k8s实战案例之部署redis单机和redis cluster

1、在k8s上部署redis单机

1.1、redis简介

redis是一款基于BSD协议，开源的非关系型数据库（nosql数据库），作者是意大利开发者Salvatore Sanfilippo在2009年发布，使用C语言编写；redis是基于内存存储，而且是目前比较流行的键值数据库（key-value database），它提供将内存通过网络远程共享的一种服务，提供类似功能的还有memcache，但相比 memcache，redis 还提供了易扩展、高性能、具备数据持久性等功能。主要的应用场景有session共享，常用于web集群中的tomcat或PHP中多web服务器的session共享；消息队列，ELK的日志缓存，部分业务的订阅发布系统；计数器，常用于访问排行榜，商品浏览数等和次数相关的数值统计场景；缓存，常用于数据查询、电商网站商品信息、新闻内容等；相对memcache，redis支持数据的持久化，可以将内存的数据保存在磁盘中，重启redis服务或者服务器之后可以从备份文件中恢复数据到内存继续使用；

1.2、PV/PVC 及 Redis 单机

由于redis的数据（主要是redis快照）都存放在存储系统中，即便redis pod挂掉，对应数据都不会丢；因为在k8s上部署redis单机，redis pod挂了，k8s会将对应pod重建，重建时会把对应pvc挂载至pod中，加载快照，从而使得redis的数据不被pod的挂掉而丢数据；

1.3、构建redis镜像

root@k8s-master01:~/k8s-data/dockerfile/web/magedu/redis# ll
total 1784
drwxr-xr-x  2 root root    4096 Jun  5 15:22 ./
drwxr-xr-x 11 root root    4096 Aug  9  2022 ../
-rw-r--r--  1 root root     717 Jun  5 15:20 Dockerfile
-rwxr-xr-x  1 root root     235 Jun  5 15:21 build-command.sh*
-rw-r--r--  1 root root 1740967 Jun 22  2021 redis-4.0.14.tar.gz
-rw-r--r--  1 root root   58783 Jun 22  2021 redis.conf
-rwxr-xr-x  1 root root      84 Jun  5 15:21 run_redis.sh*
root@k8s-master01:~/k8s-data/dockerfile/web/magedu/redis# cat Dockerfile 
#Redis Image
# 导入自定义centos基础镜像
FROM harbor.ik8s.cc/baseimages/magedu-centos-base:7.9.2009 
# 添加redis源码包至/usr/local/src
ADD redis-4.0.14.tar.gz /usr/local/src
# 编译安装redis
RUN ln -sv /usr/local/src/redis-4.0.14 /usr/local/redis && cd /usr/local/redis && make && cp src/redis-cli /usr/sbin/ && cp src/redis-server  /usr/sbin/ && mkdir -pv /data/redis-data 
# 添加redis配置文件
ADD redis.conf /usr/local/redis/redis.conf 
# 暴露redis服务端口
EXPOSE 6379

#ADD run_redis.sh /usr/local/redis/run_redis.sh
#CMD ["/usr/local/redis/run_redis.sh"]
# 添加启动脚本
ADD run_redis.sh /usr/local/redis/entrypoint.sh
# 启动redis
ENTRYPOINT ["/usr/local/redis/entrypoint.sh"]
root@k8s-master01:~/k8s-data/dockerfile/web/magedu/redis# cat build-command.sh 
#!/bin/bash
TAG=$1
#docker build -t harbor.ik8s.cc/magedu/redis:${TAG} .
#sleep 3
#docker push  harbor.ik8s.cc/magedu/redis:${TAG}

nerdctl build -t  harbor.ik8s.cc/magedu/redis:${TAG} .
nerdctl push harbor.ik8s.cc/magedu/redis:${TAG}
root@k8s-master01:~/k8s-data/dockerfile/web/magedu/redis# cat run_redis.sh 
#!/bin/bash
# Redis启动命令
/usr/sbin/redis-server /usr/local/redis/redis.conf
# 使用tail -f 在pod内部构建守护进程
tail -f  /etc/hosts
root@k8s-master01:~/k8s-data/dockerfile/web/magedu/redis# grep -v '^#\|^$' redis.conf 
bind 0.0.0.0
protected-mode yes
port 6379
tcp-backlog 511
timeout 0
tcp-keepalive 300
daemonize yes
supervised no
pidfile /var/run/redis_6379.pid
loglevel notice
logfile ""
databases 16
always-show-logo yes
save 900 1
save 5 1
save 300 10
save 60 10000
stop-writes-on-bgsave-error no
rdbcompression yes
rdbchecksum yes
dbfilename dump.rdb
dir /data/redis-data
slave-serve-stale-data yes
slave-read-only yes
repl-diskless-sync no
repl-diskless-sync-delay 5
repl-disable-tcp-nodelay no
slave-priority 100
requirepass 123456
lazyfree-lazy-eviction no
lazyfree-lazy-expire no
lazyfree-lazy-server-del no
slave-lazy-flush no
appendonly no
appendfilename "appendonly.aof"
appendfsync everysec
no-appendfsync-on-rewrite no
auto-aof-rewrite-percentage 100
auto-aof-rewrite-min-size 64mb
aof-load-truncated yes
aof-use-rdb-preamble no
lua-time-limit 5000
slowlog-log-slower-than 10000
slowlog-max-len 128
latency-monitor-threshold 0
notify-keyspace-events ""
hash-max-ziplist-entries 512
hash-max-ziplist-value 64
list-max-ziplist-size -2
list-compress-depth 0
set-max-intset-entries 512
zset-max-ziplist-entries 128
zset-max-ziplist-value 64
hll-sparse-max-bytes 3000
activerehashing yes
client-output-buffer-limit normal 0 0 0
client-output-buffer-limit slave 256mb 64mb 60
client-output-buffer-limit pubsub 32mb 8mb 60
hz 10
aof-rewrite-incremental-fsync yes
root@k8s-master01:~/k8s-data/dockerfile/web/magedu/redis# 

1.3.1、验证rdis镜像是否上传至harbor?

1.4、测试redis 镜像

1.4.1、验证将redis镜像运行为容器，看看是否正常运行?

1.4.2、远程连接redis，看看是否可正常连接？

能够将redis镜像运行为容器，并且能够通过远程主机连接至redis进行数据读写，说明我们构建的reids镜像没有问题；

1.5、创建PV和PVC

1.5.1、在nfs服务器上准备redis数据存储目录

root@harbor:~# mkdir -pv /data/k8sdata/magedu/redis-datadir-1
mkdir: created directory '/data/k8sdata/magedu/redis-datadir-1'
root@harbor:~# cat /etc/exports
# /etc/exports: the access control list for filesystems which may be exported
#               to NFS clients.  See exports(5).
#
# Example for NFSv2 and NFSv3:
# /srv/homes       hostname1(rw,sync,no_subtree_check) hostname2(ro,sync,no_subtree_check)
#
# Example for NFSv4:
# /srv/nfs4        gss/krb5i(rw,sync,fsid=0,crossmnt,no_subtree_check)
# /srv/nfs4/homes  gss/krb5i(rw,sync,no_subtree_check)
#
/data/k8sdata/kuboard *(rw,no_root_squash)
/data/volumes *(rw,no_root_squash)
/pod-vol *(rw,no_root_squash)
/data/k8sdata/myserver *(rw,no_root_squash)
/data/k8sdata/mysite *(rw,no_root_squash)

/data/k8sdata/magedu/images *(rw,no_root_squash)
/data/k8sdata/magedu/static *(rw,no_root_squash)


/data/k8sdata/magedu/zookeeper-datadir-1 *(rw,no_root_squash)
/data/k8sdata/magedu/zookeeper-datadir-2 *(rw,no_root_squash)
/data/k8sdata/magedu/zookeeper-datadir-3 *(rw,no_root_squash)


/data/k8sdata/magedu/redis-datadir-1 *(rw,no_root_squash) 

root@harbor:~# exportfs -av
exportfs: /etc/exports [1]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/kuboard".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [2]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/volumes".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [3]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/pod-vol".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [4]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/myserver".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [5]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/mysite".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [7]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/images".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [8]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/static".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [11]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/zookeeper-datadir-1".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [12]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/zookeeper-datadir-2".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [13]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/zookeeper-datadir-3".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [16]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/redis-datadir-1".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exporting *:/data/k8sdata/magedu/redis-datadir-1
exporting *:/data/k8sdata/magedu/zookeeper-datadir-3
exporting *:/data/k8sdata/magedu/zookeeper-datadir-2
exporting *:/data/k8sdata/magedu/zookeeper-datadir-1
exporting *:/data/k8sdata/magedu/static
exporting *:/data/k8sdata/magedu/images
exporting *:/data/k8sdata/mysite
exporting *:/data/k8sdata/myserver
exporting *:/pod-vol
exporting *:/data/volumes
exporting *:/data/k8sdata/kuboard
root@harbor:~# 

1.5.2、创建pv

root@k8s-master01:~/k8s-data/yaml/magedu/redis/pv# cat redis-persistentvolume.yaml     
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: redis-datadir-pv-1
spec:
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteOnce
  nfs:
    path: /data/k8sdata/magedu/redis-datadir-1 
    server: 192.168.0.42
root@k8s-master01:~/k8s-data/yaml/magedu/redis/pv# 

1.5.3、创建pvc

root@k8s-master01:~/k8s-data/yaml/magedu/redis/pv# cat redis-persistentvolumeclaim.yaml 
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: redis-datadir-pvc-1 
  namespace: magedu
spec:
  volumeName: redis-datadir-pv-1 
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 10Gi
root@k8s-master01:~/k8s-data/yaml/magedu/redis/pv# 

1.6、部署redis服务

root@k8s-master01:~/k8s-data/yaml/magedu/redis# cat redis.yaml
kind: Deployment
#apiVersion: extensions/v1beta1
apiVersion: apps/v1
metadata:
  labels:
    app: devops-redis 
  name: deploy-devops-redis
  namespace: magedu
spec:
  replicas: 1 
  selector:
    matchLabels:
      app: devops-redis
  template:
    metadata:
      labels:
        app: devops-redis
    spec:
      containers:
        - name: redis-container
          image: harbor.ik8s.cc/magedu/redis:v4.0.14 
          imagePullPolicy: Always
          volumeMounts:
          - mountPath: "/data/redis-data/"
            name: redis-datadir
      volumes:
        - name: redis-datadir
          persistentVolumeClaim:
            claimName: redis-datadir-pvc-1 

---
kind: Service
apiVersion: v1
metadata:
  labels:
    app: devops-redis
  name: srv-devops-redis
  namespace: magedu
spec:
  type: NodePort
  ports:
  - name: http
    port: 6379 
    targetPort: 6379
    nodePort: 36379 
  selector:
    app: devops-redis
  sessionAffinity: ClientIP
  sessionAffinityConfig:
    clientIP:
      timeoutSeconds: 10800
root@k8s-master01:~/k8s-data/yaml/magedu/redis# 

上述报错说我们的服务端口超出范围，这是因为我们在初始化k8s集群时指定的服务端口范围；

1.6.1、修改nodeport端口范围

编辑/etc/systemd/system/kube-apiserver.service,将其--service-node-port-range选项指定的值修改即可；其他两个master节点也需要修改哦

1.6.2、重载kube-apiserver.service,重启kube-apiserver

root@k8s-master01:~# systemctl daemon-reload                 
root@k8s-master01:~# systemctl restart kube-apiserver.service
root@k8s-master01:~# 

再次部署redis

1.7、验证redis数据读写

1.7.1、连接k8s任意节点的36376端口，测试redis读写数据

1.8、验证redis pod 重建对应数据是否丢失？

1.8.1、查看redis快照文件是否存储到存储上呢？

root@harbor:~# ll /data/k8sdata/magedu/redis-datadir-1
total 12
drwxr-xr-x 2 root root 4096 Jun  5 16:29 ./
drwxr-xr-x 8 root root 4096 Jun  5 15:53 ../
-rw-r--r-- 1 root root  116 Jun  5 16:29 dump.rdb
root@harbor:~# 

可以看到刚才我们向redis写入数据，对应redis在规定时间内发现key的变化就做了快照，因为redis数据目录时通过pv/pvc挂载的nfs，所以我们在nfs对应目录里时可以正常看到这个快照文件的；

1.8.2、删除redis pod 等待k8s重建redis pod

1.8.3、验证重建后的redis pod数据

可以看到k8s重建后的redis pod 还保留着原有pod的数据；这说明k8s重建时挂载了前一个pod的pvc;

2、在k8s上部署redis集群

2.1、PV/PVC及Redis Cluster-StatefulSet

redis cluster相比redis单机要稍微复杂一点，我们也是通过pv/pvc将redis cluster数据存放在存储系统中，不同于redis单机，redis cluster对存入的数据会做crc16计算，然后和16384做取模计算，得出一个数字，这个数字就是存入redis cluster的一个槽位；即redis cluster将16384个槽位，平均分配给集群所有master节点，每个master节点存放整个集群数据的一部分；这样一来就存在一个问题，如果master宕机，那么对应槽位的数据也就不可用，为了防止master单点故障，我们还需要对master做高可用，即专门用一个slave节点对master做备份，master宕机的情况下，对应slave会接管master继续向集群提供服务，从而实现redis cluster master的高可用；如上图所示，我们使用3主3从的redis cluster，redis0,1,2为master，那么3，4，5就对应为0，1，2的slave，负责备份各自对应的master的数据；这六个pod都是通过k8s集群的pv/pvc将数据存放在存储系统中；

2.2、创建PV

2.2.1、在nfs上准备redis cluster 数据目录

root@harbor:~# mkdir -pv /data/k8sdata/magedu/redis{0,1,2,3,4,5}
mkdir: created directory '/data/k8sdata/magedu/redis0'
mkdir: created directory '/data/k8sdata/magedu/redis1'
mkdir: created directory '/data/k8sdata/magedu/redis2'
mkdir: created directory '/data/k8sdata/magedu/redis3'
mkdir: created directory '/data/k8sdata/magedu/redis4'
mkdir: created directory '/data/k8sdata/magedu/redis5'
root@harbor:~# tail -6 /etc/exports 
/data/k8sdata/magedu/redis0 *(rw,no_root_squash)
/data/k8sdata/magedu/redis1 *(rw,no_root_squash)
/data/k8sdata/magedu/redis2 *(rw,no_root_squash)
/data/k8sdata/magedu/redis3 *(rw,no_root_squash)
/data/k8sdata/magedu/redis4 *(rw,no_root_squash)
/data/k8sdata/magedu/redis5 *(rw,no_root_squash)
root@harbor:~# exportfs  -av
exportfs: /etc/exports [1]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/kuboard".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [2]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/volumes".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [3]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/pod-vol".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [4]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/myserver".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [5]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/mysite".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [7]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/images".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [8]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/static".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [11]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/zookeeper-datadir-1".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [12]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/zookeeper-datadir-2".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [13]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/zookeeper-datadir-3".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [16]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/redis-datadir-1".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [18]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/redis0".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [19]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/redis1".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [20]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/redis2".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [21]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/redis3".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [22]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/redis4".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exportfs: /etc/exports [23]: Neither 'subtree_check' or 'no_subtree_check' specified for export "*:/data/k8sdata/magedu/redis5".
  Assuming default behaviour ('no_subtree_check').
  NOTE: this default has changed since nfs-utils version 1.0.x

exporting *:/data/k8sdata/magedu/redis5
exporting *:/data/k8sdata/magedu/redis4
exporting *:/data/k8sdata/magedu/redis3
exporting *:/data/k8sdata/magedu/redis2
exporting *:/data/k8sdata/magedu/redis1
exporting *:/data/k8sdata/magedu/redis0
exporting *:/data/k8sdata/magedu/redis-datadir-1
exporting *:/data/k8sdata/magedu/zookeeper-datadir-3
exporting *:/data/k8sdata/magedu/zookeeper-datadir-2
exporting *:/data/k8sdata/magedu/zookeeper-datadir-1
exporting *:/data/k8sdata/magedu/static
exporting *:/data/k8sdata/magedu/images
exporting *:/data/k8sdata/mysite
exporting *:/data/k8sdata/myserver
exporting *:/pod-vol
exporting *:/data/volumes
exporting *:/data/k8sdata/kuboard
root@harbor:~# 

2.2.2、创建pv

root@k8s-master01:~/k8s-data/yaml/magedu/redis-cluster# cat pv/redis-cluster-pv.yaml 
apiVersion: v1
kind: PersistentVolume
metadata:
  name: redis-cluster-pv0
spec:
  capacity:
    storage: 5Gi
  accessModes:
    - ReadWriteOnce
  nfs:
    server: 192.168.0.42
    path: /data/k8sdata/magedu/redis0 

---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: redis-cluster-pv1
spec:
  capacity:
    storage: 5Gi
  accessModes:
    - ReadWriteOnce
  nfs:
    server: 192.168.0.42
    path: /data/k8sdata/magedu/redis1 

---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: redis-cluster-pv2
spec:
  capacity:
    storage: 5Gi
  accessModes:
    - ReadWriteOnce
  nfs:
    server: 192.168.0.42
    path: /data/k8sdata/magedu/redis2 

---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: redis-cluster-pv3
spec:
  capacity:
    storage: 5Gi
  accessModes:
    - ReadWriteOnce
  nfs:
    server: 192.168.0.42
    path: /data/k8sdata/magedu/redis3 

---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: redis-cluster-pv4
spec:
  capacity:
    storage: 5Gi
  accessModes:
    - ReadWriteOnce
  nfs:
    server: 192.168.0.42
    path: /data/k8sdata/magedu/redis4 

---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: redis-cluster-pv5
spec:
  capacity:
    storage: 5Gi
  accessModes:
    - ReadWriteOnce
  nfs:
    server: 192.168.0.42
    path: /data/k8sdata/magedu/redis5 
root@k8s-master01:~/k8s-data/yaml/magedu/redis-cluster# 

2.3、部署redis cluster

2.3.1、基于redis.conf文件创建configmap

root@k8s-master01:~/k8s-data/yaml/magedu/redis-cluster# cat 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
root@k8s-master01:~/k8s-data/yaml/magedu/redis-cluster# 

2.3.2、创建configmap

root@k8s-master01:~/k8s-data/yaml/magedu/redis-cluster# kubectl create cm redis-conf --from-file=./redis.conf -n magedu 
configmap/redis-conf created
root@k8s-master01:~/k8s-data/yaml/magedu/redis-cluster# kubectl get cm -n magedu 
NAME               DATA   AGE
kube-root-ca.crt   1      35h
redis-conf         1      6s
root@k8s-master01:~/k8s-data/yaml/magedu/redis-cluster# 

2.3.3、验证configmap

root@k8s-master01:~/k8s-data/yaml/magedu/redis-cluster# kubectl describe cm redis-conf -n magedu 
Name:         redis-conf
Namespace:    magedu
Labels:       <none>
Annotations:  <none>

Data
====
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


BinaryData
====

Events:  <none>
root@k8s-master01:~/k8s-data/yaml/magedu/redis-cluster#

2.3.4、部署redis cluster

root@k8s-master01:~/k8s-data/yaml/magedu/redis-cluster# cat redis.yaml 
apiVersion: v1
kind: Service
metadata:
  name: redis
  namespace: magedu
  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: magedu
  labels:
    app: redis
spec:
  type: NodePort
  selector:
    app: redis
    appCluster: redis-cluster
  ports:
  - name: redis-access
    protocol: TCP
    port: 6379
    targetPort: 6379
    nodePort: 36379

---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: redis
  namespace: magedu
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:4.0.14
        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: magedu
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 5Gi
root@k8s-master01:~/k8s-data/yaml/magedu/redis-cluster# 

上述配置清单，主要用sts控制器创建了6个pod副本，每个副本都使用configmap中的配置文件作为redis配置文件，使用pvc模板指定pod在k8s上自动关联pv，并在magedu名称空间创建pvc,即只要k8s上有空余的pv，对应pod就会在magedu这个名称空间按pvc模板信息创建pvc；当然我们可以使用存储类自动创建pvc，也可以提前创建好pvc，一般情况下使用sts控制器，我们可以使用pvc模板的方式来指定pod自动创建pvc(前提是k8s有足够的pv可用)；

应用配置清单部署redis cluster

使用sts控制器创建pod，pod名称是sts控制器的名称-id，使用pvc模板创建pvc的名称为pvc模板名称-pod名称,即pvc模板名-sts控制器名-id;

