Google Cloud App Engine
- App Engine helps build highly scalable applications on a fully managed serverless platform
- App Engine provides PaaS and helps build and deploy apps quickly using popular languages or bring your own language runtimes and frameworks.
- App Engine allows to scale the applications from zero to planet scale without having to manage infrastructure
- Each Cloud project can contain only a single App Engine application
- App Engine is regional, which means the infrastructure that runs the apps is located in a specific region, and Google manages it so that it is available redundantly across all of the zones within that region
- App Engine application location or region cannot be changed once created
- App Engine is well suited to applications that are designed using a microservice architecture
- App Engine creates a default bucket in Cloud Storage for each app creation
Standard vs Flexible Environment
Refer blog post Standard vs Flexible Environment
App Engine Scaling
- App Engine can automatically create and shut down instances as traffic fluctuates, or a number of instances can be specified to run regardless of the amount of traffic
- App Engine supports the following scaling types, which controls how and when instances are created:
- Basic (Standard Only)
- creates instances when the application receives requests.
- each instance will be shut down when the application becomes idle.
- is ideal for work that is intermittent or driven by user activity.
- creates instances based on request rate, response latencies, and other application metrics.
- thresholds can be specified for each of these metrics, as well as a minimum number instances to keep running at all times.
- specifies the number of instances that continuously run regardless of the load level.
- allows tasks such as complex initializations and applications that rely on the state of the memory over time.
- Basic (Standard Only)
App engine allows traffic management to an application version by migrating or splitting traffic.
- Traffic migration smoothly switches request routing
- Gradually moves traffic from the versions currently receiving traffic to one or more specified versions
- Standard environment allows you to choose to route requests to the target version, either immediately or gradually.
- Flexible environment only allows immediate traffic migration
- Traffic splitting distributes a percentage of traffic to versions of the application.
- Allows canary deployments or conduct A/B testing between the versions and provides control over the pace when rolling out features
- Traffic can be split to move 100% of traffic to a single version or to route percentages of traffic to multiple versions.
- Traffic splitting is applied to URLs that do not explicitly target a version.
- Traffic split is supported by using either an IP address or HTTP cookie.
- Default behaviour for splitting traffic is to do it by IP.
- Setting up IP address traffic split is easier, but a cookie split is more precise
- For traffic splitting, execute
gcloud app deploy --no-promoteto make a new version of the application available and then run
gcloud app services set-trafficto start sending the new version traffic. Use
--splitsflag with two versions and weight
GCP 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).
- GCP services are updated everyday and both the answers and questions might be outdated soon, so research accordingly.
- GCP exam questions are not updated to keep up the pace with GCP updates, so even if the underlying feature has changed the question might not be updated
- Open to further feedback, discussion and correction.
- You have a website hosted on App Engine standard environment. You want 1% of your users to see a new test version of the website. You want to minimize complexity. What should you do?
- Deploy the new version in the same application and use the –migrate option.
- Deploy the new version in the same application and use the –splits option to give a weight of 99 to the current version and a weight of 1 to the new version.
- Create a new App Engine application in the same project. Deploy the new version in that application. Use the App Engine library to proxy 1% of the requests to the new version.
- Create a new App Engine application in the same project. Deploy the new version in that application. Configure your network load balancer to send 1% of the traffic to that new application.
- You have created an App engine application in the us-central region. However, you found out the network team has configured all the VPN connections in the asia-east2 region, which are not possible to move. How can you change the location efficiently?
- Change the region in app.yaml and redeploy
- From App Engine console, change the region of the application
- Change the region in application.xml within the application and redeploy
- Create a new project in the asia-east2 region and create app engine in the project