k8s部署redis cluster集群的实现

目录

Redis 介绍

为什么要用Redis

什么是Redis Cluster集群

k8s以StatefulSet方式部署redis cluster集群：

部署nfs

创建pv

部署redis

初始化redis集群

Redis 介绍

Redis代表REmote DIctionary Server是一种开源的内存中数据存储，通常用作数据库，缓存或消息代理。它可以存储和操作高级数据类型，例如列表，地图，集合和排序集合。

由于Redis接受多种格式的密钥，因此可以在服务器上执行操作，从而减少了客户端的工作量。

它仅将磁盘用于持久性，而将数据完全保存在内存中。

Redis是一种流行的数据存储解决方案，并被GitHub，Pinterest，Snapchat，Twitter，StackOverflow，Flickr等技术巨头所使用。

为什么要用Redis

它的速度非常快。它是用ANSI C编写的，并且可以在POSIX系统上运行，例如Linux，Mac OS X和Solaris。

Redis通常被排名为最流行的键/值数据库和最流行的与容器一起使用的NoSQL数据库。

其缓存解决方案减少了对云数据库后端的调用次数。

应用程序可以通过其客户端API库对其进行访问。

所有流行的编程语言都支持Redis。

它是开源且稳定的。

什么是Redis Cluster集群

Redis Cluster是一组Redis实例，旨在通过对数据库进行分区来扩展数据库，从而使其更具弹性。

群集中的每个成员（无论是主副本还是辅助副本）都管理哈希槽的子集。如果主机无法访问，则其从机将升级为主机。在由三个主节点组成的最小Redis群集中，每个主节点都有一个从节点（以实现最小的故障转移），每个主节点都分配有一个介于0到16,383之间的哈希槽范围。节点A包含从0到5000的哈希槽，节点B从5001到10000，节点C从10001到16383。

群集内部的通信是通过内部总线进行的，使用协议传播有关群集的信息或发现新节点。

k8s以StatefulSet方式部署redis cluster集群：

1. 部署nfs

2. 创建pv

3. 部署redis

4. 初始化redis集群

主机说明：

系统 ip 角色 cpu 内存 hostname

CentOS 7.8	192.168.30.128	master	>=2	>=2G	master1
CentOS 7.8	192.168.30.129	master	>=2	>=2G	master2
CentOS 7.8	192.168.30.130	node	>=2	>=2G	node1
CentOS 7.8	192.168.30.131	node	>=2	>=2G	node2
CentOS 7.8	192.168.30.132	node	>=2	>=2G	node3

kubectl get node NAME STATUS ROLES AGE VERSION master1 Ready master 33d v1.14.0 master2 Ready master 33d v1.14.0 node1 Ready <none> 33d v1.14.0 node2 Ready <none> 33d v1.14.0 node3 Ready <none> 33d v1.14.0 部署nfs

在master2节点上做nfs共享，

yum -y install nfs-utils rpcbind mkdir -p /data/redis/{cluster0,cluster1,cluster2,cluster3,cluster4,cluster5} vim /etc/exports /data/redis/cluster0 192.168.30.0/24(rw,sync,no_root_squash) /data/redis/cluster1 192.168.30.0/24(rw,sync,no_root_squash) /data/redis/cluster2 192.168.30.0/24(rw,sync,no_root_squash) /data/redis/cluster3 192.168.30.0/24(rw,sync,no_root_squash) /data/redis/cluster4 192.168.30.0/24(rw,sync,no_root_squash) /data/redis/cluster5 192.168.30.0/24(rw,sync,no_root_squash) chmod -R 755 /data/redis exportfs -arv systemctl enable rpcbind && systemctl start rpcbind systemctl enable nfs && systemctl start nfs

