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docker 实现redis集群搭建

摘要 :接触docker以来,似乎养成了一种习惯,安装什么应用软件都想往docker方向做,今天就想来尝试下使用docker搭建redis集群。

首先,我们需要理论知识: Redis Cluster Redis
的分布式解决方案,它解决了redis单机中心化的问题,分布式数据库——首要解决把整个数据集按照分区规则映射到多个节点的问题。

这边就需要知道分区规则——哈希分区规则。 Redis Cluster 采用哈希分区规则中的虚拟槽分区。所有的键根据哈希函数映射到 0 ~ 16383 ,计算公式: slot = CRC16(key)&16383 。每一个节点负责维护一部分槽以及槽所映射的键值数据。

一、创建redis docker基础镜像

  1. 下载redis安装包,使用版本为:4.0.1

    [root@etcd1 tmp]# cd docker_redis_cluster/
    [root@etcd2 docker_redis_cluster]# wget http://download.redis.io/releases/redis-4.0.1.tar.gz
  1. 解压编译redis

    [root@etcd1 docker_redis_cluster]# cd redis-4.0.1/
    [root@etcd1 redis-4.0.1]# make
  1. 修改redis配置
/tmp/docker_redis_cluster/redis-4.0.1/redis.conf

修改bind ip地址

# ~~~ WARNING ~~~ If the computer running Redis is directly exposed to
the

    # internet, binding to all the interfaces is dangerous and will expose the
    # instance to everybody on the internet. So by default we uncomment the
    # following bind directive, that will force Redis to listen only into
    # the IPv4 lookback interface address (this means Redis will be able to
    # accept connections only from clients running into the same computer it
    # is running).
    #
    # IF YOU ARE SURE YOU WANT YOUR INSTANCE TO LISTEN TO ALL THE INTERFACES
    # JUST COMMENT THE FOLLOWING LINE.
    # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    #bind 127.0.0.1
    bind 0.0.0.0

将守护进程yes改成no

# By default Redis does not run as a daemon. Use 'yes' if you need it.

    # Note that Redis will write a pid file in /var/run/redis.pid when daemonized.
    daemonize no

将密码项注释去掉,添加新密码

# Warning: since Redis is pretty fast an outside user can try up to

    # 150k passwords per second against a good box. This means that you should
    # use a very strong password otherwise it will be very easy to break.
    #
    # requirepass foobared

修改为

# Warning: since Redis is pretty fast an outside user can try up to

    # 150k passwords per second against a good box. This means that you should
    # use a very strong password otherwise it will be very easy to break.
    #
    requirepass 123456

因为配置了密码,所以,配置中另外一处主从连接也需要配置密码

# If the master is password protected (using the "requirepass"
configuration

    # directive below) it is possible to tell the slave to authenticate before
    # starting the replication synchronization process, otherwise the master will
    # refuse the slave request.
    #
    # masterauth <master-password>

修改为

# If the master is password protected (using the "requirepass"
configuration

    # directive below) it is possible to tell the slave to authenticate before
    # starting the replication synchronization process, otherwise the master will
    # refuse the slave request.
    #
    # masterauth <master-password>
    masterauth 123456

设置日志路径


# Specify the log file name. Also the empty string can be used to
force

    # Redis to log on the standard output. Note that if you use standard
    # output for logging but daemonize, logs will be sent to /dev/null
    logfile "/var/log/redis/redis-server.log"

配置集群相关信息,去掉配置项前面的注释


# Normal Redis instances can't be part of a Redis Cluster; only nodes
that are

    # started as cluster nodes can. In order to start a Redis instance as a
    # cluster node enable the cluster support uncommenting the following:
    #
    cluster-enabled yes

    # Every cluster node has a cluster configuration file. This file is not
    # intended to be edited by hand. It is created and updated by Redis nodes.
    # Every Redis Cluster node requires a different cluster configuration file.
    # Make sure that instances running in the same system do not have
    # overlapping cluster configuration file names.
    #
    cluster-config-file nodes-6379.conf

    # Cluster node timeout is the amount of milliseconds a node must be unreachable
    # for it to be considered in failure state.
    # Most other internal time limits are multiple of the node timeout.
    #
    cluster-node-timeout 15000
  1. 镜像制作

[root@etcd3 docker_redis_cluster]# cd /tmp/docker_redis_cluster

    [root@etcd3 docker_redis_cluster]# vi Dockerfile 
    # Redis
    # Version 4.0.1

