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For static volume, the user will manually mounts already existing image as a volume to the application pods. As its a rbd Image, if the PVC is of type fileSystem the image will be mapped, formatted and mounted on the node, If the user resizes the image on the ceph cluster. User cannot not automatically resize the filesystem created on the rbd image. Even if deletes and recreates the kubernetes objects, the new size will not be visible on the node. With this changes During the NodeStageVolumeRequest the nodeplugin will check the size of the mapped rbd image on the node using the devicePath. and also the rbd image size on the ceph cluster. If the size is not matching it will do the file system resize on the node as part of the NodeStageVolumeRequest RPC call. The user need to do below operation to see new size * Resize the rbd image in ceph cluster * Scale down all the application pods using the static PVC. * Make sure no application pods which are using the static PVC is running on a node. * Scale up all the application pods. Validate the new size in application pod mounted volume. Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>
271 lines
10 KiB
Markdown
271 lines
10 KiB
Markdown
# Static PVC with ceph-csi
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- [Static PVC with ceph-csi](#static-pvc-with-ceph-csi)
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- [RBD static PVC](#rbd-static-pvc)
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- [Create RBD image](#create-rbd-image)
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- [Create RBD static PV](#create-rbd-static-pv)
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- [RBD Volume Attributes in PV](#rbd-volume-attributes-in-pv)
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- [Create RBD static PVC](#create-rbd-static-pvc)
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- [Resize RBD image](#resize-rbd-image)
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- [CephFS static PVC](#cephfs-static-pvc)
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- [Create CephFS subvolume](#create-cephfs-subvolume)
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- [Create CephFS static PV](#create-cephfs-static-pv)
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- [Node stage secret ref in CephFS PV](#node-stage-secret-ref-in-cephfs-pv)
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- [CephFS volume attributes in PV](#cephfs-volume-attributes-in-pv)
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- [Create CephFS static PVC](#create-cephfs-static-pvc)
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This document outlines how to create static PV and static PVC from
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existing rbd image/cephFS volume.
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**warning** static PVC can be created, deleted, mounted and unmounted but
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currently ceph-csi doesn't support other operations like snapshot,clone,
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resize, etc for static PVC
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## RBD static PVC
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RBD images created manually can be mounted and unmounted to an app, below step
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shows how to create a rbd image, static PV, static PVC
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### Create RBD image
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If you already have a rbd image created and contains some data which you want
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to access by the application pod you can skip this step.
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Lets create a new rbd image in ceph cluster which we are going to use for
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static PVC
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```console
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rbd create static-image --size=1024 --pool=replicapool
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```
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### Create RBD static PV
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To create the rbd PV you need to know the `rbd image name`,`clusterID` and
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`pool` name in which the rbd image is created
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```yaml
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apiVersion: v1
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kind: PersistentVolume
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metadata:
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name: fs-static-pv
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spec:
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accessModes:
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- ReadWriteOnce
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capacity:
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storage: 1Gi
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csi:
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driver: rbd.csi.ceph.com
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fsType: ext4
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nodeStageSecretRef:
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# node stage secret name
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name: csi-rbd-secret
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# node stage secret namespace where above secret is created
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namespace: default
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volumeAttributes:
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# Required options from storageclass parameters need to be added in volumeAttributes
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"clusterID": "ba68226a-672f-4ba5-97bc-22840318b2ec"
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"pool": "replicapool"
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"staticVolume": "true"
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"imageFeatures": "layering"
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#mounter: rbd-nbd
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# volumeHandle should be same as rbd image name
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volumeHandle: static-image
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persistentVolumeReclaimPolicy: Retain
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# 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`
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volumeMode: Filesystem
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```
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### RBD Volume Attributes in PV
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Below table explains the list of volume attributes can be set when creating a
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static RBD PV
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| Attributes | Description | Required |
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| :-----------: | :--------------------------------------------------------------------------------------------------------------------------------------------------: | :------: |
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| clusterID | The clusterID 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 |
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| pool | The pool name in which rbd image is created | Yes |
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| staticVolume | Value must be set to `true` to mount and unmount static rbd PVC | Yes |
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| imageFeatures | CSI RBD currently supports `layering, journaling, exclusive-lock` features. If `journaling` is enabled, must enable `exclusive-lock` too | Yes |
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| mounter | If set to `rbd-nbd`, use `rbd-nbd` on nodes that have `rbd-nbd` and `nbd` kernel modules to map rbd images | No |
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**Note** ceph-csi does not supports rbd image deletion for static PV.
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`persistentVolumeReclaimPolicy` in PV spec must be set to `Retain` to avoid PV
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delete attempt in csi-provisioner.
