redis-cluster介绍

redis-cluster集群

Redis集群搭建的方式有多种，例如使用zookeeper等，但从redis 3.0之后版本支持redis-cluster集群，Redis-Cluster采用无中心结构，每个节点保存数据和整个集群状态,每个节点都和其他所有节点连接。其redis-cluster架构图如下：

其结构特点：

•  所有的redis节点彼此互联(PING-PONG机制),内部使用二进制协议优化传输速度和带宽。
•  节点的fail是通过集群中超过半数的节点检测失效时才生效。
•  客户端与redis节点直连,不需要中间proxy层.客户端不需要连接集群所有节点,连接集群中任何一个可用节点即可。
•  redis-cluster把所有的物理节点映射到[0-16383]slot上（不一定是平均分配）,cluster 负责维护node<->slot<->value。
•  Redis集群预分好16384个桶，当需要在 Redis 集群中放置一个 key-value 时，根据 CRC16(key) mod 16384的值，决定将一个key放到哪个桶中。

1.1 Redis Cluster主从模式

1. redis cluster 为了保证数据的高可用性，加入了主从模式，一个主节点对应一个或多个从节点，主节点提供数据存取，从节点则是从主节点拉取数据备份，当这个主节点挂掉后，就会有这个从节点选取一个来充当主节点，从而保证集群不会挂掉。
2. 上面那个例子里, 集群有ABC三个主节点, 如果这3个节点都没有加入从节点，如果B挂掉了，我们就无法访问整个集群了。A和C的slot也无法访问。
3. 所以我们在集群建立的时候，一定要为每个主节点都添加了从节点, 比如像这样, 集群包含主节点A、B、C, 以及从节点A1、B1、C1, 那么即使B挂掉系统也可以继续正确工作。
4. B1节点替代了B节点，所以Redis集群将会选择B1节点作为新的主节点，集群将会继续正确地提供服务。 当B重新开启后，它就会变成B1的从节点。
5. 不过需要注意，如果节点B和B1同时挂了，Redis集群就无法继续正确地提供服务了。

redis架构如图：

• 10.0.0.61       Redis01
• 10.0.0.62       Redis02
• 10.0.0.63       Redis03
• 在每个节点搭建两个redis，在任意一个节点安装ruby环境
• 记得关闭防火墙，或者开放对应端口

 1.2  在每个节点安装redis

[root@redis01 ~]# cd /usr/local/src/
[root@redis01 src]# wget http://download.redis.io/releases/redis-3.2.8.tar.gz
--2017-12-26 18:27:29--  http://download.redis.io/releases/redis-3.2.8.tar.gz
Resolving download.redis.io (download.redis.io)... 109.74.203.151
Connecting to download.redis.io (download.redis.io)|109.74.203.151|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 1547237 (1.5M) [application/x-gzip]
Saving to: ‘redis-3.2.8.tar.gz’

100%[==================================================================================================================================>] 1,547,237   32.3KB/s   in 23s    

2017-12-26 18:27:53 (64.7 KB/s) - ‘redis-3.2.8.tar.gz’ saved [1547237/1547237]
[root@redis01 src]# tar xf redis-3.2.8.tar.gz
[root@redis01 src]# cd redis-3.2.8/
[root@redis01 redis-3.2.8]# make
[root@redis01 redis-3.2.8]# make PREFIX=/usr/local/redis_m install
[root@redis01 ~]# echo "export PATH=/usr/local/redis_m/bin:$PATH" >>/etc/profile
[root@redis01 ~]# source /etc/profile
[root@redis01 ~]# cd /usr/local/redis_m/
[root@redis01 redis_m]# mkdir -p conf
[root@redis01 redis_m]# cp /usr/local/src/redis-3.2.8/redis.conf conf/

• 修改redis_m的redis.conf

bind 10.0.0.61
protected-mode yes
port 6379
tcp-backlog 511
timeout 0
tcp-keepalive 300
cluster-enabled yes
cluster-config-file nodes_6379.conf  #启动首次生成
cluster-node-timeout 15000　　
daemonize yes
supervised no
pidfile "/var/run/redis_6379.pid"
loglevel notice
logfile ""
databases 16
save 900 1
save 300 10
save 60 10000
stop-writes-on-bgsave-error yes
rdbcompression yes
rdbchecksum yes
dbfilename "dump.rdb"
dir "/usr/local/redis_m/conf"
slave-serve-stale-data yes
slave-read-only yes
repl-diskless-sync no
repl-diskless-sync-delay 5
repl-disable-tcp-nodelay no
slave-priority 100
appendonly no
appendfilename "appendonly.aof"
appendfsync everysec
no-appendfsync-on-rewrite no
auto-aof-rewrite-percentage 100
auto-aof-rewrite-min-size 64mb
aof-load-truncated yes
lua-time-limit 5000
slowlog-log-slower-than 10000
slowlog-max-len 128
latency-monitor-threshold 0
notify-keyspace-events ""
hash-max-ziplist-entries 512
hash-max-ziplist-value 64
list-max-ziplist-size -2
list-compress-depth 0
set-max-intset-entries 512
zset-max-ziplist-entries 128
zset-max-ziplist-value 64
hll-sparse-max-bytes 3000
activerehashing yes
client-output-buffer-limit normal 0 0 0
client-output-buffer-limit slave 256mb 64mb 60
client-output-buffer-limit pubsub 32mb 8mb 60
hz 10
aof-rewrite-incremental-fsync yes

