在Kubernetes集群上部署redis集群

左手的ㄟ右手 2022-05-10 10:58 525阅读 0赞

# 一、实验环境 #

操作系统：CentOS Linux release 7.2.1511 (Core)

GlusterFS： 4.1

redis：4.9.105

# docker pull redis:5.0-rc5-alpine3.8  // 官方镜像
    # docker pull racccosta/redis    // redis集群构建工具

docker版本

# docker version
    Client:
     Version:      1.12.3
     API version:  1.24
     Go version:   go1.6.3
     Git commit:   6b644ec
     Built:        
     OS/Arch:      linux/amd64

# 二、方案思路 #

每个Master都可以拥有多个Slave。当Master下线后，Redis集群会从多个Slave中选举出一个新的Master作为替代，而旧Master重新上线后变成新Master的Slave。

![image][]

# 三、部署过程 #

1.  创建GlusterFS存储
2.  创建PV

## 创建GlusterFS存储 ##

打算创建一个6节点的Redis集群，所以共享了6个目录。

#!/bin/bash
    for loop in 0 1 2 3 4 5
    do
    gluster volume create redis-vol-$loop replica 3 paasm1:/dcos/redis-brick/pv$loop paasm2:/dcos/redis-brick/pv$loop paashar:/dcos/redis-brick/pv$loop;
    gluster volume start redis-vol-$loop;
    done

## 创建GlusterFS端点定义 ##

# vi glusterfs-endpoints.yml

---
    kind: Endpoints
    apiVersion: v1
    metadata:
      name: glusterfs-cluster
      namespace: kube-system
    subsets:
    - addresses:
      - ip: 10.142.71.120
      ports:
      - port: 7096
    - addresses:
      - ip: 10.142.71.121
      ports:
      - port: 7096
    - addresses:
      - ip: 10.142.71.123
      ports:
      - port: 7096

# kubectl apply -f glusterfs-endpoints.yml

## 配置 service ##

# vi glusterfs-service.yml

---
    kind: Service
    apiVersion: v1
    metadata:
      name: glusterfs-cluster
      namespace: kube-system
    spec:
      ports:
      - port: 7096

# kubectl apply -f glusterfs-service.yml

## 创建PV ##

每一个Redis Pod都需要一个独立的PV来存储自己的数据，因此包含6个PV：

# vi glusterfs-pv.yml

apiVersion: v1
    kind: PersistentVolume
    metadata:
      name: pv000
      namespace: kube-system
    spec:
      capacity:
        storage: 2Gi
      accessModes:
        - ReadWriteMany
      glusterfs:
        endpoints: "glusterfs-cluster"
        path: "redis-vol-0"
        readOnly: false
    
    ---
    apiVersion: v1
    kind: PersistentVolume
    metadata:
      name: pv001
      namespace: kube-system
    spec:
      capacity:
        storage: 2Gi
      accessModes:
        - ReadWriteMany
      glusterfs:
        endpoints: "glusterfs-cluster"
        path: "redis-vol-1"
        readOnly: false
        
    ---
    apiVersion: v1
    kind: PersistentVolume
    metadata:
      name: pv002
      namespace: kube-system
    spec:
      capacity:
        storage: 2Gi
      accessModes:
        - ReadWriteMany
      glusterfs:
        endpoints: "glusterfs-cluster"
        path: "redis-vol-2"
        readOnly: false
        
        
    ---
    apiVersion: v1
    kind: PersistentVolume
    metadata:
      name: pv003
      namespace: kube-system
    spec:
      capacity:
        storage: 2Gi
      accessModes:
        - ReadWriteMany
      glusterfs:
        endpoints: "glusterfs-cluster"
        path: "redis-vol-3"
        readOnly: false
        
    ---
    apiVersion: v1
    kind: PersistentVolume
    metadata:
      name: pv004
      namespace: kube-system
    spec:
      capacity:
        storage: 2Gi
      accessModes:
        - ReadWriteMany
      glusterfs:
        endpoints: "glusterfs-cluster"
        path: "redis-vol-4"
        readOnly: false
    
