Verifying HPA

15.5 Verifying HPA

To verify the Horizontal Pod Autoscaler (HPA) works, perform the following steps:

Check the current status of the Oracle Identity Governance (OIG) servers:

kubectl get pods -n oigns

The output will look similar to the following:

NAME                                                        READY   STATUS      RESTARTS   AGE
governancedomain-adminserver                                1/1     Running     0          20m
governancedomain-oim-server1                                1/1     Running     0          17m
governancedomain-soa-server1                                1/1     Running     0          17m

In the above example only governancedomain-oim-server1 is running.

To test HPA can scale up the WebLogic cluster governancedomain-oim-cluster, run the following commands:
```
kubectl exec --stdin --tty governancedomain-oim-server1 -n oigns -- /bin/bash
```
This will take you inside a bash shell inside the oim_server1 pod:
```
[oracle@governancedomain-oim-server1 oracle]$
```
Inside the bash shell, run the following command to increase the load on the CPU:
```
[oracle@governancedomain-oim-server1 oracle]$ dd if=/dev/zero of=/dev/null
```
This command will continue to run in the foreground.
In a command window outside the bash shell, run the following command to view the current CPU usage:
```
kubectl get hpa -n oigns
```
The output will look similar to the following:
```
NAME                               REFERENCE                              TARGETS    MINPODS   MAXPODS   REPLICAS   AGE
governancedomain-oim-cluster-hpa   Cluster/governancedomain-oim-cluster   386%/70%   1         5         1          2m47s
```
In the above example the CPU has increased to 386%. As this is above the 70% limit, the autoscaler increases the replicas on the Cluster resource, and the operator responds by starting additional cluster members.

Run the following to see if any more OIG Managed Servers are started:

kubectl get pods -n oigns

The output will look similar to the following:

NAME                                                        READY   STATUS      RESTARTS      AGE
governancedomain-adminserver                                1/1     Running     0          30m
governancedomain-oim-server1                                1/1     Running     0          27m
governancedomain-oim-server2                                1/1     Running     0          10m
governancedomain-oim-server3                                1/1     Running     0          10m
governancedomain-oim-server4                                1/1     Running     0          10m
governancedomain-oim-server5                                1/1     Running     0          10m
governancedomain-soa-server1                                1/1     Running     0          27m

In the example above four more OIG managed servers have been started (oig-server2 - oig-server5).

Note:

It may take some time for the server to appear and start. Once the servers are at READY status of 1/1, the servers are started.

To stop the load on the CPU, in both bash shells, issue a Control C, and then exit the bash shell:

[oracle@governancedomain-oim-server1 oracle]$ dd if=/dev/zero of=/dev/null
^C
[oracle@governancedomain-oim-server1 oracle]$ exit

Run the following command to view the current CPU usage:

kubectl get hpa -n oigns

The output will look similar to the following:

NAME                               REFERENCE                              TARGETS   MINPODS   MAXPODS   REPLICAS   AGE
governancedomain-oim-cluster-hpa   Cluster/governancedomain-oim-cluster   33%/70%   1         5         5          37m

In the above example CPU has dropped to 33%. As this is below the 70% threshold, you should see the autoscaler scale down the servers:

kubectl get pods -n oigns

The output will look similar to the following:

NAME                                                        READY   STATUS        RESTARTS      AGE
governancedomain-adminserver                                1/1     Running       0             43m
governancedomain-oim-server1                                1/1     Running       0             40m
governancedomain-oim-server2                                1/1     Running       0             13m
governancedomain-oim-server3                                1/1     Running       0             13m
governancedomain-oim-server4                                1/1     Running       0             13m
governancedomain-oim-server5                                0/1     Terminating   0             13m
governancedomain-soa-server1                                1/1     Running       0             40m

Eventually, all the servers except oim-server1 will disappear:

NAME                                                     READY   STATUS        RESTARTS      AGE
governancedomain-adminserver                             1/1     Running       0             44m
governancedomain-oim-server1                             1/1     Running       0             41m
governancedomain-soa-server1                             1/1     Running       0             41m