2.4、初始化redis cluster

2.4.1、在k8s上创建临时容器,安装redis cluster 初始化工具

root@k8s-master01:~/k8s-data/yaml/magedu/redis-cluster# kubectl run -it ubuntu1804 --image=ubuntu:18.04 --restart=Never -n magedu bash
If you don't see a command prompt, try pressing enter.
root@ubuntu1804:/#
root@ubuntu1804:/# apt update
# 安装必要工具
root@ubuntu1804:/# apt install python2.7 python-pip redis-tools dnsutils iputils-ping net-tools
# 更新pip
root@ubuntu1804:/# pip install --upgrade pip
# 使用pip安装redis cluster初始化工具redis-trib
root@ubuntu1804:/# pip install redis-trib==0.5.1
root@ubuntu1804:/#

2.4.2、初始化redis cluster

root@ubuntu1804:/# redis-trib.py create \
 `dig +short redis-0.redis.magedu.svc.cluster.local`:6379 \
 `dig +short redis-1.redis.magedu.svc.cluster.local`:6379 \
 `dig +short redis-2.redis.magedu.svc.cluster.local`:6379 

在k8s上我们使用sts创建pod，对应pod的名称是固定不变的，所以我们初始化redis 集群就直接使用redis pod名称就可以直接解析到对应pod的IP地址；在传统虚拟机或物理机上初始化redis集群，我们可用直接使用IP地址，原因是物理机或虚拟机IP地址是固定的，在k8s上pod的IP地址是不固定的；

2.4.3、给master指定slave

• 给redis-0指定slave为 redis-3

root@ubuntu1804:/# redis-trib.py replicate \
 --master-addr `dig +short redis-0.redis.magedu.svc.cluster.local`:6379 \
 --slave-addr `dig +short redis-3.redis.magedu.svc.cluster.local`:6379

• 给redis-1指定slave为 redis-4

root@ubuntu1804:/# redis-trib.py replicate \
 --master-addr `dig +short redis-1.redis.magedu.svc.cluster.local`:6379 \
 --slave-addr `dig +short redis-4.redis.magedu.svc.cluster.local`:6379

• 给redis-2指定slave为 redis-5

root@ubuntu1804:/# redis-trib.py replicate \
--master-addr `dig +short redis-2.redis.magedu.svc.cluster.local`:6379 \
--slave-addr `dig +short redis-5.redis.magedu.svc.cluster.local`:6379

2.5、验证redis cluster状态

2.5.1、进入redis cluster 任意pod 查看集群信息

2.5.2、查看集群节点

集群节点信息中记录了master节点id和slave id，其中slave后面会对应master的id，表示该slave备份对应master数据；

2.5.3、查看当前节点信息

127.0.0.1:6379> info
# Server
redis_version:4.0.14
redis_git_sha1:00000000
redis_git_dirty:0
redis_build_id:165c932261a105d7
redis_mode:cluster
os:Linux 5.15.0-73-generic x86_64
arch_bits:64
multiplexing_api:epoll
atomicvar_api:atomic-builtin
gcc_version:8.3.0
process_id:1
run_id:aa8ef00d843b4f622374dbb643cf27cdbd4d5ba3
tcp_port:6379
uptime_in_seconds:4303
uptime_in_days:0
hz:10
lru_clock:8272053
executable:/data/redis-server
config_file:/etc/redis/redis.conf

# Clients
connected_clients:1
client_longest_output_list:0
client_biggest_input_buf:0
blocked_clients:0

# Memory
used_memory:2642336
used_memory_human:2.52M
used_memory_rss:5353472
used_memory_rss_human:5.11M
used_memory_peak:2682248
used_memory_peak_human:2.56M
used_memory_peak_perc:98.51%
used_memory_overhead:2559936
used_memory_startup:1444856
used_memory_dataset:82400
used_memory_dataset_perc:6.88%
total_system_memory:16740012032
total_system_memory_human:15.59G
used_memory_lua:37888
used_memory_lua_human:37.00K
maxmemory:0
maxmemory_human:0B
maxmemory_policy:noeviction
mem_fragmentation_ratio:2.03
mem_allocator:jemalloc-4.0.3
active_defrag_running:0
lazyfree_pending_objects:0

