cnblogs.com/cxbhakim/p/9151720.html
摘要
接觸docker以來，似乎養成了一種習慣，安裝什麼應用軟件都想往docker方向做，今天就想來嘗試下使用docker搭建redis集群。
首先，我們需要理論知識：Redis Cluster是Redis的分佈式解決方案，它解決了redis單機中心化的問題，分佈式數據庫——首要解決把整個數據集按照分區規則映射到多個節點的問題。
這邊就需要知道分區規則——哈希分區規則。Redis Cluster 採用哈希分區規則中的虛擬槽分區。所有的鍵根據哈希函數映射到0 ～ 16383，計算公式：slot = CRC16(key)&16383。每一個節點負責維護一部分槽以及槽所映射的鍵值數據。
一、創建redis docker基礎鏡像
1.下載redis安裝包，使用版本為：4.0.1
<code>[root@etcd1 tmp]# mkdir docker_redis_cluster
[root@etcd1 tmp]# cd docker_redis_cluster/
[root@etcd2 docker_redis_cluster]# wget http://download.redis.io/releases/redis-4.0.1.tar.gz/<code>
2.解壓編譯redis
<code>[root@etcd1 docker_redis_cluster]# tar zxvf redis-4.0.1.tar.gz
[root@etcd1 docker_redis_cluster]# cd redis-4.0.1/
[root@etcd1 redis-4.0.1]# make/<code>
3.修改redis配置
<code>[root@etcd3 redis-4.0.1]# vi /tmp/docker_redis_cluster/redis-4.0.1/redis.conf/<code>
修改bind ip地址
<code># ~~~ 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/<code>
將守護進程yes改成no
<code># 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/<code>
將密碼項註釋去掉，添加新密碼
<code># 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/<code>
修改為
<code># 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/<code>
因為配置了密碼，所以，配置中另外一處主從連接也需要配置密碼
<code># 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>/<code>
修改為
<code># 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/<master-password>/<code>
設置日誌路徑
<code># 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"配置集群相關信息，去掉配置項前面的註釋/<code>
配置集群相關信息，去掉配置項前面的註釋
<code># 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/<code>
4.鏡像製作
<code>[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源碼包複製到鏡像的根路徑下，ADD命令會在複製過後自動解包。被複制的對象必須處於Dockerfile同一路徑，且ADD後面必須使用相對路徑
RUN mkdir -p $REDIS_HOME/redis # 創建安裝目錄
ADD redis-4.0.1/redis.conf $REDIS_HOME/redis/ # 將一開始編譯產生並修改後的配置複製到安裝目錄
RUN yum -y update # 更新yum源
RUN yum install -y gcc make # 安裝編譯需要的工具
WORKDIR /redis-4.0.1
RUN make
RUN mv /redis-4.0.1/src/redis-server $REDIS_HOME/redis/ # 編譯後，容器中只需要可執行文件redis-server
WORKDIR /
RUN rm -rf /redis-4.0.1 # 刪除解壓文件
RUN yum remove -y gcc make # 安裝編譯完成之後，可以刪除多餘的gcc跟make
VOLUME ["/var/log/redis"] # 添加數據卷
EXPOSE 6379 # 暴露6379端口，也可以暴露多個端口，這裡不需要如此/<code>
PS.當前鏡像非可執行鏡像，所以沒有包含ENTRYPOINT和CMD指令
5.構建鏡像
<code># 切換中國源
[root@etcd3 docker_redis_cluster]# vi /etc/docker/daemon.json
{
"registry-mirrors": ["https://registry.docker-cn.com"]
}
# 編譯
[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/<code>
鏡像製作完成，製作中間可能會報： Public key for glibc-headers-2.17-222.el7.x86_64.rpm is not installed 錯誤，這時候需要在鏡像配置中添加一句命令：
<code>...
