Deploy an Application

If all verification steps in the preceding stages were satisfied, then Replicated PV Mayastor has been successfully deployed within the cluster. In order to verify basic functionality, we will now dynamically provision a Persistent Volume based on a Replicated PV Mayastor StorageClass, mount that volume within a small test pod which we'll create, and use the Flexible I/O Tester utility within that pod to check that I/O to the volume is processed correctly.

Define the PVC

Use kubectl to create a PVC based on a StorageClass that you created in the previous stage. In the example shown below, we will consider that StorageClass to have been named "mayastor-1". Replace the value of the field "storageClassName" with the name of your own Replicated PV Mayastor-based StorageClass.

For the purposes of this quickstart guide, it is suggested to name the PVC "ms-volume-claim", as this is what will be illustrated in the example steps which follow.

Command

cat <<EOF | kubectl create -f -

apiVersion: v1

kind: PersistentVolumeClaim

metadata:

name: ms-volume-claim

spec:

accessModes:

- ReadWriteOnce

resources:

requests:

storage: 1Gi

storageClassName: mayastor-1

EOF

YAML

apiVersion: v1

kind: PersistentVolumeClaim

metadata:

name: ms-volume-claim

spec:

accessModes:

- ReadWriteOnce

resources:

requests:

storage: 1Gi

storageClassName: INSERT_YOUR_STORAGECLASS_NAME_HERE

If you used the storage class example from previous stage, then volume binding mode is set to WaitForFirstConsumer. That means, that the volume won't be created until there is an application using the volume. We will go ahead and create the application pod and then check all resources that should have been created as part of that in kubernetes.

Deploy the FIO Test Pod

The Replicated PV Mayastor CSI driver will cause the application pod and the corresponding Replicated PV Mayastor volume's NVMe target/controller ("Nexus") to be scheduled on the same Replicated PV Mayastor Node, in order to assist with restoration of volume and application availabilty in the event of a storage node failure.

Command (GitHub Latest)

kubectl apply -f https://raw.githubusercontent.com/openebs/mayastor/v1.0.9/deploy/fio.yaml

YAML

kind: Pod

apiVersion: v1

metadata:

name: fio

spec:

nodeSelector:

openebs.io/engine: mayastor

volumes:

- name: ms-volume

persistentVolumeClaim:

claimName: ms-volume-claim

containers:

- name: fio

image: nixery.dev/shell/fio

args:

- sleep

- "1000000"

volumeMounts:

- mountPath: "/volume"

name: ms-volume

Verify the Volume and the Deployment

We will now verify the Volume Claim and that the corresponding Volume and Replicated PV Mayastor Volume resources have been created and are healthy.

Verify the Volume Claim

The status of the PVC should be "Bound".

Command

kubectl get pvc ms-volume-claim

Example Output

NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE

ms-volume-claim Bound pvc-fe1a5a16-ef70-4775-9eac-2f9c67b3cd5b 1Gi RWO mayastor-1 15s

Verify the Persistent Volume

info

Substitute the example volume name with that shown under the "VOLUME" heading of the output returned by the preceding "get pvc" command, as executed in your own cluster.

Command

kubectl get pv pvc-fe1a5a16-ef70-4775-9eac-2f9c67b3cd5b

Example Output

NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE

pvc-fe1a5a16-ef70-4775-9eac-2f9c67b3cd5b 1Gi RWO Delete Bound default/ms-volume-claim mayastor-1 16m

Verify the Replicated PV Mayastor Volume

The status of the volume should be "online".

info

To verify the status of volume Kubectl plugin is used.

Command

kubectl mayastor get volumes

Example Output

ID REPLICAS TARGET-NODE ACCESSIBILITY STATUS SIZE

18e30e83-b106-4e0d-9fb6-2b04e761e18a 3 aks-agentpool-12194210-0 nvmf Online 1073741824

Verify the Application

Verify that the pod has been deployed successfully, having the status "Running". It may take a few seconds after creating the pod before it reaches that status, proceeding via the "ContainerCreating" state.

info

The example FIO pod resource declaration included with this release references a PVC named ms-volume-claim, consistent with the example PVC created in this section of the quickstart. If you have elected to name your PVC differently, deploy the Pod using the example YAML, modifying the claimName field appropriately.

Command

kubectl get pod fio

Example Output

NAME READY STATUS RESTARTS AGE

fio 1/1 Running 0 34s

Run the FIO Tester Application

We now execute the FIO Test utility against the Replicated PV Mayastor for 60 seconds, checking that I/O is handled as expected and without errors. In this quickstart example, we use a pattern of random reads and writes, with a block size of 4k and a queue depth of 16.