    FROM Centos:7  

    ENV REDIS_HOME /usr/local  

    ADD redis-4.0.1.tar.gz / # 本地的redis源码包复制到镜像的根路径下,ADD命令会在复制过后自动解包。被复制的对象必须处于Dockerfile同一路径,且ADD后面必须使用相对路径
    RUN mkdir -p $REDIS_HOME/redis # 创建安装目录
    ADD redis-4.0.1/redis.conf $REDIS_HOME/redis/  # 将一开始编译产生并修改后的配置复制到安装目录

    RUN yum -y update  # 更新yum源
    RUN yum install -y gcc make # 安装编译需要的工具

    WORKDIR /redis-4.0.1
    RUN make
    RUN mv /redis-4.0.1/src/redis-server  $REDIS_HOME/redis/   # 编译后,容器中只需要可执行文件redis-server

    WORKDIR /
    RUN rm -rf /redis-4.0.1          # 删除解压文件

    RUN yum remove -y gcc make   # 安装编译完成之后,可以删除多余的gcc跟make

    VOLUME ["/var/log/redis"]  # 添加数据卷

    EXPOSE 6379   # 暴露6379端口,也可以暴露多个端口,这里不需要如此

PS.当前镜像非可执行镜像,所以没有包含ENTRYPOINT和CMD指令

  1. 构建镜像

# 切换中国源

    [root@etcd3 docker_redis_cluster]# vi /etc/docker/daemon.json
    {
      "registry-mirrors": ["https://registry.docker-cn.com"]
    }

    # 编译
    [root@etcd3 docker_redis_cluster]# docker build -t hakimdstx/cluster-redis .
    ...

    Complete!
     ---> 546cb1d34f35
    Removing intermediate container 6b6556c5f28d
    Step 14/15 : VOLUME /var/log/redis
     ---> Running in 05a6642e4046
     ---> e7e2fb8676b2
    Removing intermediate container 05a6642e4046
    Step 15/15 : EXPOSE 6379
     ---> Running in 5d7abe1709e2
     ---> 2d1322475f79
    Removing intermediate container 5d7abe1709e2
    Successfully built 2d1322475f79

镜像制作完成,制作中间可能会报: Public key for glibc-headers- 2.17 – 222
.el7.x86_64.rpm is not installed 错误,这时候需要在镜像配置中添加一句命令:

...

    RUN rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
    RUN yum -y update  # 更新yum源
    RUN yum install -y gcc make # 安装编译需要的工具

查看镜像:


[root@etcd3 docker_redis_cluster]# docker images

    REPOSITORY                                  TAG                 IMAGE ID            CREATED             SIZE
    hakimdstx/cluster-redis                     4.0.1               1fca5a08a4c7        14 seconds ago      435 MB
    centos                                      7                   49f7960eb7e4        2 days ago          200 MB

以上,redis 基础镜像就制作完成了

二、制作redis节点镜像

  1. 基于此前制作的redis基础镜像创建一个redis节点镜像

[root@etcd3 tmp]# mkdir docker_redis_nodes

    [root@etcd3 tmp]# cd docker_redis_nodes
    [root@etcd3 docker_redis_nodes]# vi Dockerfile
    # Redis Node
    # Version 4.0.1  

    FROM hakimdstx/cluster-redis:4.0.1

    # MAINTAINER_INFO
    MAINTAINER hakim 1194842583@qq.com

    ENTRYPOINT ["/usr/local/redis/redis-server", "/usr/local/redis/redis.conf"]
  1. 构建redis节点镜像

[root@etcd3 docker_redis_nodes]# docker build -t hakimdstx/nodes-
redis:4.0.1 .

    Sending build context to Docker daemon 2.048 kB
    Step 1/3 : FROM hakimdstx/cluster-redis:4.0.1
     ---> 1fca5a08a4c7
    Step 2/3 : MAINTAINER hakim 1194842583@qq.com
     ---> Running in cc6e07eb2c36
     ---> 55769d3bfacb
    Removing intermediate container cc6e07eb2c36
    Step 3/3 : ENTRYPOINT /usr/local/redis/redis-server /usr/local/redis/redis.conf
     ---> Running in f5dedf88f6f6
     ---> da64da483559
    Removing intermediate container f5dedf88f6f6
    Successfully built da64da483559
  1. 查看镜像

[root@etcd3 docker_redis_nodes]# docker images

    REPOSITORY                                  TAG                 IMAGE ID            CREATED             SIZE
    hakimdstx/nodes-redis                       4.0.1               da64da483559        51 seconds ago      435 MB
    hakimdstx/cluster-redis                     4.0.1               1fca5a08a4c7        9 minutes ago       435 MB
    centos                                      7                   49f7960eb7e4        2 days ago          200 MB

三、运行redis集群

  1. 运行redis容器

[root@etcd3 docker_redis_nodes]# docker run -d --name redis-6379 -p
6379:6379 hakimdstx/nodes-redis:4.0.1

