ungleich-k8s/archive/v3/rook/README.md

## TL;DR

We got rook running IPv6 only and are using a combination of the
[helm operator
chart](https://rook.io/docs/rook/v1.7/helm-operator.html) in
combination with custom
[CephCluster](https://rook.io/docs/rook/v1.7/ceph-cluster-crd.html)
and [CephBlockPool](https://rook.io/docs/rook/v1.7/ceph-block.html)
objects.

## v1: original rook manifests

```
git clone https://github.com/rook/rook.git
cd rook/cluster/examples/kubernetes/ceph
kubectl apply  -f crds.yaml -f common.yaml
kubectl apply  -f operator.yaml
kubectl get -n rook-ceph pods --watch
kubectl apply -f cluster.yaml
kubectl apply -f csi/rbd/storageclass.yaml
kubectl apply -f toolbox.yaml
```

## v2 with included manifests

* Patched for IPv6 support
* Including RBD support
* Including CephFS support

```
for yaml in crds common operator cluster storageclass-cephfs storageclass-rbd toolbox; do
    kubectl apply -f ${yaml}.yaml
done
```

Deleting (in case of teardown):

```
for yaml in crds common operator cluster storageclass-cephfs storageclass-rbd toolbox; do
    kubectl delete -f ${yaml}.yaml
done
```

## v3 via helm

```
helm repo add rook-release https://charts.rook.io/release
helm repo update
helm install --create-namespace --namespace rook-ceph rook-ceph rook-release/rook-ceph
helm install --create-namespace --namespace rook-ceph rook-ceph-cluster \
   --set operatorNamespace=rook-ceph rook-release/rook-ceph-cluster -f rook/values.yaml
```

## Debugging / ceph toolbox

```
kubectl -n rook-ceph exec -it deploy/rook-ceph-tools -- bash
```

## Creating a sample RBD device / PVC

```
kubectl apply -f pvc.yaml
```

Checks:

```
kubectl get pvc
kubectl describe pvc

kubectl get pv
kubectl describe pv
```

Digging into ceph, seeing the actual image:

```
[20:05] server47.place7:~# kubectl -n rook-ceph exec -it deploy/rook-ceph-tools -- rbd -p replicapool ls
csi-vol-d3c96f79-c7ba-11eb-8e52-1ed2f2d63451
[20:11] server47.place7:~#
```

## Filesystem

```
[21:06] server47.place7:~/ungleich-k8s/rook# kubectl -n rook-ceph get pod -l app=rook-ceph-mds
NAME                                    READY   STATUS            RESTARTS   AGE
rook-ceph-mds-myfs-a-5f547fd7c6-qmp2r   1/1     Running           0          16s
rook-ceph-mds-myfs-b-dd78b444b-49h5h    0/1     PodInitializing   0          14s
[21:06] server47.place7:~/ungleich-k8s/rook# kubectl -n rook-ceph get pod -l app=rook-ceph-mds
NAME                                    READY   STATUS    RESTARTS   AGE
rook-ceph-mds-myfs-a-5f547fd7c6-qmp2r   1/1     Running   0          20s
rook-ceph-mds-myfs-b-dd78b444b-49h5h    1/1     Running   0          18s
[21:06] server47.place7:~/ungleich-k8s/rook# kubectl -n rook-ceph exec -it deploy/rook-ceph-tools -- ceph -s
  cluster:
    id:     049110d9-9368-4750-b3d3-6ca9a80553d7
    health: HEALTH_WARN
            mons are allowing insecure global_id reclaim

  services:
    mon: 3 daemons, quorum a,b,d (age 98m)
    mgr: a(active, since 97m), standbys: b
    mds: 1/1 daemons up, 1 hot standby
    osd: 6 osds: 6 up (since 66m), 6 in (since 67m)

  data:
    volumes: 1/1 healthy
    pools:   4 pools, 97 pgs
    objects: 31 objects, 27 KiB
    usage:   40 MiB used, 45 GiB / 45 GiB avail
    pgs:     97 active+clean

  io:
    client:   3.3 KiB/s rd, 2.8 KiB/s wr, 2 op/s rd, 1 op/s wr

[21:07] server47.place7:~/ungleich-k8s/rook#
```

## DefaultStorageClass

By default none of the created storage classes are the "default" of
the cluster. So we need to set one of them, if persistentvolumeclaims
should be deployed:

```
[21:22] server47.place7:~/ungleich-k8s/rook# kubectl patch storageclass rook-ceph-block -p '{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"true"}}}'
```

## Deleting in case rook gets stuck

* Need to manually go through the list, the patching of finalizersdoes
  not work reliable

Especially these:

```
  finalizers:
  - cephblockpool.ceph.rook.io
```

## Other flux related problems

* The host is not cleared / old /var/lib/rook is persisting

## Troubleshooting: PVC stuck pending, no csi-{cephfs,rbd}provisioner-plugin pod in rook-ceph namespace

2021-07-31: it seems that the provisioner plugin tend to silently die.
Restarting the `rook-ceph-operator` deployment will get them back up:

```
kubectl rollout restart deployment/rook-ceph-operator -n rook-ceph
```