across large groups of EC2 or on-premises instances
    • Systems Manager Run Command provides safe, secure remote management of your instances at scale without logging into the servers, replacing the need for bastion hosts, SSH, or remote PowerShell
    • Session Manager provides secure and auditable instance management without the need to open inbound ports, maintain bastion hosts, or manage SSH keys.
  • AWS Organizations
    • is an account management service that enables consolidating multiple AWS accounts into an organization that can be managed centrally.
    • can configure Organization Trail to centrally log all CloudTrail logs.
    • Service Control Policies
      • acts as guardrails and specifies the services and actions that users and roles can use in the accounts that the SCP affects.
      • are similar to IAM permission policies except that they don’t grant any permissions.
  • AWS Trusted Advisor
    • inspects the AWS environment to make recommendations for system performance, saving money, availability, and closing security gaps
  • CloudFormation
    • Deletion Policy to prevent, retain, or backup RDS, EBS Volumes
    • Stack policy can prevent stack resources from being unintentionally updated or deleted during a stack update. Stack Policy only applies for Stack updates and not stack deletion.
    • CloudFormation Guard provides an open-source, general-purpose, policy-as-code evaluation tool.
  • Control Tower
    • to setup, govern, and secure a multi-account environment
    • strongly recommended guardrails cover EBS encryption

Storage & Databases

  • Simple Storage Service – S3
    • Undertstand S3 Security in detail
    • S3 Encryption supports both data at rest and data in transit encryption.
      • Data in transit encryption can be provided by enabling communication via SSL or using client-side encryption
      • Data at rest encryption can be provided using Server Side or Client Side encryption
      • Enforce S3 Encryption at Rest using default encryption of bucket policies
      • Enforce S3 encryption in transit using secureTransport in the S3 bucket policy
    • S3 permissions can be handled using
    • S3 Object Lock helps to store objects using a WORM model and can help prevent objects from being deleted or overwritten for a fixed amount of time or indefinitely.
    • S3 Block Public Access provides controls across an entire AWS Account or at the individual S3 bucket level to ensure that objects never have public access, now and in the future.
    • S3 Access Points simplify data access for any AWS service or customer application that stores data in S3.
    • S3 Versioning with MFA Delete can be enabled on a bucket to ensure that data in the bucket cannot be accidentally overwritten or deleted.
    • S3 Access Analyzer monitors the access policies, ensuring that the policies provide only the intended access to your S3 resources.
  • Glacier Vault Lock helps deploy and enforce compliance controls for individual S3 Glacier vaults with a vault lock policy.
  • EBS Encryption
  • Relational Database Services – RDS
    • is a web service that makes it easier to set up, operate, and scale a relational database in the cloud.
    • supports the same encryption at rest methods as EBS
    • does not support enabling encryption after creation. Need to create a snapshot, copy the snapshot to an encrypted snapshot, and restore it as an encrypted DB.

Compute

Integration Tools

  • Know how CloudWatch integration with SNS and Lambda can help in notification (Topics are not required to be in detail)

Whitepapers and articles

On the Exam Day

  • Make sure you are relaxed and get some good night’s sleep. The exam is not tough if you are well-prepared.
  • If you are taking the AWS Online exam
    • Try to join at least 30 minutes before the actual time as I have had issues with both PSI and Pearson with long wait times.
    • The online verification process does take some time and usually, there are glitches.
    • Remember, you would not be allowed to take the take if you are late by more than 30 minutes.
    • Make sure you have your desk clear, no hand-watches, or external monitors, keep your phones away, and nobody can enter the room.

Finally, All the Best 🙂

AWS DynamoDB Accelerator – DAX

DynamoDB Accelerator - DAX
~ Last updated on : ~ jayendrapatil ~ 2 Comments

AWS DynamoDB Accelerator DAX

  • DynamoDB Accelerator (DAX) is a fully managed, highly available, in-memory cache for DynamoDB that delivers up to a 10x performance improvement – from ms to µs – even at millions of requests per second.
  • DAX as a managed service handles the cache invalidation, data population, or cluster management.
  • DAX provides API compatibility with DynamoDB. Therefore, it requires only minimal functional changes to use with an existing application.
  • DAX saves costs by reducing the read load (RCU) on DynamoDB.
  • DAX helps prevent hot partitions.
  • DAX is intended for high-performance read applications. As a write-through cache, DAX writes directly so that the writes are immediately reflected in the item cache.
  • DAX only supports eventual consistency and strong consistency requests are passed through to DynamoDB.
  • DAX is fault-tolerant and scalable.
  • DAX cluster has a primary node and zero or more read-replica nodes. Upon a failure for a primary node, DAX will automatically failover and elect a new primary. For scaling, add or remove read replicas.
  • DAX supports server-side encryption.
  • DAX supports encryption in transit, ensuring that all requests and responses between the application and the cluster are encrypted by TLS, and connections to the cluster can be authenticated by verification of a cluster x509 certificate.

DynamoDB Accelerator - DAX

DAX Cluster

  • DAC cluster is a logical grouping of one or more nodes that DAX manages as a unit.
  • One of the nodes in the cluster is designated as the primary node, and the other nodes (if any) are read replicas.
  • Primary Node is responsible for
    • Fulfilling application requests for cached data.
    • Handling write operations to DynamoDB.
    • Evicting data from the cache according to the cluster’s eviction policy.
  • Read replicas are responsible for
    • Fulfilling application requests for cached data.
    • Evicting data from the cache according to the cluster’s eviction policy.
  • Only the primary node writes to DynamoDB, read replicas don’t write to DynamoDB.
  • For production, it is recommended to have DAX with at least three nodes with each node placed in different Availability Zones.
  • Three nodes are required for a DAX cluster to be fault-tolerant.
  • A DAX cluster in an AWS Region can only interact with DynamoDB tables that are in the same Region.

