max-in-flight-v2.md

• State: discussing
• Start date: ?
• End date: ?
• Docs: ?
• Related: cloudfoundry/bosh#1943

Summary

max_in_flight configuration should offer a way to roll updates across all availability zones at the same time.

Motivation

Currently max_in_flight is limited to a single AZ. Especially during fresh deployments that may be a non-optimal strategy. It should be possible to configure max_in_flight to do updates within X number of AZs in parallel.

Details

instance_groups:
- name: foo
  update: # <-- backwards compat
    ...
  plan:
    create:
      ...
    update: 
      ...
    delete: 
      ...

Drawbacks

...

Unresolved questions

• should there be create/update/delete section?
  • does create apply to new instances when scaling up