PWX-24444: Antihyperconvergence scheduling of sharedv4 service pods

[pp511]

Signed-off-by: Priyanshu Pandey ppandey@purestorage.com

What type of PR is this?

feature
unit-test

What this PR does / why we need it:

• Introduce a new parameter stork.libopenstorage.org/preferRemoteNodeOnly parameter to be applied to StorageClass.
  Pods using this StorageClass should only be scheduled on the nodes where volume replica nodes do not exist. This behavior should be strictly enforced.
• For Pods using SharedV4 Service volumes, Stork should give higher score to nodes where SharedV4 Service volumes do not exist.
• Refer to PWX-24444 for further details

Does this PR change a user-facing CRD or CLI?:
No

Is a release note needed?:

*  Stork will try to schedule application pods using SharedV4 service volumes to run on nodes where volume replica does not exist such that it uses NFS mountpoint and when a failover happens application pods will not be restarted.
* StorageClass parameter "stork.libopenstorage.org/preferRemoteNodeOnly": "true" can be used to strictly enforce this behavior.

Does this change need to be cherry-picked to a release branch?:
yes 2.12.2

Notes For the Reviewer

• Pod annotation preferLocalNodeOnly doesn't apply for SharedV4 service volumes
• StorageClass parameter preferRemoteNodeOnly applies only to SharedV4 service volumes
• In case a Pod uses both SharedV4 service and regular volumes, scoring will prioritize antihyperconvergence based on sharedv4 volume replicas

[cnbu-jenkins]

Can one of the admins verify this patch?

[codecov]

Codecov Report

Base: 67.79% // Head: 68.15% // Increases project coverage by +0.36% 🎉

Coverage data is based on head (c19a17d) compared to base (0e32660).
Patch coverage: 91.66% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1222      +/-   ##
==========================================
+ Coverage   67.79%   68.15%   +0.36%     
==========================================
  Files          42       42              
  Lines        4769     4820      +51     
==========================================
+ Hits         3233     3285      +52     
+ Misses       1214     1212       -2     
- Partials      322      323       +1     

Impacted Files	Coverage Δ
pkg/extender/extender.go	82.56% <91.66%> (+2.46%)	⬆️

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[adityadani]

lgtm! Really good set of UTs.
Please add the release note once you are ready to merge