    1673a7d859ea83257d5bf14d82ebf717fb31405c185ce96a05f597d8f855aa7d
    [root@etcd3 docker_redis_nodes]# docker run -d --name redis-6380 -p 6380:6379 hakimdstx/nodes-redis:4.0.1    
    df6ebce6f12a6f3620d5a29adcfbfa7024e906c3af48f21fa7e1fa524a361362
    [root@etcd3 docker_redis_nodes]# docker run -d --name redis-6381 -p 6381:6379 hakimdstx/nodes-redis:4.0.1   
    396e174a1d9235228b3c5f0266785a12fb1ea49efc7ac755c9e7590e17aa1a79
    [root@etcd3 docker_redis_nodes]# docker run -d --name redis-6382 -p 6382:6379 hakimdstx/nodes-redis:4.0.1 
    d9a71dd3f969094205ffa7596c4a04255575cdd3acca2d47fe8ef7171a3be528
    [root@etcd3 docker_redis_nodes]# docker run -d --name redis-6383 -p 6383:6379 hakimdstx/nodes-redis:4.0.1 
    73e4f843d8cb28595456e21b04f97d18ce1cdf8dc56d1150844ba258a3781933
    [root@etcd3 docker_redis_nodes]# docker run -d --name redis-6384 -p 6384:6379 hakimdstx/nodes-redis:4.0.1 
    10c62aafa4dac47220daf5bf3cec84406f086d5261599b54ec6c56bb7da97d6d
  1. 查看容器信息

[root@etcd3 redis]# docker ps

    CONTAINER ID        IMAGE                         COMMAND                  CREATED             STATUS              PORTS                    NAMES
    10c62aafa4da        hakimdstx/nodes-redis:4.0.1   "/usr/local/redis/..."   3 seconds ago       Up 2 seconds        0.0.0.0:6384->6379/tcp   redis-6384
    73e4f843d8cb        hakimdstx/nodes-redis:4.0.1   "/usr/local/redis/..."   12 seconds ago      Up 10 seconds       0.0.0.0:6383->6379/tcp   redis-6383
    d9a71dd3f969        hakimdstx/nodes-redis:4.0.1   "/usr/local/redis/..."   20 seconds ago      Up 18 seconds       0.0.0.0:6382->6379/tcp   redis-6382
    396e174a1d92        hakimdstx/nodes-redis:4.0.1   "/usr/local/redis/..."   3 days ago          Up 3 days           0.0.0.0:6381->6379/tcp   redis-6381
    df6ebce6f12a        hakimdstx/nodes-redis:4.0.1   "/usr/local/redis/..."   3 days ago          Up 3 days           0.0.0.0:6380->6379/tcp   redis-6380
    1673a7d859ea        hakimdstx/nodes-redis:4.0.1   "/usr/local/redis/..."   3 days ago          Up 3 days           0.0.0.0:6379->6379/tcp   redis-6379
  1. 运行 redis 集群容器

通过远程连接,查看redis info replication 信息


[root@etcd2 ~]#  redis-cli -h 192.168.10.52 -p 6379

        192.168.10.52:6379> info replication
        NOAUTH Authentication required.
        192.168.10.52:6379> auth 123456
        OK
        192.168.10.52:6379> info replication
        # Replication
        role:master
        connected_slaves:0
        master_replid:2f0a7b50aed699fa50a79f3f7f9751a070c50ee9
        master_replid2:0000000000000000000000000000000000000000
        master_repl_offset:0
        second_repl_offset:-1
        repl_backlog_active:0
        repl_backlog_size:1048576
        repl_backlog_first_byte_offset:0
        repl_backlog_histlen:0
        192.168.10.52:6379>
        # 其余基本信息同上 

可以看到,客户连接之后,因为之前设置了密码,所以需要先输入密码认证,否则就无法通过。以上信息,我们知道所有的redis都是master角色
role:master ,这显然不是我们所希望的。

