k8s部署cassandra集群

Apache Cassandra 是一个可大规模扩展的开源 NoSQL 数据库。Cassandra 非常适合管理跨多个数据中心和云的大量结构化、半结构化和非结构化数据。
Access-server 则是通过akka框架实现了去中心化的集群，也同样适合使用Kubernetes进行集群部署。
利用 Kubernetes 提供的服务能力，比如 PersistentVolume 和 StatefulSet，我们可以提供一种具有容灾能力的 Cassandra和Access-server 安装，并确保它的数据（状态）是安全的。

1、创建pv

[root@localhost cassandra]# cat local-volumes.yaml 
apiVersion: v1
kind: PersistentVolume
metadata:
  name: cassandra-storage-1
  labels:
    type: local
    app: cassandra
spec:
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: /tmp/data/cassandra-storage-1
  persistentVolumeReclaimPolicy: Recycle
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: cassandra-storage-2
  labels:
    type: local
    app: cassandra
spec:
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: /tmp/data/cassandra-storage-2
  persistentVolumeReclaimPolicy: Recycle
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: cassandra-storage-3
  labels:
    type: local
    app: cassandra
spec:
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: /tmp/data/cassandra-data-3
  persistentVolumeReclaimPolicy: Recycle

2、创建svc

[root@localhost test]# cat cassandra-service.yaml 
apiVersion: v1
kind: Service
metadata:
  name: cassandra
  labels:
    app: cassandra
spec:
  clusterIP: None
  ports:
    - port: 9042
  selector:
    app: cassandra

3、创建cassandra StatefulSet

[root@localhost test]# cat cassandta-statefulset.yaml 
---
apiVersion: "apps/v1beta1"
kind: StatefulSet
metadata:
  name: cassandra
spec:
  serviceName: cassandra
  replicas: 3
  template:
    metadata:
      labels:
        app: cassandra
    spec:
      containers:
        - name: cassandra
          image: cassandra:3.11
          imagePullPolicy: IfNotPresent
          resources:
            requests:
              memory: "1Gi"
              cpu: "0.5"
            limits:
              memory: "1Gi"
              cpu: "0.5"
          securityContext:
            capabilities:
              add:
                - IPC_LOCK
          lifecycle:
            preStop:
              exec:
                command:
                - /bin/sh
                - -c
                - nodetool drain
          ports:
            - containerPort: 7000
              name: intra-node
            - containerPort: 7001
              name: tls-intra-node
            - containerPort: 7199
              name: jmx
            - containerPort: 9042
              name: cql
          env:
            - name: CASSANDRA_SEEDS
              value: "cassandra-0.cassandra.default.svc.cluster.local,cassandra-1.cassandra.default.svc.cluster.local,cassandra-2.cassandra.default.svc.cluster.local"
            - name: MAX_HEAP_SIZE
              value: 512M
            - name: HEAP_NEWSIZE
              value: 100M
            - name: CASSANDRA_CLUSTER_NAME
              value: "cx"
            - name: CASSANDRA_DC
              value: "DC1"
            - name: CASSANDRA_RACK
              value: "Rack1"
            - name: CASSANDRA_ENDPOINT_SNITCH
              value: GossipingPropertyFileSnitch
          volumeMounts:
            - name: cassandra-storage
              mountPath: /var/lib/cassandra
  volumeClaimTemplates:
    - metadata:
        name: cassandra-storage
        annotations:  # comment line if you want to use a StorageClass
          # or specify which StorageClass
          volume.beta.kubernetes.io/storage-class: ""   # comment line if you
          # want to use a StorageClass or specify which StorageClass
      spec:
        accessModes: ["ReadWriteOnce"]
        resources:
          requests:
            storage: 10Gi