ceph-csi/docs/static-pvc.md
Madhu Rajanna 8163552b81 Add doc for rbd static pvc support
Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>
2020-02-18 12:34:46 +00:00

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# Static PVC with ceph-csi
- [Static PVC with ceph-csi](#static-pvc-with-ceph-csi)
- [RBD static PVC](#rbd-static-pvc)
- [Create RBD image](#create-rbd-image)
- [Create RBD static PV](#create-rbd-static-pv)
- [RBD Volume Attributes in PV](#rbd-volume-attributes-in-pv)
- [Create RBD static PVC](#create-rbd-static-pvc)
This document outlines how to create static PV and static PVC from existing rbd image
**warning** static PVC can be created, deleted, mounted and unmounted but
currently ceph-csi doesn't support other operations like snapshot,clone,
resize, etc for static PVC
## RBD static PVC
RBD images created manually can be mounted and unmounted to an app, below step
shows how to create a rbd image, static PV, static PVC
### Create RBD image
If you already have a rbd image created and contains some data which you want
to access by the application pod you can skip this step.
Lets create a new rbd image in ceph cluster which we are going to use for
static PVC
```bash
[$]rbd create static-image --size=1024 --pool=replicapool
```
### Create RBD static PV
To create the rbd PV you need to know the `rbd image name`,`clusterID` and
`pool` name in which the rbd image is created
```yaml
apiVersion: v1
kind: PersistentVolume
metadata:
name: fs-static-pv
spec:
accessModes:
- ReadWriteOnce
capacity:
storage: 1Gi
csi:
driver: rbd.csi.ceph.com
fsType: ext4
nodeStageSecretRef:
# node stage secret name
name: csi-rbd-secret
# node stage secret namespace where above secret is created
namespace: default
volumeAttributes:
# Required options from storageclass parameters need to be added in volumeAttributes
"clusterID": "ba68226a-672f-4ba5-97bc-22840318b2ec"
"pool": "replicapool"
"staticVolume": "true"
#mounter: rbd-nbd
# volumeHandle should be same as rbd image name
volumeHandle: static-image
persistentVolumeReclaimPolicy: Retain
# The volumeMode can be either `Filesystem` or `Block` if you are creating Filesystem PVC it should be `Filesystem`, if you are creating Block PV you need to change it to `Block`
volumeMode: Filesystem
```
### RBD Volume Attributes in PV
Below table explains the list of volume attributes can be set when creating a
static RBD PV
| Attributes | Description | Required |
| :----------: | :----------------------------------------------------------------------------------------------------------------------------------------: | :------: |
| clusterID | The is used by the CSI plugin to uniquely identify and use a Ceph cluster (this is the key in configmap created duing ceph-csi deployment) | Yes |
| pool | The pool name in which rbd image is created | Yes |
| staticVolume | Value must be set to `true` to mount and unmount static rbd PVC | yes |
| mounter | If set to `rbd-nbd`, use `rbd-nbd` on nodes that have `rbd-nbd` and `nbd` kernel modules to map rbd images | No |
**Note** ceph-csi does not supports rbd image deletion for static PV.
`persistentVolumeReclaimPolicy` in PV spec must be set to `Retain` to avoid PV
delete attempt in csi-provisioner.
```bash
[$] kubectl create -f fs-static-pv.yaml
persistentvolume/fs-static-pv created
```
### Create RBD static PVC
To create the rbd PVC you need to know the PV name which is created above
```yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: fs-static-pvc
namespace: default
spec:
accessModes:
# ReadWriteMany is only supported for Block PVC
- ReadWriteOnce
resources:
requests:
storage: 1Gi
# The volumeMode can be either `Filesystem` or `Block` if you are creating Filesystem PVC it should be `Filesystem`, if you are creating Block PV you need to change it to `Block`
volumeMode: Filesystem
# volumeName should be same as PV name
volumeName: fs-static-pv
```
```bash
[$] kubectl create -f fs-static-pvc.yaml
persistentvolumeclaim/fs-static-pvc created
```
**Note** deleting PV and PVC doesnot deleted the backend rbd image, user need to
manually delete the rbd image if required