k8s_basic_storage

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k8s_basic_storage [2020/05/22 15:03] – [Create PV] andonovjk8s_basic_storage [2020/05/25 12:49] (current) – [Dynamic Provisioning] andonovj
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 Firstly, as we said, we have to configure, the PV, let's take one example of a PV: Firstly, as we said, we have to configure, the PV, let's take one example of a PV:
  
-<Code:bash|Example of PV Yaml>+<Code:bash|PV Specs>
 kind: PersistentVolume kind: PersistentVolume
 apiVersion: v1                                 <- It is first Class object, just like Pod, Deployment and so on apiVersion: v1                                 <- It is first Class object, just like Pod, Deployment and so on
Line 56: Line 56:
   storageClassName: ps-fast                    <- Indicate that it is in "ps-fast" storage Class   storageClassName: ps-fast                    <- Indicate that it is in "ps-fast" storage Class
   capacity:   capacity:
-    storage: 10Gi                              <- We allocate 10 GBs +    storage: 50Gi                              <- We allocate 50 GBs 
-  persistentVolumeReclaimPolicy: Retain        <- What to happen after you remove a PVC?+  persistentVolumeReclaimPolicy: Retain         
 +#                                   ^ 
 +#                                   | 
 +#                   What to happen after you remove a PVC?
 #Retain - Keep it in "protected" mode #Retain - Keep it in "protected" mode
 #Delete(Default) - This will DELETE the PV after removing the PVC #Delete(Default) - This will DELETE the PV after removing the PVC
 +#
   accessModes:   accessModes:
     - ReadWriteOnce                - ReadWriteOnce           
Line 74: Line 78:
  
 You can see the description for each important attritube above. So that covers the explanation :) You can see the description for each important attritube above. So that covers the explanation :)
 +So, how we create it then ? Well, like any other kubernetes' object, we APPLY it:
 +
 +<Code:bash|Create PV>
 +ubuntu@k8s-master:~/volume1$ kubectl apply -f pov1.yml
 +persistentvolume/ps-pv created
 +ubuntu@k8s-master:~/volume1$ kubectl get pv
 +NAME    CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM   STORAGECLASS   REASON   AGE
 +ps-pv   50Gi       RWO            Retain           Available           ps-fast                 3s
 +ubuntu@k8s-master:~/volume1$ kubectl get pvc
 +No resources found in default namespace.
 +ubuntu@k8s-master:~/volume1$
 +</Code>
 +
 +To use it, we need a PVC, to claim it and pod so we have a container to present it to.
 +
 +====Create PVC====
 +As we already said, PVC "claims" the PV. Without PVC, the PV is useless, without PVC the PV is useless. They need to exist together.
 +
 +So let's check the specs for the PVC.
 +
 +<Code:Code|PVC specs>
 +apiVersion: v1
 +kind: PersistentVolumeClaim
 +metadata:
 +  name: ps-pvc
 +spec:
 +  storageClassName: ps-fast
 +  accessModes:
 +    - ReadWriteOnce
 +  resources:
 +    requests:
 +      storage: 50Gi
 +</Code>
 +
 +I will not go through this description as the attributes repeat, but you get the picture. We create a claim, and we hope that some volume can fulfil it :) As again, the PVC is a first class object, we can simply "apply" it:
 +
 +<Code:bash|Create PVC>
 +ubuntu@k8s-master:~/volume1$ kubectl apply -f pvc.yml
 +persistentvolumeclaim/ps-pvc created
 +ubuntu@k8s-master:~/volume1$ kubectl get pvc
 +NAME     STATUS   VOLUME   CAPACITY   ACCESS MODES   STORAGECLASS   AGE
 +ps-pvc   Bound    ps-pv    50Gi       RWO            ps-fast        3s
 +ubuntu@k8s-master:~/volume1$ kubectl get pv
 +NAME    CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM            STORAGECLASS   REASON   AGE
 +ps-pv   50Gi       RWO            Retain           Bound    default/ps-pvc   ps-fast                 5m8s
 +ubuntu@k8s-master:~/volume1$
 +</Code>
 +
 +We see that, we have bounded them and we see the claim in the Persistent Volume description. 
 +It is important to note that the PVC will bind to ANY PV which has the SAME or MORE of the requested storage. For example if the PVC wants to claim 50 GBs and we have PV with 20 GBs, it will bind. 