nfs部署完毕。对于需要使用nfs的node节点，都要安装nfs：

yum -y install nfs-utils 创建pv

创建pv：

mkdir -p /home/k8s/redis && cd /home/k8s/redis vim pv.yaml apiVersion: v1 kind: PersistentVolume metadata: name: nfs-pv0 spec: capacity: storage: 1Gi accessModes: - ReadWriteMany nfs: server: 192.168.30.129 path: /data/redis/cluster0 --- apiVersion: v1 kind: PersistentVolume metadata: name: nfs-pv1 spec: capacity: storage: 1Gi accessModes: - ReadWriteMany nfs: server: 192.168.30.129 path: /data/redis/cluster1 --- apiVersion: v1 kind: PersistentVolume metadata: name: nfs-pv2 spec: capacity: storage: 1Gi accessModes: - ReadWriteMany nfs: server: 192.168.30.129 path: /data/redis/cluster2 --- apiVersion: v1 kind: PersistentVolume metadata: name: nfs-pv3 spec: capacity: storage: 1Gi accessModes: - ReadWriteMany nfs: server: 192.168.30.129 path: /data/redis/cluster3 --- apiVersion: v1 kind: PersistentVolume metadata: name: nfs-pv4 spec: capacity: storage: 1Gi accessModes: - ReadWriteMany nfs: server: 192.168.30.129 path: /data/redis/cluster4 --- apiVersion: v1 kind: PersistentVolume metadata: name: nfs-pv5 spec: capacity: storage: 1Gi accessModes: - ReadWriteMany nfs: server: 192.168.30.129 path: /data/redis/cluster5 kubectl apply -f pv.yaml kubectl get pv NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE nfs-pv0 1Gi RWX Retain Available 3s nfs-pv1 1Gi RWX Retain Available 3s nfs-pv2 1Gi RWX Retain Available 3s nfs-pv3 1Gi RWX Retain Available 3s nfs-pv4 1Gi RWX Retain Available 3s nfs-pv5 1Gi RWX Retain Available 3s

pv创建完毕。

部署redis
vim namespace.yaml apiVersion: v1 kind: Namespace metadata: name: public-service vim redis.conf appendonly yes cluster-enabled yes cluster-config-file /var/lib/redis/nodes.conf cluster-node-timeout 5000 dir /var/lib/redis port 6379 vim redis.yaml apiVersion: v1 kind: Service metadata: name: redis namespace: public-service labels: app: redis spec: selector: app: redis appCluster: redis-cluster ports: - name: redis port: 6379 clusterIP: None --- apiVersion: v1 kind: Service metadata: name: redis-access namespace: public-service labels: app: redis spec: selector: app: redis appCluster: redis-cluster ports: - name: redis-access protocol: TCP port: 6379 targetPort: 6379 --- apiVersion: apps/v1 kind: StatefulSet metadata: name: redis namespace: public-service spec: serviceName: redis replicas: 6 selector: matchLabels: app: redis appCluster: redis-cluster 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: redis:latest command: - "redis-server" args: - "/etc/redis/redis.conf" - "--protected-mode" - "no" resources: requests: cpu: "500m" memory: "500Mi" ports: - containerPort: 6379 name: redis protocol: TCP - containerPort: 16379 name: cluster protocol: TCP volumeMounts: - name: conf mountPath: /etc/redis - name: data mountPath: /var/lib/redis volumes: - name: conf configMap: name: redis-conf items: - key: redis.conf path: redis.conf volumeClaimTemplates: - metadata: name: data namespace: public-service spec: accessModes: [ "ReadWriteMany" ] resources: requests: storage: 1Gi kubectl apply -f namespace.yaml kubectl create configmap redis-conf --from-file=redis.conf -n public-service kubectl apply -f redis.yaml kubectl get svc -n public-service NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE redis ClusterIP None <none> 6379/TCP 20s redis-access ClusterIP 10.96.2.100 <none> 6379/TCP 20s kubectl get pod -n public-service NAME READY STATUS RESTARTS AGE redis-0 1/1 Running 0 2m43s redis-1 1/1 Running 0 2m18s redis-2 1/1 Running 0 108s redis-3 1/1 Running 0 80s redis-4 1/1 Running 0 48s redis-5 1/1 Running 0 30s kubectl get pvc -n public-service NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE data-redis-0 Bound nfs-pv4 1Gi RWX 3m4s data-redis-1 Bound nfs-pv0 1Gi RWX 2m39s data-redis-2 Bound nfs-pv1 1Gi RWX 2m9s data-redis-3 Bound nfs-pv2 1Gi RWX 101s data-redis-4 Bound nfs-pv3 1Gi RWX 69s data-redis-5 Bound nfs-pv5 1Gi RWX 51s