    ---
    apiVersion: v1
    kind: PersistentVolume
    metadata:
      name: pv005
      namespace: kube-system
    spec:
      capacity:
        storage: 2Gi
      accessModes:
        - ReadWriteMany
      glusterfs:
        endpoints: "glusterfs-cluster"
        path: "redis-vol-5"
        readOnly: false

# kubectl apply -f glusterfs-pv.yml

## 创建Headless service ##

# vi redis-service.yml

apiVersion: v1
    kind: Service
    metadata:
      name: redis-service
      namespace: kube-system
      labels:
        app: redis
    spec:
      ports:
      - name: redis-port
        port: 6379
      clusterIP: None
      selector:
        app: redis
        appCluster: redis-cluster

# kubectl apply -f redis-service.yml

## 创建Redis 集群 ##

# vi redis.yml

apiVersion: apps/v1beta1
    kind: StatefulSet
    metadata:
      name: redis-app
      namespace: kube-system
    spec:
      serviceName: "redis-service"
      replicas: 6
      template:
        metadata:
          labels:
            app: redis
            appCluster: redis-cluster
        spec:
          terminationGracePeriodSeconds: 20
          affinity:
            podAntiAffinity:
              preferredDuringSchedulingIgnoredDuringExecution:
              - weight: 100
                podAffinityTerm:
                  labelSelector:
                    matchExpressions:
                    - key: app
                      operator: In
                      values:
                      - redis
                  topologyKey: kubernetes.io/hostname
          containers:
          - name: redis
            image: hub.cmss.com:5000/registry.paas/library/redis:5.0
            command:
              - "redis-server"
            args:
              - "--protected-mode"
              - "no"
              - "--cluster-enabled"
              - "yes"
              - "--appendonly"
              - "yes"
            resources:
              requests:
                cpu: "100m"
                memory: "100Mi"
            ports:
                - name: redis
                  containerPort: 6379
                  protocol: "TCP"
                - name: cluster
                  containerPort: 16379
                  protocol: "TCP"
            volumeMounts:
              - name: "redis-data"
                mountPath: "/data"
      volumeClaimTemplates:
      - metadata:
          name: redis-data
        spec:
          accessModes: ["ReadWriteMany"]
          resources:
            requests:
              storage: 2Gi

# kubectl apply -f redis.yml

总共创建了6个Redis节点(Pod)，其中3个将用于master，另外3个分别作为master的slave

Redis的数据存储路径使用volumeClaimTemplates声明, 其会绑定到我们先前创建的PV上

# kubectl get pv -n kube-system

可以看到之前创建的6个PV都被绑定

NAME      CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS    CLAIM                                STORAGECLASS   REASON    AGE
    pv000     2Gi        RWX            Retain           Bound     kube-system/redis-data-redis-app-2                            1h
    pv001     2Gi        RWX            Retain           Bound     kube-system/redis-data-redis-app-3                            1h
    pv002     2Gi        RWX            Retain           Bound     kube-system/redis-data-redis-app-4                            1h
    pv003     2Gi        RWX            Retain           Bound     kube-system/redis-data-redis-app-5                            1h
    pv004     2Gi        RWX            Retain           Bound     kube-system/redis-data-redis-app-0                            1h
    pv005     2Gi        RWX            Retain           Bound     kube-system/redis-data-redis-app-1                            1h

## 初始化Redis集群 ##

为了方便redis-trib的使用, 可以创建 /usr/local/bin/redis-trib 文件

#!/bin/bash
    /usr/bin/docker run -it --privileged --rm \
    --net=host \
    redis-trib:latest \
    "$@"

# chmod 777 /usr/local/bin/redis-trib

直接使用
    # redis-trib
    
    Usage: redis-trib <command> <options> <arguments ...>
    
      create          host1:port1 ... hostN:portN
                      --replicas <arg>
      check           host:port
      info            host:port
      fix             host:port
                      --timeout <arg>
      reshard         host:port
                      --from <arg>
                      --to <arg>
                      --slots <arg>
                      --yes
                      --timeout <arg>
                      --pipeline <arg>
      rebalance       host:port
                      --weight <arg>
                      --auto-weights
                      --use-empty-masters
                      --timeout <arg>
                      --simulate
                      --pipeline <arg>
                      --threshold <arg>
      add-node        new_host:new_port existing_host:existing_port
                      --slave
                      --master-id <arg>
      del-node        host:port node_id
      set-timeout     host:port milliseconds
      call            host:port command arg arg .. arg
      import          host:port
                      --from <arg>
                      --copy
                      --replace
      help            (show this help)
    
    For check, fix, reshard, del-node, set-timeout you can specify the host and port of any working node in the cluster.

