Is it safe to have multiple replicas running in k8s? about ha-fusion

[disruptivepatternmaterial]

I've been wanting to do what you have done (move everything to k8s). Do you have some of you setup, configs, etc... you'd be willing share somewhere?

If I helps I have 2 copies of this project running using docker compose on different ports. So should work for k8s fine as you describe.

[evanfoster]

I've been wanting to do what you have done (move everything to k8s). Do you have some of you setup, configs, etc... you'd be willing share somewhere?

If I helps I have 2 copies of this project running using docker compose on different ports. So should work for k8s fine as you describe.

Hey @disruptivepatternmaterial,

I can share a bit of what I've done, although it'll be a few days as I'm currently away from my cluster.

W.r.t. the two copies you're running, are they both sharing the same volume mount for their persistent config? Or do you have two separate volume mounts?

[matt8707]

I'm removing the kubernetes section, feel free to create a new repo with instructions and I'll link to that
1d90189

[evanfoster]

Understood. I may just do that.

I am still curious about whether or not it's safe to have multiple concurrent processes accessing the data meant to be stored in that volume. It's less a Kubernetes specific question and more of an application design question. I can dig into the app myself and get this info, but I figure it's worth asking. Like, that volume is used for the dashboard configs, right? If so, then I'm guessing there's no sort of locking mechanism in place around reads and writes which would make concurrent access unsafe. That's totally fine, I just don't know if it's used for config or as a cache.

If it isn't safe, then I might try to implement some form of optional leader election. I've never written typescript so I don't know how easy or hard that would be or if you'd be willing to accept a PR for that, but it's something I've considered since I saw your comment yesterday.