redis-access这个service方便集群内访问redis集群，redis部署完毕。

初始化redis集群

使用Redis-tribe工具进行集群的初始化。

下载redis-tribe：

kubectl run -it ubuntu --image=ubuntu --restart=Never -n public-service bash root@ubuntu:/# cat > /etc/apt/sources.list << EOF deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial main restricted deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-updates main restricted deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial universe deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-updates universe deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial multiverse deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-updates multiverse deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-backports main restricted universe multiverse deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-security main restricted deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-security universe deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-security multiverse EOF root@ubuntu:/# apt-get update root@ubuntu:/# apt-get install -y libncursesw5 libreadline6 libtinfo5 --allow-remove-essential root@ubuntu:/# apt-get install -y libpython2.7-stdlib python2.7 python-pip redis-tools dnsutils root@ubuntu:/# pip install --upgrade pip root@ubuntu:/# pip install redis-trib==0.5.1

初始化集群：

root@ubuntu:/# redis-trib.py create \ `dig +short redis-0.redis.public-service.svc.cluster.local`:6379 \ `dig +short redis-1.redis.public-service.svc.cluster.local`:6379 \ `dig +short redis-2.redis.public-service.svc.cluster.local`:6379 root@ubuntu:/# redis-trib.py replicate \ --master-addr `dig +short redis-0.redis.public-service.svc.cluster.local`:6379 \ --slave-addr `dig +short redis-3.redis.public-service.svc.cluster.local`:6379 root@ubuntu:/# redis-trib.py replicate \ --master-addr `dig +short redis-1.redis.public-service.svc.cluster.local`:6379 \ --slave-addr `dig +short redis-4.redis.public-service.svc.cluster.local`:6379 root@ubuntu:/# redis-trib.py replicate \ --master-addr `dig +short redis-2.redis.public-service.svc.cluster.local`:6379 \ --slave-addr `dig +short redis-5.redis.public-service.svc.cluster.local`:6379 root@ubuntu:/# exit

查看集群：

kubectl exec -it -n public-service redis-0 bash root@redis-0:/data# redis-cli -c 127.0.0.1:6379> CLUSTER NODES #列出节点信息 aac2b3d320da67eedf3512ed0e38a1cdce5bc8fe 172.10.2.55:6379@16379 slave 7c4d60cf32685484ea6c5cb4493a937dfbf6b8a5 0 1592276224727 3 connected 2efad514b2f3c7fe4530dd6dc63c0df8ffdb793d 172.10.2.54:6379@16379 master - 0 1592276224224 1 connected 0-5461 524f03526a4b683d7d4de19296431810bfdc22cf 172.10.3.60:6379@16379 slave df5bc3c2e2851d63cdb9f762efde6e1b0d38efed 0 1592276223117 5 connected 7c4d60cf32685484ea6c5cb4493a937dfbf6b8a5 172.10.4.77:6379@16379 myself,master - 0 1592276224000 2 connected 5462-10922 df5bc3c2e2851d63cdb9f762efde6e1b0d38efed 172.10.3.59:6379@16379 master - 0 1592276223217 0 connected 10923-16383 c1dbaaef4a583e372c43eed52c22cd9ad7184d18 172.10.4.78:6379@16379 slave 2efad514b2f3c7fe4530dd6dc63c0df8ffdb793d 0 1592276223719 4 connected 127.0.0.1:6379> CLUSTER INFO #集群状态 cluster_state:ok cluster_slots_assigned:16384 cluster_slots_ok:16384 cluster_slots_pfail:0 cluster_slots_fail:0 cluster_known_nodes:6 cluster_size:3 cluster_current_epoch:5 cluster_my_epoch:2 cluster_stats_messages_ping_sent:514 cluster_stats_messages_pong_sent:491 cluster_stats_messages_meet_sent:2 cluster_stats_messages_sent:1007 cluster_stats_messages_ping_received:491 cluster_stats_messages_pong_received:516 cluster_stats_messages_received:1007

