Cluster Redis: três modos

Others 2021-01-24 05:57:57 views: null

O mais forte: modo de cluster

Referência: https://blog.csdn.net/miss1181248983/article/details/90056960

 

Construção do modo de cluster

  • Preparação ambiental:
三台机器，分别开启两个redis服务（端口）

192.168.30.128              端口：7001,7002

192.168.30.129              端口：7003,7004

192.168.30.130              端口：7005,7006
  • Modifique o arquivo de configuração:

192.168.30.128

# mkdir /usr/local/redis/cluster

# cp /usr/local/redis/redis.conf /usr/local/redis/cluster/redis_7001.conf

# cp /usr/local/redis/redis.conf /usr/local/redis/cluster/redis_7002.conf

# chown -R redis:redis /usr/local/redis

# mkdir -p /data/redis/cluster/{redis_7001,redis_7002} && chown -R redis:redis /data/redis

# vim /usr/local/redis/cluster/redis_7001.conf

bind 192.168.30.128
port 7001
daemonize yes
pidfile "/var/run/redis_7001.pid"
logfile "/usr/local/redis/cluster/redis_7001.log"
dir "/data/redis/cluster/redis_7001"
#replicaof 192.168.30.129 6379
masterauth 123456
requirepass 123456
appendonly yes
cluster-enabled yes
cluster-config-file nodes_7001.conf
cluster-node-timeout 15000

# vim /usr/local/redis/cluster/redis_7002.conf

bind 192.168.30.128
port 7002
daemonize yes
pidfile "/var/run/redis_7002.pid"
logfile "/usr/local/redis/cluster/redis_7002.log"
dir "/data/redis/cluster/redis_7002"
#replicaof 192.168.30.129 6379
masterauth "123456"
requirepass "123456"
appendonly yes
cluster-enabled yes
cluster-config-file nodes_7002.conf
cluster-node-timeout 15000

A configuração das outras duas máquinas é consistente com 192.168.30.128, então omitida aqui

  • Inicie o serviço redis:
# redis-server /usr/local/redis/cluster/redis_7001.conf

# tail -f /usr/local/redis/cluster/redis_7001.log

# redis-server /usr/local/redis/cluster/redis_7002.conf

# tail -f /usr/local/redis/cluster/redis_7002.log

As outras duas máquinas inicializam de acordo com 192.168.30.128, portanto, omitido aqui

  • Instale o Ruby e crie um cluster (versão inferior):

Se a versão do redis for relativamente baixa, você precisará instalar o Ruby. Escolha qualquer máquina para instalar o Ruby

# yum -y groupinstall "Development Tools"

# yum install -y gdbm-devel libdb4-devel libffi-devel libyaml libyaml-devel ncurses-devel openssl-devel readline-devel tcl-devel

# mkdir -p ~/rpmbuild/{BUILD,BUILDROOT,RPMS,SOURCES,SPECS,SRPMS}

# wget http://cache.ruby-lang.org/pub/ruby/2.2/ruby-2.2.3.tar.gz -P ~/rpmbuild/SOURCES

# wget http://raw.githubusercontent.com/tjinjin/automate-ruby-rpm/master/ruby22x.spec -P ~/rpmbuild/SPECS

# rpmbuild -bb ~/rpmbuild/SPECS/ruby22x.spec

# rpm -ivh ~/rpmbuild/RPMS/x86_64/ruby-2.2.3-1.el7.x86_64.rpm

# gem install redis                 #目的是安装这个，用于配置集群

# cp /usr/local/redis/src/redis-trib.rb /usr/bin/

# redis-trib.rb create --replicas 1 192.168.30.128:7001 192.168.30.128:7002 192.168.30.129:7003 192.168.30.129:7004 192.168.30.130:7005 192.168.30.130:7006
  • Crie um cluster:

Estou aqui para redis 5.0.4, então não preciso instalar o ruby, apenas criar um cluster

# redis-cli -a 123456 --cluster create 192.168.30.128:7001 192.168.30.128:7002 192.168.30.129:7003 192.168.30.129:7004 192.168.30.130:7005 192.168.30.130:7006 --cluster-replicas 1

Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
>>> Performing hash slots allocation on 6 nodes...
Master[0] -> Slots 0 - 5460
Master[1] -> Slots 5461 - 10922
Master[2] -> Slots 10923 - 16383
Adding replica 192.168.30.129:7004 to 192.168.30.128:7001
Adding replica 192.168.30.130:7006 to 192.168.30.129:7003
Adding replica 192.168.30.128:7002 to 192.168.30.130:7005
M: 80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001
   slots:[0-5460] (5461 slots) master
S: b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002
   replicates 6788453ee9a8d7f72b1d45a9093838efd0e501f1
M: 4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003
   slots:[5461-10922] (5462 slots) master
S: b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004
   replicates 80c80a3f3e33872c047a8328ad579b9bea001ad8
M: 6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005
   slots:[10923-16383] (5461 slots) master
S: 277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006
   replicates 4d74ec66e898bf09006dac86d4928f9fad81f373
Can I set the above configuration? (type 'yes' to accept): yes                  #输入yes，接受上面配置
>>> Nodes configuration updated
>>> Assign a different config epoch to each node
>>> Sending CLUSTER MEET messages to join the cluster

pode ser visto,

192.168.30.128:7001是master，它的slave是192.168.30.129:7004；

192.168.30.129:7003是master，它的slave是192.168.30.130:7006；

192.168.30.130:7005是master，它的slave是192.168.30.128:7002

Gere automaticamente o arquivo nodes.conf:

# ls /data/redis/cluster/redis_7001/
appendonly.aof  dump.rdb  nodes-7001.conf

# vim /data/redis/cluster/redis_7001/nodes-7001.conf 

6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557454406312 5 connected 10923-16383
277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557454407000 6 connected
b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557454408371 5 connected
80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 myself,master - 0 1557454406000 1 connected 0-5460
b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557454407366 4 connected
4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557454407000 3 connected 5461-10922
vars currentEpoch 6 lastVoteEpoch 0

Operação de cluster

  • Faça login no cluster:
# redis-cli -c -h 192.168.30.128 -p 7001 -a 123456                  # -c，使用集群方式登录
  • 1
  • Veja as informações do cluster:
192.168.30.128:7001> CLUSTER INFO                   #集群状态

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:1
cluster_stats_messages_ping_sent:580
cluster_stats_messages_pong_sent:551
cluster_stats_messages_sent:1131
cluster_stats_messages_ping_received:546
cluster_stats_messages_pong_received:580
cluster_stats_messages_meet_received:5
cluster_stats_messages_received:1131
  • Listar informações do nó:
192.168.30.128:7001> CLUSTER NODES                  #列出节点信息

6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557455176000 5 connected 10923-16383
277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557455174000 6 connected
b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557455175000 5 connected
80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 myself,master - 0 1557455175000 1 connected 0-5460
b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557455174989 4 connected
4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557455175995 3 connected 5461-10922

Este é o mesmo que o conteúdo do arquivo nodes.conf

  • entrada de dados:
192.168.30.128:7001> set key111 aaa
-> Redirected to slot [13680] located at 192.168.30.130:7005                #说明数据到了192.168.30.130:7005上
OK

192.168.30.130:7005> set key222 bbb
-> Redirected to slot [2320] located at 192.168.30.128:7001                 #说明数据到了192.168.30.128:7001上
OK

192.168.30.128:7001> set key333 ccc
-> Redirected to slot [7472] located at 192.168.30.129:7003                 #说明数据到了192.168.30.129:7003上
OK

192.168.30.129:7003> get key111
-> Redirected to slot [13680] located at 192.168.30.130:7005
"aaa"

192.168.30.130:7005> get key333
-> Redirected to slot [7472] located at 192.168.30.129:7003
"ccc"

192.168.30.129:7003>

Percebe-se que o cluster redis é descentralizado, cada nó é igual e qual nó está conectado pode obter e definir dados.

Claro, a igualdade se refere ao nó mestre, porque o nó escravo não fornece serviços, mas serve como backup para o nó mestre correspondente.

  • Adicionar nós:

Adicione um nó em 192.168.30.129:

# cp /usr/local/redis/cluster/redis_7003.conf /usr/local/redis/cluster/redis_7007.conf

# vim /usr/local/redis/cluster/redis_7007.conf

bind 192.168.30.129
port 7007
daemonize yes
pidfile "/var/run/redis_7007.pid"
logfile "/usr/local/redis/cluster/redis_7007.log"
dir "/data/redis/cluster/redis_7007"
#replicaof 192.168.30.129 6379
masterauth "123456"
requirepass "123456"
appendonly yes
cluster-enabled yes
cluster-config-file nodes_7007.conf
cluster-node-timeout 15000

# mkdir /data/redis/cluster/redis_7007

# chown -R redis:redis /usr/local/redis && chown -R redis:redis /data/redis

# redis-server /usr/local/redis/cluster/redis_7007.conf

Adicione um nó em 192.168.30.130:

# cp /usr/local/redis/cluster/redis_7005.conf /usr/local/redis/cluster/redis_7008.conf

# vim /usr/local/redis/cluster/redis_7007.conf

bind 192.168.30.130
port 7008
daemonize yes
pidfile "/var/run/redis_7008.pid"
logfile "/usr/local/redis/cluster/redis_7008.log"
dir "/data/redis/cluster/redis_7008"
#replicaof 192.168.30.130 6379
masterauth "123456"
requirepass "123456"
appendonly yes
cluster-enabled yes
cluster-config-file nodes_7008.conf
cluster-node-timeout 15000

# mkdir /data/redis/cluster/redis_7008

# chown -R redis:redis /usr/local/redis && chown -R redis:redis /data/redis

# redis-server /usr/local/redis/cluster/redis_7008.conf

Adicione nós ao cluster:

192.168.30.129:7003> CLUSTER MEET 192.168.30.129 7007
OK

192.168.30.129:7003> CLUSTER NODES

4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 myself,master - 0 1557457361000 3 connected 5461-10922
80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 master - 0 1557457364746 1 connected 0-5460
277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557457362000 6 connected
b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557457363000 4 connected
b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557457362000 5 connected
e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557457362729 0 connected
6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557457363739 5 connected 10923-16383

192.168.30.129:7003> CLUSTER MEET 192.168.30.130 7008
OK

192.168.30.129:7003> CLUSTER NODES

4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 myself,master - 0 1557457489000 3 connected 5461-10922
80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 master - 0 1557457489000 1 connected 0-5460
277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557457489000 6 connected
b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557457488000 4 connected
b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557457489472 5 connected
1a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 master - 0 1557457489259 0 connected
e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557457489000 0 connected
6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557457490475 5 connected 10923-16383
  •  