 +
 +However, if our PVC wants to claim 20GBs and we have only 50 GB PV, then we are screwed and the PVC won't bind.
 +Congrats, we have a pvc to present to any pod we want to have storage.
 +
 +So let's create the Pod
 +
 +====Create a POD with Persistent Storage====
 +As always, here example of the POD YML:
 +
 +<Code:bash|Pod Specs>
 +apiVersion: v1
 +kind: Pod
 +metadata:
 +  name: first-pod
 +spec:
 +  volumes:
 +    - name: fast50g
 +      persistentVolumeClaim:
 +        claimName: ps-pvc
 +  containers:
 +    - name: ctr1
 +      image: ubuntu:latest
 +      command:
 +      - /bin/bash
 +      - "-c"
 +      - "sleep 60m"
 +      volumeMounts:
 +      - mountPath: "/data"
 +        name: fast50g
 +</Code>
 +
 +Again, I think explaination is useless here as the things are self explaining and as always we can just create:
 +
 +<Code:bash|Create Pod>
 +ubuntu@k8s-master:~/volume1$ kubectl apply -f pod.yml
 +pod/first-pod created
 +ubuntu@k8s-master:~/volume1$ kubectl get pods
 +NAME                            READY   STATUS    RESTARTS   AGE
 +first-pod                       1/1     Running   0          99s
 +ubuntu@k8s-master:~/volume1$
 +</Code>
 +
 +====Get on the Pod====
 +As we installed that pod on Kubernetes with 1 master and 2 workers. It didn't had to end up on the mater, in fact it ended up on Worker 1 :) So let's check it there. On Worker1, we can list all the Pods as usual and connect to our one
 +
 +<Code:bash|List all pods>
 +root@node-1:~# docker container ls
 +CONTAINER ID        IMAGE                     COMMAND                  CREATED             STATUS              PORTS               NAMES
 +ca7f18335d32        ubuntu                    "/bin/bash -c 'sleep…"   4 minutes ago       Up 4 minutes                            k8s_ctr1_first-pod_default_d5fc44c3-81c7-4a63-9e00-cf9650c26c58_0
 +d2e5fddd1d2d        k8s.gcr.io/pause:3.2      "/pause"                 5 minutes ago       Up 5 minutes                            k8s_POD_first-pod_default_d5fc44c3-81c7-4a63-9e00-cf9650c26c58_0
 +c6694424e858        andonovj/httpserverdemo   "dotnet HttpServerDe…"   2 hours ago         Up 2 hours                              k8s_hello-pod_hello-deploy-7f44bd8b96-qz6cr_default_6fb3b168-ab19-47e9-be9c-f016f214f092_1
 +60ea2607bd11        andonovj/httpserverdemo   "dotnet HttpServerDe…"   2 hours ago         Up 2 hours                              k8s_hello-pod_hello-deploy-7f44bd8b96-4c76j_default_4b9f70f8-0d5d-4a19-aea0-8f393412f939_1
 +3ea2eeed5344        andonovj/httpserverdemo   "dotnet HttpServerDe…"   2 hours ago         Up 2 hours                              k8s_hello-pod_hello-deploy-7f44bd8b96-7tvcs_default_f4dc2924-7a87-44c9-bb5b-c3010b0451be_1
 +4742768bace2        andonovj/httpserverdemo   "dotnet HttpServerDe…"   2 hours ago         Up 2 hours                              k8s_hello-pod_hello-deploy-7f44bd8b96-9lnrm_default_821d3183-7c5e-413e-99a1-144bb13caff4_1
 +fd7678069cdd        k8s.gcr.io/pause:3.2      "/pause"                 2 hours ago         Up 2 hours                              k8s_POD_hello-deploy-7f44bd8b96-qz6cr_default_6fb3b168-ab19-47e9-be9c-f016f214f092_1
 +598a580a0ab0        k8s.gcr.io/pause:3.2      "/pause"                 2 hours ago         Up 2 hours                              k8s_POD_hello-deploy-7f44bd8b96-4c76j_default_4b9f70f8-0d5d-4a19-aea0-8f393412f939_1