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 # 安裝編譯需要的工具/<code>
查看鏡像：
<code>[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/<code>
以上，redis 基礎鏡像就製作完成了
二、製作redis節點鏡像
1.基於此前製作的redis基礎鏡像創建一個redis節點鏡像
<code>[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 [email protected]
ENTRYPOINT ["/usr/local/redis/redis-server", "/usr/local/redis/redis.conf"]/<code>
2.構建redis節點鏡像
<code>[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 [email protected]
---> 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/<code>
3.查看鏡像
<code>[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/<code>
三、運行redis集群
1.運行redis容器
<code>[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/<code>
2.查看容器信息
<code>[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 re/<code>
3.運行 redis 集群容器
a.通過遠程連接，查看redis info replication 信息
<code>[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>
# 其餘基本信息同上/<code>
可以看到，客戶連接之後，因為之前設置了密碼，所以需要先輸入密碼認證，否則就無法通過。以上信息，我們知道所有的redis都是master角色 role:master ，這顯然不是我們所希望的。
b.在配置之前我們需要查看所有容器當前的IP地址
<code>[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
[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",/<code>
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
c.配置redis
d.ert
4.Redis Cluster 的集群感知操作
<code>//集群(cluster)
CLUSTER INFO 打印集群的信息
CLUSTER NODES 列出集群當前已知的所有節點（node），以及這些節點的相關信息。
//節點(node)
CLUSTER MEET<port> 將 ip 和 port 所指定的節點添加到集群當中，讓它成為集群的一份子。 /<code>
CLUSTER FORGET <node> 從集群中移除 node_id 指定的節點。
CLUSTER REPLICATE <node> 將當前節點設置為 node_id 指定的節點的從節點。
CLUSTER SAVECONFIG 將節點的配置文件保存到硬盤裡面。
//槽(slot)
CLUSTER ADDSLOTS <slot> [slot ...] 將一個或多個槽（slot）指派（assign）給當前節點。
CLUSTER DELSLOTS <slot> [slot ...] 移除一個或多個槽對當前節點的指派。
CLUSTER FLUSHSLOTS 移除指派給當前節點的所有槽，讓當前節點變成一個沒有指派任何槽的節點。
CLUSTER SETSLOT <slot> NODE <node> 將槽 slot 指派給 node_id 指定的節點，如果槽已經指派給另一個節點，那麼先讓另一個節點刪除該槽>，然後再進行指派。
CLUSTER SETSLOT <slot> MIGRATING <node> 將本節點的槽 slot 遷移到 node_id 指定的節點中。
CLUSTER SETSLOT <slot> IMPORTING <node> 從 node_id 指定的節點中導入槽 slot 到本節點。
CLUSTER SETSLOT <slot> STABLE 取消對槽 slot 的導入（import）或者遷移（migrate）。
//鍵 (key)
CLUSTER KEYSLOT計算鍵 key 應該被放置在哪個槽上。 /<slot>/<node>/<slot>/<node>/<slot>/<node>/<slot>/<slot>/<slot>/<node>/<node>/<port>
CLUSTER COUNTKEYSINSLOT <slot> 返回槽 slot 目前包含的鍵值對數量。
CLUSTER GETKEYSINSLOT <slot> <count> 返回 count 個 slot 槽中的鍵。 /<count>/<slot>/<slot>
redis 集群感知：節點握手——是指一批運行在集群模式的節點通過Gossip協議彼此通信，達到感知對方的過程。
<code>192.168.10.52:6379> CLUSTER MEET 172.17.0.3 6379
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/<code>
當前已經使這六個節點組成集群，但是現在還無法工作，因為集群節點還沒有分配槽（slot）。
a.分配槽信息
查看172.17.0.2:6379 的槽個數
<code>192.168.10.52:6379> CLUSTER INFO
cluster_state:fail
cluster_slots_assigned:0 # 被分配槽的個數為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/<code>
上面看到集群狀態是失敗的，原因是槽位沒有分配，而且需要一次性把16384個槽位完全分配了，集群才可用。
b.分配槽位
分配槽位：CLUSTER ADDSLOTS 槽位，一個槽位只能分配一個節點，16384個槽位必須分配完，不同節點不能衝突。
所以通過腳本進行分配 addslots.sh：
<code>#!/bin/bash
# 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/<code>
其中， -a 123456 表示需要輸入的密碼。
<code>192.168.10.52:6379> CLUSTER INFO
cluster_state:fail # 集群狀態為失敗
cluster_slots_assigned:16101 # 沒有完全分配結束
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 # 集群狀態為成功
cluster_slots_assigned:16384 # 已經全部分配完成
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
/<code>
綜上可知，當全部槽位分配完成之後，集群還是可行的，如果我們手欠，移除一個槽位，那麼集群就立馬那不行了，自己去試試吧 ——CLUSTER DELSLOTS 0 。
5.如何變成高可用性
以上我們已經搭建了一套完整的可運行的redis cluster，但是每個節點都是單點，這樣子可能出現，一個節點掛掉，整個集群因為槽位分配不完全而崩潰，因此，我們需要為每個節點配置副本備用節點。