在本机搭建第二个redis

[root@redis01 conf]# cd /usr/local/
[root@redis01 conf]# cp -r redis_m redis_s
#修改节点2 redis_s的配置文件
bind 10.0.0.61
protected-mode yes
port 6380
tcp-backlog 511
timeout 0
tcp-keepalive 300
cluster-enabled yes
cluster-config-file nodes_6380.conf
cluster-node-timeout 15000
daemonize yes
supervised no
pidfile "/var/run/redis_6380.pid"
loglevel notice
logfile ""
databases 16
save 900 1
save 300 10
save 60 10000
stop-writes-on-bgsave-error yes
rdbcompression yes
rdbchecksum yes
dbfilename "dump.rdb"
dir "/usr/local/redis_s/conf"
slave-serve-stale-data yes
slave-read-only yes
repl-diskless-sync no
repl-diskless-sync-delay 5
repl-disable-tcp-nodelay no
slave-priority 100
appendonly no
appendfilename "appendonly.aof"
appendfsync everysec
no-appendfsync-on-rewrite no
auto-aof-rewrite-percentage 100
auto-aof-rewrite-min-size 64mb
aof-load-truncated yes
lua-time-limit 5000
slowlog-log-slower-than 10000
slowlog-max-len 128
latency-monitor-threshold 0
notify-keyspace-events ""
hash-max-ziplist-entries 512
hash-max-ziplist-value 64
list-max-ziplist-size -2
list-compress-depth 0
set-max-intset-entries 512
zset-max-ziplist-entries 128
zset-max-ziplist-value 64
hll-sparse-max-bytes 3000
activerehashing yes
client-output-buffer-limit normal 0 0 0
client-output-buffer-limit slave 256mb 64mb 60
client-output-buffer-limit pubsub 32mb 8mb 60
hz 10
aof-rewrite-incremental-fsync yes

• 每台机器都部署两个redis，重复上述操作。

• 部署完成在任意节点安装ruby环境

[root@redis01 src]# pwd
/usr/local/src/redis-3.2.8/src
[root@redis01 src]# cp redis-trib.rb /usr/local/bin/
[root@redis01 src]# yum -y install ruby ruby-devel rubygems rpm-build
[root@redis01 src]# gem install redis --version 3.0.0
Fetching: redis-3.0.0.gem (100%)
Successfully installed redis-3.0.0
Parsing documentation for redis-3.0.0
Installing ri documentation for redis-3.0.0
1 gem installed
#启动redis
[root@redis01 ~]# redis-server /usr/local/redis_m/conf/redis.conf 
[root@redis01 ~]# redis-server /usr/local/redis_s/conf/redis.conf 
[root@redis01 ~]# netstat -lntup|grep redis
tcp        0      0 10.0.0.61:6379          0.0.0.0:*               LISTEN      7226/redis-server 1 
tcp        0      0 10.0.0.61:6380          0.0.0.0:*               LISTEN      7230/redis-server 1 
tcp        0      0 10.0.0.61:16379         0.0.0.0:*               LISTEN      7226/redis-server 1 
tcp        0      0 10.0.0.61:16380         0.0.0.0:*               LISTEN      7230/redis-server 1

 2 .1 创建集群

启动集群

[root@redis01 ~]#  redis-trib.rb create --replicas 1 10.0.0.61:6379 10.0.0.62:6379 10.0.0.63:6379 10.0.0.61:6380 10.0.0.62:6380 10.0.0.63:6380
>>> Creating cluster
##省略
M: 7876243e1de6e81316ff299d0cbd9f50dee6a6a6 10.0.0.61:6379
   slots:0-5460 (5461 slots) master
   1 additional replica(s)
M: 98b24b670b08b6f87c805d7225738b2119d1c1f3 10.0.0.63:6379
   slots:10923-16383 (5461 slots) master
   1 additional replica(s)
S: 2f8dde5cfb03dd02331abf0560c3ab2e6fcfee0b 10.0.0.63:6380
   slots: (0 slots) slave
   replicates 98b24b670b08b6f87c805d7225738b2119d1c1f3
S: a4212518794b6afacd9dc703a061bcba2ecd9683 10.0.0.62:6380
   slots: (0 slots) slave
   replicates 7876243e1de6e81316ff299d0cbd9f50dee6a6a6
S: ce3105e44480c1c312918b01f6415767adc1e253 10.0.0.61:6380
   slots: (0 slots) slave
   replicates c3d233cd5aa613b271e117c43a8d2a3f7702cdb5
M: c3d233cd5aa613b271e117c43a8d2a3f7702cdb5 10.0.0.62:6379
   slots:5461-10922 (5462 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.

 进入到集群

[root@redis01 ~]# redis-cli -h 10.0.0.61 -c -p 6379

 查看cluster集群 

[root@redis01 ~]# redis-trib.rb check 10.0.0.61:6379