Allow for namespace selectors

[dhananjaysathe]

In a usecase where one has dynamic namespaces being created through a higher order api and it would like to back these up on schedule - it can be cumbersome to do so with namespace names .

It would be more natural and declarative to just label them and use that as a selector .
Esp relevant to the he ark schedule feature as you cant create a new BackupSpec each time.
In the normal backup case one could write an api abstraction that gathers a list of namespace names and then calls the backup api with a slice.

[dhananjaysathe]

Cc @ncdc

[ncdc]

cc @jbeda @dhanmm

[rosskukulinski]

Hi @dhananjaysathe - could you provide a little more context regarding your dynamic namespaces? I'm curious about what's being used to create your namespaces.

[dhananjaysathe]

hi @rosskukulinski we use kube as a provisioning layer for dynamic workloads. These are managed by a higher order platform using service brokers and helm. Each workload gets put into its own isolated name-space. So what i would want to do is take backups of a particular users workloads and allow him to restore them to a point in time. SO instead of specifying exact namespace names i would use lables and selectors to map to a backup job/schedule.

[rosskukulinski]

Cool! Thanks for the additional context @dhananjaysathe. We're in the planning process for the next few releases as well as the road to 1.0. Once I have a better understanding of if/when this might be worked on, I'll let you know.

Also, we're happy to take contributions if you or anyone else has some time. We love mentoring/on-boarding folks to the project!

[skriss]

closing this out as a dupe of #2477.