DynamoDB Accelerator Operations

  • Eventual Read operations
    • If DAX has the item available (a cache hit), DAX returns the item without accessing DynamoDB.
    • If DAX does not have the item available (a cache miss), DAX passes the request through to DynamoDB. When it receives the response from DynamoDB, DAX returns the results to the application. But it also writes the results to the cache on the primary node.
  • Strongly Consistent Read operations
    • DAX passes the request through to DynamoDB. The results from DynamoDB are not cached in DAX. but simply returned.
    • DAX is not ideal for applications that require strongly consistent reads (or that cannot tolerate eventually consistent reads).
  • For Write operations
    • Data is first written to the DynamoDB table, and then to the DAX cluster.
    • Operation is successful only if the data is successfully written to both the table and to DAX.
    • Is not ideal for applications that are write-intensive, or that do not perform much read activity.

DynamoDB Accelerator Caches

  • DAX cluster has two distinct caches – Item cache and Query cache
  • Item cache
    • item cache to store the results from GetItem and BatchGetItem operations.
    • Item remains in the DAX item cache, subject to the Time to Live (TTL) setting and the least recently used (LRU) algorithm for the cache
    • DAX provides a write-through cache, keeping the DAX item cache consistent with the underlying DynamoDB tables.
  • Query cache
    • DAX caches the results from Query and Scan requests in its query cache.
    • Query and Scan results don’t affect the item cache at all, as the result set is saved in the query cache – not in the item cache.
    • Writes to the Item cache don’t affect the Query cache
  • Item and Query cache has a default 5 minutes TTL setting.
  • DAX assigns a timestamp to every entry it writes to the cache. The entry expires if it has remained in the cache for longer than the TTL setting
  • DAX maintains an LRU list for both Item and Query cache. LRU list tracks the item addition and last read time. If the cache becomes full, DAX evicts older items (even if they haven’t expired yet) to make room for new entries
  • LRU algorithm is always enabled for both the item and query cache and is not user-configurable.

DynamoDB Accelerator Write Strategies

Write-Through

  • DAX item cache implements a write-through policy
  • For write operations, DAX ensures that the cached item is synchronized with the item as it exists in DynamoDB.

Write-Around

  • Write-around strategy reduces write latency
  • Ideal for bulk uploads or writing large quantities of data
  • Item cache doesn’t remain in sync with the data in DynamoDB.

DynamoDB Accelerator Scenarios

  • As an in-memory cache, DAX increases performance and reduces the response times of eventually consistent read workloads by an order of magnitude from single-digit milliseconds to microseconds.
  • DAX reduces operational and application complexity by providing a managed service that is API-compatible with DynamoDB. It requires only minimal functional changes to use with an existing application.
  • For read-heavy or bursty workloads, DAX provides increased throughput and potential operational cost savings by reducing the need to overprovision read capacity units.

AWS Certification Exam Practice Questions

  • Questions are collected from Internet and the answers are marked as per my knowledge and understanding (which might differ with yours).
  • AWS services are updated everyday and both the answers and questions might be outdated soon, so research accordingly.
  • AWS exam questions are not updated to keep up the pace with AWS updates, so even if the underlying feature has changed the question might not be updated
  • Open to further feedback, discussion and correction.
  1. A company has setup an application in AWS that interacts with DynamoDB. DynamoDB is currently responding in milliseconds, but the application response guidelines require it to respond within microseconds. How can the performance of DynamoDB be further improved?
    1. Use ElastiCache in front of DynamoDB
    2. Use DynamoDB inbuilt caching
    3. Use DynamoDB Accelerator
    4. Use RDS with ElastiCache instead

References

AWS_DynamoDB_Accelerator

AWS Service Catalog

AWS Service Catalog
~ jayendrapatil ~ 1 Comment

AWS Service Catalog

  • AWS Service Catalog helps centrally manage cloud resources to achieve governance at scale of the infrastructure as code (IaC) templates, written in CloudFormation or Terraform.
  • allows IT administrators to create, manage, and distribute catalogs of approved products to end users, who can then access the products they need in a personalized portal.
  • can help control which users have access to each product to enforce compliance with organizational business policies while making sure the customers can quickly deploy the cloud resources they need.
  • increases agility and reduces costs as end users can find and launch only the products they need from a controlled catalog.
  • is a regional service and Portfolios and products are a regional construct that will need to be created per region and are only visible/usable on the regions in which they were created.
  • supports VPC Endpoints to privately access Service Catalog APIs from VPC without the need for an Internet gateway, NAT gateway, or VPN connection.

AWS Service Catalog
Source: AWS

Service Catalog Portfolios and Products

  • Service Catalog portfolio is a collection of products, with configuration information that determines who can use those products and how they can use them.
  • Each Service Catalog product is based on an infrastructure-as-code (IaC) template using CloudFormation or Terraform.
  • Customized portfolios can be created for each type of user in an organization and selectively granted access to the appropriate portfolio.
  • When an administrator adds a new version of a product to a portfolio, that version is automatically available to all current portfolio users.
  • Same product can be included in multiple portfolios.
  • Portfolios can be shared with other AWS accounts and extended by applying additional constraints.

Service Catalog Access Control

  • Launch Constraint
    • provide AWS Service Catalog with the capability to perform actions on behalf of users even when those users do not have the necessary IAM permissions to perform those actions directly.
    • is an IAM Role that AWS Service Catalog assumes when an end user launches a product.
    • Service Catalog products without a launch constraint will launch and manage products using the end user’s IAM credentials; if the end user credentials are not sufficient for those activities, errors will result either in provisioning or in management activities.
  • Template Constraint
    • define rules that limit the parameter values that a user enters when launching a product
    • is applied when provisioning a new product or updating a product that is already in use.
    • applies the most restrictive constraint among all constraints applied to the portfolio and the product.
    • are not supported for Terraform configurations

Service Catalog AppRegistry

  • Service Catalog AppRegistry allows organizations to understand the application context of their AWS resources.
  • AppRegistry provides a repository for the information that describes the applications and associated resources that you use within your enterprise.
  • AppRegistry provides a single, up-to-date, definition of applications within their AWS environment.

