CODEWITHSUNDEEP
kubernetes
DrGecko
DrGecko

Reputation: 889

How do i configure a Kubernetes Replication Controller to ensure there is a replica on each worker node/minion?

Is there a way to configure an RC such that i have a single replica on each of my worker nodes?

I just created a x2 replica RC for elasticsearch and it has placed both instances onto just one of my worker nodes. I would prefer to have one instance on each of my worker nodes.

This is particularity important for an application like elasticsearch that would use persistent storage on the docker host - having two elasticsearch instances using the same datastore would likely cause issues.

How is this possible to achieve?

Environment:

1x Kubernetes master - physical server running CoreOS
2x Kubernetes nodes - physical servers running CoreOS

Upvotes: 0

Views: 889

Answers (1)

Jordan Liggitt
Jordan Liggitt

Reputation: 18111

You can't choose nodes directly for pods created by scaling up a replication controller. The scheduler assigns nodes based on constraints. You can artificially prevent pods from going to the same node by making them use a resource a node only has one of, like a hostPort.

The daemon controller proposal (https://github.com/kubernetes/kubernetes/pull/13368) sounds more like what you want, which would let you spread pods across nodes

Upvotes: 3

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