Duration: 5:00
We have seem that ReplicationControllers keep the same ammount of replicas running. Let’s check the number of pods again. Execute:
[vagrant@rhel-cdk kubernetes]$ kubectl get pods
NAME READY STATUS RESTARTS AGE
frontend-ui-6jy22 1/1 Running 0 24m
frontend-ui-7tcgx 1/1 Running 0 24m
guestbook-service-gxjnx 1/1 Running 0 19m
helloworld-service-vertx-edux9 1/1 Running 0 20m
helloworld-service-vertx-lq1m0 1/1 Running 0 21m
mysql-q9k7p 1/1 Running 0 21m
Scaling the number of replicas of our Hello World service is as simple as running :
[vagrant@rhel-cdk kubernetes]$ kubectl scale rc helloworld-service-vertx --replicas=6
replicationcontroller "helloworld-service-vertx" scaled
You can very quickly see that the replication controller has been updated:
[vagrant@rhel-cdk kubernetes]$ kubectl get rc
CONTROLLER CONTAINER(S) IMAGE(S) SELECTOR REPLICAS AGE
frontend-ui frontend-ui rafabene/microservices-frontend:1.0 app=frontend-ui 2 8m
guestbook-service guestbook-service rafabene/microservices-guestbook:1.0 app=guestbook-service,lab=kubernetes-lab 1 2m
helloworld-service-vertx helloworld-service-vertx rafabene/microservices-helloworld-vertx:1.0 app=helloworld-service-vertx,lab=kubernetes-lab 6 3m
mysql mysql openshift/mysql-56-centos7 app=mysql,lab=kubernetes-lab 1 4m
[vagrant@rhel-cdk kubernetes]$ kubectl get pods
NAME READY STATUS RESTARTS AGE
frontend-ui-6jy22 1/1 Running 0 26m
frontend-ui-7tcgx 1/1 Running 0 26m
guestbook-service-gxjnx 1/1 Running 0 22m
helloworld-service-vertx-1rdd4 0/1 ContainerCreating 0 2s
helloworld-service-vertx-cbevk 0/1 ContainerCreating 0 2s
helloworld-service-vertx-edux9 1/1 Running 0 22m
helloworld-service-vertx-lq1m0 1/1 Running 0 23m
helloworld-service-vertx-lt0k9 0/1 ContainerCreating 0 2s
helloworld-service-vertx-t8z4i 0/1 ContainerCreating 0 2s
mysql-q9k7p 1/1 Running 0 23m
Reduce the number of replicas back to 2 so that we can free up resources for the later labs:
[vagrant@rhel-cdk kubernetes]$ kubectl scale rc helloworld-service-vertx --replicas=2