Linux Redis集群搭建与集群客户端实现

ゝ一纸荒年。 2022-05-28 05:12 314阅读 0赞

硬件环境

本文适用的硬件环境如下

Linux版本：CentOS release 6.7 (Final)
    Redis版本：3.2.1

Redis已经成功安装，安装路径为/home/idata/yangfan/local/redis-3.2.1。

我们要在单台机器上搭建Redis集群，方式是通过不同的TCP端口启动多个实例，然后组成集群。

1、启动Redis多个实例

我们在Redis安装目录下创建目录cluster，并编写7000.conf~7005.conf 6个配置文件，这6个配置文件用来启动6个实例，后面将使用这6个实例组成集群。

以7000.conf为例，配置文件需要填写如下几项。

![复制代码][copycode.gif]

port  7000                                        //端口7000,7002,7003        
    bind 10.93.84.53                                     //默认ip为127.0.0.1 需要改为其他节点机器可访问的ip 否则创建集群时无法访问对应的端口，无法创建集群
    daemonize    yes                               //redis后台运行
    pidfile  ./redis_7000.pid          //pidfile文件对应7000,7001,7002
    cluster-enabled  yes                           //开启集群  把注释#去掉
    cluster-config-file  nodes_7000.conf   //集群的配置  配置文件首次启动自动生成 7000,7001,7002
    cluster-node-timeout  15000                //请求超时  默认15秒，可自行设置
    appendonly  yes                           //aof日志开启  有需要就开启，它会每次写操作都记录一条日志

![复制代码][copycode.gif]

分别启动6个实例

./bin/redis-server cluster/conf/7000.conf
    ./bin/redis-server cluster/conf/7001.conf 
    ./bin/redis-server cluster/conf/7002.conf 
    ./bin/redis-server cluster/conf/7003.conf 
    ./bin/redis-server cluster/conf/7004.conf 
    ./bin/redis-server cluster/conf/7005.conf

启动成功后，看一下进程

![复制代码][copycode.gif]

# ps -ef | grep redis | grep cluster
    idata    15711 22329  0 18:40 pts/10   00:00:00 ./bin/redis-server 10.93.84.53:7000 [cluster] idata 15740 22329 0 18:40 pts/10 00:00:00 ./bin/redis-server 10.93.84.53:7001 [cluster] idata 15810 22329 0 18:40 pts/10 00:00:00 ./bin/redis-server 10.93.84.53:7002 [cluster] idata 17023 22329 0 18:42 pts/10 00:00:00 ./bin/redis-server 10.93.84.53:7003 [cluster] idata 17030 22329 0 18:42 pts/10 00:00:00 ./bin/redis-server 10.93.84.53:7004 [cluster] idata 17035 22329 0 18:42 pts/10 00:00:00 ./bin/redis-server 10.93.84.53:7005 [cluster]

![复制代码][copycode.gif]

至此，ip=10.93.84.53机器上创建了6个实例，端口号为port=7000~7005。

Redis 3.0以上的集群方式是通过Redis安装目录下的bin/redis-trib.rb脚本搭建。

这个脚本是用Ruby编写的，尝试运行，如果打印如下，你可以跳过本文的第二部分。

![复制代码][copycode.gif]

idata@qa-f1502-xg01.xg01:~/yangfan/local/redis-3.2.1/bin$ ruby redis-trib.rb 
    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.

![复制代码][copycode.gif]

如果执行失败，那么不幸的是你的机器没有Ruby运行的环境，那么你需要安装Ruby。进入第二部分。

2、安装ruby

下面的过程都是在root权限下完成的。

1）yum安装ruby和依赖的包。

# yum -y install ruby ruby-devel rubygems rpm-build

一般来说，这一步是能正常完成的。

2）使用gem这个命令来安装redis接口

gem是ruby的一个工具包

# gem install redis

安装过程出错

[![1061021-20171012174253855-788152672.png][]][1061021-20171012174253855-788152672.png 1]

郁闷，看样子要升级ruby版本。

3）升级Ruby的版本

安装rvm，我不知道这是个什么东西，但是感觉像是Ruby的一个包管理器。

# curl -L get.rvm.io | bash -s stable

WTF，又出问题了

![1061021-20171012174712262-309614231.png][]

气急败坏的照着他说的做

![复制代码][copycode.gif]

# gpg2 --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3
    gpg: keyring `/root/.gnupg/secring.gpg' created
    gpg: requesting key D39DC0E3 from hkp server keys.gnupg.net
    gpg: /root/.gnupg/trustdb.gpg: trustdb created
    gpg: key D39DC0E3: public key "Michal Papis (RVM signing) <mpapis@gmail.com>" imported
    gpg: no ultimately trusted keys found
    gpg: Total number processed: 1
    gpg:               imported: 1  (RSA: 1)

