Building Google Cloud Platform Solutions

Change management

When dealing with large fleets of mission-critical servers, change management can become a delicate process. MIGs address this issue with the concept of rolling updates. To roll out an update to all instances of a managed instance group, developers first define a new instance template. This template can then be used to create new instances within the group in a manner that maintains service operation.

Let's try this out with our hello-mig instance group. First, create a new instance template (v2.0 of hello-mig-template). As before, we'll do this from the command line, using a script included in this book's source code, chapter_07/example_01/03-update-instance-template.sh:

gcloud compute instance-templates create hello-migs-template-v2 ...