Como você pode ver, os novos nós são todos adicionados ao cluster como o mestre

  • Alterar a identidade do nó:

Altere a identidade do nó 192.168.30.130:7008 recém-adicionado para o nó escravo de 192.168.30.129:7007

# redis-cli -c -h 192.168.30.130 -p 7008 -a 123456 cluster replicate e51ab166bc0f33026887bcf8eba0dff3d5b0bf14
  •  

cluster replicateSeguido por node_id, altere a identidade do nó correspondente. Você também pode fazer login no cluster para alterar

# redis-cli -c -h 192.168.30.130 -p 7008 -a 123456

192.168.30.130:7008> CLUSTER REPLICATE e51ab166bc0f33026887bcf8eba0dff3d5b0bf14
OK

192.168.30.130:7008> CLUSTER NODES

277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557458316881 3 connected
80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 master - 0 1557458314864 1 connected 0-5460
4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557458316000 3 connected 5461-10922
6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557458315872 5 connected 10923-16383
b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557458317890 5 connected
1a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 myself,slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557458315000 7 connected
b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557458315000 1 connected
e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557458314000 0 connected

Verifique o arquivo nodes.conf correspondente, você pode encontrar mudanças, ele registra as informações do nó do cluster atual

# cat /data/redis/cluster/redis_7001/nodes-7001.conf

1a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557458236169 7 connected
6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557458235000 5 connected 10923-16383
277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557458234103 6 connected
b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557458235129 5 connected
80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 myself,master - 0 1557458234000 1 connected 0-5460
b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557458236000 4 connected
e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557458236000 0 connected
4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557458233089 3 connected 5461-10922
vars currentEpoch 7 lastVoteEpoch 0
  • Excluir nó:
192.168.30.130:7008> CLUSTER FORGET 1a1c7f02fce87530bd5abdfc98df1cffce4f1767
(error) ERR I tried hard but I can't forget myself...               #无法删除登录节点

192.168.30.130:7008> CLUSTER FORGET e51ab166bc0f33026887bcf8eba0dff3d5b0bf14
(error) ERR Can't forget my master!                 #不能删除自己的master节点

192.168.30.130:7008> CLUSTER FORGET 6788453ee9a8d7f72b1d45a9093838efd0e501f1
OK              #可以删除其它的master节点

192.168.30.130:7008> CLUSTER NODES

277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557458887328 3 connected
80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 master - 0 1557458887000 1 connected 0-5460
4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557458886000 3 connected 5461-10922
b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave - 0 1557458888351 5 connected
1a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 myself,slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557458885000 7 connected
b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557458883289 1 connected
e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557458885310 0 connected

192.168.30.130:7008> CLUSTER FORGET b4d3eb411a7355d4767c6c23b4df69fa183ef8bc
OK              #可以删除其它的slave节点

192.168.30.130:7008> CLUSTER NODES

277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557459031397 3 connected
80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 master - 0 1557459032407 1 connected 0-5460
4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557459035434 3 connected 5461-10922
6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557459034000 5 connected 10923-16383
1a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 myself,slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557459032000 7 connected
b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557459034000 1 connected
e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557459034427 0 connected
  • Arranjo de preservação:
192.168.30.130:7008> CLUSTER SAVECONFIG                 #将节点配置信息保存到硬盘
OK
 
# cat /data/redis/cluster/redis_7001/nodes-7001.conf

1a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557458236169 7 connected
6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557458235000 5 connected 10923-16383
277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557458234103 6 connected
b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557458235129 5 connected
80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 myself,master - 0 1557458234000 1 connected 0-5460
b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557458236000 4 connected
e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557458236000 0 connected
4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557458233089 3 connected 5461-10922
vars currentEpoch 7 lastVoteEpoch 0

# redis-cli -c -h 192.168.30.130 -p 7008 -a 123456
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.

192.168.30.130:7008> CLUSTER NODES
277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557459500741 3 connected
80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 master - 0 1557459500000 1 connected 0-5460
4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557459501000 3 connected 5461-10922
6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557459500000 5 connected 10923-16383
b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557459499737 5 connected
1a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 myself,slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557459499000 7 connected
b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557459501750 1 connected
e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557459498000 0 connected

Pode-se observar que o nó excluído anteriormente foi restaurado novamente, porque o arquivo de configuração correspondente não foi excluído e a CLUSTER SAVECONFIGrestauração foi realizada .

  • O nó mestre simulado está inativo:

192.168.30.128

# netstat -lntp |grep 7001
tcp        0      0 192.168.30.128:17001    0.0.0.0:*               LISTEN      6701/redis-server 1 
tcp        0      0 192.168.30.128:7001     0.0.0.0:*               LISTEN      6701/redis-server 1 

# kill 6701

192.168.30.130:7008> CLUSTER NODES

277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557461178000 3 connected
80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 master,fail - 1557460950483 1557460947145 1 disconnected
4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557461174922 3 connected 5461-10922
6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557461181003 5 connected 10923-16383
b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557461179993 5 connected
1a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 myself,slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557461176000 7 connected
b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 master - 0 1557461178981 8 connected 0-5460
e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557461179000 0 connected

A linha correspondente a 7001 pode ser vista que o mestre falhou e o status foi desconectado; e a linha correspondente a 7004, o escravo tornou-se mestre.

