Redis-集群

Posted 2021-03-15 暗里着迷

搭建redis集群有两种方式，原理一样，一个是通过redis提供的脚本文件来启动默认的集群实例，另一个是手动配置。

 

一.默认脚本启动

在redis的安装的utils/create-cluster目录下，有个create-cluster执行文件，查看文件我们只需要改两个地方：

#!/bin/bash

# Settings
PORT=30000
TIMEOUT=2000
NODES=6
REPLICAS=1

# You may want to put the above config parameters into config.sh in order to
# override the defaults without modifying this script.

if [ -a config.sh ]
then
    source "config.sh"
fi

# Computed vars
ENDPORT=$((PORT+NODES))

if [ "$1" == "start" ]
then
    while [ $((PORT < ENDPORT)) != "0" ]; do
        PORT=$((PORT+1))
        echo "Starting $PORT"
        ../../src/redis-server --port $PORT --cluster-enabled yes --cluster-config-file nodes-${PORT}.conf --cluster-node-timeout $TIMEOUT --appendonly yes --appendfilename appendonly-${PORT}.aof --dbfilename dump-${PORT}.rdb --logfile ${PORT}.log --daemonize yes
    done
    exit 0
fi

if [ "$1" == "create" ]
then
    HOSTS=""
    while [ $((PORT < ENDPORT)) != "0" ]; do
        PORT=$((PORT+1))
        HOSTS="$HOSTS 127.0.0.1:$PORT"
    done
    ../../src/redis-cli --cluster create $HOSTS --cluster-replicas $REPLICAS
    exit 0
fi

if [ "$1" == "stop" ]
then
    while [ $((PORT < ENDPORT)) != "0" ]; do
        PORT=$((PORT+1))
        echo "Stopping $PORT"
        ../../src/redis-cli -p $PORT shutdown nosave
    done
    exit 0
fi

if [ "$1" == "watch" ]
then
    PORT=$((PORT+1))
    while [ 1 ]; do
        clear
        date
        ../../src/redis-cli -p $PORT cluster nodes | head -30
        sleep 1
    done
    exit 0
fi

if [ "$1" == "tail" ]
then
    INSTANCE=$2
    PORT=$((PORT+INSTANCE))
    tail -f ${PORT}.log
    exit 0
fi

if [ "$1" == "call" ]
then
    while [ $((PORT < ENDPORT)) != "0" ]; do
        PORT=$((PORT+1))
        ../../src/redis-cli -p $PORT $2 $3 $4 $5 $6 $7 $8 $9
    done
    exit 0
fi

if [ "$1" == "clean" ]
then
    rm -rf *.log
    rm -rf appendonly*.aof
    rm -rf dump*.rdb
    rm -rf nodes*.conf
    exit 0
fi

if [ "$1" == "clean-logs" ]
then
    rm -rf *.log
    exit 0
fi

echo "Usage: $0 [start|create|stop|watch|tail|clean]"
echo "start       -- Launch Redis Cluster instances."
echo "create      -- Create a cluster using redis-cli --cluster create."
echo "stop        -- Stop Redis Cluster instances."
echo "watch       -- Show CLUSTER NODES output (first 30 lines) of first node."
echo "tail <id>   -- Run tail -f of instance at base port + ID."
echo "clean       -- Remove all instances data, logs, configs."
echo "clean-logs  -- Remove just instances logs."

NODES=6 6表示启动6个redis实例
REPLICAS=1 1表示副本的数量，6个实例，那么就是3主3从

1.启动实例，

默认将启动6个实例，端口从30001~30006

./create-cluster start

 

2.分配槽，redis默认有16384个槽，执行此命令，然后输入yes,3个主节点将均分这些槽

./create-cluster create

 

3.清除集群，执行后，当前路径下默认生成的一些配置文件就都被删除了

./create-cluster stop
./create-cluster clean

 

二.手动执行命令创建集群(推荐)

1. 首先我们要准备6个新的redis实例，并修改好对应配置文件中的内容：

cluster-enabled yes 
cluster-config-file  nodes-6379.conf 
cluster-node-timeout 2000 
appendonly yes 
appendfilename appendonly-6379.aof 
dbfilename dump-6379.rdb 
logfile 6379.log 
daemonize yes

端口号自己的定义，aof要不要开根据自己业务来，后台运行。

 

2. 启动这些实例：

redis-server 30001.conf

redis-server 30002.conf
...

 

3. redis-cli 客户端提供了创建集群的命令,通过如下命令查看：

redis-cli --cluster help

Cluster Manager Commands:
  create         host1:port1 ... hostN:portN
                 --cluster-replicas <arg>
  check          host:port
                 --cluster-search-multiple-owners
  info           host:port
  fix            host:port
                 --cluster-search-multiple-owners
  reshard        host:port
                 --cluster-from <arg>
                 --cluster-to <arg>
                 --cluster-slots <arg>
                 --cluster-yes
                 --cluster-timeout <arg>
                 --cluster-pipeline <arg>
                 --cluster-replace
  rebalance      host:port
                 --cluster-weight <node1=w1...nodeN=wN>
                 --cluster-use-empty-masters
                 --cluster-timeout <arg>
                 --cluster-simulate
                 --cluster-pipeline <arg>
                 --cluster-threshold <arg>
                 --cluster-replace
  add-node       new_host:new_port existing_host:existing_port
                 --cluster-slave
                 --cluster-master-id <arg>
  del-node       host:port node_id
  call           host:port command arg arg .. arg
  set-timeout    host:port milliseconds
  import         host:port
                 --cluster-from <arg>
                 --cluster-copy
                 --cluster-replace
  help           

For check, fix, reshard, del-node, set-timeout you can specify the host and port of any working node in the cluster.