前面我們已經提前創建了6個備用節點，搭建集群花了三個，因此還有剩下三個直接可以用來做備用副本。
<code>192.168.10.52:6379> 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 # 總共6個節點
cluster_size:3 # 集群為 3 個節點
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/<code>
查看所有節點的id
<code>192.168.10.52:6379> CLUSTER NODES
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 0-54/<code>
編寫腳本，添加副本節點
<code>[root@etcd2 tmp]# vi addSlaveNodes.sh
#!/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 f45f9109f2297a83b1ac36f9e1db/<code>
注意：
1、作為備用的節點，必須是未分配槽位的，否者會操作失敗 (error) ERR To set a master the node must be empty and without assigned slots 。
2、需要從需要添加的節點上面執行操作，CLUSTER REPLICATE [node_id] ，使當前節點成為 node_id 的副本節點。
3、添加從節點（集群複製），複製的原理和單機的Redis複製原理一樣，區別是：集群下的從節點也需要運行在cluster模式下，要先添加到集群裡面，再做複製。
查看所有節點信息：
<code>192.168.10.52:6379> CLUSTER NODES
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/<code>
可以看到我們現在實現了三主三從的一個高可用集群。
6.高可用測試——故障轉移
查看當前運行狀態：
<code>192.168.10.52:6379> CLUSTER NODES
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/<code>
以上，運行正常
嘗試關閉一個master，選擇端口為6380的容器，停掉之後：
<code>192.168.10.52:6379> CLUSTER NODES
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/<code>
以上，發現整個集群都失敗了，從節點沒有自動升級為主節點，怎麼回事？？
重啟停掉的容器，經排查日誌信息 [root@df6ebce6f12a /]# tail -f /var/log/redis/redis-server.log ：
<code>1:S 11 Jun 09:57:46.712 # Cluster state changed: ok
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./<code>
可以看到，主從之間訪問需要auth，之前忘記了配置 redis.conf 中的 # masterauth <master-password> ，所以導致主從之間無法通訊。修改配置之後，自動故障轉移正常。/<master-password>
有時候需要實施人工故障轉移
登錄6380端口的從節點：6383，執行 CLUSTER FAILOVER 命令：
<code>192.168.10.52:6383> CLUSTER FAILOVER
(error) ERR Master is down or failed, please use CLUSTER FAILOVER FORCE/<code>
發現因為master已經down了，所以我們需要執行強制轉移
<code>192.168.10.52:6383> CLUSTER FAILOVER FORCE
OK/<code>
查看當前 cluster node 情況：
<code>192.168.10.52:6383> CLUSTER NODES
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/<code>
從節點已經升級為master節點。這時候，我們嘗試重啟了，6380節點的redis（其實是重新啟動停掉的容器）：
<code>192.168.10.52:6383> CLUSTER NODES
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/<code>
我們發現，6380節點反而變成了 6383節點的從節點。
現在集群應該是完整的了，所以，集群狀態應該已經恢復了，我們查看下：
<code>192.168.10.52:6383> 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: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
/<code>
OK，沒有問題。
7.集群訪問
客戶端在初始化的時候只需要知道一個節點的地址即可，客戶端會先嚐試向這個節點執行命令，比如 get key ，如果key所在的slot剛好在該節點上，則能夠直接執行成功。如果slot不在該節點，則節點會返回MOVED錯誤，同時把該slot對應的節點告訴客戶端，客戶端可以去該節點執行命令
<code>192.168.10.52:6383> get hello
(error) MOVED 866 172.17.0.2:6379
192.168.10.52:6379> set number 20004
(error) MOVED 7743 172.17.0.3:6379/<code>
另外，redis集群版只使用db0，select命令雖然能夠支持select 0。其他的db都會返回錯誤。
<code>192.168.10.52:6383> select 0
OK
192.168.10.52:6383> select 1
(error) ERR SELECT is not allowed in cluster mode/<code>
報錯問題
docker redis集群連接報錯的問題，具體報錯如下：
node節點沒有全部添加進去，添加之後，依然有上述問題。想到是跨主機訪問，應該是路由尋址不了導致的。當初寫上述教程的時候，docker是以默認的網絡模式bridge模式運行的，畢竟當初是以學習整理文檔為主，主要是單機訪問。
但是，實際應用化場景中，多是公網跨主機訪問，問題明朗了，想著集群這東西最好還是設置成共享主機公網ip比較好，於是解決如下：
1.在docker運行時，執行網絡模式為：host。2.端口衝突解決，畢竟host模式下，容器會佔用宿主機的端口，於是，我們就從配置下手，在宿主機上生成配置redis-60001.conf,redis-60002.conf,redis-60003.conf…，有多少端口建多少個文件，最終運行一個容器，掛載一個配置到容器中用於覆蓋主機中的配置。
最終的運行方式如下：
<code>docker run -d --name redis-6380 --net host -v /tmp/redis.conf:/usr/local/redis/redis.conf hakimdstx/nodes-redis:4.0.1/<code>
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