![复制代码][copycode.gif]

然后重新下载rvm安装，成功了。

![复制代码][copycode.gif]

# curl -L get.rvm.io | bash -s stable 
      % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                     Dload  Upload   Total   Spent    Left  Speed
    100 24090  100 24090    0     0  18023      0  0:00:01  0:00:01 --:--:--  129k
    Downloading https://github.com/rvm/rvm/archive/1.29.3.tar.gz
    Downloading https://github.com/rvm/rvm/releases/download/1.29.3/1.29.3.tar.gz.asc
    gpg: Signature made Mon 11 Sep 2017 04:59:21 AM CST using RSA key ID BF04FF17
    gpg: Good signature from "Michal Papis (RVM signing) <mpapis@gmail.com>"
    gpg:                 aka "Michal Papis <michal.papis@toptal.com>"
    gpg:                 aka "[jpeg image of size 5015]"
    gpg: WARNING: This key is not certified with a trusted signature!
    gpg:          There is no indication that the signature belongs to the owner.
    Primary key fingerprint: 409B 6B17 96C2 7546 2A17  0311 3804 BB82 D39D C0E3
         Subkey fingerprint: 62C9 E5F4 DA30 0D94 AC36  166B E206 C29F BF04 FF17
    GPG verified '/usr/local/rvm/archives/rvm-1.29.3.tgz'
    Creating group 'rvm'
    
    Installing RVM to /usr/local/rvm/
    Installation of RVM in /usr/local/rvm/ is almost complete:
    
      * First you need to add all users that will be using rvm to 'rvm' group,
        and logout - login again, anyone using rvm will be operating with `umask u=rwx,g=rwx,o=rx`.
    
      * To start using RVM you need to run `source /etc/profile.d/rvm.sh`
        in all your open shell windows, in rare cases you need to reopen all shell windows.

![复制代码][copycode.gif]

接着，source环境，让rvm可用。

# source /usr/local/rvm/scripts/rvm

查看Ruby可用版本

![复制代码][copycode.gif]

# rvm list known
    # MRI Rubies
    [ruby-]1.8.6[-p420]
    [ruby-]1.8.7[-head] # security released on head
    [ruby-]1.9.1[-p431]
    [ruby-]1.9.2[-p330]
    [ruby-]1.9.3[-p551]
    [ruby-]2.0.0[-p648]
    [ruby-]2.1[.10]
    [ruby-]2.2[.7]
    [ruby-]2.3[.4]
    [ruby-]2.4[.1]

![复制代码][copycode.gif]

可以看到最新的版本是2.4.1，那么我们装最新的吧。

![复制代码][copycode.gif]

# rvm install 2.4.1
    Searching for binary rubies, this might take some time.
    No binary rubies available for: centos/6/x86_64/ruby-2.4.1.
    Continuing with compilation. Please read 'rvm help mount' to get more information on binary rubies.
    Checking requirements for centos.
    Installing requirements for centos.
    Installing required packages: libffi-devel, libyaml-devel......
    Requirements installation successful.
    Installing Ruby from source to: /usr/local/rvm/rubies/ruby-2.4.1, this may take a while depending on your cpu(s)...
    ruby-2.4.1 - #downloading ruby-2.4.1, this may take a while depending on your connection...
    
    curl: (35) SSL connect error
    There was an error(35).
    Checking fallback: https://ftp.ruby-lang.org/pub/ruby/2.4/ruby-2.4.1.tar.bz2
      % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                     Dload  Upload   Total   Spent    Left  Speed
    100 11.9M  100 11.9M    0     0  1753k      0  0:00:07  0:00:07 --:--:-- 2919k
    ruby-2.4.1 - #extracting ruby-2.4.1 to /usr/local/rvm/src/ruby-2.4.1....
    ruby-2.4.1 - #applying patch /usr/local/rvm/patches/ruby/2.4.1/random_c_using_NR_prefix.patch.
    ruby-2.4.1 - #configuring..................................................................
    ruby-2.4.1 - #post-configuration..
    ruby-2.4.1 - #compiling..............................................................................................
    ruby-2.4.1 - #installing.........................
    ruby-2.4.1 - #making binaries executable..
    ruby-2.4.1 - #downloading rubygems-2.6.14
      % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                     Dload  Upload   Total   Spent    Left  Speed
    100  751k  100  751k    0     0   443k      0  0:00:01  0:00:01 --:--:--  628k
    No checksum for downloaded archive, recording checksum in user configuration.
    ruby-2.4.1 - #extracting rubygems-2.6.14....
    ruby-2.4.1 - #removing old rubygems.........
    ruby-2.4.1 - #installing rubygems-2.6.14...........................
    ruby-2.4.1 - #gemset created /usr/local/rvm/gems/ruby-2.4.1@global
    ruby-2.4.1 - #importing gemset /usr/local/rvm/gemsets/global.gems...............................................
    ruby-2.4.1 - #generating global wrappers........
    ruby-2.4.1 - #gemset created /usr/local/rvm/gems/ruby-2.4.1
    ruby-2.4.1 - #importing gemsetfile /usr/local/rvm/gemsets/default.gems evaluated to empty gem list
    ruby-2.4.1 - #generating default wrappers........
    ruby-2.4.1 - #adjusting #shebangs for (gem irb erb ri rdoc testrb rake).
    Install of ruby-2.4.1 - #complete 
    Ruby was built without documentation, to build it run: rvm docs generate-ri