 +8cc487d0c45e        andonovj/httpserverdemo   "dotnet HttpServerDe…"   2 hours ago         Up 2 hours                              k8s_hello-pod_hello-deploy-7f44bd8b96-gnvwr_default_f467d445-34c7-4dc9-ac37-e483be950d72_1
 +a64e7f2c167c        k8s.gcr.io/pause:3.2      "/pause"                 2 hours ago         Up 2 hours                              k8s_POD_hello-deploy-7f44bd8b96-7tvcs_default_f4dc2924-7a87-44c9-bb5b-c3010b0451be_1
 +97da605cd3c7        k8s.gcr.io/pause:3.2      "/pause"                 2 hours ago         Up 2 hours                              k8s_POD_hello-deploy-7f44bd8b96-9lnrm_default_821d3183-7c5e-413e-99a1-144bb13caff4_1
 +e7c8dcebe1be        k8s.gcr.io/pause:3.2      "/pause"                 2 hours ago         Up 2 hours                              k8s_POD_hello-deploy-7f44bd8b96-gnvwr_default_f467d445-34c7-4dc9-ac37-e483be950d72_1
 +71c9f4548392        0d40868643c6              "/usr/local/bin/kube…"   2 hours ago         Up 2 hours                              k8s_kube-proxy_kube-proxy-sbtcp_kube-system_f627745a-760f-442a-a371-27350c3e638d_3
 +420f51aa6c56        k8s.gcr.io/pause:3.2      "/pause"                 2 hours ago         Up 2 hours                              k8s_POD_kube-proxy-sbtcp_kube-system_f627745a-760f-442a-a371-27350c3e638d_3
 +b9cc5715f753        3610c051aa19              "start_runit"            2 hours ago         Up 2 hours                              k8s_calico-node_calico-node-5rqvv_kube-system_add6c10e-7693-41b0-953a-0ed2c3e2f671_3
 +9b86b11b3b61        k8s.gcr.io/pause:3.2      "/pause"                 2 hours ago         Up 2 hours                              k8s_POD_calico-node-5rqvv_kube-system_add6c10e-7693-41b0-953a-0ed2c3e2f671_3
 +root@node-1:~# docker exec -it ca7f18335d32 /bin/bash
 +root@first-pod:/# df -h
 +Filesystem      Size  Used Avail Use% Mounted on
 +overlay         9.7G  3.9G  5.8G  40% /
 +tmpfs            64M     0   64M   0% /dev
 +tmpfs           730M     0  730M   0% /sys/fs/cgroup
 +/dev/sda1       9.7G  3.9G  5.8G  40% /data
 +shm              64M     0   64M   0% /dev/shm
 +tmpfs           730M   12K  730M   1% /run/secrets/kubernetes.io/serviceaccount
 +tmpfs           730M     0  730M   0% /proc/acpi
 +tmpfs           730M     0  730M   0% /proc/scsi
 +tmpfs           730M     0  730M   0% /sys/firmware
 +root@first-pod:/# cd /data
 +root@first-pod:/data# ls -alrt
 +total 8
 +drwxr-xr-x 2 root root 4096 May 22 15:23 .
 +drwxr-xr-x 1 root root 4096 May 22 15:23 ..
 +root@first-pod:/data# pwd
 +/data
 +root@first-pod:/data# touch test
 +root@first-pod:/data# ls -alrt
 +total 8
 +drwxr-xr-x 1 root root 4096 May 22 15:23 ..
 +-rw-r--r-- 1 root root    0 May 22 15:29 test
 +drwxr-xr-x 2 root root 4096 May 22 15:29 .
 +</Code>
 +
 +So we have created a simple text file on the pod, under mount: "/data". According our logic that file should be available on the host server under the defined volume destination:
 +
 +<Code:bash|Check the Volume>
 +root@node-1:/home/ubuntu/volume1# hostname
 +node-1
 +root@node-1:/home/ubuntu/volume1# ls -lart
 +total 8
 +drwxr-xr-x 4 ubuntu ubuntu 4096 May 22 15:23 ..
 +-rw-r--r-- 1 root   root      0 May 22 15:29 test
 +drwxr-xr-x 2 root   root   4096 May 22 15:29 .
 +root@node-1:/home/ubuntu/volume1# pwd
 +/home/ubuntu/volume1
 +root@node-1:/home/ubuntu/volume1#
 +</Code>
 +Lo and behold, the simple text file is on persistent storage and won't be affected if the container crashes for example. It will stay there safe and sound on the host server.