2. 在配置之前我们需要查看所有容器当前的IP地址   

        CONTAINER ID        IMAGE                         COMMAND                  CREATED             STATUS              PORTS                    NAMES
        10c62aafa4da        hakimdstx/nodes-redis:4.0.1   "/usr/local/redis/..."   3 seconds ago       Up 2 seconds        0.0.0.0:6384->6379/tcp   redis-6384
        73e4f843d8cb        hakimdstx/nodes-redis:4.0.1   "/usr/local/redis/..."   12 seconds ago      Up 10 seconds       0.0.0.0:6383->6379/tcp   redis-6383
        d9a71dd3f969        hakimdstx/nodes-redis:4.0.1   "/usr/local/redis/..."   20 seconds ago      Up 18 seconds       0.0.0.0:6382->6379/tcp   redis-6382
        396e174a1d92        hakimdstx/nodes-redis:4.0.1   "/usr/local/redis/..."   3 days ago          Up 3 days           0.0.0.0:6381->6379/tcp   redis-6381
        df6ebce6f12a        hakimdstx/nodes-redis:4.0.1   "/usr/local/redis/..."   3 days ago          Up 3 days           0.0.0.0:6380->6379/tcp   redis-6380
        1673a7d859ea        hakimdstx/nodes-redis:4.0.1   "/usr/local/redis/..."   3 days ago          Up 3 days           0.0.0.0:6379->6379/tcp   redis-6379
        [root@etcd3 redis]# 
        [root@etcd3 redis]# docker inspect 10c62aafa4da 73e4f843d8cb d9a71dd3f969 396e174a1d92 df6ebce6f12a 1673a7d859ea | grep IPA
                    "SecondaryIPAddresses": null,
                    "IPAddress": "172.17.0.7",
                            "IPAMConfig": null,
                            "IPAddress": "172.17.0.7",
                    "SecondaryIPAddresses": null,
                    "IPAddress": "172.17.0.6",
                            "IPAMConfig": null,
                            "IPAddress": "172.17.0.6",
                    "SecondaryIPAddresses": null,
                    "IPAddress": "172.17.0.5",
                            "IPAMConfig": null,
                            "IPAddress": "172.17.0.5",
                    "SecondaryIPAddresses": null,
                    "IPAddress": "172.17.0.4",
                            "IPAMConfig": null,
                            "IPAddress": "172.17.0.4",
                    "SecondaryIPAddresses": null,
                    "IPAddress": "172.17.0.3",
                            "IPAMConfig": null,
                            "IPAddress": "172.17.0.3",
                    "SecondaryIPAddresses": null,
                    "IPAddress": "172.17.0.2",
                            "IPAMConfig": null,
                            "IPAddress": "172.17.0.2",

可以知道:
redis-6379:172.17.0.2,redis-6380:172.17.0.3,redis-6381:172.17.0.4,redis-6382:172.17.0.5,redis-6383:172.17.0.6,redis-6384:172.17.0.7

3. 配置redis 
4. ert 
  1. Redis Cluster 的集群感知操作

    CLUSTER INFO 打印集群的信息  
    CLUSTER NODES 列出集群当前已知的所有节点(node),以及这些节点的相关信息。   

    //节点(node)  
    CLUSTER MEET <ip> <port> 将 ip 和 port 所指定的节点添加到集群当中,让它成为集群的一份子。  
    CLUSTER FORGET <node_id> 从集群中移除 node_id 指定的节点。  
    CLUSTER REPLICATE <node_id> 将当前节点设置为 node_id 指定的节点的从节点。  
    CLUSTER SAVECONFIG 将节点的配置文件保存到硬盘里面。   

    //槽(slot)  
    CLUSTER ADDSLOTS <slot> [slot ...] 将一个或多个槽(slot)指派(assign)给当前节点。  
    CLUSTER DELSLOTS <slot> [slot ...] 移除一个或多个槽对当前节点的指派。  
    CLUSTER FLUSHSLOTS 移除指派给当前节点的所有槽,让当前节点变成一个没有指派任何槽的节点。  
    CLUSTER SETSLOT <slot> NODE <node_id> 将槽 slot 指派给 node_id 指定的节点,如果槽已经指派给另一个节点,那么先让另一个节点删除该槽>,然后再进行指派。  
    CLUSTER SETSLOT <slot> MIGRATING <node_id> 将本节点的槽 slot 迁移到 node_id 指定的节点中。  
    CLUSTER SETSLOT <slot> IMPORTING <node_id> 从 node_id 指定的节点中导入槽 slot 到本节点。  
    CLUSTER SETSLOT <slot> STABLE 取消对槽 slot 的导入(import)或者迁移(migrate)。   

    //键 (key)  
    CLUSTER KEYSLOT <key> 计算键 key 应该被放置在哪个槽上。  
    CLUSTER COUNTKEYSINSLOT <slot> 返回槽 slot 目前包含的键值对数量。  
    CLUSTER GETKEYSINSLOT <slot> <count> 返回 count 个 slot 槽中的键。  

