Storage/AZ affinity when using multiple availability zones

[seanknox]

Thanks for releasing alea! I'm excited to try it out in our cluster.

We run a multi-AZ Kubernetes/Deis cluster on AWS. How do you maintain storage/AZ affinity across k8s nodes?

[wearethefoos]

Hi @seanknox the storage templates currently only support GCE. To make them work on AWS, we will need to alter the storage templates to work with the aws ebs provisioner. More info can be found here: http://kubernetes.io/docs/user-guide/persistent-volumes/#storageclasses

While creating a storage class, you can pass in an AZ, or leave it up to the provisioner to pick a random one. I don't know if storage can be managed easily across AZs

As for making this work on AWS, it might be as simple as adding some overrides in the settings.yaml, but we will have to test that. I will be happy to do so and report back the results.

Also, @rimusz might know more about this currently.

[rimusz]

@seanknox for AWS you cloud use such storage manifest:

kind: StorageClass
apiVersion: storage.k8s.io/v1beta1
metadata:
  name: standard
provisioner: kubernetes.io/aws-ebs
parameters:
  type: gp2
  zone: us-west-2
#  iopsPerGB: "10"

You need such manifest per each AZ.

And to maintain storage/AZ affinity across k8s nodes, your back end services need to be clustered so then you spread them across AZ.

There is no magic k8s to do that automatically, it all depends what you use, if e.g mondo or postgres can be set as a cluster, then you spread tehm around AZ.