Command

kubectl exec -it fio -- fio --name=benchtest --size=800m --filename=/volume/test --direct=1 --rw=randrw --ioengine=libaio --bs=4k --iodepth=16 --numjobs=8 --time_based --runtime=60

Example Output

benchtest: (g=0): rw=randrw, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T) 4096B-4096B, ioengine=libaio, iodepth=16

fio-3.20

Starting 1 process

benchtest: Laying out IO file (1 file / 800MiB)

Jobs: 1 (f=1): [m(1)][100.0%][r=376KiB/s,w=340KiB/s][r=94,w=85 IOPS][eta 00m:00s]

benchtest: (groupid=0, jobs=1): err= 0: pid=19: Thu Aug 27 20:31:49 2020

read: IOPS=679, BW=2720KiB/s (2785kB/s)(159MiB/60011msec)

slat (usec): min=6, max=19379, avg=33.91, stdev=270.47

clat (usec): min=2, max=270840, avg=9328.57, stdev=23276.01

lat (msec): min=2, max=270, avg= 9.37, stdev=23.29

clat percentiles (msec):

| 1.00th=[ 3], 5.00th=[ 3], 10.00th=[ 4], 20.00th=[ 4],

| 30.00th=[ 4], 40.00th=[ 4], 50.00th=[ 4], 60.00th=[ 4],

| 70.00th=[ 4], 80.00th=[ 4], 90.00th=[ 7], 95.00th=[ 45],

| 99.00th=[ 136], 99.50th=[ 153], 99.90th=[ 165], 99.95th=[ 178],

| 99.99th=[ 213]

bw ( KiB/s): min= 184, max= 9968, per=100.00%, avg=2735.00, stdev=3795.59, samples=119

iops : min= 46, max= 2492, avg=683.60, stdev=948.92, samples=119

write: IOPS=678, BW=2713KiB/s (2778kB/s)(159MiB/60011msec); 0 zone resets

slat (usec): min=6, max=22191, avg=45.90, stdev=271.52

clat (usec): min=454, max=241225, avg=14143.39, stdev=34629.43

lat (msec): min=2, max=241, avg=14.19, stdev=34.65

clat percentiles (msec):

| 1.00th=[ 3], 5.00th=[ 3], 10.00th=[ 3], 20.00th=[ 3],

| 30.00th=[ 3], 40.00th=[ 3], 50.00th=[ 3], 60.00th=[ 3],

| 70.00th=[ 3], 80.00th=[ 4], 90.00th=[ 22], 95.00th=[ 110],

| 99.00th=[ 155], 99.50th=[ 157], 99.90th=[ 169], 99.95th=[ 197],

| 99.99th=[ 228]

bw ( KiB/s): min= 303, max= 9904, per=100.00%, avg=2727.41, stdev=3808.95, samples=119

iops : min= 75, max= 2476, avg=681.69, stdev=952.25, samples=119

lat (usec) : 4=0.01%, 250=0.01%, 500=0.01%, 750=0.01%, 1000=0.01%

lat (msec) : 2=0.02%, 4=82.46%, 10=7.20%, 20=1.62%, 50=1.50%

lat (msec) : 100=2.58%, 250=4.60%, 500=0.01%

cpu : usr=1.19%, sys=3.28%, ctx=134029, majf=0, minf=17

IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=100.0%, 32=0.0%, >=64=0.0%

submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%

complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.1%, 32=0.0%, 64=0.0%, >=64=0.0%

issued rwts: total=40801,40696,0,0 short=0,0,0,0 dropped=0,0,0,0

latency : target=0, window=0, percentile=100.00%, depth=16

Run status group 0 (all jobs):

READ: bw=2720KiB/s (2785kB/s), 2720KiB/s-2720KiB/s (2785kB/s-2785kB/s), io=159MiB (167MB), run=60011-60011msec

WRITE: bw=2713KiB/s (2778kB/s), 2713KiB/s-2713KiB/s (2778kB/s-2778kB/s), io=159MiB (167MB), run=60011-60011msec

Disk stats (read/write):

sdd: ios=40795/40692, merge=0/9, ticks=375308/568708, in_queue=891648, util=99.53%

If no errors are reported in the output then PV has been correctly configured and is operating as expected.

See Also

• Installation
• Configuration