三、运行redis集群
1.运行redis容器
[root@etcd3 docker_redis_nodes]# docker run -d --name redis-6379 -p 6379:6379 hakimdstx/nodes-redis:4.0.1 1673a7d859ea83257d5bf14d82ebf717fb31405c185ce96a05f597d8f855aa7d [root@etcd3 docker_redis_nodes]# docker run -d --name redis-6380 -p 6380:6379 hakimdstx/nodes-redis:4.0.1 df6ebce6f12a6f3620d5a29adcfbfa7024e906c3af48f21fa7e1fa524a361362 [root@etcd3 docker_redis_nodes]# docker run -d --name redis-6381 -p 6381:6379 hakimdstx/nodes-redis:4.0.1 396e174a1d9235228b3c5f0266785a12fb1ea49efc7ac755c9e7590e17aa1a79 [root@etcd3 docker_redis_nodes]# docker run -d --name redis-6382 -p 6382:6379 hakimdstx/nodes-redis:4.0.1 d9a71dd3f969094205ffa7596c4a04255575cdd3acca2d47fe8ef7171a3be528 [root@etcd3 docker_redis_nodes]# docker run -d --name redis-6383 -p 6383:6379 hakimdstx/nodes-redis:4.0.1 73e4f843d8cb28595456e21b04f97d18ce1cdf8dc56d1150844ba258a3781933 [root@etcd3 docker_redis_nodes]# docker run -d --name redis-6384 -p 6384:6379 hakimdstx/nodes-redis:4.0.1 10c62aafa4dac47220daf5bf3cec84406f086d5261599b54ec6c56bb7da97d6d
2.查看容器信息
[root@etcd3 redis]# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 10c62aafa4da hakimdstx/nodes-redis:4.0.1 "/usr/local/redis/..." 3 seconds ago Up 2 seconds 0.0.0.0:6384->6379/tcp redis-6384 73e4f843d8cb hakimdstx/nodes-redis:4.0.1 "/usr/local/redis/..." 12 seconds ago Up 10 seconds 0.0.0.0:6383->6379/tcp redis-6383 d9a71dd3f969 hakimdstx/nodes-redis:4.0.1 "/usr/local/redis/..." 20 seconds ago Up 18 seconds 0.0.0.0:6382->6379/tcp redis-6382 396e174a1d92 hakimdstx/nodes-redis:4.0.1 "/usr/local/redis/..." 3 days ago Up 3 days 0.0.0.0:6381->6379/tcp redis-6381 df6ebce6f12a hakimdstx/nodes-redis:4.0.1 "/usr/local/redis/..." 3 days ago Up 3 days 0.0.0.0:6380->6379/tcp redis-6380 1673a7d859ea hakimdstx/nodes-redis:4.0.1 "/usr/local/redis/..." 3 days ago Up 3 days 0.0.0.0:6379->6379/tcp redis-6379
3.运行 redis 集群容器
1.通过远程连接,查看redis info replication 信息
[root@etcd2 ~]# redis-cli -h 192.168.10.52 -p 6379 192.168.10.52:6379> info replication NOAUTH Authentication required. 192.168.10.52:6379> auth 123456 OK 192.168.10.52:6379> info replication # Replication role:master connected_slaves:0 master_replid:2f0a7b50aed699fa50a79f3f7f9751a070c50ee9 master_replid2:0000000000000000000000000000000000000000 master_repl_offset:0 second_repl_offset:-1 repl_backlog_active:0 repl_backlog_size:1048576 repl_backlog_first_byte_offset:0 repl_backlog_histlen:0 192.168.10.52:6379> # 其余基本信息同上
可以看到,客户连接之后,因为之前设置了密码,所以需要先输入密码认证,否则就无法通过。以上信息,我们知道所有的redis都是master角色 role:master ,这显然不是我们所希望的。
2.在配置之前我们需要查看所有容器当前的IP地址
[root@etcd3 redis]# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 10c62aafa4da hakimdstx/nodes-redis:4.0.1 "/usr/local/redis/..." 3 seconds ago Up 2 seconds 0.0.0.0:6384->6379/tcp redis-6384 73e4f843d8cb hakimdstx/nodes-redis:4.0.1 "/usr/local/redis/..." 12 seconds ago Up 10 seconds 0.0.0.0:6383->6379/tcp redis-6383 d9a71dd3f969 hakimdstx/nodes-redis:4.0.1 "/usr/local/redis/..." 20 seconds ago Up 18 seconds 0.0.0.0:6382->6379/tcp redis-6382 396e174a1d92 hakimdstx/nodes-redis:4.0.1 "/usr/local/redis/..." 3 days ago Up 3 days 0.0.0.0:6381->6379/tcp redis-6381 df6ebce6f12a hakimdstx/nodes-redis:4.0.1 "/usr/local/redis/..." 3 days ago Up 3 days 0.0.0.0:6380->6379/tcp redis-6380 1673a7d859ea hakimdstx/nodes-redis:4.0.1 "/usr/local/redis/..." 3 days ago Up 3 days 0.0.0.0:6379->6379/tcp redis-6379 [root@etcd3 redis]# [root@etcd3 redis]# docker inspect 10c62aafa4da 73e4f843d8cb d9a71dd3f969 396e174a1d92 df6ebce6f12a 1673a7d859ea | grep IPA "SecondaryIPAddresses": null, "IPAddress": "172.17.0.7", "IPAMConfig": null, "IPAddress": "172.17.0.7", "SecondaryIPAddresses": null, "IPAddress": "172.17.0.6", "IPAMConfig": null, "IPAddress": "172.17.0.6", "SecondaryIPAddresses": null, "IPAddress": "172.17.0.5", "IPAMConfig": null, "IPAddress": "172.17.0.5", "SecondaryIPAddresses": null, "IPAddress": "172.17.0.4", "IPAMConfig": null, "IPAddress": "172.17.0.4", "SecondaryIPAddresses": null, "IPAddress": "172.17.0.3", "IPAMConfig": null, "IPAddress": "172.17.0.3", "SecondaryIPAddresses": null, "IPAddress": "172.17.0.2", "IPAMConfig": null, "IPAddress": "172.17.0.2",
可以知道: redis-6379:172.17.0.2,redis-6380:172.17.0.3,redis-6381:172.17.0.4,redis-6382:172.17.0.5,redis-6383:172.17.0.6,redis-6384:172.17.0.7
3.配置redis
4.ert
4.Redis Cluster 的集群感知操作
//集群(cluster) CLUSTER INFO 打印集群的信息 CLUSTER NODES 列出集群当前已知的所有节点(node),以及这些节点的相关信息。 //节点(node) CLUSTER MEET <ip> <port> 将 ip 和 port 所指定的节点添加到集群当中,让它成为集群的一份子。 CLUSTER FORGET <node_id> 从集群中移除 node_id 指定的节点。 CLUSTER REPLICATE <node_id> 将当前节点设置为 node_id 指定的节点的从节点。 CLUSTER SAVECONFIG 将节点的配置文件保存到硬盘里面。 //槽(slot) CLUSTER ADDSLOTS <slot> [slot ...] 将一个或多个槽(slot)指派(assign)给当前节点。 CLUSTER DELSLOTS <slot> [slot ...] 移除一个或多个槽对当前节点的指派。 CLUSTER FLUSHSLOTS 移除指派给当前节点的所有槽,让当前节点变成一个没有指派任何槽的节点。 CLUSTER SETSLOT <slot> NODE <node_id> 将槽 slot 指派给 node_id 指定的节点,如果槽已经指派给另一个节点,那么先让另一个节点删除该槽>,然后再进行指派。 CLUSTER SETSLOT <slot> MIGRATING <node_id> 将本节点的槽 slot 迁移到 node_id 指定的节点中。 CLUSTER SETSLOT <slot> IMPORTING <node_id> 从 node_id 指定的节点中导入槽 slot 到本节点。 CLUSTER SETSLOT <slot> STABLE 取消对槽 slot 的导入(import)或者迁移(migrate)。
//键 (key) CLUSTER KEYSLOT <key> 计算键 key 应该被放置在哪个槽上。 CLUSTER COUNTKEYSINSLOT <slot> 返回槽 slot 目前包含的键值对数量。 CLUSTER GETKEYSINSLOT <slot> <count> 返回 count 个 slot 槽中的键。
redis 集群感知:节点握手——是指一批运行在集群模式的节点通过Gossip协议彼此通信,达到感知对方的过程。
192.168.10.52:6379> CLUSTER MEET 172.17.0.3 6379 OK 192.168.10.52:6379> CLUSTER MEET 172.17.0.4 6379 OK 192.168.10.52:6379> CLUSTER MEET 172.17.0.5 6379 OK 192.168.10.52:6379> CLUSTER MEET 172.17.0.6 6379 OK 192.168.10.52:6379> CLUSTER MEET 172.17.0.7 6379 OK 192.168.10.52:6379> CLUSTER NODES 54cb5c2eb8e5f5aed2d2f7843f75a9284ef6785c 172.17.0.3:6379@16379 master - 0 1528697195600 1 connected f45f9109f2297a83b1ac36f9e1db5e70bbc174ab 172.17.0.4:6379@16379 master - 0 1528697195600 0 connected ae86224a3bc29c4854719c83979cb7506f37787a 172.17.0.7:6379@16379 master - 0 1528697195600 5 connected 98aebcfe42d8aaa8a3375e4a16707107dc9da683 172.17.0.6:6379@16379 master - 0 1528697194000 4 connected 0bbdc4176884ef0e3bb9b2e7d03d91b0e7e11f44 172.17.0.5:6379@16379 master - 0 1528697194995 3 connected 760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 172.17.0.2:6379@16379 myself,master - 0 1528697195000 2 connected
当前已经使这六个节点组成集群,但是现在还无法工作,因为集群节点还没有分配槽(slot)。
1.分配槽信息
查看172.17.0.2:6379 的槽个数
192.168.10.52:6379> CLUSTER INFO cluster_state:fail cluster_slots_assigned:0 # 被分配槽的个数为0 cluster_slots_ok:0 cluster_slots_pfail:0 cluster_slots_fail:0 cluster_known_nodes:6 cluster_size:0
上面看到集群状态是失败的,原因是槽位没有分配,而且需要一次性把16384个槽位完全分配了,集群才可用。
2..分配槽位
分配槽位: CLUSTER ADDSLOTS 槽位,一个槽位只能分配一个节点,16384个槽位必须分配完,不同节点不能冲突。
所以通过脚本进行分配 addslots.sh:
#!/bin/bash # node1 192.168.10.52 172.17.0.2 n=0 for ((i=n;i<=5461;i++)) do /usr/local/bin/redis-cli -h 192.168.10.52 -p 6379 -a 123456 CLUSTER ADDSLOTS $i done # node2 192.168.10.52 172.17.0.3 n=5462 for ((i=n;i<=10922;i++)) do /usr/local/bin/redis-cli -h 192.168.10.52 -p 6380 -a 123456 CLUSTER ADDSLOTS $i done # node3 192.168.10.52 172.17.0.4 n=10923 for ((i=n;i<=16383;i++)) do /usr/local/bin/redis-cli -h 192.168.10.52 -p 6381 -a 123456 CLUSTER ADDSLOTS $i done
其中, -a 123456 表示需要输入的密码。
192.168.10.52:6379> CLUSTER INFO cluster_state:fail # 集群状态为失败 cluster_slots_assigned:16101 # 没有完全分配结束 cluster_slots_ok:16101 cluster_slots_pfail:0 cluster_slots_fail:0 cluster_known_nodes:6 cluster_size:3 cluster_current_epoch:5 cluster_my_epoch:2 cluster_stats_messages_ping_sent:266756 cluster_stats_messages_pong_sent:266528 cluster_stats_messages_meet_sent:10 cluster_stats_messages_sent:533294 cluster_stats_messages_ping_received:266527 cluster_stats_messages_pong_received:266666 cluster_stats_messages_meet_received:1 cluster_stats_messages_received:533194<br> 192.168.10.52:6379> CLUSTER INFO cluster_state:ok # 集群状态为成功 cluster_slots_assigned:16384 # 已经全部分配完成 cluster_slots_ok:16384 cluster_slots_pfail:0 cluster_slots_fail:0 cluster_known_nodes:6 cluster_size:3 cluster_current_epoch:5 cluster_my_epoch:2 cluster_stats_messages_ping_sent:266757 cluster_stats_messages_pong_sent:266531 cluster_stats_messages_meet_sent:10 cluster_stats_messages_sent:533298 cluster_stats_messages_ping_received:266530 cluster_stats_messages_pong_received:266667 cluster_stats_messages_meet_received:1 cluster_stats_messages_received:533198