![复制代码][copycode.gif]

至此，我们升级了Ruby的版本。

4）安装gem redis接口，成功！

![复制代码][copycode.gif]

gem install redis
    Fetching: redis-4.0.1.gem (100%)
    Successfully installed redis-4.0.1
    Parsing documentation for redis-4.0.1
    Installing ri documentation for redis-4.0.1
    Done installing documentation for redis after 0 seconds
    1 gem installed

![复制代码][copycode.gif]

5）安装rubygems，成功！

![复制代码][copycode.gif]

# yum install -y rubygems
    Loaded plugins: fastestmirror, security
    Setting up Install Process
    Loading mirror speeds from cached hostfile
    base                                                                                                                                                   | 3.7 kB     00:00     
    didi_jenkins_enable                                                                                                                                    | 1.5 kB     00:00     
    didi_op_toa_enable                                                                                                                                     | 1.5 kB     00:00     
    didi_txjenkins_enable                                                                                                                                  | 1.5 kB     00:00     
    didi_update                                                                                                                                            | 1.5 kB     00:00     
    epel                                                                                                                                                   | 4.3 kB     00:00     
    extras                                                                                                                                                 | 3.4 kB     00:00     
    tmprepo                                                                                                                                                | 1.5 kB     00:00     
    updates                                                                                                                                                | 3.4 kB     00:00     
    Package rubygems-1.3.7-5.el6.noarch already installed and latest version
    Nothing to do

![复制代码][copycode.gif]

至此，我们的Ruby和运行redis-trib.rb需要的环境安装完成了。

3、Redis集群搭建

有了Ruby执行环境，可以开始将之前的6个实例组建成集群了。

命令方式：

ruby ./bin/redis-trib.rb create --replicas 1 10.93.84.53:7000 10.93.84.53:7001 10.93.84.53:7002 10.93.84.53:7003 10.93.84.53:7004 10.93.84.53:7005

--replicas 1表示为集群的master节点创建1个副本。那么6个实例里，有三个master，有三个是slave。
    
    后面跟上6个实例就好了，形式就是ip:port

执行情况：

![复制代码][copycode.gif]

# ruby ./bin/redis-trib.rb create --replicas 1 10.93.84.53:7000 10.93.84.53:7001 10.93.84.53:7002 10.93.84.53:7003 10.93.84.53:7004 10.93.84.53:7005
    >>> Creating cluster
    >>> Performing hash slots allocation on 6 nodes...
    Using 3 masters:
    10.93.84.53:7000
    10.93.84.53:7001
    10.93.84.53:7002
    Adding replica 10.93.84.53:7003 to 10.93.84.53:7000
    Adding replica 10.93.84.53:7004 to 10.93.84.53:7001
    Adding replica 10.93.84.53:7005 to 10.93.84.53:7002
    M: 6346ae8c7af7949658619fcf4021cc7aca454819 10.93.84.53:7000
       slots:0-5460 (5461 slots) master
    M: 5ac973bceab0d486c497345fe884ff54d1bb225a 10.93.84.53:7001
       slots:5461-10922 (5462 slots) master
    M: cc46a4a1c0ec3f621b6b5405c6c10b7cffe73932 10.93.84.53:7002
       slots:10923-16383 (5461 slots) master
    S: 92f62ec93a0550d962f81213ca7e9b3c9c996afd 10.93.84.53:7003
       replicates 6346ae8c7af7949658619fcf4021cc7aca454819
    S: 942c9f97dc68198c39f425d13df0d8e3c40c5a58 10.93.84.53:7004
       replicates 5ac973bceab0d486c497345fe884ff54d1bb225a
    S: a92a81532b63652bbd862be6f19a9bd8832e5e05 10.93.84.53:7005
       replicates cc46a4a1c0ec3f621b6b5405c6c10b7cffe73932
    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 10.93.84.53:7000)
    M: 6346ae8c7af7949658619fcf4021cc7aca454819 10.93.84.53:7000
       slots:0-5460 (5461 slots) master
       1 additional replica(s)
    S: a92a81532b63652bbd862be6f19a9bd8832e5e05 10.93.84.53:7005
       slots: (0 slots) slave
       replicates cc46a4a1c0ec3f621b6b5405c6c10b7cffe73932
    M: 5ac973bceab0d486c497345fe884ff54d1bb225a 10.93.84.53:7001
       slots:5461-10922 (5462 slots) master
       1 additional replica(s)
    S: 942c9f97dc68198c39f425d13df0d8e3c40c5a58 10.93.84.53:7004
       slots: (0 slots) slave
       replicates 5ac973bceab0d486c497345fe884ff54d1bb225a
    S: 92f62ec93a0550d962f81213ca7e9b3c9c996afd 10.93.84.53:7003
       slots: (0 slots) slave
       replicates 6346ae8c7af7949658619fcf4021cc7aca454819
    M: cc46a4a1c0ec3f621b6b5405c6c10b7cffe73932 10.93.84.53:7002
       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.