# Persistence
loading:0
rdb_changes_since_last_save:0
rdb_bgsave_in_progress:0
rdb_last_save_time:1685992849
rdb_last_bgsave_status:ok
rdb_last_bgsave_time_sec:0
rdb_current_bgsave_time_sec:-1
rdb_last_cow_size:245760
aof_enabled:1
aof_rewrite_in_progress:0
aof_rewrite_scheduled:0
aof_last_rewrite_time_sec:-1
aof_current_rewrite_time_sec:-1
aof_last_bgrewrite_status:ok
aof_last_write_status:ok
aof_last_cow_size:0
aof_current_size:0
aof_base_size:0
aof_pending_rewrite:0
aof_buffer_length:0
aof_rewrite_buffer_length:0
aof_pending_bio_fsync:0
aof_delayed_fsync:0

# Stats
total_connections_received:7
total_commands_processed:17223
instantaneous_ops_per_sec:1
total_net_input_bytes:1530962
total_net_output_bytes:108793
instantaneous_input_kbps:0.04
instantaneous_output_kbps:0.00
rejected_connections:0
sync_full:1
sync_partial_ok:0
sync_partial_err:1
expired_keys:0
expired_stale_perc:0.00
expired_time_cap_reached_count:0
evicted_keys:0
keyspace_hits:0
keyspace_misses:0
pubsub_channels:0
pubsub_patterns:0
latest_fork_usec:853
migrate_cached_sockets:0
slave_expires_tracked_keys:0
active_defrag_hits:0
active_defrag_misses:0
active_defrag_key_hits:0
active_defrag_key_misses:0

# Replication
role:master
connected_slaves:1
slave0:ip=10.200.155.175,port=6379,state=online,offset=1120,lag=1
master_replid:60381a28fee40b44c409e53eeef49215a9d3b0ff
master_replid2:0000000000000000000000000000000000000000
master_repl_offset:1120
second_repl_offset:-1
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:1
repl_backlog_histlen:1120

# CPU
used_cpu_sys:12.50
used_cpu_user:7.51
used_cpu_sys_children:0.01
used_cpu_user_children:0.00

# Cluster
cluster_enabled:1

# Keyspace
127.0.0.1:6379> 

2.5.4、验证redis cluster读写数据是否正常？

2.5.4.1、手动连接redis cluster 进行数据读写

手动连接redis 集群master节点进行数据读写，存在一个问题就是当我们写入的key经过crc16计算对16384取模后，对应槽位可能不在当前节点，redis它会告诉我们该key该在哪里去写；从上面的截图可用看到，现在redis cluster 是可用正常读写数据的

2.5.4.2、使用python脚本连接redis cluster 进行数据读写

root@k8s-master01:~/k8s-data/yaml/magedu/redis-cluster# cat redis-client-test.py
#!/usr/bin/env python
#coding:utf-8
#Author:Zhang ShiJie
#python 2.7/3.8
#pip install redis-py-cluster

import sys,time
from rediscluster import RedisCluster
def init_redis():
    startup_nodes = [
        {'host': '192.168.0.34', 'port': 36379},
        {'host': '192.168.0.35', 'port': 36379},
        {'host': '192.168.0.36', 'port': 36379},
        {'host': '192.168.0.34', 'port': 36379},
        {'host': '192.168.0.35', 'port': 36379},
        {'host': '192.168.0.36', 'port': 36379},
    ]
    try:
        conn = RedisCluster(startup_nodes=startup_nodes,
                            # 有密码要加上密码哦
                            decode_responses=True, password='')
        print('连接成功！！！！！1', conn)
        #conn.set("key-cluster","value-cluster")
        for i in range(100):
            conn.set("key%s" % i, "value%s" % i)
            time.sleep(0.1)
            data = conn.get("key%s" % i)
            print(data)

        #return conn

    except Exception as e:
        print("connect error ", str(e))
        sys.exit(1)

init_redis()
root@k8s-master01:~/k8s-data/yaml/magedu/redis-cluster# 

运行脚本，向redis cluster 写入数据

root@k8s-master01:~/k8s-data/yaml/magedu/redis-cluster# python redis-client-test.py
Traceback (most recent call last):
  File "/root/k8s-data/yaml/magedu/redis-cluster/redis-client-test.py", line 8, in <module>
    from rediscluster import RedisCluster
ModuleNotFoundError: No module named 'rediscluster'
root@k8s-master01:~/k8s-data/yaml/magedu/redis-cluster#

