Redis HA篇 +哨兵搭建

说明：本文为面向Redis哨兵搭建的指导手册
标签：Redis哨兵、Redis高可用、Redis故障转移、Redis 4.0.2
注意：文中删去了不需要的多余部分，让初学者一目了然一学就会
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★ 前言
※ 该文档架构采用：单机1主2从3哨兵架构（相当于6个redis）
※ 系统信息：Centos 6.3 x86_64 4GB内存
※ 如果主从有密码，哨兵也需要密码才能去控制他们
※ 为了方便初学者学习了解redis本文简化了所有步骤
※ Redis全称“remote dictionary server”中文远程字典服务
※ Redis属于NoSql数据库中的key-value类型
※ Redis的哨兵机制是redis2.8开始支持，而集群模式是redis3.0开始支持。
※ Redis的sentinel系统用于管理多个redis服务器，该系统主要执行三个任务：监控、提醒、自动故障转移。
※ Redis的主为读写模式，从为只读模式；
※ Redis的更多参数介绍参考本人其他相关文档

★ 相关文章
※ Redis 运维篇+安装单实例
※ Redis HA篇  +主从搭建
※ Redis HA篇  +哨兵搭建
※ Redis HA篇  +集群搭建

★ 哨兵工作机制
自动监控并切换主从状态及主从的配置文件

★ 搭建哨兵前提条件
# 提前配置好主从环境，并拉起主从
# 需要开启3个会话，分别执行挂起
/soft/redis-4.0.2/src/redis-server /soft/redis-4.0.2/redis_6380.conf
/soft/redis-4.0.2/src/redis-server /soft/redis-4.0.2/redis_6381.conf
/soft/redis-4.0.2/src/redis-server /soft/redis-4.0.2/redis_6382.conf

★ 配置哨兵
※ 复制配置文件
cp /soft/redis-4.0.2/sentinel.conf    /soft/redis-4.0.2/sentinel_26380.conf
cp /soft/redis-4.0.2/sentinel.conf    /soft/redis-4.0.2/sentinel_26381.conf
cp /soft/redis-4.0.2/sentinel.conf    /soft/redis-4.0.2/sentinel_26382.conf

※ 修改配置文件（主）
# 相关文件位置：
/soft/redis-4.0.2/sentinel_26380.conf
# 修改哨兵端口：port
sed -i 's/^port 26379/port 26380/g' /soft/redis-4.0.2/sentinel_26380.conf
cat /soft/redis-4.0.2/sentinel_26380.conf |grep "^port 263"
# 配置主服务器
sed -i 's/sentinel monitor mymaster 127.0.0.1 6379 2/sentinel monitor mymaster 127.0.0.1 6380 2/g' /soft/redis-4.0.2/sentinel_26380.conf
cat /soft/redis-4.0.2/sentinel_26380.conf |grep "^sentinel monitor"

※ 修改配置文件（从A）
# 相关文件位置：
/soft/redis-4.0.2/sentinel_26381.conf
# 修改哨兵端口：port
sed -i 's/^port 26379/port 26381/g' /soft/redis-4.0.2/sentinel_26381.conf
cat /soft/redis-4.0.2/sentinel_26381.conf |grep "^port 263"
# 配置主服务器
sed -i 's/sentinel monitor mymaster 127.0.0.1 6379 2/sentinel monitor mymaster 127.0.0.1 6380 2/g' /soft/redis-4.0.2/sentinel_26381.conf
cat /soft/redis-4.0.2/sentinel_26381.conf |grep "^sentinel monitor"

※ 修改配置文件（从B）
# 相关文件位置：
/soft/redis-4.0.2/sentinel_26382.conf
# 修改哨兵端口：port
sed -i 's/^port 26379/port 26382/g' /soft/redis-4.0.2/sentinel_26382.conf
cat /soft/redis-4.0.2/sentinel_26382.conf |grep "^port 263"
# 配置主服务器
sed -i 's/sentinel monitor mymaster 127.0.0.1 6379 2/sentinel monitor mymaster 127.0.0.1 6380 2/g' /soft/redis-4.0.2/sentinel_26382.conf
cat /soft/redis-4.0.2/sentinel_26382.conf |grep "^sentinel monitor"

