a) Scaling Up/Down OID Pods

Introduction

This section describes how to increase or decrease the number of OID pods in the Kubernetes deployment.

View existing OID pods

By default the oid helm chart deployment starts two pods: oidhost1 and oidhost2.

The number of pods started is determined by the replicaCount, which is set to 1 by default. A value of 1 starts the two pods above.

To scale up or down the number of OID pods, set replicaCount accordingly.

Run the following command to view the number of pods in the OID deployment:

$ kubectl --namespace <namespace> get pods -o wide

For example:

$ kubectl --namespace oidns get pods -o wide

The output will look similar to the following:

NAME           READY   STATUS    RESTARTS   AGE   IP             NODE            NOMINATED NODE   READINESS GATES
pod/oidhost1   1/1     Running   0          34m   10.244.0.195   <Worker Node>   <none>           <none>
pod/oidhost2   1/1     Running   0          34m   10.244.0.194   <Worker Node>   <none>           <none>

Scaling up OID pods

In this example, replicaCount is increased to 2 which creates a new OID pod oidhost3 with associated services created.

You can scale up the number of OID pods using one of the following methods:

  1. Using a YAML file
  2. Using --set argument

Using a YAML file

  1. Navigate to the $WORKDIR/kubernetes/helm directory:

    $ cd $WORKDIR/kubernetes/helm

  2. Create a oid-scaleup-override.yaml file that contains:

    replicaCount: 2

  3. Run the following command to scale up the OID pods:

    $ helm upgrade --namespace <namespace> \
--values oid-scaleup-override.yaml \
<release_name> oid --reuse-values

    For example:

    $ helm upgrade --namespace oidns \
--values oid-scaleup-override.yaml \
oid oid --reuse-values

Using --set argument

  1. Run the following command to scale up the OID pods:

    $ helm upgrade --namespace <namespace> \
--set replicaCount=2 \
<release_name> oid --reuse-values

    For example:

    $ helm upgrade --namespace oidns \
--set replicaCount=2 \
oid oid --reuse-values

Verify the pods

  1. Verify the new OID pod oidhost3 and has started:

    $ kubectl get pod,service -o wide -n <namespace>

    For example:

    $ kubectl get pods -n oidns

    The output will look similar to the following:

    NAME           READY   STATUS    RESTARTS   AGE     IP           NODE            NOMINATED NODE   READINESS GATES
pod/oidhost1   1/1     Running   0          45m   10.244.0.194   <Worker Node>   <none>           <none>
pod/oidhost2   1/1     Running   0          45m   10.244.0.193   <Worker Node>   <none>           <none>
pod/oidhost3   1/1     Running   0          17m   10.244.0.195   <Worker Node>   <none>           <none>
     
NAME                   TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)                               AGE
service/oid-lbr-ldap   ClusterIP   10.110.118.113   <none>        3060/TCP,3131/TCP                     45m
service/oidhost1       ClusterIP   10.97.17.125     <none>        3060/TCP,3131/TCP,7001/TCP,7002/TCP   45m
service/oidhost2       ClusterIP   10.106.32.187    <none>        3060/TCP,3131/TCP                     45m
service/oidhost3       ClusterIP   10.105.33.184    <none>        3060/TCP,3131/TCP                     17m

    Note: It will take several minutes before all the services listed above show. While the oidhost3 pod has a STATUS of 0/1 the pod is started but the OID server associated with it is currently starting. While the pod is starting you can check the startup status in the pod log, by running the following command:

    $ kubectl logs oidhost3 -n oidns

Scaling down OID pods

Scaling down OID pods is performed in exactly the same as in Scaling up OID pods except the replicaCount is reduced to the required number of pods.

Once the kubectl command is executed the pod(s) will move to a Terminating state. In the example below replicaCount was reduced from 2 to 1 and hence oidhost3 has moved to Terminating:

$ kubectl get pods -n oidns
   
NAME           READY   STATUS        RESTARTS   AGE   IP             NODE            NOMINATED NODE   READINESS GATES
pod/oidhost1   1/1     Running       0          49m   10.244.0.194   <Worker Node>   <none>           <none>
pod/oidhost2   1/1     Running       0          49m   10.244.0.193   <Worker Node>   <none>           <none>
pod/oidhost3   1/1     Terminating   0          21m   10.244.0.195   <Worker Node>   <none>           <none>

The pod will take a minute or two to stop and then will disappear:

$ kubectl get pods -n oidns
   
NAME           READY   STATUS        RESTARTS   AGE   IP             NODE            NOMINATED NODE   READINESS GATES
pod/oidhost1   1/1     Running       0          51m   10.244.0.194   <Worker Node>   <none>           <none>
pod/oidhost2   1/1     Running       0          51m   10.244.0.193   <Worker Node>   <none>           <none>