AWS Certification Exam Practice Questions

  • Questions are collected from Internet and the answers are marked as per my knowledge and understanding (which might differ with yours).
  • AWS services are updated everyday and both the answers and questions might be outdated soon, so research accordingly.
  • AWS exam questions are not updated to keep up the pace with AWS updates, so even if the underlying feature has changed the question might not be updated
  • Open to further feedback, discussion and correction.
  1. A company has several business units that want to use Amazon EC2. The company wants to require all business units to provision their EC2 instances by using only approved EC2 instance configurations. What should a SysOps administrator do to implement this requirement?
    1. Create an EC2 instance launch configuration. Allow the business units to launch EC2 instances by specifying this launch configuration in the AWS Management Console.
    2. Develop an IAM policy that limits the business units to provision EC2 instances only. Instruct the business units to launch instances by using an AWS CloudFormation template.
    3. Publish a product and launch constraint role for EC2 instances by using AWS Service Catalog. Allow the business units to perform actions in AWS Service Catalog only.
    4. Share an AWS CloudFormation template with the business units. Instruct the business units to pass a role to AWS CloudFormation to allow the service to manage EC2 instances.

AWS CloudFormation

~ Last updated on : ~ jayendrapatil ~ 35 Comments

AWS CloudFormation

  • AWS CloudFormation gives developers and systems administrators an easy way to create and manage a collection of related AWS resources, provision and update them in an orderly and predictable fashion.
  • CloudFormation consists of
    • Template
      • is an architectural diagram and provides logical resources
      • a JSON or YAML-format, text-based file that describes all the AWS resources needed to deploy and run the application.
    • Stack
      • is the end result of that diagram and provisions physical resources mapped to the logical resources.
      • is the set of AWS resources that are created and managed as a single unit when CloudFormation instantiates a template.
  • CloudFormation template can be used to set up the resources consistently and repeatedly over and over across multiple regions.
  • Resources can be updated, deleted, and modified in a controlled and predictable way, in effect applying version control to the infrastructure as done for software code
  • AWS CloudFormation Template consists of elements:-
    • List of AWS resources and their configuration values
    • An optional template file format version number
    • An optional list of template parameters (input values supplied at stack creation time)
    • An optional list of output values like public IP address using the Fn:GetAtt function
    • An optional list of data tables used to lookup static configuration values for e.g., AMI names per AZ
  • CloudFormation supports Chef & Puppet Integration to deploy and configure right down the application layer
  • CloudFormation provides a set of application bootstrapping scripts that enable you to install packages, files, and services on the EC2 instances by simply describing them in the CloudFormation template
  • By default, automatic rollback on error feature is enabled, which will cause all the AWS resources that CloudFormation created successfully for a stack up to the point where an error occurred to be deleted.
  • In case of automatic rollback, charges would still be applied for the resources, the time they were up and running
  • CloudFormation provides a WaitCondition resource that acts as a barrier, blocking the creation of other resources until a completion signal is received from an external source e.g. application or management system
  • CloudFormation allows deletion policies to be defined for resources in the template for e.g. resources to be retained or snapshots can be created before deletion useful for preserving S3 buckets when the stack is deleted

AWS CloudFormation Concepts

AWS CloudFormation, you work with templates and stacks

Templates

  • act as blueprints for building AWS resources.
  • is a JSON or YAML formatted text file, saved with any extension, such as .json, .yaml, .template, or .txt.
  • have additional capabilities to build complex sets of resources and reuse those templates in multiple contexts for e.g. using input parameters to create generic and reusable templates
  • Name used for a resource within the template is a logical name but when CloudFormation creates the resource, it generates a physical name that is based on the combination of the logical name, the stack name, and a unique ID

Stacks

  • Stacks manage related resources as a single unit,
  • Collection of resources can be created, updated, and deleted by creating, updating, and deleting stacks.
  • All the resources in a stack are defined by the stack’s AWS CloudFormation template
  • CloudFormation makes underlying service calls to AWS to provision and configure the resources in the stack and can perform only actions that the users have permission to do.

Change Sets

  • Change Sets presents a summary or preview of the proposed changes that CloudFormation will make when a stack is updated.
  • Change Sets help check how the changes might impact running resources, especially critical resources, before implementing them.
  • CloudFormation makes the changes to the stack only when the change set is executed, allowing you to decide whether to proceed with the proposed changes or explore other changes by creating another change set.
  • Change sets don’t indicate whether AWS CloudFormation will successfully update a stack for e.g. if account limits are hit or the user does not have permission.

CloudFormation Change Sets

Custom Resources

  • Custom resources help write custom provisioning logic in templates that CloudFormation runs anytime the stacks are created, updated, or deleted.
  • Custom resources help include resources that aren’t available as AWS CloudFormation resource types and can still be managed in a single stack.
  • AWS recommends using CloudFormation Registry instead.

Nested Stacks

  • Nested stacks are stacks created as part of other stacks.
  • A nested stack can be created within another stack by using the AWS::CloudFormation::Stack resource.
  • Nested stacks can be used to define common, repeated patterns and components and create dedicated templates which then can be called from other stacks.
  • Root stack is the top-level stack to which all the nested stacks ultimately belong. Nested stacks can themselves contain other nested stacks, resulting in a hierarchy of stacks.
  • In addition, each nested stack has an immediate parent stack. For the first level of nested stacks, the root stack is also the parent stack.
  • Certain stack operations, such as stack updates, should be initiated from the root stack rather than performed directly on nested stacks themselves.