  • Reinicie o nó 7001:
# redis-server /usr/local/redis/cluster/redis_7001.conf

192.168.30.130:7008> CLUSTER NODES

277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557461307000 3 connected
80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 slave b6331cbc986794237c83ed2d5c30777c1551546e 0 1557461305441 8 connected
4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557461307962 3 connected 5461-10922
6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557461304935 5 connected 10923-16383
b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557461306000 5 connected
1a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 myself,slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557461305000 7 connected
b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 master - 0 1557461308972 8 connected 0-5460
e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557461307000 0 connected

Pode-se ver que o nó 7001 é um nó escravo após a inicialização e é um nó escravo de 7004. Ou seja, se o nó mestre morrer, seu nó escravo se tornará o novo nó mestre e continuará a fornecer serviços, e se o nó mestre original for reiniciado, ele se tornará o nó escravo do novo nó mestre.

Além disso, se o nó 7007 for usado para teste, será descoberto que o nó 7008 não mudará, porque não há dados no nó 7007. Os dados do cluster são divididos em três partes. Se 16384 slots forem alocados por slot hash, os intervalos de slot assumidos pelos três nós são:

节点7004覆盖0－5460
节点7003覆盖5461－10922
节点7005覆盖10923－16383

 

 

 

 

 

 

 

 

 

 

Modo mestre-escravo

Introdução ao modo mestre-escravo

O modo mestre-escravo é o mais simples dos três modos: Na replicação mestre-escravo, o banco de dados é dividido em duas categorias: mestre e escravo.

Dentre elas, a replicação mestre-escravo possui as seguintes características:

* 主数据库可以进行读写操作，当读写操作导致数据变化时会自动将数据同步给从数据库

* 从数据库一般都是只读的，并且接收主数据库同步过来的数据

* 一个master可以拥有多个slave，但是一个slave只能对应一个master

* slave挂了不影响其他slave的读和master的读和写，重新启动后会将数据从master同步过来

* master挂了以后，不影响slave的读，但redis不再提供写服务，master重启后redis将重新对外提供写服务

* master挂了以后，不会在slave节点中重新选一个master

Mecanismo de Trabalho:

Quando o escravo é iniciado, ele envia ativamente um comando SYNC ao mestre. Depois de receber o comando SYNC, o mestre salva o instantâneo (persistência RDB) e armazena em cache o comando para salvar o instantâneo em segundo plano e, a seguir, envia o arquivo de instantâneo salvo e o comando armazenado em cache para o escravo. O escravo carrega os arquivos de instantâneo e comandos de execução de cache após receber os arquivos de instantâneo e comandos.

Depois que a replicação é inicializada, cada comando de gravação recebido pelo mestre será enviado ao escravo de forma síncrona para garantir a consistência dos dados mestre-escravo.

Configurações de segurança:

Quando o nó mestre define a senha,

客户端访问master需要密码

启动slave需要密码，在配置文件中配置即可

客户端访问slave不需要密码

Desvantagens:

Pode-se ver acima que o nó mestre é o único no modo mestre-escravo. Se o mestre falhar, o redis não pode fornecer serviços de gravação externos.

Construção do modo mestre-escravo

  • Preparação ambiental:
master节点                  192.168.30.128

slave节点                   192.168.30.129

slave节点                   192.168.30.130
  • Baixe e instale tudo:
# cd /software

# wget http://download.redis.io/releases/redis-5.0.4.tar.gz

# tar zxf redis-5.0.4.tar.gz && mv redis-5.0.4/ /usr/local/redis

# cd /usr/local/redis && make && make install

# echo $?
0
  • Todos configurados como serviços:

Arquivo de serviço

# vim /usr/lib/systemd/system/redis.service

[Unit]
Description=Redis persistent key-value database
After=network.target
After=network-online.target
Wants=network-online.target

[Service]
ExecStart=/usr/local/bin/redis-server /usr/local/redis/redis.conf --supervised systemd
ExecStop=/usr/libexec/redis-shutdown
Type=notify
User=redis
Group=redis
RuntimeDirectory=redis
RuntimeDirectoryMode=0755

[Install]
WantedBy=multi-user.target

script de desligamento

# vim /usr/libexec/redis-shutdown

#!/bin/bash
#
# Wrapper to close properly redis and sentinel
test x"$REDIS_DEBUG" != x && set -x

REDIS_CLI=/usr/local/bin/redis-cli

# Retrieve service name
SERVICE_NAME="$1"
if [ -z "$SERVICE_NAME" ]; then
   SERVICE_NAME=redis
fi

# Get the proper config file based on service name
CONFIG_FILE="/usr/local/redis/$SERVICE_NAME.conf"

# Use awk to retrieve host, port from config file
HOST=`awk '/^[[:blank:]]*bind/ { print $2 }' $CONFIG_FILE | tail -n1`
PORT=`awk '/^[[:blank:]]*port/ { print $2 }' $CONFIG_FILE | tail -n1`
PASS=`awk '/^[[:blank:]]*requirepass/ { print $2 }' $CONFIG_FILE | tail -n1`
SOCK=`awk '/^[[:blank:]]*unixsocket\s/ { print $2 }' $CONFIG_FILE | tail -n1`

# Just in case, use default host, port
HOST=${HOST:-127.0.0.1}
if [ "$SERVICE_NAME" = redis ]; then
    PORT=${PORT:-6379}
else
    PORT=${PORT:-26739}
fi

