Feature proposal - Affinities

[yellowmegaman]

I'd like to understand how to achieve wider interpretation in constraints.

Use case:

constraint {
  attribute = "${attr.unique.hostname}"
  regexp = "media"
}

But what happens when host media is down or drained? What i'd want - to have "preferred hosts" and ability to launch the app/container elsewhere if host is suddenly down down.

like:

regexp = value
regexp_preferred = value

Thanks a lot in advance!

[jippi]

I guess a feature like this would make sense once allocation rebalance / force allocation movement is in place :)

[dadgar]

Hey this would be solved with affinities and not constraints. You would have two affinities, one for the preferred with a high weight and and then the secondary value with a lower weight. I am going to rename the issue.

To be clear this is on the roadmap.

[yellowmegaman]

Awesome! Thanks for clarification. Any milestone it can be attached to?
AFAIK roadmap is kept secret ;)

[dadgar]

@yellowmegaman Not at this time. It will not be 0.6.0 and likely not 0.7 so some time after that.

[yellowmegaman]

Well, patience is golden, it's in plans and that's great.

[yellowmegaman]

Since creating this issue, I've reworked all containers to be host-independent, even databases. But not load balancers.

But still, sometimes i wish i could place priority for databases to be on higher IOPS instance/geo stuff without making strict constraint.

[jippi]

See #4513 - it will land in 0.9

[yellowmegaman]

@jippi thanks!)

[endocrimes]

Hey folks, Affinities have landed as part of the 0.9 betas - You can find documentation here. 😄

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