 +
 +As we mentioned, that kind of persistent storage allocation DOESN'T SCALE and let's see why:
 +
 +{{ :kubernetes_storage_ps_yml_map.jpg?800 |}}
 +
 +You see that, mapping and mapping and mapping :) Let's see what we can do about it.
 +
 =====Dynamic Provisioning===== =====Dynamic Provisioning=====
-Let's configure Dynamic storage.+Let's configure Dynamic storage. The idea here is that, we (as administrators) care only of the PVC, NOT the PV. So we create the PVC and the provisioner creates teh PV himself. 
 + 
 +Now, for Dynamic provisioning with NFS I had to re-configure the cluster. In a nutshell make sure that teh API IP which you give when you initiate the cluster has the same subnet of the pod network.  
 + 
 +For example: 
 + 
 +<Code:bash|Initiate Cluster for NFS> 
 +kubeadm init --ignore-preflight-errors=NumCPU --apiserver-advertise-address=192.168.50.10 --pod-network-cidr=192.168.50.0/24 
 +</Code> 
 + 
 +Calico by default is using: 192.168.0.0/16 so I modified it to: 192.168.50.0/24 so it will match the network of the API Advertise IP. 
 + 
 +So let's get going. In the begining, I had something like that: 
 + 
 +<Code:bash|Overview> 
 +NAMESPACE     NAME                                       READY   STATUS    RESTARTS   AGE     IP                NODE         NOMINATED NODE   READINESS GATES 
 +kube-system   calico-kube-controllers-77c5fc8d7f-fcnh7   1/1     Running   0          3m56s   192.168.235.195   k8s-master   <none>           <none> 
 +kube-system   calico-node-94qkt                          1/1     Running   0          66s     192.168.50.12     node-2       <none>           <none> 
 +kube-system   calico-node-j54sq                          1/1     Running   0          2m18s   192.168.50.11     node-1       <none>           <none> 
 +kube-system   calico-node-rc4t6                          1/1     Running   0          3m56s   192.168.50.10     k8s-master   <none>           <none> 
 +kube-system   coredns-66bff467f8-d7hr5                   1/1     Running   0          10m     192.168.235.193   k8s-master   <none>           <none> 
 +kube-system   coredns-66bff467f8-jmwk7                   1/1     Running   0          10m     192.168.235.194   k8s-master   <none>           <none> 
 +kube-system   etcd-k8s-master                            1/1     Running   0          10m     192.168.50.10     k8s-master   <none>           <none> 
 +kube-system   kube-apiserver-k8s-master                  1/1     Running   0          10m     192.168.50.10     k8s-master   <none>           <none> 
 +kube-system   kube-controller-manager-k8s-master         1/1     Running   0          10m     192.168.50.10     k8s-master   <none>           <none> 
 +kube-system   kube-proxy-8td28                           1/1     Running   0          66s     192.168.50.12     node-2       <none>           <none> 
 +kube-system   kube-proxy-bljr8                           1/1     Running   0          10m     192.168.50.10     k8s-master   <none>           <none> 
 +kube-system   kube-proxy-dcnqt                           1/1     Running   0          2m18s   192.168.50.11     node-1       <none>           <none> 
 +kube-system   kube-scheduler-k8s-master                  1/1     Running   0          10m     192.168.50.10     k8s-master   <none>           <none> 
 +ubuntu@k8s-master:~$ 
 +</Code> 
 + 
 +So we have to create the following: 
 + 
 +  * Deployment 
 +  * Service Account 
 +  * Service 
 +  * RBAC 
 +  * Storage Class 
 +  * Claim 
 + 
 +====Create the Deployment,Service and Service Account==== 
 +You can see the deployment,service and service account's  YML below: 
 + 
 +<Code:bash|Components YML> 
 +apiVersion: v1 
 +kind: ServiceAccount 
 +metadata: 
 +  name: nfs-provisioner 
 +--- 
 +kind: Service 
 +apiVersion: v1 
 +metadata: 
 +  name: nfs-provisioner 
 +  labels: 
