Rolling updates

To perform a rolling update of your service, discontinuing no more than N virtual machine instances at a time:

1. Define the instance template you need.
2. Set the deployment policy with a non-zero value for max_unavailable, which stands for the maximum number of instances to discontinue at a time.
3. Start group updating.

For example, to update an instance group sequentially, discontinuing one VM instance at a time, configure deploy-policy as follows:

...
deploy-policy:
    max_unavailable: 1
    max_expansion: 0
    ...
...

The group will be updated as follows: