有同事問我，三個redis sentinel節點，宕機兩個節點以后，是否還能夠正常的通過redis sentinel正常訪問redis的數據。我想了想，理論上是可以的，但是我沒試過，今天有時間就測試了一下。搭建環境和測試代碼的過程一波三折，以下是配置信息。虛擬機使用的是CENTOS7 ，docker是現成的，redis鏡像的版本redis_version:7.0.11 , python是python3
使用docker compose 快速啟動 redis節點和sentinel集群，這樣會比較快。
docker-compose.yml
version: '3.0'
services:master:image: rediscontainer_name: redis-masterports:- 6379:6379# 這個模式不要用 host，會有問題，用bridgenetwork_mode: bridgecommand: redis-server /usr/local/etc/redis/redis.confvolumes:- ./redis1.conf:/usr/local/etc/redis/redis.confslave1:image: rediscontainer_name: redis-slave-1ports:- 6380:6380network_mode: bridgecommand: redis-server /usr/local/etc/redis/redis.conf --slaveof 10.4.7.124 6379volumes:- ./redis2.conf:/usr/local/etc/redis/redis.confslave2:image: rediscontainer_name: redis-slave-2ports:- 6381:6381network_mode: bridgecommand: redis-server /usr/local/etc/redis/redis.conf --slaveof 10.4.7.124 6379volumes:- ./redis3.conf:/usr/local/etc/redis/redis.confsentinel1:image: rediscontainer_name: redis-sentinel-1ports:- 26379:26379network_mode: bridgecommand: redis-sentinel /usr/local/etc/redis/sentinel.confvolumes:- ./sentinel1.conf:/usr/local/etc/redis/sentinel.confsentinel2:image: rediscontainer_name: redis-sentinel-2ports:- 26380:26380network_mode: bridgecommand: redis-sentinel /usr/local/etc/redis/sentinel.confvolumes:- ./sentinel2.conf:/usr/local/etc/redis/sentinel.confsentinel3:image: rediscontainer_name: redis-sentinel-3ports:- 26381:26381network_mode: bridgecommand: redis-sentinel /usr/local/etc/redis/sentinel.confvolumes:- ./sentinel3.conf:/usr/local/etc/redis/sentinel.conf
redis1.conf
bind 0.0.0.0
protected-mode no
port 6379
tcp-backlog 511
timeout 0
tcp-keepalive 300
daemonize no
supervised no
pidfile /var/run/redis_6379.pid
loglevel notice
logfile ""
databases 16
always-show-logo yes
save 900 1
save 300 10
save 60 10000
stop-writes-on-bgsave-error yes
rdbcompression yes
rdbchecksum yes
dbfilename dump.rdb
dir ./
replica-serve-stale-data yes
replica-read-only yes
repl-diskless-sync no
repl-diskless-sync-delay 5
repl-disable-tcp-nodelay no
replica-priority 100
lazyfree-lazy-eviction no
lazyfree-lazy-expire no
lazyfree-lazy-server-del no
replica-lazy-flush no
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
aof-use-rdb-preamble 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
stream-node-max-bytes 4096
stream-node-max-entries 100
activerehashing yes
client-output-buffer-limit normal 0 0 0
client-output-buffer-limit replica 256mb 64mb 60
client-output-buffer-limit pubsub 32mb 8mb 60
hz 10
dynamic-hz yes
aof-rewrite-incremental-fsync yes
rdb-save-incremental-fsync yes
redis2.conf
bind 0.0.0.0
# 這個模式要no，否則不好連接測試
protected-mode no
port 6380
tcp-backlog 511
timeout 0
tcp-keepalive 300
daemonize no
supervised no
pidfile /var/run/redis_6380.pid
loglevel notice
logfile ""
databases 16
always-show-logo yes
save 900 1
save 300 10
save 60 10000
stop-writes-on-bgsave-error yes
rdbcompression yes
rdbchecksum yes
dbfilename dump.rdb
dir ./
replica-serve-stale-data yes
replica-read-only yes
repl-diskless-sync no
repl-diskless-sync-delay 5
repl-disable-tcp-nodelay no
replica-priority 100
lazyfree-lazy-eviction no
lazyfree-lazy-expire no
lazyfree-lazy-server-del no
replica-lazy-flush no
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
aof-use-rdb-preamble 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
stream-node-max-bytes 4096
stream-node-max-entries 100
activerehashing yes
client-output-buffer-limit normal 0 0 0
client-output-buffer-limit replica 256mb 64mb 60
client-output-buffer-limit pubsub 32mb 8mb 60
hz 10
dynamic-hz yes
aof-rewrite-incremental-fsync yes
rdb-save-incremental-fsync yes
redis3.conf
bind 0.0.0.0
protected-mode no
port 6381
tcp-backlog 511
timeout 0
tcp-keepalive 300
daemonize no
supervised no
pidfile /var/run/redis_6381.pid
loglevel notice
logfile ""
databases 16
always-show-logo yes
save 900 1
save 300 10
save 60 10000
stop-writes-on-bgsave-error yes
rdbcompression yes
rdbchecksum yes
dbfilename dump.rdb
dir ./
replica-serve-stale-data yes
replica-read-only yes
repl-diskless-sync no
repl-diskless-sync-delay 5
repl-disable-tcp-nodelay no
replica-priority 100
lazyfree-lazy-eviction no
lazyfree-lazy-expire no
lazyfree-lazy-server-del no
replica-lazy-flush no
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
aof-use-rdb-preamble 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
stream-node-max-bytes 4096
stream-node-max-entries 100
activerehashing yes
client-output-buffer-limit normal 0 0 0
client-output-buffer-limit replica 256mb 64mb 60
client-output-buffer-limit pubsub 32mb 8mb 60
hz 10
dynamic-hz yes
aof-rewrite-incremental-fsync yes
rdb-save-incremental-fsync yes
sentinel1.conf
port 26379
sentinel monitor mymaster 10.4.7.124 6379 2
sentinel down-after-milliseconds mymaster 10000
sentinel failover-timeout mymaster 180000
sentinel parallel-syncs mymaster 1sentinel2.conf
port 26380
sentinel monitor mymaster 10.4.7.124 6379 2
sentinel down-after-milliseconds mymaster 10000
sentinel failover-timeout mymaster 180000
sentinel parallel-syncs mymaster 1
sentinel3.conf
port 26381
sentinel monitor mymaster 10.4.7.124 6379 2
sentinel down-after-milliseconds mymaster 10000
sentinel failover-timeout mymaster 180000
sentinel parallel-syncs mymaster 1
啟動所有服務
docker-compose up -d
docker compose up -d
[root@docker_124 sentinel]# docker compose up -d
[+] Running 6/6? Container redis-slave-2 Started 0.1s ? Container redis-sentinel-1 Started 0.1s ? Container redis-sentinel-2 Started 0.1s ? Container redis-sentinel-3 Started 0.1s ? Container redis-master Started 0.1s ? Container redis-slave-1 Started
停止所有服務
docker-compose down
[root@docker_124 sentinel]# docker compose up -d
[+] Running 6/6? Container redis-slave-2 Started 0.1s ? Container redis-sentinel-1 Started 0.1s ? Container redis-sentinel-2 Started 0.1s ? Container redis-sentinel-3 Started 0.1s ? Container redis-master Started 0.1s ? Container redis-slave-1 Started
集群啟動好以后，測試是否正常啟動
[root@docker_124 sentinel]# docker run -it --rm redis redis-cli -h 10.4.7.124 -p 6379 info replication
# Replication
role:master
connected_slaves:2
slave0:ip=172.17.0.1,port=6380,state=online,offset=170743,lag=1
slave1:ip=172.17.0.1,port=6381,state=online,offset=170743,lag=0
master_failover_state:no-failover
master_replid:c85254ee815510a442514fa73aeba46fc8fb018f
master_replid2:0000000000000000000000000000000000000000
master_repl_offset:170743
second_repl_offset:-1
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:1
repl_backlog_histlen:170743[root@docker_124 sentinel]# docker run -it --rm redis redis-cli -h 10.4.7.124 -p 6380
[root@docker_124 sentinel]# docker run -it --rm redis redis-cli -h 10.4.7.124 -p 6381
[root@docker_124 sentinel]# docker run -it --rm redis redis-cli -h 10.4.7.124 -p 26380
[root@docker_124 sentinel]# docker run -it --rm redis redis-cli -h 10.4.7.124 -p 26381
[root@docker_124 sentinel]# docker run -it --rm redis redis-cli -h 10.4.7.124 -p 26379
10.4.7.124:26379> sentinel master mymaster1) "name"2) "mymaster"3) "ip"4) "10.4.7.124"5) "port"6) "6379"7) "runid"8) "8c21a5f4a8fdcabb3677603800a66a2b41c62f3c"9) "flags"
10) "master"……省略……[root@docker_124 sentinel]# docker run -it --rm redis redis-cli -h 10.4.7.124 -p 26379 sentinel slaves mymaster
1) 1) "name"2) "172.17.0.1:6381"3) "ip"4) "172.17.0.1"5) "port"6) "6381"7) "runid"8) "10053461cfeedbf53aec9f0afa66570f079483f6"9) "flags"10) "slave"……省略……
環境正常啟動后可以運行Python腳本進行測試
測試python腳本
from redis.sentinel import Sentinel
import time
import random# 生成隨機字符串
def generate_random_str(randomlength=16):random_str = ''base_str = 'ABCDEFGHIGKLMNOPQRSTUVWXYZabcdefghigklmnopqrstuvwxyz0123456789'length = len(base_str) - 1for i in range(randomlength):random_str += base_str[random.randint(0, length)]return random_str# 連接Redis Sentinel
sentinel = Sentinel([('10.4.7.124', 26379),('10.4.7.124', 26380),('10.4.7.124', 26381)],socket_timeout=0.5)# 獲取主服務器地址
master = sentinel.master_for('mymaster', socket_timeout=0.5, db=0)
w_ret = master.set('foo', 'bar')
print(master)
# 輸出：('192.168.31.87', 26379)
# 獲取從服務器地址
slave = sentinel.slave_for('mymaster', socket_timeout=0.5, db=0)
print(slave)
# 輸出：[('192.168.31.88', 26379)]while True:print('master:', master.get('foo'))# master 向redis 插入隨機數據master.set('foo', generate_random_str(10))print('sleep 1s')time.sleep(1)python 程序啟動后會每秒請求sentinel地址獲取redis連接設置值，然后我將sentinel集群的節點停掉兩個（包括master節點），依然可以正常設置值，在redis的 master節點可以獲取最新設置的值，說明sentinel節點停掉兩個仍是可用狀態。
參考文檔
-
Dock-compose 搭建redis-sentinel測試環境
https://www.cnblogs.com/leffss/p/12082361.html
-
python3連接redis sentinel集群
https://blog.csdn.net/u012887259/article/details/102425691
-
解決 WARNING: Published ports are discarded when using host network mode 問題
https://blog.csdn.net/zengNLP/article/details/127220244
-
安裝 docker compose
我安裝完只能用
docker compose不能用docker-compose，不知道為什么。yum -y install docker-compose-pluginhttps://blog.csdn.net/pushiqiang/article/details/78682323
https://zhuanlan.zhihu.com/p/570108654
----變量的線程安全分析)
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