I'm a beginner in kubernetes, and when I was reading the book, I found that it is not recommended to use hostpath as the volume type for production environment, because it will lead to binding between pod and node, but if you don't use hostpath, then if you use other volume types, when reading and writing files, will it lead to extra network IO, and will this performance suffer? Will this have an additional performance impact?

CodePudding user response：

hostpath is, as the name suggests, reading and writing from a place on the host where the pod is running. If the host goes down, or the pod gets evicted or otherwise removed from the node, that data is (normally) lost. This is why the "binding" is mentioned -- the pod must stay on that same node otherwise it will lose that data.

Using a volume type and having volumes provisioned is better as the disk and the pod can be reattached together on another node and you will not lose the data.

In terms of I/O, there would indeed be a miniscule difference, since you're no longer talking to the node's local disk but a mounted disk.

hostPath volumes are generally used for temporary files or storage that can be lost without impact to the pod, in much the same way you would use /tmp on a desktop machine/

CodePudding user response：

To get a local volume you can use the volume type Local volume, but you need a local volume provisioner that can allocate and recycle volumes for you.

Since local volumes are disks on the host, there are no performance trade-offs. But it is more common to use network located volumes provided by a cloud provider, and they do have a latency trade-off.

CodePudding user response：

It is generally not recommended to use the hostPath volume type in production environments because it is tightly coupled to the node where the pod is running. If the pod is scheduled to run on a different node, the volume will not be accessible, which can lead to data loss or application failure.

Using other volume types, such as NFS or cloud-based storage solutions, can potentially add additional network overhead when reading and writing files. However, the performance impact of this overhead will depend on various factors, such as the type of storage being used, the size and frequency of the read and write operations, and the network infrastructure.

In general, using persistent volumes for storing data can improve the resiliency and availability of applications, as the data is not lost when the pod is restarted or rescheduled on a different node. However, it is important to carefully evaluate the trade-offs between performance and reliability when choosing a volume type for production environments.

I hope this helps! Let me know if you have any further questions.