Drift Detection

  • Drift detection enables you to detect whether a stack’s actual configuration differs, or has drifted, from its expected configuration.
  • Drift detection help identify stack resources to which configuration changes have been made outside of CloudFormation management
  • Drift detection can detect drift on an entire stack or individual resources
  • Corrective action can be taken to make sure the stack resources are again in sync with the definitions in the stack template, such as updating the drifted resources directly so that they agree with their template definition
  • Resolving drift helps to ensure configuration consistency and successful stack operations.
  • CloudFormation detects drift on those AWS resources that support drift detection. Resources that don’t support drift detection are assigned a drift status of NOT_CHECKED.
  • Drift detection can be performed on stacks with the following statuses: CREATE_COMPLETE, UPDATE_COMPLETE, UPDATE_ROLLBACK_COMPLETE, and UPDATE_ROLLBACK_FAILED.
  • CloudFormation does not detect drift on any nested stacks that belong to that stack. Instead, you can initiate a drift detection operation directly on the nested stack.

CloudFormation Template Anatomy

  • Resources (required)
    • Specifies the stack resources and their properties, such as an EC2 instance or an S3 bucket that would be created.
    • Resources can be referred to in the Resources and Outputs sections
  • Parameters (optional)
    • Pass values to the template at runtime (during stack creation or update)
    • Parameters can be referred from the Resources and Outputs sections
    • Can be referred using Fn::Ref or !Ref
  • Mappings (optional)
    • A mapping of keys and associated values that used to specify conditional parameter values, similar to a lookup table.
    • Can be referred using Fn::FindInMap or !FindInMap
  • Outputs (optional)
    • Describes the values that are returned whenever you view your stack’s properties.
  • Format Version (optional)
    • AWS CloudFormation template version that the template conforms to.
  • Description (optional)
    • A text string that describes the template. This section must always follow the template format version section.
  • Metadata (optional)
    • Objects that provide additional information about the template.
  • Rules (optional)
    • Validates a parameter or a combination of parameters passed to a template during stack creation or stack update.
  • Conditions (optional)
    • Conditions control whether certain resources are created or whether certain resource properties are assigned a value during stack creation or update.
  • Transform (optional)
    • For serverless applications (also referred to as Lambda-based applications), specifies the version of the AWS Serverless Application Model (AWS SAM) to use.
    • When you specify a transform, you can use AWS SAM syntax to declare resources in the template. The model defines the syntax that you can use and how it’s processed.

CloudFormation Template Sample

CloudFormation Access Control

  • IAM
    • IAM can be applied with CloudFormation to access control for users whether they can view stack templates, create stacks, or delete stacks
    • IAM permissions need to be provided for the user to the AWS services and resources provisioned when the stack is created
    • Before a stack is created, AWS CloudFormation validates the template to check for IAM resources that it might create
  • Service Role
    • A service role is an AWS IAM role that allows AWS CloudFormation to make calls to resources in a stack on the user’s behalf
    • By default, AWS CloudFormation uses a temporary session that it generates from the user credentials for stack operations.
    • For a service role, AWS CloudFormation uses the role’s credentials.
    • When a service role is specified, AWS CloudFormation always uses that role for all operations that are performed on that stack.

Template Resource Attributes

  • CreationPolicy Attribute
    • is invoked during the associated resource creation.
    • can be associated with a resource to prevent its status from reaching create complete until CloudFormation receives a specified number of success signals or the timeout period is exceeded.
    • helps to wait on resource configuration actions before stack creation proceeds for e.g. software installation on an EC2 instance
  • DeletionPolicy Attribute
    • preserve or (in some cases) backup a resource when its stack is deleted
    • CloudFormation deletes the resource if a resource has no DeletionPolicy attribute, by default.
    • To keep a resource when its stack is deleted,
      • default, Delete where the resources would be deleted.
      • specify Retain for that resource, to prevent deletion.
      • specify Snapshot to create a snapshot before deleting the resource, if the snapshot capability is supported e.g. RDS, EC2 volume, etc.
  • DependsOn Attribute
    • helps determine dependency order and specify that the creation of a specific resource follows another.
    • the resource is created only after the creation of the resource specified in the DependsOn attribute.
  • Metadata Attribute
    • enables association of structured data with a resource
  • UpdatePolicy Attribute
    • Defines how AWS CloudFormation handles updates to the resources
    • For AWS::AutoScaling::AutoScalingGroup resources, CloudFormation invokes one of three update policies depending on the type of change or whether a scheduled action is associated with the Auto Scaling group.
      • The AutoScalingReplacingUpdate and AutoScalingRollingUpdate policies apply only when you do one or more of the following:
        • Change the Auto Scaling group’s AWS::AutoScaling::LaunchConfiguration
        • Change the Auto Scaling group’s VPCZoneIdentifier property
        • Change the Auto Scaling group’s LaunchTemplate property
        • Update an Auto Scaling group that contains instances that don’t match the current LaunchConfiguration.
      • The AutoScalingScheduledAction policy applies when you update a stack that includes an Auto Scaling group with an associated scheduled action.
    • For AWS::Lambda::Alias resources, CloudFormation performs a CodeDeploy deployment when the version changes on the alias.

CloudFormation Termination Protection

  • Termination protection helps prevent a stack from being accidentally deleted.
  • Termination protection on stacks is disabled by default.
  • Termination protection can be enabled on a stack creation
  • Termination protection can be set on a stack with any status except DELETE_IN_PROGRESS or DELETE_COMPLETE
  • Enabling or disabling termination protection on a stack sets it for any nested stacks belonging to that stack as well. You can’t enable or disable termination protection directly on a nested stack.
  • If a user attempts to directly delete a nested stack belonging to a stack that has termination protection enabled, the operation fails and the nested stack remains unchanged.
  • If a user performs a stack update that would delete the nested stack, AWS CloudFormation deletes the nested stack accordingly.