redis 集群感知:节点握手——是指一批运行在集群模式的节点通过 Gossip 协议彼此通信,达到感知对方的过程。


    OK
    192.168.10.52:6379> CLUSTER MEET 172.17.0.4 6379
    OK
    192.168.10.52:6379> CLUSTER MEET 172.17.0.5 6379
    OK
    192.168.10.52:6379> CLUSTER MEET 172.17.0.6 6379
    OK
    192.168.10.52:6379> CLUSTER MEET 172.17.0.7 6379
    OK
    192.168.10.52:6379>  CLUSTER NODES
    54cb5c2eb8e5f5aed2d2f7843f75a9284ef6785c 172.17.0.3:6379@16379 master - 0 1528697195600 1 connected
    f45f9109f2297a83b1ac36f9e1db5e70bbc174ab 172.17.0.4:6379@16379 master - 0 1528697195600 0 connected
    ae86224a3bc29c4854719c83979cb7506f37787a 172.17.0.7:6379@16379 master - 0 1528697195600 5 connected
    98aebcfe42d8aaa8a3375e4a16707107dc9da683 172.17.0.6:6379@16379 master - 0 1528697194000 4 connected
    0bbdc4176884ef0e3bb9b2e7d03d91b0e7e11f44 172.17.0.5:6379@16379 master - 0 1528697194995 3 connected
    760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 172.17.0.2:6379@16379 myself,master - 0 1528697195000 2 connected

当前已经使这六个节点组成集群,但是现在还无法工作,因为集群节点还没有分配槽(slot)。

1. 分配槽信息   

查看172.17.0.2:6379 的槽个数


        cluster_state:fail
        cluster_slots_assigned:0    # 被分配槽的个数为0
        cluster_slots_ok:0
        cluster_slots_pfail:0
        cluster_slots_fail:0
        cluster_known_nodes:6
        cluster_size:0
        cluster_current_epoch:5
        cluster_my_epoch:2
        cluster_stats_messages_ping_sent:260418
        cluster_stats_messages_pong_sent:260087
        cluster_stats_messages_meet_sent:10
        cluster_stats_messages_sent:520515
        cluster_stats_messages_ping_received:260086
        cluster_stats_messages_pong_received:260328
        cluster_stats_messages_meet_received:1
        cluster_stats_messages_received:520415

上面看到集群状态是失败的,原因是槽位没有分配,而且需要一次性把16384个槽位完全分配了,集群才可用。

2. 分配槽位 

分配槽位 : CLUSTER ADDSLOTS 槽位, 一个槽位只能分配一个节点,16384个槽位必须分配完,不同节点不能冲突 。
所以通过脚本进行分配 addslots.sh:


        # node1 192.168.10.52   172.17.0.2
        n=0
        for ((i=n;i<=5461;i++))
        do
           /usr/local/bin/redis-cli -h 192.168.10.52 -p 6379 -a 123456  CLUSTER ADDSLOTS $i
        done

        # node2 192.168.10.52    172.17.0.3
        n=5462
        for ((i=n;i<=10922;i++))
        do
           /usr/local/bin/redis-cli -h 192.168.10.52 -p 6380 -a 123456 CLUSTER ADDSLOTS $i
        done

        # node3 192.168.10.52    172.17.0.4
        n=10923
        for ((i=n;i<=16383;i++))
        do
           /usr/local/bin/redis-cli -h 192.168.10.52 -p 6381 -a 123456 CLUSTER ADDSLOTS $i
        done

其中, -a 123456 表示需要输入的密码。


        cluster_state:fail           # 集群状态为失败
        cluster_slots_assigned:16101    # 没有完全分配结束
        cluster_slots_ok:16101
        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:266756
        cluster_stats_messages_pong_sent:266528
        cluster_stats_messages_meet_sent:10
        cluster_stats_messages_sent:533294
        cluster_stats_messages_ping_received:266527
        cluster_stats_messages_pong_received:266666
        cluster_stats_messages_meet_received:1
        cluster_stats_messages_received:533194  

        192.168.10.52:6379> CLUSTER INFO
        cluster_state:ok                   # 集群状态为成功
        cluster_slots_assigned:16384       # 已经全部分配完成
        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:266757
        cluster_stats_messages_pong_sent:266531
        cluster_stats_messages_meet_sent:10
        cluster_stats_messages_sent:533298
        cluster_stats_messages_ping_received:266530
        cluster_stats_messages_pong_received:266667
        cluster_stats_messages_meet_received:1
        cluster_stats_messages_received:533198

综上可知, 当全部槽位分配完成之后,集群还是可行的,如果我们手欠,移除一个槽位,那么集群就立马那不行了,自己去试试吧 —— CLUSTER
DELSLOTS 0 。

