Reapply "fix: make application templates namespaced (#694)" (#719)

[razvan]

Description

see title

Definition of Done Checklist

• Not all of these items are applicable to all PRs, the author should update this template to only leave the boxes in that are relevant
• Please make sure all these things are done and tick the boxes

Author

• Changes are OpenShift compatible
• CRD changes approved
• CRD documentation for all fields, following the style guide.
• Helm chart can be installed and deployed operator works
• Integration tests passed (for non trivial changes)
• Changes need to be "offline" compatible
• Links to generated (nightly) docs added
• Release note snippet added

Reviewer

• Code contains useful comments
• Code contains useful logging statements
• (Integration-)Test cases added
• Documentation added or updated. Follows the style guide.
• Changelog updated
• Cargo.toml only contains references to git tags (not specific commits or branches)

Acceptance

• Feature Tracker has been updated
• Proper release label has been added
• Links to generated (nightly) docs added
• Release note snippet added
• Add type/deprecation label & add to the deprecation schedule
• Add type/experimental label & add to the experimental features tracker

[NickLarsenNZ]

Let's run with it. @lfrancke indicated it was fine.

I do think we need some instructions for spark-k8s-operator users.

Release Note

Caution

In this release, SparkApplicationTemplate becomes namespace scoped.
This is a breaking change and requires manual coordination.

For those not using the SparkApplicationTemplate

Before upgrading the spark-k8s-operator, scale it down to 0, then delete the Cluster Scoped CRD for SparkApplicationTemplate.

Perform the spark-k8s-operator upgrade per release-notes.

When the operator comes up, it will create a namespace scoped SparkApplicationTemplate.

For those that do use the SparkApplicationTemplate

The SparkApplicationTemplate needs to be deleted, and it will be automatically created.

You will need to reapply your SparkApplicationTemplate after setting metadata.namespace on each. Have these ready to deploy before doing the operator upgrade.

Follow the instructions above, and then apply your namespaced SparkApplicationTemplates once the operator comes up.

I'm unsure if anything needs to be done with existing SparkApplications or jobs created by the template.