# Setup additional parameters
# e.g password-protected redis instances
[ -z "$PASS"  ] || ADDITIONAL_PARAMS="-a $PASS"

# shutdown the service properly
if [ -e "$SOCK" ] ; then
        $REDIS_CLI -s $SOCK $ADDITIONAL_PARAMS shutdown
else
        $REDIS_CLI -h $HOST -p $PORT $ADDITIONAL_PARAMS shutdown
fi

# chmod +x /usr/libexec/redis-shutdown

# useradd -s /sbin/nologin redis

# chown -R redis:redis /usr/local/redis

# chown -R reids:redis /data/redis

# yum install -y bash-completion && source /etc/profile                 #命令补全

# systemctl daemon-reload

# systemctl enable redis
  • Alterar configuração:

192.168.30.128

# mkdir -p /data/redis

# vim /usr/local/redis/redis.conf

bind 192.168.30.128               #监听ip，多个ip用空格分隔
daemonize yes               #允许后台启动
logfile "/usr/local/redis/redis.log"                #日志路径
dir /data/redis                 #数据库备份文件存放目录
masterauth 123456               #slave连接master密码，master可省略
requirepass 123456              #设置master连接密码，slave可省略

appendonly yes                  #在/data/redis/目录生成appendonly.aof文件，将每一次写操作请求都追加到appendonly.aof 文件中

# echo 'vm.overcommit_memory=1' >> /etc/sysctl.conf

# sysctl -p

192.168.30.129

# mkdir -p /data/redis

# vim /usr/local/redis/redis.conf

bind 192.168.30.129
daemonize yes
logfile "/usr/local/redis/redis.log"
dir /data/redis
replicaof 192.168.30.128 6379
masterauth 123456
requirepass 123456
appendonly yes

# echo 'vm.overcommit_memory=1' >> /etc/sysctl.conf

# sysctl -p

192.168.30.130

# mkdir -p /data/redis

# vim /usr/local/redis/redis.conf

bind 192.168.30.130
daemonize yes
logfile "/usr/local/redis/redis.log"
dir /data/redis
replicaof 192.168.30.128 6379
masterauth 123456
requirepass 123456
appendonly yes

# echo 'vm.overcommit_memory=1' >> /etc/sysctl.conf

# sysctl -p
  • Comece todos os redis:
# systemctl start redis
  • 1
  • Ver o status do cluster:
# redis-cli -h 192.168.30.128 -a 123456
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.

192.168.30.128:6379> info replication
# Replication
role:master
connected_slaves:2
slave0:ip=192.168.30.129,port=6379,state=online,offset=168,lag=1
slave1:ip=192.168.30.130,port=6379,state=online,offset=168,lag=1
master_replid:fb4941e02d5032ad74c6e2383211fc58963dbe90
master_replid2:0000000000000000000000000000000000000000
master_repl_offset:168
second_repl_offset:-1
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:1
repl_backlog_histlen:168

# redis-cli -h 192.168.30.129 -a 123456 info replication

Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
# Replication
role:slave
master_host:192.168.30.128
master_port:6379
master_link_status:up
master_last_io_seconds_ago:1
master_sync_in_progress:0
slave_repl_offset:196
slave_priority:100
slave_read_only:1
connected_slaves:0
master_replid:fb4941e02d5032ad74c6e2383211fc58963dbe90
master_replid2:0000000000000000000000000000000000000000
master_repl_offset:196
second_repl_offset:-1
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:1
repl_backlog_histlen:196
  • Apresentação de dados:
192.168.30.128:6379> keys *
(empty list or set)

192.168.30.128:6379> set key1 100
OK

192.168.30.128:6379> set key2 lzx
OK

192.168.30.128:6379> keys *
1) "key1"
2) "key2"

# redis-cli -h 192.168.30.129 -a 123456
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.

192.168.30.129:6379> keys *
1) "key2"
2) "key1"

192.168.30.129:6379> CONFIG GET dir
1) "dir"
2) "/data/redis"

192.168.30.129:6379> CONFIG GET dbfilename
1) "dbfilename"
2) "dump.rdb"

192.168.30.129:6379> get key1
"100"

192.168.30.129:6379> get key2
"lzx"

192.168.30.129:6379> set key3 aaa
(error) READONLY You can't write against a read only replica.

# redis-cli -h 192.168.30.130 -a 123456
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.

192.168.30.130:6379> keys *
1) "key2"
2) "key1"

192.168.30.130:6379> CONFIG GET dir
1) "dir"
2) "/data/redis"

192.168.30.130:6379> CONFIG GET dbfilename
1) "dbfilename"
2) "dump.rdb"

192.168.30.130:6379> get key1
"100"

192.168.30.130:6379> get key2
"lzx"

192.168.30.130:6379> set key3 aaa
(error) READONLY You can't write against a read only replica.

Pode-se ver que os dados gravados no nó mestre são rapidamente sincronizados para o nó escravo e os dados não podem ser gravados no nó escravo.

Modo sentinela

Introdução ao modo Sentinela

A desvantagem do modo mestre-escravo é que ele não tem alta disponibilidade. Depois que o mestre trava, o Redis não fornecerá mais operações externas de gravação, então o sentinela passou a existir.