★ 启动所有哨兵
# 需要开启3个会话，分别执行挂起
/soft/redis-4.0.2/src/redis-sentinel /soft/redis-4.0.2/sentinel_26380.conf
/soft/redis-4.0.2/src/redis-sentinel /soft/redis-4.0.2/sentinel_26381.conf
/soft/redis-4.0.2/src/redis-sentinel /soft/redis-4.0.2/sentinel_26382.conf

★ 查看主从状态
echo "info replication" | /soft/redis-4.0.2/src/redis-cli -p 6380 |grep role
echo "info replication" | /soft/redis-4.0.2/src/redis-cli -p 6381 |grep role
echo "info replication" | /soft/redis-4.0.2/src/redis-cli -p 6382 |grep role

★ 查看状态详情
echo "info replication" | /soft/redis-4.0.2/src/redis-cli -p 6380
echo "info replication" | /soft/redis-4.0.2/src/redis-cli -p 6381
echo "info replication" | /soft/redis-4.0.2/src/redis-cli -p 6382
echo "info Sentinel" | /soft/redis-4.0.2/src/redis-cli -p 26380
echo "info Sentinel" | /soft/redis-4.0.2/src/redis-cli -p 26381
echo "info Sentinel" | /soft/redis-4.0.2/src/redis-cli -p 26382

★ 测试数据传输
# 插入/查看数据
echo "set zzt_01 'hello zzt'" | /soft/redis-4.0.2/src/redis-cli -p 6380
echo "get zzt_01" | /soft/redis-4.0.2/src/redis-cli -p 6380
echo "get zzt_01" | /soft/redis-4.0.2/src/redis-cli -p 6381
echo "get zzt_01" | /soft/redis-4.0.2/src/redis-cli -p 6382
# 清理数据
echo "del zzt_01" | /soft/redis-4.0.2/src/redis-cli -p 6380
echo "get zzt_01" | /soft/redis-4.0.2/src/redis-cli -p 6380

★ 测试从节点自动重启
该模式下，从节点重启后会自动加入主从，并且会自动同步主库数据

★ 测试主节点自动重启
哨兵会自动判断主节点状态，并重新选举主节点；
原主节点重启后会自动以从的身份加入主从
该模式的主从切换是自动的，所以一般推荐使用自动管理的哨兵模式

★ 测试某个哨兵实例自动重启
哨兵自动重启并不影响主从的自动选举和切换
哨兵自动重启后可以自动加入哨兵组
 

★ 案例

※ 主从信息
[root@main redis-4.0.2]# /soft/redis-4.0.2/src/redis-cli -p 6380
127.0.0.1:6380> info 
# Server
redis_version:4.0.2
redis_git_sha1:00000000
redis_git_dirty:0
redis_build_id:cd424730de8d0575
redis_mode:standalone
os:Linux 2.6.32-279.el6.x86_64 x86_64
arch_bits:64
multiplexing_api:epoll
atomicvar_api:sync-builtin
gcc_version:4.4.6
process_id:42813
run_id:54f9160f14949b6d2fa23b0e5c03db717ac7caa5
tcp_port:6380
uptime_in_seconds:2248
uptime_in_days:0
hz:10
lru_clock:3696251
executable:/soft/redis-4.0.2/src/redis-server
config_file:/soft/redis-4.0.2/redis_6380.conf

# Clients
connected_clients:7
client_longest_output_list:0
client_biggest_input_buf:0
blocked_clients:0

# Memory
used_memory:2074094
used_memory_human:1.98M
used_memory_rss:2732032
used_memory_rss_human:2.61M
used_memory_peak:2154072
used_memory_peak_human:2.05M
used_memory_peak_perc:96.29%
used_memory_overhead:2068937
used_memory_startup:835755
used_memory_dataset:5157
used_memory_dataset_perc:0.42%
total_system_memory:4004020224
total_system_memory_human:3.73G
used_memory_lua:37888
used_memory_lua_human:37.00K
maxmemory:0
maxmemory_human:0B
maxmemory_policy:noeviction
mem_fragmentation_ratio:1.32
mem_allocator:libc
active_defrag_running:0
lazyfree_pending_objects:0

# Persistence
loading:0
rdb_changes_since_last_save:0
rdb_bgsave_in_progress:0
rdb_last_save_time:1614306740
rdb_last_bgsave_status:ok
rdb_last_bgsave_time_sec:0
rdb_current_bgsave_time_sec:-1
rdb_last_cow_size:204800
aof_enabled:0
aof_rewrite_in_progress:0
aof_rewrite_scheduled:0
aof_last_rewrite_time_sec:-1
aof_current_rewrite_time_sec:-1
aof_last_bgrewrite_status:ok
aof_last_write_status:ok
aof_last_cow_size:0