这里提示没有找到rediscluster模块，解决办法就是通过pip安装redis-py-cluster模块即可；

安装redis-py-cluster模块

运行脚本连接redis cluster进行数据读写

连接redis pod，验证数据是否正常写入？

从上面的截图可用看到三个reids cluster master pod各自都存放了一部分key,并非全部；说明刚才我们用python脚本把数据正常写入了redis cluster;

验证在slave 节点是否可用正常读取数据？

从上面的截图可以了解到在slave节点是不可以读取数据；

到slave对应的master节点读取数据

上述验证说明了redis cluster 只有master可以读写数据，slave只是对master数据做备份，不可以在slave上读写数据；

2.6、验证验证redis cluster高可用

2.6.1、在k8s node节点将redis:4.0.14镜像上传至本地harbor

• 修改镜像tag

root@k8s-node01:~# nerdctl tag redis:4.0.14 harbor.ik8s.cc/redis-cluster/redis:4.0.14

• 上传redis镜像至本地harbor

root@k8s-node01:~# nerdctl push harbor.ik8s.cc/redis-cluster/redis:4.0.14
INFO[0000] pushing as a reduced-platform image (application/vnd.docker.distribution.manifest.list.v2+json, sha256:1ae9e0f790001af4b9f83a2b3d79c593c6f3e9a881b754a99527536259fb6625) 
WARN[0000] skipping verifying HTTPS certs for "harbor.ik8s.cc" 
index-sha256:1ae9e0f790001af4b9f83a2b3d79c593c6f3e9a881b754a99527536259fb6625:    done           |++++++++++++++++++++++++++++++++++++++| 
manifest-sha256:5bd4fe08813b057df2ae55003a75c39d80a4aea9f1a0fbc0fbd7024edf555786: done           |++++++++++++++++++++++++++++++++++++++| 
config-sha256:191c4017dcdd3370f871a4c6e7e1d55c7d9abed2bebf3005fb3e7d12161262b8:   done           |++++++++++++++++++++++++++++++++++++++| 
elapsed: 1.4 s                                                                    total:  8.5 Ki (6.1 KiB/s)                                       
root@k8s-node01:~# 

2.6.2、修改redis cluster部署清单镜像和镜像拉取策略

修改镜像为本地harbor镜像和拉取策略是方便我们测试redis cluster的高可用；

2.6.3、重新apply redis cluster部署清单

root@k8s-master01:~/k8s-data/yaml/magedu/redis-cluster# kubectl apply -f redis.yaml
service/redis unchanged
service/redis-access unchanged
statefulset.apps/redis configured
root@k8s-master01:~/k8s-data/yaml/magedu/redis-cluster# 

这里相当于给redis cluster更新，他们之间的集群关系还存在，因为集群关系配置都保存在远端存储之上；

• 验证pod是否都正常running?
  
• 验证集群状态和集群关系
  

不同于之前，这里rdis-0变成了slave ,redis-3变成了master；从上面的截图我们也发现，在k8s上部署redis cluster pod重建以后（IP地址发生变化），对应集群关系不会发生变化；对应master和salve一对关系始终只是再对应的master和salve两个pod中切换，这其实就是高可用；

2.6.4、停掉本地harbor，删除redis master pod，看看对应slave是否会提升为master？

• 停止harbor服务

root@harbor:~# systemctl stop harbor

• 删除redis-3,看看redis-0是否会提升为master？
  

可用看到我们把redis-3删除（相当于master宕机）以后，对应slave提升为master了；

2.6.5、恢复harbor服务，看看对应redis-3恢复会议后是否还是redis-0的slave呢？

• 恢复harbor服务
  
• 验证redis-3pod是否恢复？
  

再次删除redis-3以后，对应pod正常被重建，并处于running状态；

• 验证redis-3的主从关系、
  

可以看到redis-3恢复以后，对应自动加入集群成为redis-0的slave;文章来源地址https://www.toymoban.com/news/detail-473706.html

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