O significado chinês de sentinela é sentinela. Como o nome sugere, sua função é monitorar o status de execução do cluster redis. Suas características são as seguintes:

* sentinel模式是建立在主从模式的基础上，如果只有一个Redis节点，sentinel就没有任何意义

* 当master挂了以后，sentinel会在slave中选择一个做为master，并修改它们的配置文件，其他slave的配置文件也会被修改，比如slaveof属性会指向新的master

* 当master重新启动后，它将不再是master而是做为slave接收新的master的同步数据

* sentinel因为也是一个进程有挂掉的可能，所以sentinel也会启动多个形成一个sentinel集群

* 多sentinel配置的时候，sentinel之间也会自动监控

* 当主从模式配置密码时，sentinel也会同步将配置信息修改到配置文件中，不需要担心

* 一个sentinel或sentinel集群可以管理多个主从Redis，多个sentinel也可以监控同一个redis

* sentinel最好不要和Redis部署在同一台机器，不然Redis的服务器挂了以后，sentinel也挂了

Mecanismo de Trabalho:

* 每个sentinel以每秒钟一次的频率向它所知的master，slave以及其他sentinel实例发送一个 PING 命令 

* 如果一个实例距离最后一次有效回复 PING 命令的时间超过 down-after-milliseconds 选项所指定的值， 则这个实例会被sentinel标记为主观下线。 

* 如果一个master被标记为主观下线，则正在监视这个master的所有sentinel要以每秒一次的频率确认master的确进入了主观下线状态

* 当有足够数量的sentinel（大于等于配置文件指定的值）在指定的时间范围内确认master的确进入了主观下线状态， 则master会被标记为客观下线 

* 在一般情况下， 每个sentinel会以每 10 秒一次的频率向它已知的所有master，slave发送 INFO 命令 

* 当master被sentinel标记为客观下线时，sentinel向下线的master的所有slave发送 INFO 命令的频率会从 10 秒一次改为 1 秒一次 

* 若没有足够数量的sentinel同意master已经下线，master的客观下线状态就会被移除；
  若master重新向sentinel的 PING 命令返回有效回复，master的主观下线状态就会被移除

Ao usar o modo sentinela, o cliente não se conecta diretamente ao Redis, mas se conecta ao ip e à porta da sentinela, e a sentinela fornece implementações de Redis de fornecimento de serviços específicos, de modo que quando o nó mestre cair, a sentinela detectará e fornecerá o novo nó mestre para os usuários.

Construção do modo sentinela

  • Preparação ambiental:
master节点              192.168.30.128          sentinel端口：26379

slave节点               192.168.30.129          sentinel端口：26379

slave节点               192.168.30.130          sentinel端口：26379
  • Alterar configuração:

O Redis foi baixado e instalado antes, mas foi omitido aqui, e o arquivo de configuração do sentinela foi modificado diretamente.

192.168.30.128

# vim /usr/local/redis/sentinel.conf

daemonize yes
logfile "/usr/local/redis/sentinel.log"
dir "/usr/local/redis/sentinel"                 #sentinel工作目录
sentinel monitor mymaster 192.168.30.128 6379 2                 #判断master失效至少需要2个sentinel同意，建议设置为n/2+1，n为sentinel个数
sentinel auth-pass mymaster 123456
sentinel down-after-milliseconds mymaster 30000                 #判断master主观下线时间，默认30s

Deve-se notar aqui que ele sentinel auth-pass mymaster 123456precisa ser configurado sentinel monitor mymaster 192.168.30.128 6379 2abaixo, caso contrário, um erro será relatado ao iniciar:

# /usr/local/bin/redis-sentinel /usr/local/redis/sentinel.conf

*** FATAL CONFIG FILE ERROR ***
Reading the configuration file, at line 104
>>> 'sentinel auth-pass mymaster 123456'
No such master with specified name.
  • Comece todos sentinela:
# mkdir /usr/local/redis/sentinel && chown -R redis:redis /usr/local/redis

# /usr/local/bin/redis-sentinel /usr/local/redis/sentinel.conf
  • Veja os registros de qualquer host:
# tail -f /usr/local/redis/sentinel.log

21574:X 09 May 2019 15:32:04.298 # Sentinel ID is 30c417116a8edbab09708037366c4a7471beb770
21574:X 09 May 2019 15:32:04.298 # +monitor master mymaster 192.168.30.128 6379 quorum 2
21574:X 09 May 2019 15:32:04.299 * +slave slave 192.168.30.129:6379 192.168.30.129 6379 @ mymaster 192.168.30.128 6379
21574:X 09 May 2019 15:32:04.300 * +slave slave 192.168.30.130:6379 192.168.30.130 6379 @ mymaster 192.168.30.128 6379
21574:X 09 May 2019 15:32:16.347 * +sentinel sentinel 79b8d61626afd4d059fb5a6a63393e9a1374e78f 192.168.30.129 26379 @ mymaster 192.168.30.128 6379
21574:X 09 May 2019 15:32:31.584 * +sentinel sentinel d7b429dcba792103ef0d80827dd0910bd9284d21 192.168.30.130 26379 @ mymaster 192.168.30.128 6379

Vários eventos no modo Sentinel:

·       +reset-master ：主服务器已被重置。

·       +slave ：一个新的从服务器已经被 Sentinel 识别并关联。

·       +failover-state-reconf-slaves ：故障转移状态切换到了 reconf-slaves 状态。

·       +failover-detected ：另一个 Sentinel 开始了一次故障转移操作，或者一个从服务器转换成了主服务器。

·       +slave-reconf-sent ：领头（leader）的 Sentinel 向实例发送了 [SLAVEOF](/commands/slaveof.html) 命令，为实例设置新的主服务器。

·       +slave-reconf-inprog ：实例正在将自己设置为指定主服务器的从服务器，但相应的同步过程仍未完成。

·       +slave-reconf-done ：从服务器已经成功完成对新主服务器的同步。

·       -dup-sentinel ：对给定主服务器进行监视的一个或多个 Sentinel 已经因为重复出现而被移除 —— 当 Sentinel 实例重启的时候，就会出现这种情况。

·       +sentinel ：一个监视给定主服务器的新 Sentinel 已经被识别并添加。

·       +sdown ：给定的实例现在处于主观下线状态。

·       -sdown ：给定的实例已经不再处于主观下线状态。

·       +odown ：给定的实例现在处于客观下线状态。

·       -odown ：给定的实例已经不再处于客观下线状态。

·       +new-epoch ：当前的纪元（epoch）已经被更新。

·       +try-failover ：一个新的故障迁移操作正在执行中，等待被大多数 Sentinel 选中（waiting to be elected by the majority）。

·       +elected-leader ：赢得指定纪元的选举，可以进行故障迁移操作了。

·       +failover-state-select-slave ：故障转移操作现在处于 select-slave 状态 —— Sentinel 正在寻找可以升级为主服务器的从服务器。

·       no-good-slave ：Sentinel 操作未能找到适合进行升级的从服务器。Sentinel 会在一段时间之后再次尝试寻找合适的从服务器来进行升级，又或者直接放弃执行故障转移操作。

·       selected-slave ：Sentinel 顺利找到适合进行升级的从服务器。

·       failover-state-send-slaveof-noone ：Sentinel 正在将指定的从服务器升级为主服务器，等待升级功能完成。

·       failover-end-for-timeout ：故障转移因为超时而中止，不过最终所有从服务器都会开始复制新的主服务器（slaves will eventually be configured to replicate with the new master anyway）。

·       failover-end ：故障转移操作顺利完成。所有从服务器都开始复制新的主服务器了。

·       +switch-master ：配置变更，主服务器的 IP 和地址已经改变。 这是绝大多数外部用户都关心的信息。

·       +tilt ：进入 tilt 模式。

·       -tilt ：退出 tilt 模式。
  • Demonstração do tempo de inatividade do mestre:

192.168.30.128

# systemctl stop redis

# tail -f /usr/local/redis/sentinel.log

22428:X 09 May 2019 15:51:29.287 # +sdown master mymaster 192.168.30.128 6379
22428:X 09 May 2019 15:51:29.371 # +odown master mymaster 192.168.30.128 6379 #quorum 2/2
22428:X 09 May 2019 15:51:29.371 # +new-epoch 1
22428:X 09 May 2019 15:51:29.371 # +try-failover master mymaster 192.168.30.128 6379
22428:X 09 May 2019 15:51:29.385 # +vote-for-leader 30c417116a8edbab09708037366c4a7471beb770 1
22428:X 09 May 2019 15:51:29.403 # d7b429dcba792103ef0d80827dd0910bd9284d21 voted for 30c417116a8edbab09708037366c4a7471beb770 1
22428:X 09 May 2019 15:51:29.408 # 79b8d61626afd4d059fb5a6a63393e9a1374e78f voted for 30c417116a8edbab09708037366c4a7471beb770 1
22428:X 09 May 2019 15:51:29.451 # +elected-leader master mymaster 192.168.30.128 6379
22428:X 09 May 2019 15:51:29.451 # +failover-state-select-slave master mymaster 192.168.30.128 6379
22428:X 09 May 2019 15:51:29.528 # +selected-slave slave 192.168.30.129:6379 192.168.30.129 6379 @ mymaster 192.168.30.128 6379
22428:X 09 May 2019 15:51:29.528 * +failover-state-send-slaveof-noone slave 192.168.30.129:6379 192.168.30.129 6379 @ mymaster 192.168.30.128 6379
22428:X 09 May 2019 15:51:29.594 * +failover-state-wait-promotion slave 192.168.30.129:6379 192.168.30.129 6379 @ mymaster 192.168.30.128 6379
22428:X 09 May 2019 15:51:30.190 # +promoted-slave slave 192.168.30.129:6379 192.168.30.129 6379 @ mymaster 192.168.30.128 6379
22428:X 09 May 2019 15:51:30.190 # +failover-state-reconf-slaves master mymaster 192.168.30.128 6379
22428:X 09 May 2019 15:51:30.258 * +slave-reconf-sent slave 192.168.30.130:6379 192.168.30.130 6379 @ mymaster 192.168.30.128 6379
22428:X 09 May 2019 15:51:30.511 # -odown master mymaster 192.168.30.128 6379
22428:X 09 May 2019 15:51:31.233 * +slave-reconf-inprog slave 192.168.30.130:6379 192.168.30.130 6379 @ mymaster 192.168.30.128 6379
22428:X 09 May 2019 15:51:31.233 * +slave-reconf-done slave 192.168.30.130:6379 192.168.30.130 6379 @ mymaster 192.168.30.128 6379
22428:X 09 May 2019 15:51:31.297 # +failover-end master mymaster 192.168.30.128 6379
22428:X 09 May 2019 15:51:31.297 # +switch-master mymaster 192.168.30.128 6379 192.168.30.129 6379
22428:X 09 May 2019 15:51:31.298 * +slave slave 192.168.30.130:6379 192.168.30.130 6379 @ mymaster 192.168.30.129 6379
22428:X 09 May 2019 15:51:31.298 * +slave slave 192.168.30.128:6379 192.168.30.128 6379 @ mymaster 192.168.30.129 6379
22428:X 09 May 2019 15:52:31.307 # +sdown slave 192.168.30.128:6379 192.168.30.128 6379 @ mymaster 192.168.30.129 6379

