Incremental update

You might need to update your service incrementally, undeploying no more than N instances at a time:

1. Define the desired template of an instance.
2. Set the deployment policy with a non-zero value of max_unavailable: the maximum number of instances to undeploy at the same time.
3. Run the update operation for the group.

For example, to update an instance group sequentially by undeploying one instance at a time, set the following parameters in the deploy-policy:

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

The group will be updated as follows: