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Exam Professional Cloud Developer topic 1 question 211 discussion

Actual exam question from Google's Professional Cloud Developer

Question #: 211
Topic #: 1

[All Professional Cloud Developer Questions]

You need to configure a Deployment on Google Kubernetes Engine (GKE). You want to include a check that verifies that the containers can connect to the database. If the Pod is failing to connect, you want a script on the container to run to complete a graceful shutdown. How should you configure the Deployment?

A. Create two jobs: one that checks whether the container can connect to the database, and another that runs the shutdown script if the Pod is failing.
B. Create the Deployment with a livenessProbe for the container that will fail if the container can't connect to the database. Configure a Prestop lifecycle handler that runs the shutdown script if the container is failing.
C. Create the Deployment with a PostStart lifecycle handler that checks the service availability. Configure a PreStop lifecycle handler that runs the shutdown script if the container is failing.
D. Create the Deployment with an initContainer that checks the service availability. Configure a Prestop lifecycle handler that runs the shutdown script if the Pod is failing.

Show Suggested Answer

Suggested Answer: B 🗳️

by kisswd at Dec. 4, 2022, 9:31 p.m.

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TNT87

Highly Voted 2 years ago

Selected Answer: B

https://cloud.google.com/architecture/best-practices-for-running-cost-effective-kubernetes-applications-on-gke#make_sure_your_applications_are_shutting_down_in_accordance_with_kubernetes_expectations

upvoted 6 times

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alpha_canary

Most Recent 8 months, 1 week ago

Selected Answer: B

"Most programs don't stop accepting requests right away. However, if you're using third-party code or are managing a system that you don't have control over, such as nginx, the preStop hook is a good option for triggering a graceful shutdown without modifying the application. One common strategy is to execute, in the preStop hook, a sleep of a few seconds to postpone the SIGTERM. This gives Kubernetes extra time to finish the Pod deletion process, and reduces connection errors on the client side." https://cloud.google.com/architecture/best-practices-for-running-cost-effective-kubernetes-applications-on-gke#:~:text=If%20your%20application%20doesn%27t%20follow%20the%20preceding%20practice%2C%20use%20the%20preStop%20hook https://kubernetes.io/docs/concepts/containers/container-lifecycle-hooks/#container-hooks

upvoted 1 times

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purushi

1 year, 4 months ago

Selected Answer: B

I go with B, that is liveness probe and if failed for max retries then call prestop hook to gracefully shutdown the container. D is also very close, but it used init container to check for the database connectivity first. I am not sure whether we can prestop hook if initContainer fails to starts.

upvoted 1 times

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Pime13

1 year, 10 months ago

Selected Answer: B

https://cloud.google.com/architecture/best-practices-for-running-cost-effective-kubernetes-applications-on-gke#make_sure_your_applications_are_shutting_down_in_accordance_with_kubernetes_expectations -> the preStop hook is a good option for triggering a graceful shutdown without modifying the application. https://kubernetes.io/docs/concepts/containers/container-lifecycle-hooks/#hook-details -> This hook is called immediately before a container is terminated due to an API request or management event such as a liveness/startup probe failure, preemption, resource contention and others. A call to the PreStop hook fails if the container is already in a terminated or completed state and the hook must complete before the TERM signal to stop the container can be sent. The Pod's termination grace period countdown begins before the PreStop hook is executed, so regardless of the outcome of the handler, the container will eventually terminate within the Pod's termination grace period. No parameters are passed to the handler.

upvoted 1 times

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telp

1 year, 11 months ago

Selected Answer: B

Answer B

upvoted 1 times

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zellck

1 year, 12 months ago

Selected Answer: B

B is the answer.

upvoted 2 times

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kisswd

2 years ago

Selected Answer: D

D could be the right answer

upvoted 2 times

[Removed]

1 year, 12 months ago

The answer is definitely D. Anytime you need to do some work before a container can be considered ready, you use init containers. With a liveness probe we would need to add an endpoint that checks whether we can connect to the database, with init containers we can separate this logic.

upvoted 1 times

[Removed]

1 year, 12 months ago

Liveness probe also supports other methods to do work beside http, but I hope you understand my message. Here's more on init containers btw: https://kubernetes.io/docs/concepts/workloads/pods/init-containers/

upvoted 1 times

zellck

1 year, 12 months ago

initContainer requires separate container to run in addition to the application container, but the question asked for script to be run in the same container.

upvoted 1 times

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