查看起的应用

# kubectl get po -n kube-system -o wide |grep redis

redis-app-0                                1/1       Running   0          53s       10.222.98.88    paasm3
    redis-app-1                                1/1       Running   0          50s       10.222.88.205   paasm2
    redis-app-2                                1/1       Running   0          47s       10.222.65.206   paasm1
    redis-app-3                                1/1       Running   0          45s       10.222.92.210   paasing
    redis-app-4                                1/1       Running   0          41s       10.222.66.47    paashar
    redis-app-5                                1/1       Running   0          38s       10.222.88.206   paasm2

利用redis-trib创建集群

添加 master 节点

# redis-trib create --replicas 1 \
        10.222.98.90:6379 \
        10.222.88.208:6379 \
        10.222.65.208:6379 \
        10.222.92.213:6379 \
        10.222.66.49:6379 \
        10.222.88.209:6379

replicas 1的意思，就是每个节点创建1个副本(即：slave)

## 创建用于访问Service ##

前面我们创建了用于实现StatefulSet的Headless Service，但该Service没有Cluster Ip，因此不能用于外界访问。所以，我们还需要创建一个Service，专用于为Redis集群提供访问和负载均：

# vi redis-access-service.yml

apiVersion: v1
    kind: Service
    metadata:
      name: redis-access-service
      namespace: kube-system
      labels:
        app: redis
    spec:
      ports:
      - name: redis-port
        protocol: "TCP"
        port: 6379
        targetPort: 6379
      selector:
        app: redis
        appCluster: redis-cluster

# kubectl apply -f redis-access-service.yml

# kubectl get svc -n kube-system |grep redis-access
    
    redis-access-service       ClusterIP   10.233.11.2     <none>        6379/TCP         16h

此时在k8s集群中可以通过10.233.11.2:6379 访问redis

检查集群状态

# redis-trib check 10.233.11.2:6379

M: 7a2984e16a9911296918822eea625e9d69e5d062 10.233.11.2:6379
       slots:5461-10922 (5462 slots) master
       1 additional replica(s)
    S: 38e2c1e93aa3fc792b0c1ae4c7c9fe71a6713a0f 10.222.66.49:6379
       slots: (0 slots) slave
       replicates 7a2984e16a9911296918822eea625e9d69e5d062
    S: 9f13a91cdc81f102f1f05ef4ac7ecfd7019ea1ca 10.222.88.209:6379
       slots: (0 slots) slave
       replicates fe586bc12346bd26548f9dc909ff9c2309b6db0a
    M: fe586bc12346bd26548f9dc909ff9c2309b6db0a 10.222.65.208:6379
       slots:10923-16383 (5461 slots) master
       1 additional replica(s)
    S: 7d8f97ab405c1cb281f19feaba439b05f7e51709 10.222.92.213:6379
       slots: (0 slots) slave
       replicates c275b4cd089b000c70bcf21f6fb6f6a6f3dbb0a3
    M: c275b4cd089b000c70bcf21f6fb6f6a6f3dbb0a3 10.222.98.90:6379
       slots:0-5460 (5461 slots) master
       1 additional replica(s)
    [OK] All nodes agree about slots configuration.
    >>> Check for open slots...
    >>> Check slots coverage...
    [OK] All 16384 slots covered.

参考： [https://www.jianshu.com/p/65c4baadf5d9][https_www.jianshu.com_p_65c4baadf5d9]

[image]: /images/20220510/7b4c961600bd43509168ca3899d1b674.png
[https_www.jianshu.com_p_65c4baadf5d9]: https://www.jianshu.com/p/65c4baadf5d9