This document shows the basic operations for scaling servers in OHS containers.
The default OHS deployment starts one OHS server (assuming replicas: 1 in ohs.yaml).
To view the running OHS servers, run the following command:
$ kubectl get pods -n <namespace>
For example:
$ kubectl get pods -n ohsns
The output should look similar to the following:
NAME READY STATUS RESTARTS AGE
ohs-domain-d5b648bc5-vkp4s 1/1 Running 0 5h17m
The number of OHS Servers running is dependent on the replicas parameter configured for OHS.
Run the following kubectl command to start additional OHS servers:
$ kubectl -n <namespace> patch deployment ohs-domain -p '{"spec": {"replicas": <replica count>}}'
where <replica count> is the number of OHS servers to start.
In the example below, two additional OHS servers are started:
$ kubectl -n ohsns patch deployment ohs-domain -p '{"spec": {"replicas": 3}}'
The output will look similar to the following:
deployment.apps/ohs-domain patched
Whilst the new OHS containers are being started, you can run the following command to monitor the progress:
$ kubectl get pods -n <namespace> -w
For example:
$ kubectl get pods -n ohsns -w
The output will look similar to the following:
NAME READY STATUS RESTARTS AGE
ohs-domain-d5b648bc5-2q8bw 0/1 ContainerCreating 0 26s
ohs-domain-d5b648bc5-qvdjn 0/1 Running 0 26s
ohs-domain-d5b648bc5-vkp4s 1/1 Running 0 5h21m
Two new OHS pods have now been created, in this example ohs-domain-d5b648bc5-2q8bw and ohs-domain-d5b648bc5-qvdjn.
To check what is happening while the pods are in ContainerCreating status, you can run:
$ kubectl describe pod <podname> -n <namespace>
To check what is happening while the pods are in 0/1 Running status, you can run:
$ kubectl logs -f <pod> -n <namespace>
Once everything is started you should see all the additional OHS containers are running (READY 1/1):
NAME READY STATUS RESTARTS AGE
ohs-domain-d5b648bc5-2q8bw 1/1 Running 0 9m34s
ohs-domain-d5b648bc5-qvdjn 1/1 Running 0 9m34s
ohs-domain-d5b648bc5-vkp4s 1/1 Running 0 5h30m
As mentioned in the previous section, the number of OHS servers running is dependent on the replicas parameter configured. To stop one or more OHS servers, perform the following steps:
Run the following kubectl command to scale down OHS servers:
$ kubectl -n <namespace> patch deployment ohs-domain -p '{"spec": {"replicas": <replica count>}}'
where <replica count> is the number of OHS servers you want to run.
In the example below, replicas is dropped to 1 so only one OHS is running:
$ kubectl -n ohsns patch deployment ohs-domain -p '{"spec": {"replicas": 1}}'
The output will look similar to the following:
deployment.apps/ohs-domain patched
Run the following kubectl command to view the pods:
$ kubectl get pods -n <namespace>
For example:
$ kubectl get pods -n ohsns
The output will look similar to the following:
NAME READY STATUS RESTARTS AGE
ohs-domain-d5b648bc5-2q8bw 0/1 Terminating 0 12m
ohs-domain-d5b648bc5-qvdjn 0/1 Terminating 0 12m
ohs-domain-d5b648bc5-vkp4s 1/1 Running 0 5h31m
Two pods now have a STATUS of Terminating. Keep executing the command until the pods have disappeared and you are left with the one OHS pod:
NAME READY STATUS RESTARTS AGE
ohs-domain-d5b648bc5-vkp4s 1/1 Running 0 5h32m