Redis Sentinel 高可用实现说明

背景：

     前面介绍了Redis 复制、Sentinel的搭建和原理说明，通过这篇文章大致能了解Sentinel的原理和实现方法以及相关的搭建。这篇文章就针对Redis Sentinel的搭建做下详细的说明。

安装：

     这里对源码编译进行一下说明，本文实例的操作系统是Ubuntu16.04，使用Redis的版本是3.2.0。安装步骤如下：

• 下载源码包：wget http://download.redis.io/releases/redis-3.2.0.tar.gz
• 安装依赖包：sudo apt-get install gcc tcl
• 解压编译   ：
  

  #tar zxvf redis-3.2.0.tar.gz
  ...
  ...
  #make
  ...
  Hint: It's a good idea to run 'make test' ;)
  #make test
  ...
  \o/ All tests passed without errors!
  ...
  #make install

  注意：这里很可能会在make test 这步出现一个错误：

  [err]: Test replication partial resync: ok psync (diskless: yes, reconnect: 1) in tests/integration/replication-psync.tcl

  Expected condition '[s -1 sync_partial_ok] > 0' to be true ([s -1 sync_partial_ok] > 0)

  出现这个问题的原因可能是"测试点在配置比较低的机器上会因为超时而过不了"，本文的环境是一个lxc的虚拟机。不过有2个方法可以避免：
  

  1:在解压目录中修改
  # vi tests/integration/replication-psync.tcl
  把 after 100 改成 after 500
  
  2：用taskset来make test
  # taskset -c 1 make test

  到此redis编译安装完成。

• 编译文件的目录里有2个配置：
  redis.conf、sentinel.conf，配置文件说明请见这篇文章。
• 本文测试的环境架构：
  3个redis实例1主、2从、3sentinel。M：10.0.3.110、S：10.0.3.92、10.0.3.66，每个redis实例上配置一个sentinel实例。修改配置文件：
  redis.conf
• 

  # Redis configuration file example.
  # ./redis-server /path/to/redis.conf
  
  ################################## INCLUDES ###################################
  
  # include /path/to/local.conf
  # include /path/to/other.conf
  
  ################################## NETWORK #####################################
  
  bind 10.0.3.110
  
  protected-mode yes
  
  port 6379
  
  tcp-backlog 511
  
  unixsocket "/tmp/redis.sock"
  unixsocketperm 700
  
  timeout 0
  
  tcp-keepalive 0
  
  ################################# GENERAL #####################################
  
  daemonize yes
  
  pidfile "/var/run/redis6379.pid"
  
  loglevel notice
  
  logfile "/var/log/redis/redis_6379.log"
  
  # syslog-enabled no
  # syslog-ident redis
  # syslog-facility local0
  
  databases 16
  supervised no
  
  ################################ SNAPSHOTTING  ################################
  
  save 900 1
  save 300 10
  save 60 10000
  
  stop-writes-on-bgsave-error yes
  
  rdbcompression yes
  
  rdbchecksum yes
  
  dbfilename "dump_6379.rdb"
  
  dir "/var/lib/redis_6379"
  
  ################################# REPLICATION #################################
  
  # slaveof <masterip> <masterport>
  masterauth "dxydxy"
  
  slave-serve-stale-data yes
  slave-read-only yes
  
  repl-diskless-sync no
  repl-diskless-sync-delay 5
  
  # repl-ping-slave-period 10
  # repl-timeout 60
  
  repl-disable-tcp-nodelay no
  repl-backlog-size 5mb
  repl-backlog-ttl 3600
  
  slave-priority 100
  
  #min-slaves-to-write 3
  #min-slaves-max-lag 10
  
  ################################## SECURITY ###################################
  
  requirepass "dxydxy"
  # rename-command CONFIG b840fc02d524045429941cc15f59e41cb7be6c52
  # rename-command CONFIG ""
  
  ################################### LIMITS ####################################
  
  maxclients 1000
  #maxmemory <bytes>
  maxmemory-policy noeviction
  # maxmemory-samples 5
  
  ############################## APPEND ONLY MODE ###############################
  
  appendonly yes
  
  appendfilename "appendonly_6379.aof"
  
  # appendfsync always
  appendfsync everysec
  # appendfsync no
  
  no-appendfsync-on-rewrite no
  auto-aof-rewrite-percentage 100
  auto-aof-rewrite-min-size 64mb
  aof-load-truncated yes
  
  ################################ LUA SCRIPTING  ###############################
  
  lua-time-limit 5000
  
  ################################ REDIS CLUSTER  ###############################
  
  # cluster-enabled yes
  # cluster-config-file nodes-6379.conf
  # cluster-node-timeout 15000
  # cluster-slave-validity-factor 10
  # cluster-migration-barrier 1
  # cluster-require-full-coverage yes
  
  ################################## SLOW LOG ###################################
  
  slowlog-log-slower-than 10000
  slowlog-max-len 128
  
  ################################ LATENCY MONITOR ##############################
  
  latency-monitor-threshold 0
  
  ############################# EVENT NOTIFICATION ##############################
  
  notify-keyspace-events ""
  
  ############################### ADVANCED CONFIG ###############################
  
  hash-max-ziplist-entries 512
  hash-max-ziplist-value 64
  
  list-max-ziplist-entries 512
  list-max-ziplist-value 64
  
  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
  
  list-max-ziplist-size -2

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