> Have you used NFS for persistent storage in prod much?
I think NFS is heavily underrated. It's a good match for things like hosting VM images on a cluster and for Kubernetes.
In the past I really wanted to use things iSCSI for hosting VM images and such things, but I've found that NFS is actually a lot faster for a lot of things. There are complications to NFS, of course, but they haven't caused me problems.
I would be happy to use it in production, and have recommended it, but it's not unconditional. It depends on a number of different factors.
The only problem with NFS is how do you manage the actual NFS infrastructure? How much experience does your org have with NFS? Do you already have a existing file storage solution in production you can expand and use that with Kubernetes?
Like if your organization already has a lot of servers running ZFS, then that is a nice thing to leverage for NFS persistent storage. Since you already have expertise in-house it would be a mistake not to take advantage of it. I wouldn't recommend this approach for people not already doing it, though.
If you can afford some sort of enterprise-grade storage appliance that takes care of dedupe, checksums, failovers, and all that happy stuff, then that's great. Use that and it'll solve your problems. Especially if there is some sort of NFS provisoner that Kubernetes supports.
The only place were I would say it's a 'Hard No' is if you have some sort of high scalability requirements. Like if you wanted to start some web hosting company or needed to have hundreds of nodes in a cluster. In that case then distributed file systems is what you need... Self-hosted storage aka "Hyper Converged Infrastructure". The cost and overhead of managing these things is then relative small to the size of the cluster and what you are trying to do.
It's scary to me to have a cluster self-host storage because storage can use a huge amount of ram and cpu at the worst times. You can go from a happy low-resource cluster, then a node fails or other component takes a shit, and then while everything is recovering and checksum'ng (and lord knows what) the resource usage goes through the roof right during a critical time. The 'perfect storm' scenarios.
I think NFS is heavily underrated. It's a good match for things like hosting VM images on a cluster and for Kubernetes.
In the past I really wanted to use things iSCSI for hosting VM images and such things, but I've found that NFS is actually a lot faster for a lot of things. There are complications to NFS, of course, but they haven't caused me problems.
I would be happy to use it in production, and have recommended it, but it's not unconditional. It depends on a number of different factors.
The only problem with NFS is how do you manage the actual NFS infrastructure? How much experience does your org have with NFS? Do you already have a existing file storage solution in production you can expand and use that with Kubernetes?
Like if your organization already has a lot of servers running ZFS, then that is a nice thing to leverage for NFS persistent storage. Since you already have expertise in-house it would be a mistake not to take advantage of it. I wouldn't recommend this approach for people not already doing it, though.
If you can afford some sort of enterprise-grade storage appliance that takes care of dedupe, checksums, failovers, and all that happy stuff, then that's great. Use that and it'll solve your problems. Especially if there is some sort of NFS provisoner that Kubernetes supports.
The only place were I would say it's a 'Hard No' is if you have some sort of high scalability requirements. Like if you wanted to start some web hosting company or needed to have hundreds of nodes in a cluster. In that case then distributed file systems is what you need... Self-hosted storage aka "Hyper Converged Infrastructure". The cost and overhead of managing these things is then relative small to the size of the cluster and what you are trying to do.
It's scary to me to have a cluster self-host storage because storage can use a huge amount of ram and cpu at the worst times. You can go from a happy low-resource cluster, then a node fails or other component takes a shit, and then while everything is recovering and checksum'ng (and lord knows what) the resource usage goes through the roof right during a critical time. The 'perfect storm' scenarios.