  1. 如何变成高可用性
    以上我们已经搭建了一套完整的可运行的redis
    cluster,但是每个节点都是单点,这样子可能出现,一个节点挂掉,整个集群因为槽位分配不完全而崩溃,因此,我们需要为每个节点配置副本备用节点。
    前面我们已经提前创建了6个备用节点,搭建集群花了三个,因此还有剩下三个直接可以用来做备用副本。

    cluster_state:ok
    cluster_slots_assigned:16384
    cluster_slots_ok:16384
    cluster_slots_pfail:0
    cluster_slots_fail:0
    cluster_known_nodes:6   # 总共6个节点
    cluster_size:3          # 集群为 3 个节点
    cluster_current_epoch:5
    cluster_my_epoch:2
    cluster_stats_messages_ping_sent:270127
    cluster_stats_messages_pong_sent:269893
    cluster_stats_messages_meet_sent:10
    cluster_stats_messages_sent:540030
    cluster_stats_messages_ping_received:269892
    cluster_stats_messages_pong_received:270037
    cluster_stats_messages_meet_received:1
    cluster_stats_messages_received:539930

查看所有节点的id


    54cb5c2eb8e5f5aed2d2f7843f75a9284ef6785c 172.17.0.3:6379@16379 master - 0 1528704114535 1 connected 5462-10922
    f45f9109f2297a83b1ac36f9e1db5e70bbc174ab 172.17.0.4:6379@16379 master - 0 1528704114000 0 connected 10923-16383
    ae86224a3bc29c4854719c83979cb7506f37787a 172.17.0.7:6379@16379 master - 0 1528704114023 5 connected
    98aebcfe42d8aaa8a3375e4a16707107dc9da683 172.17.0.6:6379@16379 master - 0 1528704115544 4 connected
    0bbdc4176884ef0e3bb9b2e7d03d91b0e7e11f44 172.17.0.5:6379@16379 master - 0 1528704114836 3 connected
    760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 172.17.0.2:6379@16379 myself,master - 0 1528704115000 2 connected 0-5461

编写脚本,添加副本节点


    #!/bin/bash

    /usr/local/bin/redis-cli -h 192.168.10.52 -p 6382 -a 123456 CLUSTER REPLICATE 760e4d0039c5ac13d04aa4791c9e6dc28544d7c7

    /usr/local/bin/redis-cli -h 192.168.10.52 -p 6383 -a 123456 CLUSTER REPLICATE 54cb5c2eb8e5f5aed2d2f7843f75a9284ef6785c

    /usr/local/bin/redis-cli -h 192.168.10.52 -p 6384 -a 123456 CLUSTER REPLICATE f45f9109f2297a83b1ac36f9e1db5e70bbc174ab

注意:1、作为备用的节点,必须是未分配槽位的,否者会操作失败 (error) ERR To set a master the node must be
empty and without assigned slots 。
2、需要从需要添加的节点上面执行操作, CLUSTER REPLICATE [node_id] ,使当前节点成为 node_id 的副本节点。
3、添加从节点(集群复制):
复制的原理和单机的Redis复制原理一样,区别是:集群下的从节点也需要运行在cluster模式下,要先添加到集群里面,再做复制。
查看所有节点信息:


    54cb5c2eb8e5f5aed2d2f7843f75a9284ef6785c 172.17.0.3:6379@16379 master - 0 1528705604149 1 connected 5462-10922
    f45f9109f2297a83b1ac36f9e1db5e70bbc174ab 172.17.0.4:6379@16379 master - 0 1528705603545 0 connected 10923-16383
    ae86224a3bc29c4854719c83979cb7506f37787a 172.17.0.7:6379@16379 slave f45f9109f2297a83b1ac36f9e1db5e70bbc174ab 0 1528705603144 5 connected
    98aebcfe42d8aaa8a3375e4a16707107dc9da683 172.17.0.6:6379@16379 slave 54cb5c2eb8e5f5aed2d2f7843f75a9284ef6785c 0 1528705603000 4 connected
    0bbdc4176884ef0e3bb9b2e7d03d91b0e7e11f44 172.17.0.5:6379@16379 slave 760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 0 1528705603000 3 connected
    760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 172.17.0.2:6379@16379 myself,master - 0 1528705602000 2 connected 0-5461

可以看到我们现在实现了三主三从的一个高可用集群。

  1. 高可用测试——故障转移
    查看当前运行状态:

    54cb5c2eb8e5f5aed2d2f7843f75a9284ef6785c 172.17.0.3:6379@16379 master - 0 1528705604149 1 connected 5462-10922
    f45f9109f2297a83b1ac36f9e1db5e70bbc174ab 172.17.0.4:6379@16379 master - 0 1528705603545 0 connected 10923-16383
    ae86224a3bc29c4854719c83979cb7506f37787a 172.17.0.7:6379@16379 slave f45f9109f2297a83b1ac36f9e1db5e70bbc174ab 0 1528705603144 5 connected
    98aebcfe42d8aaa8a3375e4a16707107dc9da683 172.17.0.6:6379@16379 slave 54cb5c2eb8e5f5aed2d2f7843f75a9284ef6785c 0 1528705603000 4 connected
    0bbdc4176884ef0e3bb9b2e7d03d91b0e7e11f44 172.17.0.5:6379@16379 slave 760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 0 1528705603000 3 connected
    760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 172.17.0.2:6379@16379 myself,master - 0 1528705602000 2 connected 0-5461