CloudFormation Stack Policy

  • Stack policy can prevent stack resources from being unintentionally updated or deleted during a stack update.
  • By default, all update actions are allowed on all resources and anyone with stack update permissions can update all of the resources in the stack.
  • During an update, some resources might require an interruption or be completely replaced, resulting in new physical IDs or completely new storage and hence need to be prevented.
  • A stack policy is a JSON document that defines the update actions that can be performed on designated resources.
  • After you set a stack policy, all of the resources in the stack are protected by default.
  • Updates on specific resources can be added using an explicit Allow statement for those resources in the stack policy.
  • Only one stack policy can be defined per stack, but multiple resources can be protected within a single policy.
  • A stack policy applies to all CloudFormation users who attempt to update the stack. You can’t associate different stack policies with different users
  • A stack policy applies only during stack updates. It doesn’t provide access controls like an IAM policy.

CloudFormation StackSets

  • CloudFormation StackSets extends the functionality of stacks by enabling you to create, update, or delete stacks across multiple accounts and Regions with a single operation.
  • Using an administrator account, an AWS CloudFormation template can be defined, managed, and used as the basis for provisioning stacks into selected target accounts across specified AWS Regions.

CloudFormation StackSets

CloudFormation Registry

  • CloudFormation registry helps manage extensions, both public and private, such as resources, modules, and hooks that are available for use in your AWS account.
  • CloudFormation registry offers several advantages over custom resources
    • Supports the modeling, provisioning, and managing of third-party application resources
    • Supports the Create, Read, Update, Delete, and List (CRUDL) operations
    • Supports drift detection on private and third-party resource types

