# Note of creating StrageClass for remote storage server (use Synology NAS as example)
> The kubernetes cluster is launch using microk8s
## Use NFS ([Reference](https://tuananh.org/2020/05/01/using-synology-nfs-as-external-storage-with-k8s/))
### Step 1. Enable NFS
`Control Panel`->`File Services`->`SMB/AFP/NFS`
`Control Panel`->`Shared Folder`->the folder->`Edit`->`NFS Permissions`
- Notice:
- Squash all user to admin
### Step 2. Deploy synology-nfs storage

microk8s kubectl apply -f nfs-client-synology.yml

Use configuration yaml file below.

# nfs-client-synology.yml.template
apiVersion: v1
kind: Namespace
metadata:
  name: synology-nfs
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nfs-client-provisioner
  labels:
    app: nfs-client-provisioner
  namespace: synology-nfs
spec:
  replicas: 1
  strategy:
    type: Recreate
  selector:
    matchLabels:
      app: nfs-client-provisioner
  template:
    metadata:
      labels:
        app: nfs-client-provisioner
    spec:
      serviceAccountName: nfs-client-provisioner
      containers:
        - name: nfs-client-provisioner
          image: quay.io/external_storage/nfs-client-provisioner:latest
          volumeMounts:
            - name: nfs-client-root
              mountPath: /persistentvolumes
          env:
            - name: PROVISIONER_NAME
              value: nfs.synology.com
            - name: NFS_SERVER
              value: ${SYNOLOGY_IP}
            - name: NFS_PATH
              value: ${VOLUME_PATH}
      volumes:
        - name: nfs-client-root
          nfs:
            server: ${SYNOLOGY_IP}
            path: ${VOLUME_PATH}
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: nfs-client-provisioner
  namespace: synology-nfs
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: nfs-client-provisioner-runner
rules:
  - apiGroups: [""]
    resources: ["persistentvolumes"]
    verbs: ["get", "list", "watch", "create", "delete"]
  - apiGroups: [""]
    resources: ["persistentvolumeclaims"]
    verbs: ["get", "list", "watch", "update"]
  - apiGroups: ["storage.k8s.io"]
    resources: ["storageclasses"]
    verbs: ["get", "list", "watch"]
  - apiGroups: [""]
    resources: ["events"]
    verbs: ["create", "update", "patch"]
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: run-nfs-client-provisioner
subjects:
  - kind: ServiceAccount
    name: nfs-client-provisioner
    namespace: synology-nfs
roleRef:
  kind: ClusterRole
  name: nfs-client-provisioner-runner
  apiGroup: rbac.authorization.k8s.io
---
kind: Role
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: leader-locking-nfs-client-provisioner
  namespace: synology-nfs
rules:
  - apiGroups: [""]
    resources: ["endpoints"]
    verbs: ["get", "list", "watch", "create", "update", "patch"]
---
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: leader-locking-nfs-client-provisioner
  namespace: synology-nfs
subjects:
  - kind: ServiceAccount
    name: nfs-client-provisioner
    namespace: synology-nfs
roleRef:
  kind: Role
  name: leader-locking-nfs-client-provisioner
  apiGroup: rbac.authorization.k8s.io
---
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: managed-nfs-storage
provisioner: nfs.synology.com
parameters:
  archiveOnDelete: "false"
  allowVolumeExpansion: "true"
  reclaimPolicy: "Delete"

- Notice
- `${SYNOLOGY_IP}`: replace to your NAS IP
- `${VOLUME_PATH}`: replace to the path you want your storage locate. e.g. `/volume2/k8s/storage`
- Tips for replace:

    sed 's@${SYNOLOGY_IP}@'"127.0.0.1"'@g;s@${VOLUME_PATH}@'"/volume2/k8s/storage"'@g' nfs-client-synology.yml.template > nfs-client-synology.yml

### Why we decide not to use it
- Squash all user to admin: too much privilege
- No auth: do the operation without login
## Use CSI(Container storage interface) ([Reference](https://github.com/jparklab/synology-csi))
### Deployment step
- Setting on Synology NAS
1. Create an user with admin privilege
2. `Control Panel`->`Security`->`Security`->`Enhance browser compatibility by skipping IP checking`: Enable it
3. `Control Panel`->`Security`->`Account`->`Auto Block`->`Allow/Block List`: Add the cluster node's IP to Allow list
- Installation step on every node in cluster
1. Install `iscsi` for iSCSI service and `go` and `make` for build binary

    apt-get update \
    apt-get install -y open-iscsi make \
    snap install go --classic

2. Set node.startup to automatic (Not sure it is requirement)([reference](https://www.synology.com/zh-tw/knowledgebase/DSM/tutorial/Virtualization/How_to_set_up_and_use_iSCSI_target_on_Linux))

    [root@Synology-FedoraVM /]# vi /etc/iscsi/iscsid.conf

    [...]
    node.startup = automatic
    [...] 

3. Build binary and copy to plugin dir

    # cd to repo dir
    export SNAP_COMMON=/var/snap/microk8s/common
    mkdir -p ${SNAP_COMMON}/var/lib/kubelet/plugins/csi.synology.com/
    
    make
    
    cp ./bin/synology-csi-driver ${SNAP_COMMON}/var/lib/kubelet/plugins/csi.synology.com/

- Deployment on Kubernetes cluster
1. Patch the deployment file describe below
2. Configurate the NAS login information in `syno-config.yml`

    ---
    # syno-config.yml file
    host: <hostname>           # ip address or hostname of the Synology NAS
    port: 5000                 # change this if you use a port other than the default one
    sslVerify: false           # set this true to use https
    username: <login>          # username
    password: <password>       # password
    loginApiVersion: 2         # Optional. Login version. From 2 to 6. Defaults to "2".
    loginHttpMethod: "auto"  # Optional. Method. "GET", "POST" or "auto" (default). "auto" uses POST on version >= 6
    sessionName: Core          # You won't need to touch this value
    enableSynoToken: no        # Optional. Set to 'true' to enable syno token. Only for versions 3 and above.
    enableDeviceToken: yes     # Optional. Set to 'true' to enable device token. Only for versions 6 and above.

3. Patch the deloyment yaml file for microk8s
- all the image patch to your own build image
- `node.yml`
- all the path to kubelet should change to the kubelet inside microk8s

4. Deploy it!!!

    microk8s kubectl create ns synology-csi
    microk8s kubectl create secret -n synology-csi generic synology-config --from-file=syno-config.yml
    microk8s kubectl create -f deploy/kubernetes/<the patched version>

### Note for mount iscsi on the linux
1. Install open-iscsi

apt-get install open-iscsi

2. Discover the node

iscsiadm -m discovery -t sendtargets -p <NAS_IP>

3. Connect to the node using target IQN(get from discover or on NAS)

iscsiadm -m mode -T iqn.2000-01.com.synology:kube-csi-pvc-example --login

4. Mount the iscsi to host path

# Check the disk path
fdisk -l

# Format it before using
mkfs -t ex4 /dev/<sd what ever>

# mount it
mount /dev/<sd what ever> <path>

5. Unmount

umount /dev/<sd what ever>

7. Don't forget to logout

iscsiadm -m mode -T iqn.2000-01.com.synology:kube-csi-pvc-example --logout