Submitted 4 weeks ago by InnerScientist@lemmy.world to selfhosted@lemmy.world
I’m looking for experiences and opinions on kubernetes CSI backends.
I want to create a highly available homelab that spans 3 locations where the pods have a preferred locations but can move if necessary.
I’ve looked at linstore or seaweedfs/garage with juicefs but I’m not sure how well the performance of those options is across the internet and how well they last in long term operation. Is anyone else hosting k3s across the internet in their homelab?
That isn’t how you would normally do it
You don’t want to try and span locations on a Container/hypervisor level. The problem is that there is likely to much latency between the sites which will screw with things.
Instead, set up replicated data types where it is necessary.
The problem is that I want failover to work if a site goes offline, this happens quite a bit with private ISP where I live and instead of waiting for the connection to be restored my idea was that kubernetes would see the failed node and replace it.
Most data will be transfered locally (with node affinity) and only on failure would the pods spread out. The problem that remained in this was storage which is why I’m here looking for options.
That isn’t going to work unfortunately
You need very low latency (something like 10ms or preferably less)
My gut says go multi cluster (or not) at that pointbut treat the remote as a service, have a local container be a proxy
I want the failover to work in case of internet or power outage, not local cluster node failure. Multiple clusters would make configuration and failover across locations difficult or am I wrong?
I guess i shouldn’t have answered, I do have experience with multiple storage-classes, but none of the classes you mention (so like i don’t really know anything about them). I envisioned you dealing with pod level storage issues and thought that’d be something most programs would have lots of difficulty dealing with, where as a more service oriented approach would expect remote failures (hence the recommendation).
All of the things you mentioned don’t seem like they have provisioners, so maybe you mean your individual nodes would have these associated remote fs’. At that point i don’t think kubelet cares, you just mount those on the machines and tell kubelet about it via host mount
Oh shit look there’s a CSI driver for juicefs juicefs.com/docs/csi/introduction/, they kinda start out recommending the host mount juicefs.com/docs/…/use_juicefs_in_kubernetes/.
We make some use of PV’s but people i find my team often tend to avoid them.
I probably should have shut my mouth from the start!
You are wrong
I tried Longhorn, and ended up concluding that it would not work reliably with Volsync. Volsync (for automatic volume restore on cluster rebuild) is a must for me.
I plan on installing Rook-Ceph. I’m also on 1Gb/s network, so it won’t be fast, but many fellow K8s home opsers are confident it will work.
Rook-ceph does need SSDs with Power Loss Protection (PLP), or it will get extremelly slow (latency). Bandwidth is not as much of an issue. Find some used Samsung PM or SM models, they aren’t expensive.
Thanks for the info!
I’ll try Rook-Ceph, Ceph has been recommended quite a lot now, but my nvme drives sadly don’t have PLP. Afaict that should still work because not all nodes will face power loss at the same time.
I’d rather start with the hardware I have and upgrade as necessary, backups are always running for emergency cases and I can’t afford to replace all hard drives.
I’ll join Home Operations once I’ve worked out how to provision my NixOS base system
The problem with non-PLP drives is that Rook-Ceph will insist that its writes get done in a way that is safe wrt power loss.
For regular consumer drives, that means it has to wait for the cache to be flushed, which takes aaaages (milliseconds!!) and that can cause all kinds of issues. PLP drives have a cache that is safe in the event of power loss, and thus Rook-Ceph is happy to write to cache and consider the operation done.
Again, 1Gb network is not a big deal, not using PLP drives could cause issues.
If you don’t need volsync and don’t need ReadWriteMany, just use Longhorn with its builtin backup system and call it a day.
I know Ceph would work for this use case, but it’s not a lighthearted choice, kind of an investment and a steep learning curve (at least it was for me).
I heard that ceph lives and dies with the network hardware. Is a slow internet connection even usable when the docs want 10 gbit/s networking between nodes?
I’m really not sure. I’ve heard of people using Ceph across datacenters. Presumably that’s with a fast-ish connection, and it’s like joining separate clusters, so you’d likely need local ceph cluster at each site then replicate between datacenters. Probably not what you’re looking for.
I’ve heard good things about Garbage S3 and that it’s usable across the internet on slow-ish connections. But it’s object storage only.
Those are block storage services, not Storage backends. Your options for SCi Provisioned are these: kubernetes.io/docs/concepts/…/storage-classes/#pr…
I would say if you’re not truly familiar with K8s, or DEEPLY familiar with Ops, don’t fuck with K8s internals. You’re gonna have a bad time.
I mean storage backends as in the provisioner, I will use local storage on the nodes with either lvm or just storage on a filesystem.
I already set up a cluster and tried linstore, I’m searching for experiences with the options because I don’t want to test them all.
You won’t find any benchmarks for distributed filesystems, because they don’t apply to any one setup. Nobody knows your network situation, disk speed, availability across clusters…etc.
I’ve been using backblaze b2 (via s3fs-fuse container + bidirectional mount propagation to a host path) and a little bit of google drive (via rclone mount + the same mounting business) within kubernetes. I only use this for tubearchivist which I consider to be disposable. No way I’m using these “devices” for anything I really care about. I haven’t tried gauging the performance of either of these, but I can say, anecdotally, that both are fine for tubearchivist to write to in a reasonable amount of time (the bottleneck is yt-dlp ingesting from youtube) and playback seems to be on par with local storage with the embedded tubearchivist player and jellyfin. I’ve had no issues with this, been using it about a year now, and overall I feel it’s a decent solution if you need a lot of cheap-ish storage that you are okay with not trusting.
Rook-ceph for sure. And echoing another comment, come join homes operations discord, we have a heap of info and people experienced with kubernetes with homelabbing discord.gg/home-operations
One thing I recently found out is that ceph wants whole drives. I could not get it to work with partitions. I got it to work with longhorn, though I’m still setting things up.
ChaosMonkey@lemmy.dbzer0.com 4 weeks ago
Longhorn is pretty easy to use. Garage works well too. Ceph is harder to use but provides both block and object storage (s3).
InnerScientist@lemmy.world 4 weeks ago
Ceph (and longhorn) want “10 Gbps network bandwidth between nodes” while I’ll have around 1gbit between nodes, or even lower.
What’s your experience with Garage?
ChaosMonkey@lemmy.dbzer0.com 4 weeks ago
I guess the network will be a bottleneck on Garage too. If you want high performance you might need a hybrid solution, like clustering of stateful apps on local storage as well as periodic full backups on a distributed storage.