手把手教你在 Kubernetes 上部署 Redis 高可用集群 |
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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，而将数据库完全保存在内存中。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。 为什么使用 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 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。 在 Kubernetes 中部署 Redis 集群在Kubernetes中部署Redis集群面临挑战，因为每个 Redis 实例都依赖于一个配置文件，该文件可以跟踪其他集群实例及其角色。为此，我们需要结合使用Kubernetes StatefulSets和PersistentVolumes。 克隆部署文件代码语言：javascript复制git clone https://github.com/llmgo/redis-sts.git创建 statefulset 类型资源代码语言：javascript复制[root@node01 redis-sts]# cat redis-sts.yml --- apiVersion: v1 kind: ConfigMap metadata: name: redis-cluster data: update-node.sh: | #!/bin/sh REDIS_NODES="/data/nodes.conf" sed -i -e "/myself/ s/[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}/${POD_IP}/" ${REDIS_NODES} exec "$@" redis.conf: |+ cluster-enabled yes cluster-require-full-coverage no cluster-node-timeout 15000 cluster-config-file /data/nodes.conf cluster-migration-barrier 1 appendonly yes protected-mode no --- apiVersion: apps/v1 kind: StatefulSet metadata: name: redis-cluster spec: serviceName: redis-cluster replicas: 6 selector: matchLabels: app: redis-cluster template: metadata: labels: app: redis-cluster spec: containers: - name: redis image: redis:5.0.5-alpine ports: - containerPort: 6379 name: client - containerPort: 16379 name: gossip command: ["/conf/update-node.sh", "redis-server", "/conf/redis.conf"] env: - name: POD_IP valueFrom: fieldRef: fieldPath: status.podIP volumeMounts: - name: conf mountPath: /conf readOnly: false - name: data mountPath: /data readOnly: false volumes: - name: conf configMap: name: redis-cluster defaultMode: 0755 volumeClaimTemplates: - metadata: name: data spec: accessModes: [ "ReadWriteOnce" ] resources: requests: storage: 5Gi storageClassName: standard $ kubectl apply -f redis-sts.yml configmap/redis-cluster created statefulset.apps/redis-cluster created $ kubectl get pods -l app=redis-cluster NAME READY STATUS RESTARTS AGE redis-cluster-0 1/1 Running 0 53s redis-cluster-1 1/1 Running 0 49s redis-cluster-2 1/1 Running 0 46s redis-cluster-3 1/1 Running 0 42s redis-cluster-4 1/1 Running 0 38s redis-cluster-5 1/1 Running 0 34s创建 service代码语言：javascript复制[root@node01 redis-sts]# cat redis-svc.yml --- apiVersion: v1 kind: Service metadata: name: redis-cluster spec: type: ClusterIP clusterIP: 10.96.0.100 ports: - port: 6379 targetPort: 6379 name: client - port: 16379 targetPort: 16379 name: gossip selector: app: redis-cluster $ kubectl apply -f redis-svc.yml service/redis-cluster created $ kubectl get svc redis-cluster NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE redis-cluster ClusterIP 10.96.0.100 6379/TCP,16379/TCP 35s初始化 redis cluster下一步是形成Redis集群。为此，我们运行以下命令并键入yes以接受配置。前三个节点成为主节点，后三个节点成为从节点。 代码语言：javascript复制$ kubectl exec -it redis-cluster-0 -- redis-cli --cluster create --cluster-replicas 1 $(kubectl get pods -l app=redis-cluster -o jsonpath='{range.items[*]}{.status.podIP}:6379 ') >>> Performing hash slots allocation on 6 nodes... Master[0] -> Slots 0 - 5460 Master[1] -> Slots 5461 - 10922 Master[2] -> Slots 10923 - 16383 Adding replica 10.244.2.11:6379 to 10.244.9.19:6379 Adding replica 10.244.9.20:6379 to 10.244.6.10:6379 Adding replica 10.244.8.15:6379 to 10.244.7.8:6379 M: 00721c43db194c8f2cacbafd01fd2be6a2fede28 10.244.9.19:6379 slots:[0-5460] (5461 slots) master M: 9c36053912dec8cb20a599bda202a654f241484f 10.244.6.10:6379 slots:[5461-10922] (5462 slots) master M: 2850f24ea6367de58fb50e632fc56fe4ba5ef016 10.244.7.8:6379 slots:[10923-16383] (5461 