Resource usage instructions of K8s PVC

The support for pvc resource(mount file resources such as checkpoint/savepoint/logs and so on) is based on pod-template at current version。

Users do not have to concern the Native-Kubernetes Session.It will be processed when Session Cluster is constructed .Native-Kubernetes Application can be constructed by configuring on StreamPark webpage using pod-template、jm-pod-template、tm-pod-template.

Here is a brief example. Two PVC flink-checkpoint， flink-savepoint should be constructed in advance

‘pod-template’ can be configured as below ：

apiVersion: v1
kind: Pod
metadata:
  name: pod-template
spec:
  containers:
    - name: flink-main-container
      volumeMounts:
        - name: checkpoint-pvc
          mountPath: /opt/flink/checkpoints
        - name: savepoint-pvc
          mountPath: /opt/flink/savepoints
  volumes:
    - name: checkpoint-pvc
      persistentVolumeClaim:
        claimName: flink-checkpoint
    - name: savepoint-pvc
      persistentVolumeClaim:
        claimName: flink-savepoint

There are three ways to provide the dependency when using rocksdb-backend.

1. Flink Base Docker Image contains the dependency（user fix the dependency conflict by themself）;

2. Put the dependency flink-statebackend-rocksdb_xx.jar to the path Workspace/jars in StreamPark ;

3. Add the rockdb-backend dependency to StreamPark Dependency(StreamPark will fix the conflict automatically) ：

   

We will provide a graceful way to generate pod-template configuration to simplify the procedure of k8s-pvc mounting in future version.