CloudFormation Helper Scripts

Refer blog Post @ CloudFormation Helper Scripts

CloudFormation Best Practices

Refer blog Post @ CloudFormation Best Practices

AWS Certification Exam Practice Questions

  • Questions are collected from Internet and the answers are marked as per my knowledge and understanding (which might differ with yours).
  • AWS services are updated everyday and both the answers and questions might be outdated soon, so research accordingly.
  • AWS exam questions are not updated to keep up the pace with AWS updates, so even if the underlying feature has changed the question might not be updated
  • Open to further feedback, discussion and correction.
  1. What does Amazon CloudFormation provide?
    1. The ability to setup Autoscaling for Amazon EC2 instances.
    2. A templated resource creation for Amazon Web Services.
    3. A template to map network resources for Amazon Web Services
    4. None of these
  2. A user is planning to use AWS CloudFormation for his automatic deployment requirements. Which of the below mentioned components are required as a part of the template?
    1. Parameters
    2. Outputs
    3. Template version
    4. Resources
  3. In regard to AWS CloudFormation, what is a stack?
    1. Set of AWS templates that are created and managed as a template
    2. Set of AWS resources that are created and managed as a template
    3. Set of AWS resources that are created and managed as a single unit
    4. Set of AWS templates that are created and managed as a single unit
  4. A large enterprise wants to adopt CloudFormation to automate administrative tasks and implement the security principles of least privilege and separation of duties. They have identified the following roles with the corresponding tasks in the company: (i) network administrators: create, modify and delete VPCs, subnets, NACLs, routing tables, and security groups (ii) application operators: deploy complete application stacks (ELB, Auto -Scaling groups, RDS) whereas all resources must be deployed in the VPCs managed by the network administrators (iii) Both groups must maintain their own CloudFormation templates and should be able to create, update and delete only their own CloudFormation stacks. The company has followed your advice to create two IAM groups, one for applications and one for networks. Both IAM groups are attached to IAM policies that grant rights to perform the necessary task of each group as well as the creation, update and deletion of CloudFormation stacks. Given setup and requirements, which statements represent valid design considerations? Choose 2 answers [PROFESSIONAL]
    1. Network stack updates will fail upon attempts to delete a subnet with EC2 instances (Subnets cannot be deleted with instances in them)
    2. Unless resource level permissions are used on the CloudFormation: DeleteStack action, network administrators could tear down application stacks (Network administrators themselves need permission to delete resources within the application stack & CloudFormation makes calls to create, modify, and delete those resources on their behalf)
    3. The application stack cannot be deleted before all network stacks are deleted (Application stack can be deleted before network stack)
    4. Restricting the launch of EC2 instances into VPCs requires resource level permissions in the IAM policy of the application group (IAM permissions need to be given explicitly to launch instances )
    5. Nesting network stacks within application stacks simplifies management and debugging, but requires resource level permissions in the IAM policy of the network group (Although stacks can be nested, Network group will need to have all the application group permissions)
  5. Your team is excited about the use of AWS because now they have access to programmable infrastructure. You have been asked to manage your AWS infrastructure in a manner similar to the way you might manage application code. You want to be able to deploy exact copies of different versions of your infrastructure, stage changes into different environments, revert back to previous versions, and identify what versions are running at any particular time (development, test, QA, production). Which approach addresses this requirement?
    1. Use cost allocation reports and AWS Opsworks to deploy and manage your infrastructure.
    2. Use AWS CloudWatch metrics and alerts along with resource tagging to deploy and manage your infrastructure.
    3. Use AWS Beanstalk and a version control system like GIT to deploy and manage your infrastructure.
    4. Use AWS CloudFormation and a version control system like GIT to deploy and manage your infrastructure.
  6. A user is usingCloudFormation to launch an EC2 instance and then configure an application after the instance is launched. The user wants the stack creation of ELB and AutoScaling to wait until the EC2 instance is launched and configured properly. How can the user configure this?
    1. It is not possible that the stack creation will wait until one service is created and launched
    2. The user can use the HoldCondition resource to wait for the creation of the other dependent resources
    3. The user can use the DependentCondition resource to hold the creation of the other dependent resources
    4. The user can use the WaitCondition resource to hold the creation of the other dependent resources
  7. A user has created a CloudFormation stack. The stack creates AWS services, such as EC2 instances, ELB, AutoScaling, and RDS. While creating the stack it created EC2, ELB and AutoScaling but failed to create RDS. What will CloudFormation do in this scenario?
    1. CloudFormation can never throw an error after launching a few services since it verifies all the steps before launching
    2. It will warn the user about the error and ask the user to manually create RDS
    3. Rollback all the changes and terminate all the created services
    4. It will wait for the user’s input about the error and correct the mistake after the input
  8. A user is planning to use AWS CloudFormation. Which of the below mentioned functionalities does not help him to correctly understand CloudFormation?
    1. CloudFormation follows the DevOps model for the creation of Dev & Test
    2. AWS CloudFormation does not charge the user for its service but only charges for the AWS resources created with it
    3. CloudFormation works with a wide variety of AWS services, such as EC2, EBS, VPC, IAM, S3, RDS, ELB, etc
    4. CloudFormation provides a set of application bootstrapping scripts which enables the user to install Software
  9. A customer is using AWS for Dev and Test. The customer wants to setup the Dev environment with CloudFormation. Which of the below mentioned steps are not required while using CloudFormation?
    1. Create a stack
    2. Configure a service
    3. Create and upload the template
    4. Provide the parameters configured as part of the template
  10. A marketing research company has developed a tracking system that collects user behavior during web marketing campaigns on behalf of their customers all over the world. The tracking system consists of an auto-scaled group of Amazon Elastic Compute Cloud (EC2) instances behind an elastic load balancer (ELB), and the collected data is stored in Amazon DynamoDB. After the campaign is terminated, the tracking system is torn down and the data is moved to Amazon Redshift, where it is aggregated, analyzed and used to generate detailed reports. The company wants to be able to instantiate new tracking systems in any region without any manual intervention and therefore adopted AWS CloudFormation. What needs to be done to make sure that the AWS CloudFormation template works in every AWS region? Choose 2 answers [PROFESSIONAL]
    1. IAM users with the right to start AWS CloudFormation stacks must be defined for every target region. (IAM users are global)
    2. The names of the Amazon DynamoDB tables must be different in every target region. (DynamoDB names should be unique only within a region)
    3. Use the built-in function of AWS CloudFormation to set the AvailabilityZone attribute of the ELB resource.
    4. Avoid using DeletionPolicies for EBS snapshots. (Don’t want the data to be retained)
    5. Use the built-in Mappings and FindInMap functions of AWS CloudFormation to refer to the AMI ID set in the ImageId attribute of the Auto Scaling::LaunchConfiguration resource.
  11. A gaming company adopted AWS CloudFormation to automate load -testing of their games. They have created an AWS CloudFormation template for each gaming environment and one for the load -testing stack. The load – testing stack creates an Amazon Relational Database Service (RDS) Postgres database and two web servers running on Amazon Elastic Compute Cloud (EC2) that send HTTP requests, measure response times, and write the results into the database. A test run usually takes between 15 and 30 minutes. Once the tests are done, the AWS CloudFormation stacks are torn down immediately. The test results written to the Amazon RDS database must remain accessible for visualization and analysis. Select possible solutions that allow access to the test results after the AWS CloudFormation load -testing stack is deleted. Choose 2 answers. [PROFESSIONAL]
    1. Define a deletion policy of type Retain for the Amazon QDS resource to assure that the RDS database is not deleted with the AWS CloudFormation stack.
    2. Define a deletion policy of type Snapshot for the Amazon RDS resource to assure that the RDS database can be restored after the AWS CloudFormation stack is deleted.
    3. Define automated backups with a backup retention period of 30 days for the Amazon RDS database and perform point -in -time recovery of the database after the AWS CloudFormation stack is deleted. (as the environment is required for limited time the automated backup will not serve the purpose)
