mirror of
https://github.com/ceph/ceph-csi.git
synced 2024-11-22 14:20:19 +00:00
539686329f
This commit address the issue- https://github.com/ceph/ceph-csi/issues/3448. Signed-off-by: riya-singhal31 <rsinghal@redhat.com>
100 lines
4.3 KiB
Markdown
100 lines
4.3 KiB
Markdown
# RBD NBD Mounter
|
||
|
||
- [RBD NBD Mounter](#rbd-nbd-mounter)
|
||
- [Overview](#overview)
|
||
- [Configuration](#configuration)
|
||
- [Configuring logging path](#configuring-logging-path)
|
||
- [Status](#status)
|
||
- [Support Matrix](#support-matrix)
|
||
- [CSI spec and Kubernetes version compatibility](#csi-spec-and-kubernetes-version-compatibility)
|
||
|
||
## Overview
|
||
|
||
The RBD CSI plugin will provision new RBD images and attach and mount those
|
||
to workloads. Currently, the default mounter is krbd, which uses the kernel
|
||
rbd driver to mount the rbd images onto the application node. Here on
|
||
at ceph-csi we will also have a userspace way of mounting the RBD images,
|
||
via RBD-NBD.
|
||
|
||
[Rbd-nbd](https://docs.ceph.com/en/latest/man/8/rbd-nbd/) is a client for
|
||
RADOS block device (rbd) images like the existing rbd kernel module. It
|
||
will map an rbd image to an NBD (Network Block Device) device, allowing
|
||
access to it as a regular local block device.
|
||
|
||
It’s worth to make a note that the rbd-nbd processes will run on the
|
||
client-side, which is inside the `csi-rbdplugin` node plugin.
|
||
|
||
## Configuration
|
||
|
||
To use the rbd-nbd mounter for RBD-backed PVs, set `mounter` to `rbd-nbd`
|
||
in the StorageClass.
|
||
|
||
Please note that the minimum recommended kernel version to use rbd-nbd is
|
||
5.4 or higher.
|
||
|
||
### Configuring logging path
|
||
|
||
If you are using the default rbd nodePlugin DaemonSet and StorageClass
|
||
templates then `cephLogDir` will be `/var/log/ceph`, this directory will be
|
||
a host-path and the default log file path will be
|
||
`/var/log/ceph/rbd-nbd-<volID>.log`. rbd-nbd creates a log file per volume
|
||
under the `cephLogDir` path on NodeStage(map) and removed the same on
|
||
the respective NodeUnstage(unmap).
|
||
|
||
- There are different strategies to maintain the logs
|
||
- `remove`: delete log file on unmap/detach (default behaviour)
|
||
- `compress`: compress the log file to gzip on unmap/detach, in case there
|
||
exists a `.gz` file from previous map/unmap of the same volume, then
|
||
override the previous log with new log.
|
||
- `preserve`: preserve the log file in text format
|
||
|
||
You can tweak the log strategies through `cephLogStrategy` option from the
|
||
storageclass yaml
|
||
|
||
- In case if you need a customized log path, you should do below:
|
||
|
||
- Edit the DaemonSet templates to change the ceph log directory host-path
|
||
- If you are using helm charts, then you can use key `cephLogDirHostPath`
|
||
|
||
```
|
||
helm install --set cephLogDirHostPath=/var/log/ceph-csi/my-dir
|
||
```
|
||
|
||
- For standard templates edit [csi-rbdplugin.yaml](../deploy/rbd/kubernetes/csi-rbdplugin.yaml)
|
||
to update `hostPath` for `ceph-logdir`.
|
||
to update `pathPrefix` spec entries.
|
||
- Update the StorageClass with the customized log directory path
|
||
- Now update rbd StorageClass for `cephLogDir`, for example
|
||
|
||
```
|
||
cephLogDir: "/var/log/prod-A-logs"
|
||
```
|
||
|
||
`NOTE`:
|
||
|
||
- On uninstall make sure to delete `cephLogDir` on host manually to freeup
|
||
some space just in case if there are any uncleaned log files.
|
||
- In case if you do not need the rbd-nbd logging to persistent at all, then
|
||
simply update the StorageClass for `cephLogDir` to use a non-persistent path.
|
||
|
||
## Status
|
||
|
||
Rbd-nbd support status: **Alpha**
|
||
|
||
## Support Matrix
|
||
|
||
| Features | Feature Status | CSI Driver Version | Ceph Cluster Version | CSI Spec Version | Kubernetes Version |
|
||
| ---------------------------------------- | -------------- | ------------------ | -------------------- | ---------------- | ------------------ |
|
||
| Creating and deleting snapshot | Alpha | >= v3.4.0 | Pacific (>=16.0.0) | >= v1.0.0 | >= v1.17.0 |
|
||
| Creating and deleting clones | Alpha | >= v3.4.0 | Pacific (>=16.0.0) | >= v1.0.0 | >= v1.17.0 |
|
||
| Creating and deleting encrypted volumes | Alpha | >= v3.4.0 | Pacific (>=16.0.0) | >= v1.0.0 | >= v1.14.0 |
|
||
| Expand volumes | Alpha | >= v3.4.0 | Pacific (>=16.0.0) | >= v1.1.0 | >= v1.15.0 |
|
||
|
||
`NOTE`: The `Alpha` status reflects possible non-backward compatible
|
||
changes in the future, and is thus not recommended for production use.
|
||
|
||
### CSI spec and Kubernetes version compatibility
|
||
|
||
Please refer to the [matrix](https://kubernetes-csi.github.io/docs/#kubernetes-releases)
|
||
in the Kubernetes documentation.
|