Introduction

Portworx is a software-defined persistent storage solution designed and purpose-built for applications deployed as containers, via container orchestrators such as Kubernetes, Nomad, Marathon,  and Docker Swarm. In this tutorial, you will learn how to install Portworx on a Kubernetes Cluster consisting of 3 nodes.  It is a clustered block storage solution providing a Cloud-Native layer from which containerized stateful applications programmatically employ block, file, and object storage services directly through the scheduler.

Portworx well complements Minio object storage by implementing a flexible, scalable, container-granular data services foundation beneath the Minio object storage server.

Minio object storage perfectly compliments Portworx by providing a simple object storage service layer on top of Portworx data services. Both products complement each other with their striking simplicity.

In this tutorial, you will learn how to deploy a 3 node Portworx Cluster, and eventually run 3 Nginx instances on the cluster using the Portworx storage mechanism.

Requirments

  1. A running Kubernetes Cluster with 1 Master and 3 nodes.
  2. Root access to all machines.
  3. If you want to learn how to deploy a Kubernetes Cluster, refer to this tutorial.

Installing PortWorx On A Kubernetes Cluster

Prepare hosts with storage

Portworx requires at least some nodes in the cluster to have dedicated storage for Portworx to use. PX will then generate virtual volumes from these storage pools. In this example, we use a 20GB block device that exists on each node.

Step 1: Verifying Cluster Readiness

By running the command : kubectl get nodes you should get a similar result:

NAME     STATUS   ROLES    AGE     VERSION
master   Ready    master   5h37m   v1.19.3
node01   Ready    <none>   5h36m   v1.19.3
node02   Ready    <none>   5h34m   v1.19.3
node03   Ready    <none>   5h31m   v1.19.3

Step 2: List block devices on all nodes

This is as easy as running the Click ssh root@node01 lsblk to list the available devices on node1.

Note the storage device vdb, which will be used by PX as one of its raw block disks. All the nodes in this setup have the vdb device.

master $ ssh root@node01 lsblk
Warning: Permanently added 'node01,172.17.0.11' (ECDSA) to the list of known hosts.
NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
fd0      2:0    1    4K  0 disk 
sr0     11:0    1 1024M  0 rom  
vda    253:0    0 97.7G  0 disk 
├─vda1 253:1    0 93.7G  0 part /
├─vda2 253:2    0    1K  0 part 
└─vda5 253:5    0  3.9G  0 part 
vdb    253:16   0   20G  0 disk

Step 3: Fetching the Portworx Spec

We will use query parameters in the curl command to customize our spec according to our kubectl version. To achieve that, we pipe the stdout of kubectl --version to stdin of awk command.

K8S_VERSION=`kubectl version --short | awk -Fv '/Server Version: /{print $3}'`

And:

curl -L -s -o px-spec.yaml "https://install.portworx.com/2.6?mc=false&kbver=${K8S_VERSION}&b=true&s=%2Fdev%2Fvdb&c=px-cluster&stork=true&st=k8s"

Step 4: Apply the PortWorks Spec

kubectl apply -f px-spec.yaml

Allow up to 5 mins for the containers to be created. Eventually, by running the command

watch kubectl get pods -n kube-system -l name=portworx -o wide

you should see something like this:

NAME             READY   STATUS    RESTARTS   AGE    IP            NODE     NOMINATED NODE   READINESS GATES
portworx-7cqpf   1/1     Running   0          7m3s   172.17.0.16   node01   <none>           <none>
portworx-hfm5q   1/1     Running   0          7m3s   172.17.0.33   node03   <none>           <none>
portworx-qspb6   1/1     Running   0          7m3s   172.17.0.32   node02   <none>           <none>

Step 5: Fetch Portworx cluster status

Portworx ships with a pxctl command line that you can use for managing Portworx.

The below command executes the pxctl status command using kubectl in one of the Portworx pods to fetch the overall cluster status.

Firstly,  you will need to set up the PX_POD environment variable.

PX_POD=$(kubectl get pods -l name=portworx -n kube-system -o jsonpath='{.items[0].metadata.name}')

Next, use kubectl to execute pxctl status on the cluster.

kubectl exec -it $PX_POD -n kube-system -- /opt/pwx/bin/pxctl status

The output of this command should be similar to this:

Status: PX is operational
License: Trial (expires in 31 days)
Node ID: 5f1e4785-7d91-4e5a-8578-a1127f6f5f80
        IP: 172.17.0.16 
        Local Storage Pool: 1 pool
        POOL    IO_PRIORITY     RAID_LEVEL      USABLE  USED    STATUS  ZONE    REGION
        0       HIGH            raid0           20 GiB  3.1 GiB Online  default default
        Local Storage Devices: 1 device
        Device  Path            Media Type              Size            Last-Scan
        0:1     /dev/vdb        STORAGE_MEDIUM_MAGNETIC 20 GiB          18 Mar 21 17:16 UTC
        * Internal kvdb on this node is sharing this storage device /dev/vdb  to store its data.
        total           -       20 GiB
        Cache Devices:
         * No cache devices
Cluster Summary
        Cluster ID: px-demo
        Cluster UUID: e0a19108-a8f4-4604-98c4-aafd5ccc062c
        Scheduler: kubernetes
        Nodes: 3 node(s) with storage (3 online)
        IP              ID                                      SchedulerNodeName       StorageNode     Used    CapacityStatus   StorageStatus   Version         Kernel                  OS
        172.17.0.32     a63a8730-6a84-4710-afab-6e92f0393b1d    node02                  Yes             3.1 GiB 20 GiB  Online   Up              2.6.3.0-4419aa4 4.4.0-62-generic        Ubuntu 16.04.2 LTS
        172.17.0.33     8097468c-022f-4bd4-8962-827c5ccc789c    node03                  Yes             3.1 GiB 20 GiB  Online   Up              2.6.3.0-4419aa4 4.4.0-62-generic        Ubuntu 16.04.2 LTS
        172.17.0.16     5f1e4785-7d91-4e5a-8578-a1127f6f5f80    node01                  Yes             3.1 GiB 20 GiB  Online   Up (This node)  2.6.3.0-4419aa4 4.4.0-62-generic        Ubuntu 16.04.2 LTS
        Warnings: 
                 WARNING: Insufficient CPU resources. Detected: 2 cores, Minimum required: 4 cores
                 WARNING: Insufficient Memory (RAM) resources. Detected: 2.0 GiB, Minimum required: 4.0 GiB
                 WARNING: Persistent journald logging is not enabled on this node.
                 WARNING: Internal Kvdb is not using dedicated drive on nodes [172.17.0.33 172.17.0.32 172.17.0.16]. This configuration is not recommended for production clusters.
Global Storage Pool
        Total Used      :  9.4 GiB
        Total Capacity  :  60 GiB

Congrats, now you have a 3-node Portworx cluster up and running!

Let’s examine now the cluster status.

  1. All 3 nodes are online and use Kubernetes node names as the Portworx node IDs.- Observe that Portworx clustered the 20GB block device from each node in a 60GB storage cluster.
  2. Portworx detected the block device media type as magnetic and created a storage pool for this. If you have different types of devices, for example, an SSD, a different storage pool is created for the SSD type.
  3. Portworx printed for us some warnings regarding our cpu cores, and about the fact but we should use a dedicated drive for our nodes.

Step 6: Create A Storage Class For Dynamic Provisioning

In order to create a Portworx storage class, we have to create the appropriate YAML file to apply. Execute the command below:

cat > portworx-sc.yaml <<EOF
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: portworx-sc
provisioner: kubernetes.io/portworx-volume
parameters:
  snap_interval: "70"
  priority_io:  "high"
  repl: "1"
  shared: "true" 
EOF

And then apply the file with:

kubectl apply -f portworx-sc.yaml

Output:

storageclass.storage.k8s.io/portworx-sc created

Now, if you execute kubectl describe storageclass portworx-sc you will see the storage class was successfully created:

Name:            portworx-sc
IsDefaultClass:  No
Annotations:     kubectl.kubernetes.io/last-applied-configuration={"apiVersion":"storage.k8s.io/v1","kind":"StorageClass","metadata":{"annotations":{},"name":"portworx-sc"},"parameters":{"priority_io":"high","repl":"1","snap_interval":"70"},"provisioner":"kubernetes.io/portworx-volume"}

Provisioner:           kubernetes.io/portworx-volume
Parameters:            priority_io=high,repl=1,snap_interval=70
AllowVolumeExpansion:  <unset>
MountOptions:          <none>
ReclaimPolicy:         Delete
VolumeBindingMode:     Immediate
Events:                <none>

Step 7: Create a Persistent Volume Claim

Now is time to create our PVC. Run the command below:

cat > portworx-volume-pvcsc.yaml <<EOF
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: pvc-sc-01
  annotations:
    volume.beta.kubernetes.io/storage-class: portworx-sc
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 10Gi
EOF

And apply the file:

kubectl apply -f portworx-volume-pvcsc.yaml

Output:

persistentvolumeclaim/pvc-sc-01 created

We can verify the PVC creation by executing:

kubectl describe pvc pvc-sc-01

And the output:

Name:          pvc-sc-01
Namespace:     default
StorageClass:  portworx-sc
Status:        Bound
Volume:        pvc-aa8f59dd-8818-11eb-af8c-0242ac11000a
Labels:        <none>
Annotations:   kubectl.kubernetes.io/last-applied-configuration:
                 {"apiVersion":"v1","kind":"PersistentVolumeClaim","metadata":{"annotations":{"volume.beta.kubernetes.io/storage-class":"portworx-sc"},"nam...
               pv.kubernetes.io/bind-completed: yes
               pv.kubernetes.io/bound-by-controller: yes
               volume.beta.kubernetes.io/storage-class: portworx-sc
               volume.beta.kubernetes.io/storage-provisioner: kubernetes.io/portworx-volume
Finalizers:    [kubernetes.io/pvc-protection]
Capacity:      10Gi
Access Modes:  RWX
VolumeMode:    Filesystem
Events:
  Type       Reason                 Age    From                         Message
  ----       ------                 ----   ----                         -------
  Normal     ProvisioningSucceeded  3m24s  persistentvolume-controller  Successfully provisioned volume pvc-aa8f59dd-8818-11eb-af8c-0242ac11000a using kubernetes.io/portworx-volume
Mounted By:  <none>

Step 8: Configure Nginx To Use PortWorx Persistent Volume Claim

Now that we have our persistent volumes and persistent volume claims set up, we will create an Nginx Deployment to the Kubernetes Cluster, to take advantage of the clustered environment across our 3 nodes. Below is the deployment we will use. Go ahead and run the command:

cat > nginx.yaml <<EOF
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  selector:
    matchLabels:
      app: nginx
  replicas: 3 # tells deployment to run 2 pods matching the template
  template:
    metadata:
      labels:
        app: nginx
    spec:
      securityContext:
        runAsUser: 2000
        runAsGroup: 2000
        fsGroup: 2000
      containers:
        - name: nginx
          image: admintuts/nginx:1.19.8-rtmp-geoip2-alpine
          ports:
            - containerPort: 3080
              name: "http-server"
            - containerPort: 3443
              name: "https-server"
          volumeMounts:
            - mountPath: "/usr/share/nginx/html"
              name: nginx-volume
          securityContext:
            allowPrivilegeEscalation: false
      volumes:
        - name: nginx-volume
          persistentVolumeClaim:
            claimName: pvc-sc-01
EOF

By executing

kubectl get pods -o wide

we get:

NAME                               READY   STATUS    RESTARTS   AGE     IP          NODE     NOMINATED NODE   READINESS GATES
nginx-deployment-756df8d64-9tf2v   1/1     Running   0          3m21s   10.42.0.3   node03   <none>           <none>
nginx-deployment-756df8d64-tfkhh   1/1     Running   0          3m21s   10.36.0.4   node02   <none>           <none>
nginx-deployment-756df8d64-tlbkn   1/1     Running   0          3m21s   10.44.0.5   node01   <none>           <none>

As you can see, each pod was scheduled in a different node, and each pod’s IP address is perfectly visible. If you want to take a closer look at what has happened below the hood, execute the command:

kubectl describe deployment nginx-deployment

Which will output:

Name:                   nginx-deployment
Namespace:              default
CreationTimestamp:      Fri, 19 Mar 2021 02:35:28 +0000
Labels:                 <none>
Annotations:            deployment.kubernetes.io/revision: 1
                        kubectl.kubernetes.io/last-applied-configuration:
                          {"apiVersion":"apps/v1","kind":"Deployment","metadata":{"annotations":{},"name":"nginx-deployment","namespace":"default"},"spec":{"replica...
Selector:               app=nginx
Replicas:               3 desired | 3 updated | 3 total | 3 available | 0 unavailable
StrategyType:           RollingUpdate
MinReadySeconds:        0
RollingUpdateStrategy:  25% max unavailable, 25% max surge
Pod Template:
  Labels:  app=nginx
  Containers:
   nginx:
    Image:        admintuts/nginx:1.19.8-rtmp-geoip2-alpine
    Ports:        3080/TCP, 3443/TCP
    Host Ports:   0/TCP, 0/TCP
    Environment:  <none>
    Mounts:
      /usr/share/nginx/html from nginx-volume (rw)
  Volumes:
   nginx-volume:
    Type:       PersistentVolumeClaim (a reference to a PersistentVolumeClaim in the same namespace)
    ClaimName:  pvc-sc-01
    ReadOnly:   false
Conditions:
  Type           Status  Reason
  ----           ------  ------
  Available      True    MinimumReplicasAvailable
  Progressing    True    NewReplicaSetAvailable
OldReplicaSets:  <none>
NewReplicaSet:   nginx-deployment-756df8d64 (3/3 replicas created)
Events:
  Type    Reason             Age    From                   Message
  ----    ------             ----   ----                   -------
  Normal  ScalingReplicaSet  3m37s  deployment-controller  Scaled up replica set nginx-deployment-756df8d64 to 3

As you can see here, all Nginx replicated containers are using the pvc-sc-o1 Persistent Volume Claim, and they are ready to accept traffic.

0 replies

Leave a Reply

Want to join the discussion?
Feel free to contribute!

Leave a Reply

Your email address will not be published. Required fields are marked *