以上,运行正常

尝试关闭一个master,选择端口为6380的容器,停掉之后:


    54cb5c2eb8e5f5aed2d2f7843f75a9284ef6785c 172.17.0.3:6379@16379 master,fail - 1528706408935 1528706408000 1 connected 5462-10922
    f45f9109f2297a83b1ac36f9e1db5e70bbc174ab 172.17.0.4:6379@16379 master - 0 1528706463000 0 connected 10923-16383
    ae86224a3bc29c4854719c83979cb7506f37787a 172.17.0.7:6379@16379 slave f45f9109f2297a83b1ac36f9e1db5e70bbc174ab 0 1528706462980 5 connected
    98aebcfe42d8aaa8a3375e4a16707107dc9da683 172.17.0.6:6379@16379 slave 54cb5c2eb8e5f5aed2d2f7843f75a9284ef6785c 0 1528706463000 4 connected
    0bbdc4176884ef0e3bb9b2e7d03d91b0e7e11f44 172.17.0.5:6379@16379 slave 760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 0 1528706463985 3 connected
    760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 172.17.0.2:6379@16379 myself,master - 0 1528706462000 2 connected 0-5461
    192.168.10.52:6379> 
    192.168.10.52:6379> CLUSTER INFO
    cluster_state:fail
    cluster_slots_assigned:16384
    cluster_slots_ok:10923
    cluster_slots_pfail:0
    cluster_slots_fail:5461
    cluster_known_nodes:6
    cluster_size:3
    cluster_current_epoch:5
    cluster_my_epoch:2
    cluster_stats_messages_ping_sent:275112
    cluster_stats_messages_pong_sent:274819
    cluster_stats_messages_meet_sent:10
    cluster_stats_messages_fail_sent:5
    cluster_stats_messages_sent:549946
    cluster_stats_messages_ping_received:274818
    cluster_stats_messages_pong_received:275004
    cluster_stats_messages_meet_received:1
    cluster_stats_messages_fail_received:1
    cluster_stats_messages_received:549824

以上,发现整个集群都失败了,从节点没有自动升级为主节点,怎么回事??
重启停掉的容器,经排查日志信息 [root@df6ebce6f12a /]# tail -f / var /log/redis/redis-
server.log :


    1:S 11 Jun 09:57:46.718 * (Non critical) Master does not understand REPLCONF listening-port: -NOAUTH Authentication required.
    1:S 11 Jun 09:57:46.718 * (Non critical) Master does not understand REPLCONF capa: -NOAUTH Authentication required.
    1:S 11 Jun 09:57:46.719 * Partial resynchronization not possible (no cached master)
    1:S 11 Jun 09:57:46.719 # Unexpected reply to PSYNC from master: -NOAUTH Authentication required.
    1:S 11 Jun 09:57:46.719 * Retrying with SYNC...
    1:S 11 Jun 09:57:46.719 # MASTER aborted replication with an error: NOAUTH Authentication required.
    1:S 11 Jun 09:57:46.782 * Connecting to MASTER 172.17.0.6:6379
    1:S 11 Jun 09:57:46.782 * MASTER <-> SLAVE sync started
    1:S 11 Jun 09:57:46.782 * Non blocking connect for SYNC fired the event.

可以看到,主从之间访问需要auth,之前忘记了配置 redis.conf 中的 # masterauth
,所以导致主从之间无法通讯。修改配置之后,自动故障转移正常。

有时候需要实施人工故障转移:

登录6380端口的从节点:6383,执行 CLUSTER FAILOVER 命令:


    (error) ERR Master is down or failed, please use CLUSTER FAILOVER FORCE

发现因为master已经down了,所以我们需要执行强制转移


    OK

查看当前 cluster node 情况:


    0bbdc4176884ef0e3bb9b2e7d03d91b0e7e11f44 172.17.0.5:6379@16379 slave 760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 0 1528707535332 3 connected
    ae86224a3bc29c4854719c83979cb7506f37787a 172.17.0.7:6379@16379 slave f45f9109f2297a83b1ac36f9e1db5e70bbc174ab 0 1528707534829 5 connected
    f45f9109f2297a83b1ac36f9e1db5e70bbc174ab 172.17.0.4:6379@16379 master - 0 1528707534527 0 connected 10923-16383
    98aebcfe42d8aaa8a3375e4a16707107dc9da683 172.17.0.6:6379@16379 myself,master - 0 1528707535000 6 connected 5462-10922
    760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 172.17.0.2:6379@16379 master - 0 1528707535834 2 connected 0-5461
    54cb5c2eb8e5f5aed2d2f7843f75a9284ef6785c 172.17.0.3:6379@16379 master,fail - 1528707472833 1528707472000 1 connected

