Why do I have to create a new instance template just to do a minor update to my instance group?

Question

Say I want to update the server for a running instance group, I have to create a new image from another instance and then create an instance template from that image and then run a rolling update on the instance group. That's an a lot of steps to do minor changes to my managed instances. Is there a less tedious/slow way to do updates to running managed instance groups?

Answer 1

Please note managed instances are based on instance template so you can not skip the step of updating it.

If you need configuration changes on all instances or a limited number of instances under the managed instance group, a rolling update is the best automated solution. With the rolling update, you can choose various options like how many instances can be taken offline for the update, whether the update affects all or just a segment of instances, and so on. You can find the detailed description in this article.

Without rollout update, a new configuration must be deployed either by creating a new managed instance group with a new version, requiring additional set up each time or through a manual, user-initiated, instance-by-instance recreate. Both of these approaches require significant manual steps. But for a minor configuration on the limited number of instances, you can still opt for manual, user-initiated configuration if that is really time-saving than the rolling update. However, if something fails in the instance it gets recreated with the original template configuration.