Document whether tasks run in serial or parallel

[simonvane]

What would you like to be added:
Document whether tasks run in serial or parallel

Why is this needed:
It is unclear whether tasks run in serial or parallel and whether a strategy can be applied to tasks and it this has just been missed in the documentation. It would be helpful if it was called out explicitly one way or another here https://kudo.dev/docs/developing-operators/tasks.html#overview.

If a strategy cannot be applied to tasks it would be interesting/useful to understand the reasoning for this.

[dbarentine]

@simonvane Does this answer your question?

Note: current implementation will apply all resources in the given order so that e.g. a Pod can mount previously created ConfigMap. However, this is not part of the specification and might change in the future (all resources can be applied concurrently). If you need happens-before-guarantee between your resources, use e.g. multiple serial steps.

[simonvane]

Thanks @dbarentine but I don't think it does.

I think this describes how the resources within a task are applied. What I was asking about is how multiple tasks within a step are run. Phases and steps have a strategy documented but I can't see anything documented about the order tasks within a step are applied and whether they are applied in parallel or serial or whether we can control this.