If you are not familiar with the oc command, refer to OpenShift - Getting Started with the oc command.
There are different ways to configure a container with environment variables.
Config Maps are used to:
Secrets are similar, used to create variables that contain encoded data (e.g. passwords). In this way, if a change is needed to a configuration file, variable, or command line option argument, you just need to update the config map or secret as opposed to having to make the change to your applications or deployments.
The oc get secret command can be used to list the secrets that have been created in the currently selected project / namespace.
~]# oc get secrets NAME TYPE DATA AGE my-secret Opaque 1 133d
The --output yaml or --output json options can be used to display the YAML or JSON details of the secret. Notice that the "foo" key contains "SGVsbG8=" and "bar" contains "V29ybGQ=". This is normal, because the secret value is base64 encoded.
~]$ oc get secrets my-secret --output yaml apiVersion: v1 data: bar: V29ybGQ= foo: SGVsbG8= kind: Secret metadata: creationTimestamp: "2021-11-18T07:12:09Z" name: mysecret namespace: default resourceVersion: "448072461" uid: 4104a646-84e2-46c3-bd59-408e2f7ee807 type: Opaque
On a Linux system, the base64 command can be used to decode the value.
~]# echo SGVsbG8= | base64 --decode Hello ~]# echo V29ybGQ= | base64 --decode World
Let's say you have a deployment named "my-deployment".
~]# oc get deployments NAME READY UP-TO-DATE AVAILABLE AGE my-deployment 1/1 1 1 8d
There are two ways to update the deployment to use the foo and bar secrets in my-secret.
The oc edit command can be used to edit the deployment.
oc edit deployment my-deployment
A secret can be made available to a container:
Here is an example of what you would have in the deployment YAML to use the value in the "foo" and "bar" keys in the secret named "my-secret".
The name of the secret, which is my-secret in this example, must be an exact match of the name of the secret returned by the oc get secrets command.
apiVersion: v1 kind: Deployment spec: template: spec: containers: - env: - name: foo-secret <- this will be the variable name/key in the container valueFrom: secretKeyRef: key: foo <- must match the key in the secret name: my-secret <- must match the secret name - name: bar-secret <- this will be the variable name/key in the container valueFrom: secretKeyRef: key: bar <- must match the key in the secret name: my-secret <- must match the secret name - image: api.openshift.example.com/myapp name: my-app
Or, envFrom can be used instead of env. With this approach, all of the variables (key/values) in the secret will be available in the container.
apiVersion: v1 kind: Deployment spec: template: spec: containers: - envFrom: - secretRef: name: my-secret <- must match secret name
Or, the oc set env command can be used.
~]$ oc set env deployment my-deployment --from secret/my-secret deployment.apps/my-deployment updated
A new pod should immediately be created after the oc edit or oc set env commands have been completed, and the oc describe pod command can be used to see that the pod is now has the "foo" and "bar" keys.
~]$ oc describe pod my-pod-65rbl Containers: my-container: Container ID: my-image Image ID: my-image Ports: 8080/TCP, 8443/TCP Host Ports: 0/TCP, 0/TCP State: Running Started: Tue, 02 Aug 2022 06:28:49 -0500 Ready: True Restart Count: 0 Environment: foo-secret: <set to the key 'foo' in secret 'my-secret'> Optional: false bar-secret: <set to the key 'bar' in secret 'my-secret'> Optional: false my-environment-variable: Hello World
The oc set env command with the --list option can be used the list the environment variables associate with a resource, such as a deployment or pod.
~]$ oc set env pod my-pod-276pc --list # pods/my-pod-276pc, container my-container # FOO from secret my-secret, key foo # BAR from secret my-secret, key bar my-environment-variable=Hello World
~]$ oc exec/my-pod-65rbl -- env foo-secret=Hello bar-secret=World