redis集群初始化完成，已经形成3主3从的cluster集群。

写入数据：

127.0.0.1:6379> SET key1 aaa OK 127.0.0.1:6379> SET key2 bbb -> Redirected to slot [4998] located at 172.10.2.54:6379 OK 172.10.2.54:6379> SET key3 ccc OK kubectl exec -it -n public-service redis-4 bash root@redis-4:/data# redis-cli -c 127.0.0.1:6379> GET key1 -> Redirected to slot [9189] located at 172.10.4.77:6379 "aaa" 172.10.4.77:6379> GET key2 -> Redirected to slot [4998] located at 172.10.2.54:6379 "bbb" 172.10.2.54:6379> GET key3 "ccc"

可以看出redis cluster集群是去中心化的，每个节点都是平等的，连接哪个节点都可以获取和设置数据。

主从切换：

选择redis-2模拟宕掉，测试主从切换，

kubectl get pod -n public-service -o wide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES redis-0 1/1 Running 0 62m 172.10.4.77 node1 <none> <none> redis-1 1/1 Running 0 62m 172.10.2.54 node2 <none> <none> redis-2 1/1 Running 0 61m 172.10.3.59 node3 <none> <none> redis-3 1/1 Running 0 61m 172.10.2.55 node2 <none> <none> redis-4 1/1 Running 0 61m 172.10.4.78 node1 <none> <none> redis-5 1/1 Running 0 61m 172.10.3.60 node3 <none> <none> ubuntu 0/1 Completed 0 57m 172.10.2.56 node2 <none> <none> kubectl exec -it -n public-service redis-2 bash root@redis-2:/data# redis-cli -c 127.0.0.1:6379> ROLE 1) "master" 2) (integer) 2898 3) 1) 1) "172.10.3.60" 2) "6379" 3) "2898"

可以看到，redis-2是master，它的slave是172.10.3.60，即redis-5。

kubectl delete pod -n public-service redis-2 #模拟节点宕掉 kubectl get pod -n public-service redis-2 -o wide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES redis-2 1/1 Running 0 38s 172.10.3.61 node3 <none> <none> kubectl exec -it -n public-service redis-2 bash root@redis-2:/data# redis-cli -c 127.0.0.1:6379> ROLE 1) "slave" 2) "172.10.3.60" 3) (integer) 6379 4) "connected" 5) (integer) 3430 kubectl exec -it -n public-service redis-5 bash root@redis-5:/data# redis-cli -c 127.0.0.1:6379> ROLE 1) "master" 2) (integer) 3584 3) 1) 1) "172.10.3.61" 2) "6379" 3) "3570" 127.0.0.1:6379> CLUSTER NODES aac2b3d320da67eedf3512ed0e38a1cdce5bc8fe 172.10.2.55:6379@16379 slave 7c4d60cf32685484ea6c5cb4493a937dfbf6b8a5 0 1592278859530 2 connected 2efad514b2f3c7fe4530dd6dc63c0df8ffdb793d 172.10.2.54:6379@16379 master - 0 1592278859000 1 connected 0-5461 c1dbaaef4a583e372c43eed52c22cd9ad7184d18 172.10.4.78:6379@16379 slave 2efad514b2f3c7fe4530dd6dc63c0df8ffdb793d 0 1592278859000 1 connected 524f03526a4b683d7d4de19296431810bfdc22cf 172.10.3.60:6379@16379 myself,master - 0 1592278857000 6 connected 10923-16383 7c4d60cf32685484ea6c5cb4493a937dfbf6b8a5 172.10.4.77:6379@16379 master - 0 1592278858021 2 connected 5462-10922 df5bc3c2e2851d63cdb9f762efde6e1b0d38efed 172.10.3.61:6379@16379 slave 524f03526a4b683d7d4de19296431810bfdc22cf 0 1592278859000 6 connected

可以看到，redis-2在重启之后变为slave，而它之前的slave——redis-5变为master，而且是新redis-2的master。

集群的主从切换没有问题。k8s部署redis cluster集群完成。

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