 +    app: nfs-provisioner 
 +spec: 
 +  ports: 
 +    - name: nfs 
 +      port: 2049 
 +    - name: nfs-udp 
 +      port: 2049 
 +      protocol: UDP 
 +    - name: nlockmgr 
 +      port: 32803 
 +    - name: nlockmgr-udp 
 +      port: 32803 
 +      protocol: UDP 
 +    - name: mountd 
 +      port: 20048 
 +    - name: mountd-udp 
 +      port: 20048 
 +      protocol: UDP 
 +    - name: rquotad 
 +      port: 875 
 +    - name: rquotad-udp 
 +      port: 875 
 +      protocol: UDP 
 +    - name: rpcbind 
 +      port: 111 
 +    - name: rpcbind-udp 
 +      port: 111 
 +      protocol: UDP 
 +    - name: statd 
 +      port: 662 
 +    - name: statd-udp 
 +      port: 662 
 +      protocol: UDP 
 +  selector: 
 +    app: nfs-provisioner 
 +--- 
 +kind: Deployment 
 +apiVersion: apps/v1 
 +metadata: 
 +  name: nfs-provisioner 
 +spec: 
 +  selector: 
 +    matchLabels: 
 +      app: nfs-provisioner 
 +  replicas: 1 
 +  strategy: 
 +    type: Recreate 
 +  template: 
 +    metadata: 
 +      labels: 
 +        app: nfs-provisioner 
 +    spec: 
 +      serviceAccount: nfs-provisioner 
 +      containers: 
 +        - name: nfs-provisioner 
 +          image: quay.io/kubernetes_incubator/nfs-provisioner:latest 
 +          ports: 
 +            - name: nfs 
 +              containerPort: 2049 
 +            - name: nfs-udp 
 +              containerPort: 2049 
 +              protocol: UDP 
 +            - name: nlockmgr 
 +              containerPort: 32803 
 +            - name: nlockmgr-udp 
 +              containerPort: 32803 
 +              protocol: UDP 
 +            - name: mountd 
 +              containerPort: 20048 
 +            - name: mountd-udp 
 +              containerPort: 20048 
 +              protocol: UDP 
 +            - name: rquotad 
 +              containerPort: 875 
 +            - name: rquotad-udp 
 +              containerPort: 875 
 +              protocol: UDP 
 +            - name: rpcbind 
 +              containerPort: 111 
 +            - name: rpcbind-udp 
 +              containerPort: 111 
 +              protocol: UDP 
 +            - name: statd 
 +              containerPort: 662 
 +            - name: statd-udp 
 +              containerPort: 662 
 +              protocol: UDP 
 +          securityContext: 
 +            capabilities: 
 +              add: 
 +                - DAC_READ_SEARCH 
 +                - SYS_RESOURCE 
 +          args: 
 +            - "-provisioner=example.com/nfs" 
 +          env: 
 +            - name: POD_IP 
 +              valueFrom: 
 +                fieldRef: 
 +                  fieldPath: status.podIP 
 +            - name: SERVICE_NAME 
 +              value: nfs-provisioner 
 +            - name: POD_NAMESPACE 
 +              valueFrom: 
 +                fieldRef: 
 +                  fieldPath: metadata.namespace 
 +          imagePullPolicy: "IfNotPresent" 
 +          volumeMounts: 
 +            - name: export-volume 
 +              mountPath: /export 
 +      volumes: 
 +        - name: export-volume 
 +          hostPath: 
 +            path: /srv 
 +ubuntu@k8s-master:~/external-storage/nfs/deploy/kubernetes$ kubectl create -f deployment.yaml 
 +serviceaccount/nfs-provisioner created 
 +service/nfs-provisioner created 
 +deployment.apps/nfs-provisioner created 
 +</Code> 
 + 
 +Then let's create the RBAC, which created the Cluster roles and maps them and of course the storage class 
 + 
 +===Create RBAC and Storage Class=== 
 +<Code:bash|Create RBAC & Storage Class> 
 +kind: ClusterRole 
 +apiVersion: rbac.authorization.k8s.io/v1 
 +metadata: 
 +  name: nfs-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"] 
 +  - apiGroups: [""] 
 +    resources: ["services", "endpoints"] 
 +    verbs: ["get"] 
 +  - apiGroups: ["extensions"] 
 +    resources: ["podsecuritypolicies"] 