slots) master S: 554a58762e3dce23ca5a75886d0ccebd2d582502 10.244.8.15:6379 replicates 2850f24ea6367de58fb50e632fc56fe4ba5ef016 S: 20028fd0b79045489824eda71fac9898f17af896 10.244.2.11:6379 replicates 00721c43db194c8f2cacbafd01fd2be6a2fede28 S: 87e8987e314e4e5d4736e5818651abc1ed6ddcd9 10.244.9.20:6379 replicates 9c36053912dec8cb20a599bda202a654f241484f Can I set the above configuration? (type 'yes' to accept): yes >>> Nodes configuration updated >>> Assign a different config epoch to each node >>> Sending CLUSTER MEET messages to join the cluster Waiting for the cluster to join ... >>> Performing Cluster Check (using node 10.244.9.19:6379) M: 00721c43db194c8f2cacbafd01fd2be6a2fede28 10.244.9.19:6379 slots:[0-5460] (5461 slots) master 1 additional replica(s) M: 9c36053912dec8cb20a599bda202a654f241484f 10.244.6.10:6379 slots:[5461-10922] (5462 slots) master 1 additional replica(s) S: 87e8987e314e4e5d4736e5818651abc1ed6ddcd9 10.244.9.20:6379 slots: (0 slots) slave replicates 9c36053912dec8cb20a599bda202a654f241484f S: 554a58762e3dce23ca5a75886d0ccebd2d582502 10.244.8.15:6379 slots: (0 slots) slave replicates 2850f24ea6367de58fb50e632fc56fe4ba5ef016 S: 20028fd0b79045489824eda71fac9898f17af896 10.244.2.11:6379 slots: (0 slots) slave replicates 00721c43db194c8f2cacbafd01fd2be6a2fede28 M: 2850f24ea6367de58fb50e632fc56fe4ba5ef016 10.244.7.8:6379 slots:[10923-16383] (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.验证集群代码语言：javascript复制[root@node01 redis-sts]# kubectl exec -it redis-cluster-0 -- redis-cli cluster info 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:6 cluster_my_epoch:1 cluster_stats_messages_ping_sent:16 cluster_stats_messages_pong_sent:22 cluster_stats_messages_sent:38 cluster_stats_messages_ping_received:17 cluster_stats_messages_pong_received:16 cluster_stats_messages_meet_received:5 cluster_stats_messages_received:38 [root@node01 redis-sts]# for x in $(seq 0 5); do echo "redis-cluster-$x"; kubectl exec redis-cluster-$x -- redis-cli role; echo; done redis-cluster-0 master 14 10.244.2.11 6379 14 redis-cluster-1 master 28 10.244.9.20 6379 28 redis-cluster-2 master 28 10.244.8.15 6379 28 redis-cluster-3 slave 10.244.7.8 6379 connected 28 redis-cluster-4 slave 10.244.9.19 6379 connected 14 redis-cluster-5 slave 10.244.6.10 6379 connected 28测试集群我们想使用集群，然后模拟节点的故障。对于前一项任务，我们将部署一个简单的 Python 应用程序，而对于后者，我们将删除一个节点并观察集群行为。 部署点击计数器应用我们将一个简单的应用程序部署到集群中，并在其前面放置一个负载平衡器。此应用程序的目的是在将计数器值作为 HTTP 响应返回之前，增加计数器并将其存储在 Redis 集群中。 代码语言：javascript复制$ kubectl apply -f app-deployment-service.yml service/hit-counter-lb created deployment.apps/hit-counter-app created在此过程中，如果我们继续加载页面，计数器将继续增加，并且在删除Pod之后，我们看到没有数据丢失。 代码语言：javascript复制$ curl `kubectl get svc hit-counter-lb -o json|jq -r .spec.clusterIP` I have been hit 20 times since deployment. $ curl `kubectl get svc hit-counter-lb -o json|jq -r .spec.clusterIP` I have been hit 21 times since deployment. $ curl `kubectl get svc hit-counter-lb -o json|jq -r .spec.clusterIP` I have been hit 22 times since deployment. $ kubectl delete pods redis-cluster-0 pod "redis-cluster-0" deleted $ kubectl delete pods redis-cluster-1 pod "redis-cluster-1" deleted $ curl `kubectl get svc hit-counter-lb -o json|jq -r .spec.clusterIP` I have been hit 23 times since deployment.参考文档[redis-cluster集群配置1] http://llmgo.cn/post/redis-003/[redis-cluster集群配置2] http://www.yunweipai.com/36338.html[Redis集群 cluster-slot操作指令] https://blog.csdn.net/shuyun123456789/article/details/60868718本文转载自：「博客园」，原文：http://tinyurl.com/vpihglin，版权归原作者所有。欢迎投稿，投稿邮箱: [email protected]。 |
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