 

4.加入集群，3主3从：

redis-cli --cluster create 127.0.0.1:30001 127.0.0.1:30002 127.0.0.1:30003 127.0.0.1:30004 127.0.0.1:30005 127.0.0.1:30006 --cluster-replicas 1

 

三.介绍下常用的集群操作命令：

1. reshard 重新分片。redis集群默认将16384个槽均分了，如果想将某一个主节点下面的N个槽的数据移至另一个主节点下（新增主节点或已有主节点重新均衡槽数）：

redis-cli --cluster reshard 127.0.0.1:30001

127.0.0.1:30001 没有固定限制，只要是redis集群中的某个主节点的ip+port即可，执行完会提示：

>>> Performing Cluster Check (using node 127.0.0.1:30001)
M: 58eb27ff6459a3375e9eaab29bc1438edc622c51 127.0.0.1:30001
slots:[0-5460] (5461 slots) master
1 additional replica(s)
S: 963652d83d92be777539c777cbde0475e98c53bd 127.0.0.1:30005
slots: (0 slots) slave
replicates a45cc489e63539924101ff4c504203f2ef2d5683
M: a45cc489e63539924101ff4c504203f2ef2d5683 127.0.0.1:30003
slots:[10923-16383] (5461 slots) master
1 additional replica(s)
S: 727ef5c4243f9b47e7c7f6bdedbe5f1d850631a9 127.0.0.1:30006
slots: (0 slots) slave
replicates 58eb27ff6459a3375e9eaab29bc1438edc622c51
M: 788b2f2855d6b760f53d9894c4c9ba5162345a1f 127.0.0.1:30002
slots:[5461-10922] (5462 slots) master
1 additional replica(s)
S: f0414dc3845188e6c977615fda959e59d14103ef 127.0.0.1:30004
slots: (0 slots) slave
replicates 788b2f2855d6b760f53d9894c4c9ba5162345a1f
[OK] All nodes agree about slots configuration.
>>> Check for open slots...
>>> Check slots coverage...
[OK] All 16384 slots covered.

 

2. How many slots do you want to move (from 1 to 16384)?

　提示输入你想移动的槽的个数，

比如输入：2000

3. What is the receiving node ID?

　提示输入你想用哪个主节点来接收这2000个槽位

比如输入：58eb27ff6459a3375e9eaab29bc1438edc622c51

4. Source node #1: 

提示输入2000个槽位由哪个节点提供，想从多个主节点拆槽位，就输入一个后回车继续输入下一个，输入完成后，输入 done 回车

5. Do you want to proceed with the proposed reshard plan (yes/no)?

提示你是否要执行这个分片计划，输入:yes

6. 再通过redis-cli --cluster check 127.0.0.1:30001 命令查看下重分片后的槽位信息：

M: 58eb27ff6459a3375e9eaab29bc1438edc622c51 127.0.0.1:30001
slots:[0-5460],[10923-12922] (7461 slots) master
1 additional replica(s)
S: 963652d83d92be777539c777cbde0475e98c53bd 127.0.0.1:30005
slots: (0 slots) slave
replicates a45cc489e63539924101ff4c504203f2ef2d5683
M: a45cc489e63539924101ff4c504203f2ef2d5683 127.0.0.1:30003
slots:[12923-16383] (3461 slots) master
1 additional replica(s)
S: 727ef5c4243f9b47e7c7f6bdedbe5f1d850631a9 127.0.0.1:30006
slots: (0 slots) slave
replicates 58eb27ff6459a3375e9eaab29bc1438edc622c51
M: 788b2f2855d6b760f53d9894c4c9ba5162345a1f 127.0.0.1:30002
slots:[5461-10922] (5462 slots) master
1 additional replica(s)
S: f0414dc3845188e6c977615fda959e59d14103ef 127.0.0.1:30004
slots: (0 slots) slave
replicates 788b2f2855d6b760f53d9894c4c9ba5162345a1f

可以看出，节点58eb27ff6459a3375e9eaab29bc1438edc622c51多出了槽位[10923-12922]，a45cc489e63539924101ff4c504203f2ef2d5683 少了2000个槽位

 

7. add-node，添加的节点可以试从节点，也可以试从节点，具体看添加时后面接的参数，根据help命令，如下：

add-node new_host:new_port existing_host:existing_port
                 --cluster-slave
                 --cluster-master-id <arg>

（1）首先我们要准备一个新的redis实例，并修改好配置文件中的内容，如:6379.conf,启动后，将此实例添加到redis集群中，下面试添加一个主节点:

redis-cli --cluster add-node 127.0.0.1:6379 127.0.0.1:30001 --cluster-master-id 58eb27ff6459a3375e9eaab29bc1438edc622c51

（2）如果想在某个主节点下挂在从节点：

redis-cli --cluster add-node 127.0.0.1:6380 127.0.0.1:6379 --cluster-slave

 

8. del-node，比较简单：

redis-cli --cluster del-node 127.0.0.1:6380 node_id

集群操作的其他命令，可以自己尝试通过help命令，去实操一把。