Como você pode ver no log, o mestre foi transferido de 192.168.30.128 para 192.168.30.129

Ver informações do cluster em 192.168.30.129

# /usr/local/bin/redis-cli -h 192.168.30.129 -p 6379 -a 123456
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.

192.168.30.129:6379> info replication
# Replication
role:master
connected_slaves:1
slave0:ip=192.168.30.130,port=6379,state=online,offset=291039,lag=1
master_replid:757aff269236ed2707ba584a86a40716c1c76d74
master_replid2:47a862fc0ff20362be29096ecdcca6d432070ee9
master_repl_offset:291182
second_repl_offset:248123
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:1
repl_backlog_histlen:291182

192.168.30.129:6379> set key4 linux
OK

Há apenas um escravo no cluster atual - 192.168.30.130, o mestre é 192.168.30.129 e 192.168.30.129 tem permissões de gravação.

Você também pode ver o arquivo de configuração do redis em 192.168.30.130.Esta replicaof 192.168.30.129 6379é uma modificação feita pelo sentinela na eleição do mestre.

Reinicie o processo em 192.168.30.128

# systemctl start redis

# tail -f /usr/local/redis/sentinel.log

22428:X 09 May 2019 15:51:31.297 # +switch-master mymaster 192.168.30.128 6379 192.168.30.129 6379
22428:X 09 May 2019 15:51:31.298 * +slave slave 192.168.30.130:6379 192.168.30.130 6379 @ mymaster 192.168.30.129 6379
22428:X 09 May 2019 15:51:31.298 * +slave slave 192.168.30.128:6379 192.168.30.128 6379 @ mymaster 192.168.30.129 6379
22428:X 09 May 2019 15:52:31.307 # +sdown slave 192.168.30.128:6379 192.168.30.128 6379 @ mymaster 192.168.30.129 6379
22428:X 09 May 2019 16:01:24.872 # -sdown slave 192.168.30.128:6379 192.168.30.128 6379 @ mymaster 192.168.30.129 6379

Ver informações do cluster

# /usr/local/bin/redis-cli -h 192.168.30.128 -p 6379 -a 123456
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.

192.168.30.128:6379> info replication
# Replication
role:slave
master_host:192.168.30.129
master_port:6379
master_link_status:up
master_last_io_seconds_ago:0
master_sync_in_progress:0
slave_repl_offset:514774
slave_priority:100
slave_read_only:1
connected_slaves:0
master_replid:757aff269236ed2707ba584a86a40716c1c76d74
master_replid2:0000000000000000000000000000000000000000
master_repl_offset:514774
second_repl_offset:-1
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:376528
repl_backlog_histlen:138247

192.168.30.128:6379> get key4
"linux"

192.168.30.128:6379> set key5
(error) ERR wrong number of arguments for 'set' command

Mesmo que 192.168.30.128 reinicie o serviço redis, ele se unirá ao cluster redis como um escravo, e 192.168.30.129 ainda é o mestre.

Modo de cluster

Introdução ao modo de cluster

O modo sentinela pode atender basicamente às necessidades de produção geral e possui alta disponibilidade. No entanto, quando a quantidade de dados é muito grande para um servidor armazenar, o modo mestre-escravo ou o modo sentinela não podem atender à demanda. Nesse momento, os dados armazenados precisam ser fragmentados e armazenados em várias instâncias do Redis. O surgimento do modo cluster é para resolver o problema da capacidade limitada de um único Redis e distribuir os dados do Redis para várias máquinas de acordo com certas regras.

Pode-se dizer que o cluster é uma combinação dos modos sentinela e mestre-escravo. A função mestre-escravo e de resseleção mestre pode ser realizada por meio do cluster, portanto, se você configurar duas cópias e três fragmentos, precisará de seis instâncias do Redis. Como os dados do Redis são alocados para máquinas diferentes no cluster de acordo com certas regras, quando a quantidade de dados é muito grande, novas máquinas podem ser adicionadas para expansão.

Para usar um cluster, você só precisa cluster-enableabrir a configuração no arquivo de configuração do redis . Cada cluster requer pelo menos três bancos de dados principais para funcionar normalmente e é muito conveniente adicionar nós.

Características do cluster:

* 多个redis节点网络互联，数据共享

* 所有的节点都是一主一从（也可以是一主多从），其中从不提供服务，仅作为备用

* 不支持同时处理多个key（如MSET/MGET），因为redis需要把key均匀分布在各个节点上，
  并发量很高的情况下同时创建key-value会降低性能并导致不可预测的行为
  
* 支持在线增加、删除节点

* 客户端可以连接任何一个主节点进行读写

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Origin blog.csdn.net/zwx_lucky/article/details/110802411
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