[Zipkin] 将数据持久化到elasticsearch，并在istio-k8s中运行

zipkin自带支持elasticsearch数据库，所以只要修改两个环境变量STORAGE_TYPE和ES_HOSTS就好了；

但是只运行zipkin会发现没法看到依赖图，elasticsearch里面也只有span的信息，没有dependencies的数据，还需要运行zipkin-dependencies镜像：

---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: zipkin
  namespace: istio-system
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: zipkin
      annotations:
        sidecar.istio.io/inject: "false"
    spec:
      containers:
      - name: zipkin
        image: docker.io/openzipkin/zipkin:latest
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 9411
        env:
        - name: STORAGE_TYPE
          value: elasticsearch
        - name: ES_HOSTS
          value: elasticsearch.logging:9200
        - name: POD_NAMESPACE
          valueFrom:
            fieldRef:
              apiVersion: v1
              fieldPath: metadata.namespace

---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: zipkin-dependencies
  namespace: istio-system
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: zipkin-dependencies
      annotations:
        sidecar.istio.io/inject: "false"
    spec:
      containers:
      - name: zipkin
        image: openzipkin/zipkin-dependencies:1.9.2
        imagePullPolicy: IfNotPresent
        env:
        - name: STORAGE_TYPE
          value: elasticsearch
        - name: ES_HOSTS
          value: elasticsearch.logging:9200
        - name: ES_INDEX
          value: zipkin
        - name: POD_NAMESPACE
          valueFrom:
            fieldRef:
              apiVersion: v1
              fieldPath: metadata.namespace
---
apiVersion: v1
kind: List
items:
- apiVersion: v1
  kind: Service
  metadata:
    name: zipkin
    namespace: istio-system
  spec:
    type: NodePort
    ports:
    - name: http
      port: 9411
      nodePort: 30005
    selector:
      app: zipkin
- apiVersion: v1
  kind: Service
  metadata:
    name: zipkin-dependencies
    namespace: istio-system
  spec:
    ports:
    - name: http
      port: 9412
    selector:
      app: zipkin-dependencies
---

* 另外，发现如果不加zipkin-dependencies的service（因为感觉它并不对外提供port访问，所以一开始没加spec.ports，但是部署时提示service必须明确spec.ports才能创建，所以我把service删了），zipkin-dependencies的pod运行会报错，我也不知道为什么，所以就随便指定了一个9412的端口给它，运行成功后发现它其实在不停重启？貌似是隔一段时间分析一下依赖，然后把依赖关系发到elasticsearch然后就completed了？有哪位旁友弄懂了这个zipkin-dependencies是怎么运行的，务必留言解答一下！

最后的elasticsearch会多出两个index：zipkin-span和zipkin-dependencies