![复制代码][copycode.gif]

可以看到16384个slot都已经创建完成，并且建立了3个master和对应的replica:

![复制代码][copycode.gif]

Using 3 masters:
    10.93.84.53:7000
    10.93.84.53:7001
    10.93.84.53:7002
    Adding replica 10.93.84.53:7003 to 10.93.84.53:7000
    Adding replica 10.93.84.53:7004 to 10.93.84.53:7001
    Adding replica 10.93.84.53:7005 to 10.93.84.53:7002
    
    。。。

[OK] All 16384 slots covered.

![复制代码][copycode.gif]

4、验证集群状态

登录集群客户端，-c标识以集群方式登录

./bin/redis-cli -h 10.93.84.53 -p 7000 -c

查看集群状态

![复制代码][copycode.gif]

10.93.84.53:7000> 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:8
    cluster_my_epoch:8
    cluster_stats_messages_sent:215
    cluster_stats_messages_received:215
    10.93.84.53:7000> cluster nodes
    942c9f97dc68198c39f425d13df0d8e3c40c5a58 10.93.84.53:7004 slave 5ac973bceab0d486c497345fe884ff54d1bb225a 0 1507806791940 5 connected
    5ac973bceab0d486c497345fe884ff54d1bb225a 10.93.84.53:7001 master - 0 1507806788937 2 connected 5461-10922
    a92a81532b63652bbd862be6f19a9bd8832e5e05 10.93.84.53:7005 slave cc46a4a1c0ec3f621b6b5405c6c10b7cffe73932 0 1507806790939 6 connected
    cc46a4a1c0ec3f621b6b5405c6c10b7cffe73932 10.93.84.53:7002 master - 0 1507806789937 3 connected 10923-16383
    6346ae8c7af7949658619fcf4021cc7aca454819 10.93.84.53:7000 myself,slave 92f62ec93a0550d962f81213ca7e9b3c9c996afd 0 0 1 connected
    92f62ec93a0550d962f81213ca7e9b3c9c996afd 10.93.84.53:7003 master - 0 1507806792941 8 connected 0-5460

![复制代码][copycode.gif]

一些原理

redis cluster在设计的时候，就考虑到了去中心化，去中间件，也就是说，集群中的每个节点都是平等的关系，都是对等的，每个节点都保存各自的数据和整个集群的状态。每个节点都和其他所有节点连接，而且这些连接保持活跃，这样就保证了我们只需要连接集群中的任意一个节点，就可以获取到其他节点的数据。

Redis集群没有并使用传统的一致性哈希来分配数据，而是采用另外一种叫做`哈希槽（hash slot）`的方式来分配的，一致性哈希对向集群中新增和删除实例的支持很好，但是哈希槽对向集群新增实例或者删除实例的话，需要额外的操作，需要手动的将slot重新平均的分配到新集群的实例中。

redis cluster 默认分配了 16384 个slot，当我们set一个key时，会用`CRC16`算法来取模得到所属的`slot`，然后将这个key分到哈希槽区间的节点上，具体算法就是：`CRC16(key)%16384。`

Redis 集群会把数据存在一个master节点，然后在这个master和其对应的salve之间进行数据同步。当读取数据时，也根据一致性哈希算法到对应的master节点获取数据。只有当一个master 挂掉之后，才会启动一个对应的salve节点，充当master。