 +    resourceNames: ["nfs-provisioner"] 
 +    verbs: ["use"] 
 +--- 
 +kind: ClusterRoleBinding 
 +apiVersion: rbac.authorization.k8s.io/v1 
 +metadata: 
 +  name: run-nfs-provisioner 
 +subjects: 
 +  - kind: ServiceAccount 
 +    name: nfs-provisioner 
 +     # replace with namespace where provisioner is deployed 
 +    namespace: default 
 +roleRef: 
 +  kind: ClusterRole 
 +  name: nfs-provisioner-runner 
 +  apiGroup: rbac.authorization.k8s.io 
 +--- 
 +kind: Role 
 +apiVersion: rbac.authorization.k8s.io/v1 
 +metadata: 
 +  name: leader-locking-nfs-provisioner 
 +rules: 
 +  - apiGroups: [""] 
 +    resources: ["endpoints"] 
 +    verbs: ["get", "list", "watch", "create", "update", "patch"] 
 +--- 
 +kind: RoleBinding 
 +apiVersion: rbac.authorization.k8s.io/v1 
 +metadata: 
 +  name: leader-locking-nfs-provisioner 
 +subjects: 
 +  - kind: ServiceAccount 
 +    name: nfs-provisioner 
 +    # replace with namespace where provisioner is deployed 
 +    namespace: default 
 +roleRef: 
 +  kind: Role 
 +  name: leader-locking-nfs-provisioner 
 +  apiGroup: rbac.authorization.k8s.io 
 +ubuntu@k8s-master:~/external-storage/nfs/deploy/kubernetes$ cat class.yaml 
 +kind: StorageClass 
 +apiVersion: storage.k8s.io/v1 
 +metadata: 
 +  name: example-nfs 
 +provisioner: example.com/nfs 
 +mountOptions: 
 +  - vers=4.1 
 +ubuntu@k8s-master:~/external-storage/nfs/deploy/kubernetes$ kubectl create -f rbac.yaml 
 +clusterrole.rbac.authorization.k8s.io/nfs-provisioner-runner created 
 +clusterrolebinding.rbac.authorization.k8s.io/run-nfs-provisioner created 
 +role.rbac.authorization.k8s.io/leader-locking-nfs-provisioner created 
 +rolebinding.rbac.authorization.k8s.io/leader-locking-nfs-provisioner created 
 +ubuntu@k8s-master:~/external-storage/nfs/deploy/kubernetes$ kubectl create -f class.yaml 
 +storageclass.storage.k8s.io/example-nfs created 
 +</Code> 
 + 
 +====Create Storage Claim==== 
 +With Dynamic provisioning, we DON'T Create the Volume, we create ONLY the claim, the volume is created automatically by the provision, that is the MAIN difference 
 + 
 +<Code:bash|Create Claim> 
 +ubuntu@k8s-master:~/external-storage/nfs/deploy/kubernetes$ cat claim.yaml 
 +kind: PersistentVolumeClaim 
 +apiVersion: v1 
 +metadata: 
 +  name: nfs 
 +  annotations: 
 +    volume.beta.kubernetes.io/storage-class: "example-nfs" 
 +spec: 
 +  accessModes: 
 +    - ReadWriteMany 
 +  resources: 
 +    requests: 
 +      storage: 10Mi 
 +ubuntu@k8s-master:~/ 
 +</Code> 
 + 
 +====Verify==== 
 +We can verify the configuration as follows: 
 + 
 + 
 +<Code:bash|Create Claim> 
 +ubuntu@k8s-master:~/external-storage/nfs/deploy/kubernetes$ kubectl get pv,pvc 
 +NAME                                                        CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM         STORAGECLASS   REASON   AGE 
 +persistentvolume/pvc-9a8aa090-7c73-4e64-94eb-dcc7805828dd   10Mi       RWX            Delete           Bound    default/nfs   example-nfs             21m 
 + 
 +NAME                        STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE 
 +persistentvolumeclaim/nfs   Bound    pvc-9a8aa090-7c73-4e64-94eb-dcc7805828dd   10Mi       RWX            example-nfs    21m 
 +ubuntu@k8s-master:~/external-storage/nfs/deploy/kubernetes$ 
 +</Code> 
 + 
 +Finally, we have a bounded PVC using Dynamic Provision. There is one very good git with all this files: 
 + 
 +<Code:bash|Configure it with GIT> 
 +ubuntu@k8s-master:~$ git clone https://github.com/kubernetes-incubator/external-storage.git^C 
 +ubuntu@k8s-master:~$ 
 +ubuntu@k8s-master:~$ ls -lart 
 +total 32 
 +-rw-r--r--  1 ubuntu ubuntu 3771 Aug 31  2015 .bashrc 
 +-rw-r--r--  1 ubuntu ubuntu  220 Aug 31  2015 .bash_logout 
 +-rw-r--r--  1 ubuntu ubuntu  655 Jul 12  2019 .profile 
 +drwxr-xr-x  4 root   root   4096 May 25 10:51 .. 