# Stats
total_connections_received:13
total_commands_processed:6346
instantaneous_ops_per_sec:5
total_net_input_bytes:260328
total_net_output_bytes:805031
instantaneous_input_kbps:0.27
instantaneous_output_kbps:4.29
rejected_connections:0
sync_full:2
sync_partial_ok:0
sync_partial_err:2
expired_keys:0
evicted_keys:0
keyspace_hits:1
keyspace_misses:0
pubsub_channels:1
pubsub_patterns:0
latest_fork_usec:183
migrate_cached_sockets:0
slave_expires_tracked_keys:0
active_defrag_hits:0
active_defrag_misses:0
active_defrag_key_hits:0
active_defrag_key_misses:0

# Replication
role:master
connected_slaves:2
slave0:ip=127.0.0.1,port=6381,state=online,offset=80670,lag=0
slave1:ip=127.0.0.1,port=6382,state=online,offset=80537,lag=1
master_replid:d38df8987f4ebac447df143c0da5bb48db2ace72
master_replid2:0000000000000000000000000000000000000000
master_repl_offset:80670
second_repl_offset:-1
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:1
repl_backlog_histlen:80670

# CPU
used_cpu_sys:2.79
used_cpu_user:0.97
used_cpu_sys_children:0.00
used_cpu_user_children:0.00

# Cluster
cluster_enabled:0

# Keyspace
db0:keys=1,expires=0,avg_ttl=0






※ 哨兵信息
[root@main redis-4.0.2]# /soft/redis-4.0.2/src/redis-cli -p 26380
127.0.0.1:26380> info
# Server
redis_version:4.0.2
redis_git_sha1:00000000
redis_git_dirty:0
redis_build_id:cd424730de8d0575
redis_mode:sentinel
os:Linux 2.6.32-279.el6.x86_64 x86_64
arch_bits:64
multiplexing_api:epoll
atomicvar_api:sync-builtin
gcc_version:4.4.6
process_id:46908
run_id:6c4bac04c26736cd49cdcaaa26738629c97f3693
tcp_port:26380
uptime_in_seconds:296
uptime_in_days:0
hz:17
lru_clock:3696135
executable:/soft/redis-4.0.2/src/redis-sentinel
config_file:/soft/redis-4.0.2/sentinel_26380.conf

# Clients
connected_clients:3
client_longest_output_list:0
client_biggest_input_buf:0
blocked_clients:0

# CPU
used_cpu_sys:0.72
used_cpu_user:0.16
used_cpu_sys_children:0.00
used_cpu_user_children:0.00

# Stats
total_connections_received:5
total_commands_processed:818
instantaneous_ops_per_sec:2
total_net_input_bytes:43915
total_net_output_bytes:5224
instantaneous_input_kbps:0.12
instantaneous_output_kbps:0.01
rejected_connections:0
sync_full:0
sync_partial_ok:0
sync_partial_err:0
expired_keys:0
evicted_keys:0
keyspace_hits:0
keyspace_misses:0
pubsub_channels:0
pubsub_patterns:0
latest_fork_usec:0
migrate_cached_sockets:0
slave_expires_tracked_keys:0
active_defrag_hits:0
active_defrag_misses:0
active_defrag_key_hits:0
active_defrag_key_misses:0

# Sentinel
sentinel_masters:1
sentinel_tilt:0
sentinel_running_scripts:0
sentinel_scripts_queue_length:0
sentinel_simulate_failure_flags:0
master0:name=mymaster,status=ok,address=127.0.0.1:6380,slaves=2,sentinels=3
127.0.0.1:26380> 




※ 插入/查看数据
[root@main ~]# echo "set zzt_01 'hello zzt'" | /soft/redis-4.0.2/src/redis-cli -p 6380
OK
[root@main ~]# echo "get zzt_01" | /soft/redis-4.0.2/src/redis-cli -p 6380
"hello zzt"
[root@main ~]# echo "get zzt_01" | /soft/redis-4.0.2/src/redis-cli -p 6381
"hello zzt"
[root@main ~]# echo "get zzt_01" | /soft/redis-4.0.2/src/redis-cli -p 6382
"hello zzt"

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