Practice Test 4 | Google Cloud Certified Professional Cloud Architect | Dumps | Mock Test
You have to quickly deploy an update to your scalable app operating with managed instance groups but you definitely know that there may be some errors.
You want to test the new app in production before fully committing to the update.
Which is the best solution?
A. Change Template and everything will be automatic
B. Change Template, then start new instances and stop the old ones
C. Change Template and ask for a Rolling update
D. Change Template and ask for a Canary update
Correct Answer: D
A is wrong. Instance Template are immutable, so you have to create a new Instance Template and update the Managed Group Definition
B is wrong. It is not advisable to do such a manual operation. It is cumbersome and prone to errors
C is wrong. With managed instance group updater, you may roll out all an update automatically. The question required a partial update.
D is correct. A canary update is a partial update to a few numbers of instances in the instance group.
You may view with console or gcloud for the currentAction being performed on each instance in your group, as well as the status of each instance.
You may roll back quickly to the previous version and control the speed of an update with the parameters: minReadySeconds (wait for the next replacement), Enable health checking (wait until healthy), tune maxUnavailable (number of Instances beyond the targetSize of the group), and maxSurge (number of instances unavailable at any time during the update)
A canary update is an update that is applied to a partial number of instances in the instance group. Canary updates let you test new features or upgrades on a subset of instances, instead of rolling out a potentially disruptive update to all your instances. If an update is not going well, you only need to roll back a small number of instances, minimizing the disruption for your users. From the perspective of the server, a canary update is the same as a standard rolling update, except that the number of instances that should be updated is less than the total size of the instance group. Like a standard rolling update, a canary update is disruptive to the instances affected; that is, the affected instances are deleted and replaced by new VM instances during the update.
For more details, please visit the following URLs:
https://cloud.google.com/compute/docs/instance-groups/
https://cloud.google.com/compute/docs/instance-groups/rolling-out-updates-to-managed-instance-groups
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