从节点已经升级为master节点。这时候,我们尝试重启了,6380节点的redis(其实是重新启动停掉的容器):


    0bbdc4176884ef0e3bb9b2e7d03d91b0e7e11f44 172.17.0.5:6379@16379 slave 760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 0 1528707556044 3 connected
    ae86224a3bc29c4854719c83979cb7506f37787a 172.17.0.7:6379@16379 slave f45f9109f2297a83b1ac36f9e1db5e70bbc174ab 0 1528707555000 5 connected
    f45f9109f2297a83b1ac36f9e1db5e70bbc174ab 172.17.0.4:6379@16379 master - 0 1528707556000 0 connected 10923-16383
    98aebcfe42d8aaa8a3375e4a16707107dc9da683 172.17.0.6:6379@16379 myself,master - 0 1528707556000 6 connected 5462-10922
    760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 172.17.0.2:6379@16379 master - 0 1528707556000 2 connected 0-5461
    54cb5c2eb8e5f5aed2d2f7843f75a9284ef6785c 172.17.0.3:6379@16379 slave 98aebcfe42d8aaa8a3375e4a16707107dc9da683 0 1528707556547 6 connected

我们发现,6380节点反而变成了 6383节点的从节点。

现在集群应该是完整的了,所以,集群状态应该已经恢复了,我们查看下:


    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:6
    cluster_stats_messages_ping_sent:19419
    cluster_stats_messages_pong_sent:19443
    cluster_stats_messages_meet_sent:1
    cluster_stats_messages_auth-req_sent:5
    cluster_stats_messages_update_sent:1
    cluster_stats_messages_sent:38869
    cluster_stats_messages_ping_received:19433
    cluster_stats_messages_pong_received:19187
    cluster_stats_messages_meet_received:5
    cluster_stats_messages_fail_received:4
    cluster_stats_messages_auth-ack_received:2
    cluster_stats_messages_received:38631

OK,没有问题。

  1. 集群访问
    客户端在初始化的时候只需要知道一个节点的地址即可,客户端会先尝试向这个节点执行命令,比如 get key
    ,如果key所在的slot刚好在该节点上,则能够直接执行成功。如果slot不在该节点,则节点会返回MOVED错误,
    同时把该slot对应的节点告诉客户端,客户端可以去该节点执行命令

    (error) MOVED 866 172.17.0.2:6379

    192.168.10.52:6379> set number 20004
    (error) MOVED 7743 172.17.0.3:6379

另外, redis集群版只使用db0,select命令虽然能够支持select 0。其他的db都会返回错误 。


    OK
    192.168.10.52:6383> select 1
    (error) ERR SELECT is not allowed in cluster mode
  1. 近期,有网友询问docker redis集群连接报错的问题,具体报错如下:

初步认为是,node节点没有全部添加进去,添加之后,依然有上述问题。想到是跨主机访问,应该是路由寻址不了导致的。当初写上述教程的时候,docker是以默认的网络模式bridge模式运行的,毕竟当初是以学习整理文档为主,主要是单机访问。但是,实际应用化场景中,多是公网跨主机访问,问题明朗了,想着集群这东西最好还是设置成共享主机公网ip比较好,于是解决如下:

1. 在docker运行时,执行网络模式为:host。 
2. 端口冲突解决,毕竟host模式下,容器会占用宿主机的端口,于是,我们就从配置下手,在宿主机上生成配置redis-60001.conf,redis-60002.conf,redis-60003.conf...,有多少端口建多少个文件,最终运行一个容器,挂载一个配置到容器中用于覆盖主机中的配置。   

最终的运行方式如下:

/tmp/redis.conf:/usr/local/redis/redis.conf  hakimdstx/nodes-redis:4.0.1

至此,网络问题得到解决。
PS.生产环境需要注意防火墙问题,不然也是会报错的。

以上

引用

1、 [ Redis Cluster部署、管理和测试
](https://www.cnblogs.com/zhoujinyi/p/6477133.html?utm_source=itdadao&utm_medium=referral
"Redis Cluster部署、管理和测试")

2、 Docker下redis的主从、持久化配置

原创文章,如若转载,请注明出自:http://www.javaobj.com/2020/06/redis-cluster-in-docker/

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