Revision management in GCP - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is revision management in Google Cloud Platform?

Revision management is the process of keeping track of changes and versions of your cloud resources or configurations, allowing you to roll back or update safely.

beginner

How does Cloud Run use revisions?

Cloud Run automatically creates a new revision each time you deploy a new version of your service, enabling traffic splitting and rollback to previous versions.

intermediate

What is the benefit of traffic splitting in revision management?

Traffic splitting lets you send a percentage of user requests to different revisions, helping test new versions safely before full rollout.

intermediate

How can you roll back to a previous revision in Cloud Run?

You can roll back by directing all traffic to a previous revision using the Cloud Console or gcloud command, restoring the earlier version instantly.

beginner

Why is revision management important in cloud infrastructure?

It helps maintain stability, enables quick recovery from errors, supports testing, and ensures smooth updates without downtime.

What happens when you deploy a new version in Cloud Run?

A A new revision is created automatically

B The old revision is deleted

C Traffic is stopped temporarily

D The service is paused

Cloud Run creates a new revision automatically for each deployment, preserving previous versions.

Which feature allows testing new versions by sending some users to it?

A Traffic splitting

B Auto scaling

C Load balancing

D Snapshotting

Traffic splitting sends a portion of requests to different revisions for safe testing.

How can you roll back to a previous revision in Cloud Run?

A Create a new revision manually

B Delete the current revision

C Restart the service

D Redirect all traffic to the previous revision

Rolling back means sending all traffic back to a previous revision without deleting anything.

Why is revision management important?

A To slow down deployments

B To increase cloud costs

C To keep track of changes and enable safe updates

D To delete old data automatically

Revision management helps track changes and update safely without breaking services.

What does a revision represent in Cloud Run?

A A billing report

B A specific deployed version of a service

C A network configuration

D A user account

A revision is a snapshot of your deployed service version in Cloud Run.

Explain how revision management works in Cloud Run and why it is useful.

Think about how you can try new versions without affecting all users.

Describe the benefits of using traffic splitting in revision management.

Imagine letting only some friends try your new recipe before serving everyone.

Practice

1. What is the main purpose of revision management in Google Cloud services?

easy

A. To track and control different versions of your cloud services

B. To increase the storage capacity of your cloud database

C. To monitor network traffic between services

D. To automatically scale the number of virtual machines

Solution

1. Step 1: Understand revision management concept

   Revision management is about keeping track of different versions of your cloud services.

2. Step 2: Identify the main goal

   The main goal is to control versions for safe updates and rollbacks.

3. Final Answer:

   To track and control different versions of your cloud services -> Option A

4. Quick Check:

   Revision management = version control [OK]

Hint: Revision management means version control of services [OK]

Common Mistakes:

• Confusing revision management with scaling
• Thinking it manages storage or network
• Mixing it with monitoring tools

2. Which gcloud command is used to list all revisions of a Cloud Run service named my-service?

easy

A. gcloud run revisions list --service=my-service

B. gcloud run services list --revisions=my-service

C. gcloud revisions describe my-service

D. gcloud run deploy revisions --service=my-service

Solution

1. Step 1: Identify correct command structure

   The command to list revisions uses gcloud run revisions list with the service flag.

2. Step 2: Match service name parameter

   Using --service=my-service correctly specifies the service.

3. Final Answer:

   gcloud run revisions list --service=my-service -> Option A

4. Quick Check:

   List revisions = gcloud run revisions list --service [OK]

Hint: List revisions with 'gcloud run revisions list --service' [OK]

Common Mistakes:

• Using 'services list' instead of 'revisions list'
• Mixing 'describe' with listing
• Wrong command order or flags

3. Given the following commands, what will be the output of gcloud run revisions list --service=my-app after deploying twice?

gcloud run deploy my-app --image=image:v1 --no-traffic
gcloud run deploy my-app --image=image:v2 --no-traffic

medium

A. One revision with image:v2

B. No revisions because traffic is zero

C. Two revisions: one with image:v1 and one with image:v2

D. Error because --no-traffic disables revisions

Solution

1. Step 1: Understand deployment with --no-traffic

   Deploying with --no-traffic creates a new revision but does not route traffic to it.

2. Step 2: Analyze multiple deployments

   Deploying twice with different images creates two separate revisions.

3. Final Answer:

   Two revisions: one with image:v1 and one with image:v2 -> Option C

4. Quick Check:

   Each deploy creates a revision even with no traffic [OK]

Hint: Each deploy creates a revision, traffic doesn't affect revision count [OK]

Common Mistakes:

• Assuming no traffic means no revision
• Thinking only latest revision exists
• Confusing traffic routing with revision creation

4. You deployed a new revision but it is not receiving traffic. Which command fixes this by routing 100% traffic to the latest revision named my-app-00002?

medium

A. gcloud run revisions set-traffic my-app-00002 --percent=100

B. gcloud run services update-traffic my-app --to-revisions my-app-00002=100

C. gcloud run services update my-app --traffic my-app-00002=100

D. gcloud run services update-traffic my-app --to-revision my-app-00002=100

Solution

1. Step 1: Identify correct command to update traffic

   The command to update traffic routing is gcloud run services update-traffic.

2. Step 2: Use correct syntax for traffic split

   The syntax --to-revisions my-app-00002=100 routes 100% traffic to that revision.

3. Final Answer:

   gcloud run services update-traffic my-app --to-revisions my-app-00002=100 -> Option B

4. Quick Check:

   Update traffic with 'services update-traffic' and '--to-revisions' [OK]

Hint: Use 'gcloud run services update-traffic' with '--to-revisions' [OK]

Common Mistakes:

• Using 'update' instead of 'update-traffic'
• Wrong flag names like '--percent'
• Trying to set traffic on revision directly

5. You want to roll back your Cloud Run service web-app to a previous revision web-app-00003 safely without downtime. Which sequence of commands achieves this?

hard

A. gcloud run deploy web-app --image=web-app-00003

B. gcloud run services update web-app --revision web-app-00003

C. gcloud run revisions delete web-app-00004 && gcloud run services update-traffic web-app --to-revisions web-app-00003=100

D. gcloud run services update-traffic web-app --to-revisions web-app-00003=100

Solution

1. Step 1: Understand rollback via traffic routing

   Rolling back means routing traffic back to an existing previous revision.

2. Step 2: Use traffic update command

   Use gcloud run services update-traffic to send 100% traffic to the old revision.

3. Step 3: Avoid deleting revisions or redeploying

   Deleting or redeploying is unnecessary and may cause downtime.

4. Final Answer:

   gcloud run services update-traffic web-app --to-revisions web-app-00003=100 -> Option D

5. Quick Check:

   Rollback by routing traffic to old revision [OK]

Hint: Rollback by updating traffic to old revision, no redeploy needed [OK]

Common Mistakes:

• Trying to redeploy old revision as image
• Deleting newer revisions unnecessarily
• Using wrong commands to update revision