Provide a way to deploy NATS Streaming as a StatefulSet

[emaincourt]

Hi,

First of all thanks a lot for the great work you've been doing with NATS/NATS Streaming.

I'm currently looking for a proper way to deploy NATS Streaming next to our NATS cluster on Kubernetes and it seems that using a file persistence mechanism, in addition with an HA topology, is pretty complicated at the moment. As the Helm chart stored in this repository makes use of a Deployment, as well as the operator, it becomes very tricky to handle horizontal scaling as volumes won't be dynamically created.

I am already aware of this Helm chart but it is still an external repository.

Would you potentially be interested in:

• Merging the aforementioned Helm chart into this repository to make it more accessible
• Migrate the current Helm Chart to make use of a StatefulSet
• Migrate the Operator to make use of a StatefulSet instead of a Deployment

In case the last two ones might be of interest to you, I could definitely take care of creating the PR. I only want to make sure this is something you might be looking for first.

This issue is more or less a duplicate/proposal to fix:

• Use statefulset for cluster. #26
• Proper PV support - ReadWriteOnce #23
• StatefullSet for NatStreaming Operator ? #50
• StatefullSet for NatStreaming Operator ? #48

Thanks in advance for reading

[wallyqs]

Al those would be very welcome changes. There is also an alternative Helm chart here https://github.com/nats-io/k8s/tree/master/helm/charts/stan that was based on this one: https://github.com/wallyqs/nats-streaming-cluster-chart

[emaincourt]

@wallyqs Thanks a lot for linking this chart, I hadn't seen it before. Will try to lock some time over the next weeks to integrate the mechanisms of both the charts into the operator and see how things go.