    4. Define an Amazon RDS Read-Replica in the load-testing AWS CloudFormation stack and define a dependency relation between master and replica via the DependsOn attribute. (read replica not needed and will be deleted when the stack is deleted)
    5. Define an update policy to prevent deletion of the Amazon RDS database after the AWS CloudFormation stack is deleted. (UpdatePolicy does not apply to RDS)
  12. When working with AWS CloudFormation Templates what is the maximum number of stacks that you can create?
    1. 5000
    2. 500
    3. 2000 (Refer link – The limit keeps on changing to check for the latest)
    4. 100
  13. What happens, by default, when one of the resources in a CloudFormation stack cannot be created?
    1. Previously created resources are kept but the stack creation terminates
    2. Previously created resources are deleted and the stack creation terminates
    3. Stack creation continues, and the final results indicate which steps failed
    4. CloudFormation templates are parsed in advance so stack creation is guaranteed to succeed.
  14. You need to deploy an AWS stack in a repeatable manner across multiple environments. You have selected CloudFormation as the right tool to accomplish this, but have found that there is a resource type you need to create and model, but is unsupported by CloudFormation. How should you overcome this challenge? [PROFESSIONAL]
    1. Use a CloudFormation Custom Resource Template by selecting an API call to proxy for create, update, and delete actions. CloudFormation will use the AWS SDK, CLI, or API method of your choosing as the state transition function for the resource type you are modeling.
    2. Submit a ticket to the AWS Forums. AWS extends CloudFormation Resource Types by releasing tooling to the AWS Labs organization on GitHub. Their response time is usually 1 day, and they complete requests within a week or two.
    3. Instead of depending on CloudFormation, use Chef, Puppet, or Ansible to author Heat templates, which are declarative stack resource definitions that operate over the OpenStack hypervisor and cloud environment.
    4. Create a CloudFormation Custom Resource Type by implementing create, update, and delete functionality, either by subscribing a Custom Resource Provider to an SNS topic, or by implementing the logic in AWS Lambda. (Refer link)
  15. What is a circular dependency in AWS CloudFormation?
    1. When a Template references an earlier version of itself.
    2. When Nested Stacks depend on each other.
    3. When Resources form a DependOn loop. (Refer link, to resolve a dependency error, add a DependsOn attribute to resources that depend on other resources in the template. Some cases for e.g. EIP and VPC with IGW where EIP depends on IGW need explicitly declaration for the resources to be created in correct order)
    4. When a Template references a region, which references the original Template.
  16. You need to run a very large batch data processing job one time per day. The source data exists entirely in S3, and the output of the processing job should also be written to S3 when finished. If you need to version control this processing job and all setup and teardown logic for the system, what approach should you use?
    1. Model an AWS EMR job in AWS Elastic Beanstalk. (cannot directly model EMR Clusters)
    2. Model an AWS EMR job in AWS CloudFormation. (EMR cluster can be modeled using CloudFormation. Refer link)
    3. Model an AWS EMR job in AWS OpsWorks. (cannot directly model EMR Clusters)
    4. Model an AWS EMR job in AWS CLI Composer. (does not exist)
  17. Your company needs to automate 3 layers of a large cloud deployment. You want to be able to track this deployment’s evolution as it changes over time, and carefully control any alterations. What is a good way to automate a stack to meet these requirements? [PROFESSIONAL]
    1. Use OpsWorks Stacks with three layers to model the layering in your stack.
    2. Use CloudFormation Nested Stack Templates, with three child stacks to represent the three logical layers of your cloud. (CloudFormation allows source controlled, declarative templates as the basis for stack automation and Nested Stacks help achieve clean separation of layers while simultaneously providing a method to control all layers at once when needed)
    3. Use AWS Config to declare a configuration set that AWS should roll out to your cloud.
    4. Use Elastic Beanstalk Linked Applications, passing the important DNS entries between layers using the metadata interface.
  18. You have been asked to de-risk deployments at your company. Specifically, the CEO is concerned about outages that occur because of accidental inconsistencies between Staging and Production, which sometimes cause unexpected behaviors in Production even when Staging tests pass. You already use Docker to get high consistency between Staging and Production for the application environment on your EC2 instances. How do you further de-risk the rest of the execution environment, since in AWS, there are many service components you may use beyond EC2 virtual machines? [PROFESSIONAL]
    1. Develop models of your entire cloud system in CloudFormation. Use this model in Staging and Production to achieve greater parity. (Only CloudFormation’s JSON Templates allow declarative version control of repeatedly deployable models of entire AWS clouds. Refer link)
    2. Use AWS Config to force the Staging and Production stacks to have configuration parity. Any differences will be detected for you so you are aware of risks.
    3. Use AMIs to ensure the whole machine, including the kernel of the virual machines, is consistent, since Docker uses Linux Container (LXC) technology, and we need to make sure the container environment is consistent.
    4. Use AWS ECS and Docker clustering. This will make sure that the AMIs and machine sizes are the same across both environments.
  19. Which code snippet below returns the URL of a load balanced web site created in CloudFormation with an AWS::ElasticLoadBalancing::LoadBalancer resource name “ElasticLoad Balancer”? [Developer]
    1. “Fn::Join” : [“”, [ “http://”, {“Fn::GetAtt” : [ “ElasticLoadBalancer”,”DNSName”]}]] (Refer link)
    2. “Fn::Join” : [“”,[ “http://”, {“Fn::GetAtt” : [ “ElasticLoadBalancer”,”Url”]}]]
    3. “Fn::Join” : [“”, [ “http://”, {“Ref” : “ElasticLoadBalancerUrl”}]]
    4. “Fn::Join” : [“”, [ “http://”, {“Ref” : “ElasticLoadBalancerDNSName”}]]
  20. For AWS CloudFormation, which stack state refuses UpdateStack calls? [Developer]
    1. <code>UPDATE_ROLLBACK_FAILED</code> (Refer link)
    2. <code>UPDATE_ROLLBACK_COMPLETE</code>
    3. <code>UPDATE_COMPLETE</code>
    4. <code>CREATE_COMPLETE</code>
  21. Which of these is not a Pseudo Parameter in AWS CloudFormation? [Developer]
    1. AWS::StackName
    2. AWS::AccountId
    3. AWS::StackArn (Refer link)
    4. AWS::NotificationARNs
  22. Which of these is not an intrinsic function in AWS CloudFormation? [Developer]
    1. Fn::SplitValue (Refer link)
    2. Fn::FindInMap
    3. Fn::Select
    4. Fn::GetAZs
  23. Which of these is not a CloudFormation Helper Script? [Developer]
    1. cfn-signal
    2. cfn-hup
    3. cfn-request (Refer link)
    4. cfn-get-metadata
  24. What method should I use to author automation if I want to wait for a CloudFormation stack to finish completing in a script? [Developer]
    1. Event subscription using SQS.
    2. Event subscription using SNS.
    3. Poll using <code>ListStacks</code> / <code>list-stacks</code>. (Only polling will make a script wait to complete. ListStacks / list-stacks is a real method. Refer link)
    4. Poll using <code>GetStackStatus</code> / <code>get-stack-status</code>. (GetStackStatus / get-stack-status does not exist)
  25. Which status represents a failure state in AWS CloudFormation? [Developer]
    1. <code>UPDATE_COMPLETE_CLEANUP_IN_PROGRESS</code> (UPDATE_COMPLETE_CLEANUP_IN_PROGRESS means an update was successful, and CloudFormation is deleting any replaced, no longer used resources)
    2. <code>DELETE_COMPLETE_WITH_ARTIFACTS</code> (DELETE_COMPLETE_WITH_ARTIFACTS does not exist)
    3. <code>ROLLBACK_IN_PROGRESS</code> (ROLLBACK_IN_PROGRESS means an UpdateStack operation failed and the stack is in the process of trying to return to the valid, pre-update state Refer link)
    4. <code>ROLLBACK_FAILED</code> (ROLLBACK_FAILED is not a CloudFormation state but UPDATE_ROLLBACK_FAILED is)
  26. Which of these is not an intrinsic function in AWS CloudFormation? [Developer]
    1. Fn::Equals
    2. Fn::If
    3. Fn::Not
    4. Fn::Parse (Complete list of Intrinsic Functions: Fn::Base64, Fn::And, Fn::Equals, Fn::If, Fn::Not, Fn::Or, Fn::FindInMap, Fn::GetAtt, Fn::GetAZs, Fn::Join, Fn::Select, Refer link)
  27. You need to create a Route53 record automatically in CloudFormation when not running in production during all launches of a Template. How should you implement this? [Developer]
    1. Use a <code>Parameter</code> for <code>environment</code>, and add a <code>Condition</code> on the Route53 <code>Resource</code> in the template to create the record only when <code>environment</code> is not <code>production</code>. (Best way to do this is with one template, and a Condition on the resource. Route53 does not allow null strings for Refer link)
    2. Create two templates, one with the Route53 record value and one with a null value for the record. Use the one without it when deploying to production.
    3. Use a <code>Parameter</code> for <code>environment</code>, and add a <code>Condition</code> on the Route53 <code>Resource</code> in the template to create the record with a null string when <code>environment</code> is <code>production</code>.
    4. Create two templates, one with the Route53 record and one without it. Use the one without it when deploying to production.

