Story (Required)

As an ArgoCD user, I want that cluster reshuffling is minimal when the sharding configuration changes.

Background (Required)

The round-robin sharding algorithm sorts the clusters based on their uid. Then, they are put in an array and distributed evenly using a modulo operation accross all shards.

If cluster at index 0 is removed, it means that all the clusters will be redistributed accross the shards. That's a lot of movement inducing context switching, potentially caches rebuild etc... and thus potential performance overhead.

Out of scope

<Defines what is not included in this story>

Approach (Required)

Look for research papers treating this problem and determine if existing algortihms does not exist?

Another simple approach could be to implement a time to leave or placement expiracy policy where the reshuffle only happens when the tick is reached.

Dependencies

Acceptance Criteria (Mandatory)

The described naive case should be successful: No reshuffling in case of the remove of the first cluster.

INVEST Checklist

Dependencies identified

Blockers noted and expected delivery timelines set

Design is implementable

Acceptance criteria agreed upon

Story estimated

Legend

Unknown

Verified

Unsatisfied

Done Checklist

• Code is completed, reviewed, documented and checked in
• Unit and integration test automation have been delivered and running cleanly in continuous integration/staging/canary environment
• Continuous Delivery pipeline(s) is able to proceed with new code included
• Customer facing documentation, API docs etc. are produced/updated, reviewed and published
• Acceptance criteria are met