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```bash
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$ kubectl create -f fs-static-pv.yaml
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persistentvolume/fs-static-pv created
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```
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### Create RBD static PVC
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To create the rbd PVC you need to know the PV name which is created above
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```yaml
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apiVersion: v1
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kind: PersistentVolumeClaim
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metadata:
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name: fs-static-pvc
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namespace: default
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spec:
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accessModes:
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# ReadWriteMany is only supported for Block PVC
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- ReadWriteOnce
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resources:
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requests:
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storage: 1Gi
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# 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`
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volumeMode: Filesystem
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# volumeName should be same as PV name
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volumeName: fs-static-pv
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```
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```bash
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$ kubectl create -f fs-static-pvc.yaml
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persistentvolumeclaim/fs-static-pvc created
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```
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### Resize RBD image
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Let us resize the RBD image in ceph cluster
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```console
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rbd resize static-image --size=2048 --pool=replicapool
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```
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Once the rbd image is resized in the ceph cluster, update the PV size and PVC
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size to match the size of the rbd image.
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Now scale down the application pod which is using `cephfs-static-pvc` and scale
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up the application pod to resize the filesystem.
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**Note** If you have mounted same static PVC to multiple application pods, make
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sure you will scale down all the application pods and make sure no application
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pods using the static PVC is running on the node and scale up all the
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application pods again(this will trigger `NodeStageVolumeRequest` which will
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resize the filesystem for static volume).
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**Note** deleting PV and PVC does not removed the backend rbd image, user need to
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manually delete the rbd image if required
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## CephFS static PVC
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CephFS subvolume created manually can be mounted and unmounted to an app,
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below steps show how to create a CephFS subvolume, static PV and static PVC.
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### Create CephFS subvolume
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If you already have a CephFS subvolume created and contains some data
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which you want to access by the application pod you can skip this step.
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Lets create a new CephFS subvolume of size 1 GiB in ceph cluster which
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we are going to use for static PVC, before that we need to create
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the subvolumegroup. **myfs** is the filesystem name(volume name) inside
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which subvolume should be created.
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```console
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ceph fs subvolumegroup create myfs testGroup
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```
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```console
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ceph fs subvolume create myfs testSubVolume testGroup --size=1073741824
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```
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**Note:** volume here refers to the filesystem.
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### Create CephFS static PV
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To create the CephFS PV you need to know the `volume rootpath`, and `clusterID`,
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here is the command to get the root path in ceph cluster
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```bash
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$ ceph fs subvolume getpath myfs testSubVolume testGroup
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/volumes/testGroup/testSubVolume
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```
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```yaml
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apiVersion: v1
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kind: PersistentVolume
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metadata:
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name: cephfs-static-pv
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spec:
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accessModes:
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- ReadWriteMany
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capacity:
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storage: 1Gi
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csi:
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driver: cephfs.csi.ceph.com
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nodeStageSecretRef:
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# node stage secret name
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name: csi-cephfs-secret
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# node stage secret namespace where above secret is created
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namespace: default
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volumeAttributes:
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# Required options from storageclass parameters need to be added in volumeAttributes
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"clusterID": "ba68226a-672f-4ba5-97bc-22840318b2ec"
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"fsName": "myfs"
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"staticVolume": "true"
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"rootPath": /volumes/testGroup/testSubVolume
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# volumeHandle can be anything, need not to be same
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# as PV name or volume name. keeping same for brevity
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volumeHandle: cephfs-static-pv
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persistentVolumeReclaimPolicy: Retain
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volumeMode: Filesystem
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```
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### Node stage secret ref in CephFS PV
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For static CephFS PV to work, userID and userKey needs to be specified in the
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secret. Static PV will not work with adminID and adminKey.
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Format for the secret should be same as detailed [here](https://github.com/ceph/ceph-csi/blob/3e656769b71a3c43d95f6875ed4934c82a8046e7/examples/cephfs/secret.yaml#L7-L10).
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### CephFS volume attributes in PV
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Below table explains the list of volume attributes can be set when creating a
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static CephFS PV
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| Attributes | Description | Required |
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| :----------: | :--------------------------------------------------------------------------------------------------------------------------------------------------: | :------: |
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| clusterID | The clusterID 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 |
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| fsName | CephFS filesystem name into which the subvolume should be created/present | Yes |
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| staticVolume | Value must be set to `true` to mount and unmount static rbd PVC | Yes |
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| rootPath | Actual path of the subvolume in ceph cluster, can be retrieved by issuing getpath command as described above | Yes |
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**Note** ceph-csi does not supports CephFS subvolume deletion for static PV.
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`persistentVolumeReclaimPolicy` in PV spec must be set to `Retain` to avoid PV
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delete attempt in csi-provisioner.
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```bash
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$ kubectl create -f cephfs-static-pv.yaml
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persistentvolume/cephfs-static-pv created
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```
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### Create CephFS static PVC
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To create the CephFS PVC you need to know the PV name which is created above
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```yaml
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apiVersion: v1
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kind: PersistentVolumeClaim
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metadata:
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name: cephfs-static-pvc
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namespace: default
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spec:
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accessModes:
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- ReadWriteMany
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resources:
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requests:
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storage: 1Gi
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volumeMode: Filesystem
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# volumeName should be same as PV name
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volumeName: cephfs-static-pv
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```
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```bash
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$ kubectl create -f cephfs-static-pvc.yaml
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persistentvolumeclaim/cephfs-static-pvc created
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```
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**Note** deleting PV and PVC does not delete the backend CephFS subvolume,
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user needs to manually delete the CephFS subvolume if required.
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