Merge release1.15 into master (#16535)

* initial commit

* promote AWS-NLB Support from alpha to beta (#14451) (#16459) (#16484)

* 1. Sync release-1.15 into master
2. Sync with en version

* 1. Add the lost yaml file.

* Update he cluster administration folder of concepts
1. Sync with 1.14 branch
2. Sync with en version

* Add yaml files which are used

content/zh/examples/admin/logging/two-files-counter-pod-agent-sidecar.yaml

@@ -0,0 +1,39 @@
+apiVersion: v1
+kind: Pod
+metadata:
+  name: counter
+spec:
+  containers:
+  - name: count
+    image: busybox
+    args:
+    - /bin/sh
+    - -c
+    - >
+      i=0;
+      while true;
+      do
+        echo "$i: $(date)" >> /var/log/1.log;
+        echo "$(date) INFO $i" >> /var/log/2.log;
+        i=$((i+1));
+        sleep 1;
+      done
+    volumeMounts:
+    - name: varlog
+      mountPath: /var/log
+  - name: count-agent
+    image: k8s.gcr.io/fluentd-gcp:1.30
+    env:
+    - name: FLUENTD_ARGS
+      value: -c /etc/fluentd-config/fluentd.conf
+    volumeMounts:
+    - name: varlog
+      mountPath: /var/log
+    - name: config-volume
+      mountPath: /etc/fluentd-config
+  volumes:
+  - name: varlog
+    emptyDir: {}
+  - name: config-volume
+    configMap:
+      name: fluentd-config