Review conflicts from 1.6-release/master merges

docs/tasks/configure-pod-container/configmap.md

@@ -305,34 +305,6 @@ SPECIAL_TYPE_KEY=charm
 log_level=INFO
 ```
 
-#### Optional ConfigMap in environment variables
-
-There might be situations where environment variables are not
-always required. These environment variables can be marked as optional in a
-pod like so:
-
-```yaml
-apiVersion: v1
-kind: Pod
-metadata:
-  name: dapi-test-pod
-spec:
-  containers:
-    - name: test-container
-      image: gcr.io/google_containers/busybox
-      command: [ "/bin/sh", "-c", "env" ]
-      env:
-        - name: SPECIAL_LEVEL_KEY
-          valueFrom:
-            configMapKeyRef:
-              name: a-config
-              key: akey
-              optional: true
-  restartPolicy: Never
-```
-
-When this pod is run, the output will be empty.
-
 ### Use-Case: Set command-line arguments with ConfigMap
 
 ConfigMaps can also be used to set the value of the command or arguments in a container.  This is
@@ -464,38 +436,6 @@ very
 You can project keys to specific paths and specific permissions on a per-file
 basis. The [Secrets](/docs/concepts/configuration/secret/) user guide explains the syntax.
 
-#### Optional ConfigMap via volume plugin
-
-Volumes and files provided by a ConfigMap can be also be marked as optional.
-The ConfigMap or the key specified does not have to exist. The mount path for
-such items will always be created.
-
-```yaml
-apiVersion: v1
-kind: Pod
-metadata:
-  name: dapi-test-pod
-spec:
-  containers:
-    - name: test-container
-      image: gcr.io/google_containers/busybox
-      command: [ "/bin/sh", "-c", "ls /etc/config" ]
-      volumeMounts:
-      - name: config-volume
-        mountPath: /etc/config
-  volumes:
-    - name: config-volume
-      configMap:
-        name: no-config
-        optional: true
-  restartPolicy: Never
-```
-
-When this pod is run, the output will be:
-
-```shell
-```
-
 ## Real World Example: Configuring Redis
 
 Let's take a look at a real-world example: configuring redis using ConfigMap.  Say that we want to inject