References

AWS Organizations Service Control Policies – SCPs

~ Last updated on : ~ jayendrapatil ~ 2 Comments

AWS Organizations Service Control Policies

  • AWS Organizations Service control policies – SCPs offer central control over the maximum available permissions for all of the accounts in the organization, ensuring member accounts stay within the organization’s access control guidelines.
  • are one type of policy that help manage the organization.
  • are available only in an organization that has all features enabled, and aren’t available if the organization has enabled only the consolidated billing features.
  • are NOT sufficient for granting access to the accounts in the organization.
  • defines a guardrail for what actions accounts within the organization root or OU can do, but IAM policies need to be attached to the users and roles in the organization’s accounts to grant permissions to them.
  • Effective permissions are the logical intersection between what is allowed by the SCP and what is allowed by the IAM and resource-based policies.
  • with an SCP attached to member accounts, identity-based and resource-based policies grant permissions to entities only if those policies and the SCP allow the action.
  • don’t affect users or roles in the management account. They affect only the member accounts in your organization.

SCPs Effects on Permissions

  • never grant permissions but define the maximum permissions for the affected accounts.
  • Users and roles must still be granted permissions with appropriate IAM permission policies. A user without any IAM permission policies has no access at all, even if the applicable SCPs allow all services and all actions.
  • limits permissions for entities in member accounts, including each AWS account root user.
  • does not limit actions performed by the master or management account.
  • does not affect any service-linked role. Service-linked roles enable other AWS services to integrate with AWS Organizations and can’t be restricted by SCPs.
  • affect only IAM users or roles that are managed by accounts that are part of the organization. They don’t affect users or roles from accounts outside the organization.
  • don’t affect resource-based policies directly.

SCPs Strategies

  • By default, an SCP named FullAWSAccess is attached to every root, OU, and account, which allows all actions and all services.
  • Blacklist or Deny Strategy
    • actions are allowed by default and services and actions to be prohibited need to be specified.
    • blacklist permissions using deny statements can be assigned in combination with the default FullAWSAccess SCP.
    • using deny statements in SCPs require less maintenance because they don’t need to be updated when AWS adds new services.
    • deny statements usually use less space, thus making it easier to stay within SCP size limits.
  • Whitelist or Allow Strategy
    • actions are prohibited by default, and you specify what services and actions are allowed.
    • whitelist permissions can be assigned, by removing the default FullAWSAccess SCP.
    • allows SCP that explicitly permits only those allowed services and actions

SCPs Testing Effects

  • don’t attach SCPs to the root of the organization without thoroughly testing the impact that the policy has on accounts.
  • Create an OU that the accounts can be moved into one at a time, or at least in small numbers, to ensure that users are not inadvertently locked out of key services.

AWS Certification Exam Practice Questions

  • Questions are collected from Internet and the answers are marked as per my knowledge and understanding (which might differ with yours).
  • AWS services are updated everyday and both the answers and questions might be outdated soon, so research accordingly.
  • AWS exam questions are not updated to keep up the pace with AWS updates, so even if the underlying feature has changed the question might not be updated
  • Open to further feedback, discussion and correction.
  1. Your company is planning on setting up multiple accounts in AWS. The IT Security department has a requirement to ensure that certain services and actions are not allowed across all accounts. How would the system admin achieve this in the most EFFECTIVE way possible?
    1. Create a common IAM policy that can be applied across all accounts
    2. Create an IAM policy per account and apply them accordingly​
    3. Deny the services to be used across accounts by contacting AWS​ support
    4. Use AWS Organizations and Service Control Policies
  2. You are in the process of implementing AWS Organizations for your company. At your previous company, you saw an Organizations implementation go bad when an SCP (Service Control Policy) was applied at the root of the organization before being thoroughly tested. In what way can an SCP be properly tested and implemented?
    1. Back up your entire Organization to S3 and restore rollback and restore if something goes wrong
    2. The SCP must be verified with AWS before it is implemented to avoid any problems.
    3. Mirror your Organizational Unit in another region. Apply the SCP and test it. Once testing is complete, attach the SCP to the root of your organization.
    4. Create an Organizational Unit (OU). Attach the SCP to this new OU. Move your accounts in one at a time to ensure that you don’t inadvertently lock users out of key services.