 +drwx------  2 ubuntu ubuntu 4096 May 25 10:51 .ssh 
 +-rw-r--r--  1 ubuntu ubuntu    0 May 25 11:21 .sudo_as_admin_successful 
 +drwxrwxr-x  4 ubuntu ubuntu 4096 May 25 11:22 .kube 
 +drwxr-xr-x  5 ubuntu ubuntu 4096 May 25 11:27 . 
 +drwxrwxr-x 17 ubuntu ubuntu 4096 May 25 11:27 external-storage                         <---- This one 
 +</Code> 
 + 
 +====Create a Pod with Dynamic Provisioning==== 
 +We can of course create a pod which will be using the NFS, let's create NGINX pod for example: 
 + 
 +<Code:bash|Create NGINX Pod> 
 +apiVersion: apps/v1 
 +kind: Deployment 
 +metadata: 
 +  labels: 
 +    app: nginx 
 +  name: nfs-nginx 
 +spec: 
 +  replicas: 1 
 +  selector: 
 +    matchLabels: 
 +      app: nginx 
 +  template: 
 +    metadata: 
 +      labels: 
 +        app: nginx 
 +    spec: 
 +      volumes: 
 +      - name: nfs # 
 +        persistentVolumeClaim: 
 +          claimName: nfs  # same name of pvc that was created 
 +      containers: 
 +      - image: nginx 
 +        name: nginx 
 +        volumeMounts: 
 +        - name: nfs # name of volume should match claimName volume 
 +          mountPath: mydata2 # mount inside of contianer 
 +ubuntu@k8s-master:~/external-storage/nfs/deploy/kubernetes$ kubectl create -f nginx.yml 
 +deployment.apps/nfs-nginx created 
 +ubuntu@k8s-master:~/external-storage/nfs/deploy/kubernetes$ kubectl get pods -o wide 
 +NAME                              READY   STATUS    RESTARTS   AGE     IP              NODE     NOMINATED NODE   READINESS GATES 
 +nfs-nginx-6b4db6f57-4mczr         1/1     Running   0          2m51s   192.168.247.2   node-2   <none>           <none> 
 +nfs-provisioner-7795cf6f4-d7m2l   1/1     Running   0          67m     192.168.247.1   node-2   <none>           <none> 
 +ubuntu@k8s-master:~/external-storage/nfs/deploy/kubernetes$ 
 +</Code> 
 + 
 +Even an ubuntu pod: 
 +<Code:bash|ubuntu pod> 
 +ubuntu@k8s-master:~$ cat pod.yml 
 +apiVersion: v1 
 +kind: Pod 
 +metadata: 
 +  name: first-pod 
 +spec: 
 +  volumes: 
 +    - name: fast10m 
 +      persistentVolumeClaim: 
 +        claimName: nfs 
 +  containers: 
 +    - name: ctr1 
 +      image: ubuntu:latest 
 +      command: 
 +      - /bin/bash 
 +      - "-c" 
 +      - "sleep 60m" 
 +      volumeMounts: 
 +      - mountPath: "/data" 
 +        name: fast10m 
 +ubuntu@k8s-master:~$ kubectl get pods -o wide 
 +NAME                              READY   STATUS    RESTARTS   AGE     IP               NODE     NOMINATED NODE   READINESS GATES 
 +first-pod                         1/1     Running   0          24s     192.168.84.131   node-1   <none>           <none> 
 +nfs-nginx-6b4db6f57-4mczr         1/1     Running   0          4m16s   192.168.247.2    node-2   <none>           <none> 
 +nfs-provisioner-7795cf6f4-d7m2l   1/1     Running   0          69m     192.168.247.1    node-2   <none>           <none> 
 +ubuntu@k8s-master:~$ 
 +</Code> 
 + 
 +Eurika, finally we are done with both types of privisioning
  • k8s_basic_storage.1590159812.txt.gz
  • Last modified: 2020/05/22 15:03
  • by andonovj