需要注意的是：必须要`3个或以上`的主节点，否则在创建集群时会失败，并且当存活的主节点数小于总节点数的一半时，整个集群就无法提供服务了。

5、python集群客户端

以Python Redis Cluster集群的使用方式为例，简单说明一下如何使用，让大家更直观的了解一下Redis集群。

Redis集群方式与单机方式在python客户端实现上是有很大不同的。

*  包不同，单机依赖包redis-py，集群依赖包redis-py-cluster
 *  对同时操作多个keys的命令(mset, mget, sinter, ...)，redis-py-cluster重写StriceRedis(单机Redis操作类)了其方法，而这些方法丧失了命令的原子性。
 *  Pipelines在集群中的表现也不同了。在单机版中，pipeline是批量batch提交redis批量执行的，但是在集群版中，是one by one提交redis执行完成直接返回，在客户端重新组合成一个列表返回。所以集群中只是看起来像是批量执行。
 *  一些命令是会Fanout(扇形)发送到集群中各个shard中执行并汇总的，如ping，keys等。一些命令是不提倡使用(blocked)，如watch，unwatch等。

我只是简单翻译了官网的一些内容，相信信息大家可以参考：

[http://redis-py-cluster.readthedocs.io/en/master/commands.html][http_redis-py-cluster.readthedocs.io_en_master_commands.html]

[http://redis-py-cluster.readthedocs.io/en/master/limitations-and-differences.html][http_redis-py-cluster.readthedocs.io_en_master_limitations-and-differences.html]

1）安装redis-py-cluster

简单的通过pip安装redis-py-cluster包。如果安装失败，可以自助下载安装。

# pip install redis-py-cluster     
    Collecting redis-py-cluster
      Downloading redis_py_cluster-1.3.4-py2.py3-none-any.whl
    Requirement already satisfied: redis>=2.10.2 in /home/idata/pythonEnv/idataPlatEnv/lib/python2.7/site-packages/redis-2.10.5-py2.7.egg (from redis-py-cluster)
    Installing collected packages: redis-py-cluster
    Successfully installed redis-py-cluster-1.3.4

2）一个简单的demo

封装了RedisCluster操作类，实现了一些方法，其实就是做了一层封装。

封装的意义是：我喜欢对这些封装增加一些装饰器，控制异常和重试等逻辑。

![复制代码][copycode.gif]

# -*- coding:utf-8 -*-
    
    from rediscluster import StrictRedisCluster
    
    redis_nodes = [
            {
        'host': '10.93.84.53', 'port': 7000},
            {
        'host': '10.93.84.53', 'port': 7001},
            {
        'host': '10.93.84.53', 'port': 7002},
            {
        'host': '10.93.84.53', 'port': 7003},
            {
        'host': '10.93.84.53', 'port': 7004},
            {
        'host': '10.93.84.53', 'port': 7005},
        ]
    
    
    class RedisCluster(object):
    
        def __init__(self, redis_nodes):
            self.cluster = StrictRedisCluster(startup_nodes=redis_nodes)
    
        # 无差别的方法
        def set(self, name, value, ex=None, px=None, nx=False, xx=False):
            return self.cluster.set(name, value, ex, px, nx, xx)
        
        # 无差别的方法
        def get(self, name):
            return self.cluster.get(name)
        
        # 扇形发送的命令
        def cluster_info(self):
            return self.cluster.cluster_info()
    
        # 重写StrictRedis的方法
        def mset(self, *args, **kwargs):
            return self.cluster.mset(args, kwargs)
        
        # 重写StrictRedis的方法
        def mget(self, keys, *args):
            return self.cluster.mget(keys, args)
        
        
    cluster = RedisCluster(redis_nodes)
    cluster.cluster_info()

[copycode.gif]: /images/20220528/d1b01491f2ab42519874c803db3124e5.png
[1061021-20171012174253855-788152672.png]: /images/20220528/88431a90875e4dc0872f64c7f437bef0.png
[1061021-20171012174253855-788152672.png 1]: http://www.cnblogs.com/carryping/p/7447823.html
[1061021-20171012174712262-309614231.png]: /images/20220528/2b86513097c0427bbfbc3a66ca62012f.png
[http_redis-py-cluster.readthedocs.io_en_master_commands.html]: http://redis-py-cluster.readthedocs.io/en/master/commands.html
[http_redis-py-cluster.readthedocs.io_en_master_limitations-and-differences.html]: http://redis-py-cluster.readthedocs.io/en/master/limitations-and-differences.html