mount-volume-from-configmap.md

Mount Volume from Config Map

This is step by step tutorial to mount volume from config map. this tutorial will use my spring-boot-sample apps

Prerequisite Steps:

$ oc login $OCP_SERVER
$ oc new-project erfin-demo
$ oc project erfin-demo
$ oc new-app quay.io/efeluzy/spring-boot-sample

Step 1 : Create your custom configuration

Create your custom configuration file on your local workstation.

$ mkdir myconfig
$ touch myconfig/my-application.properties
$ vim myconfig/my-application.properties
....
server.port=9090

....

Step 2 : Create ConfigMap on ocp

$ oc create configmap erfin-config --from-file=myconfig/

Validate new configmap

$ oc describe configmap erfin-config

Step 3 : Mount ConfigMap as Volume

$ oc set volume deployment/spring-boot-sample \
    --add \
    --type=configmap \
    --configmap-name=erfin-config \
    --mount-path=/myconfig

This step will mount configmap on pods at /myconfig folder. check deployment

$ oc describe deployment/spring-boot-sample

...

spring-boot-sample:
    Image:        quay.io/efeluzy/spring-boot-sample@sha256:3e02091f772c664b46599959b7268f70a24dc5c3bfa21248a2b7608356dc2a39
    Port:         8080/TCP
    Host Port:    0/TCP
    Environment:  <none>
    Mounts:
      /myconfig from volume-h7crg (rw)

Check myconfig on pods:

$ oc get pods
$ oc rsh spring-boot-sample-xxxx-xxxx
$ ls -ltr /myconfig

...
total 0
lrwxrwxrwx    1 root     root            32 Jul 29 05:35 my-application.properties -> ..data/my-application.properties