综上可知,当全部槽位分配完成之后,集群还是可行的,如果我们手欠,移除一个槽位,那么集群就立马那不行了,自己去试试吧 ——CLUSTER DELSLOTS 0 。
5.如何变成高可用性
以上我们已经搭建了一套完整的可运行的redis cluster,但是每个节点都是单点,这样子可能出现,一个节点挂掉,整个集群因为槽位分配不完全而崩溃,因此,我们需要为每个节点配置副本备用节点。
前面我们已经提前创建了6个备用节点,搭建集群花了三个,因此还有剩下三个直接可以用来做备用副本。
192.168.10.52:6379> CLUSTER INFO cluster_state:ok cluster_slots_assigned:16384 cluster_slots_ok:16384 cluster_slots_pfail:0 cluster_slots_fail:0 cluster_known_nodes:6 # 总共6个节点 cluster_size:3 # 集群为 3 个节点 cluster_current_epoch:5 cluster_my_epoch:2 cluster_stats_messages_ping_sent:270127 cluster_stats_messages_pong_sent:269893 cluster_stats_messages_meet_sent:10 cluster_stats_messages_sent:540030 cluster_stats_messages_ping_received:269892 cluster_stats_messages_pong_received:270037 cluster_stats_messages_meet_received:1 cluster_stats_messages_received:539930
查看所有节点的id
192.168.10.52:6379> CLUSTER NODES 54cb5c2eb8e5f5aed2d2f7843f75a9284ef6785c 172.17.0.3:6379@16379 master - 0 1528704114535 1 connected 5462-10922 f45f9109f2297a83b1ac36f9e1db5e70bbc174ab 172.17.0.4:6379@16379 master - 0 1528704114000 0 connected 10923-16383 ae86224a3bc29c4854719c83979cb7506f37787a 172.17.0.7:6379@16379 master - 0 1528704114023 5 connected 98aebcfe42d8aaa8a3375e4a16707107dc9da683 172.17.0.6:6379@16379 master - 0 1528704115544 4 connected 0bbdc4176884ef0e3bb9b2e7d03d91b0e7e11f44 172.17.0.5:6379@16379 master - 0 1528704114836 3 connected 760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 172.17.0.2:6379@16379 myself,master - 0 1528704115000 2 connected 0-5461
编写脚本,添加副本节点
[root@etcd2 tmp]# vi addSlaveNodes.sh #!/bin/bash /usr/local/bin/redis-cli -h 192.168.10.52 -p 6382 -a 123456 CLUSTER REPLICATE 760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 /usr/local/bin/redis-cli -h 192.168.10.52 -p 6383 -a 123456 CLUSTER REPLICATE 54cb5c2eb8e5f5aed2d2f7843f75a9284ef6785c /usr/local/bin/redis-cli -h 192.168.10.52 -p 6384 -a 123456 CLUSTER REPLICATE f45f9109f2297a83b1ac36f9e1db5e70bbc174ab
注意:1、作为备用的节点,必须是未分配槽位的,否者会操作失败 (error) ERR To set a master the node must be empty and without assigned slots 。
2、需要从需要添加的节点上面执行操作,CLUSTER REPLICATE [node_id] ,使当前节点成为 node_id 的副本节点。
3、添加从节点(集群复制): 复制的原理和单机的Redis复制原理一样,区别是:集群下的从节点也需要运行在cluster模式下,要先添加到集群里面,再做复制。
查看所有节点信息:
192.168.10.52:6379> CLUSTER NODES 54cb5c2eb8e5f5aed2d2f7843f75a9284ef6785c 172.17.0.3:6379@16379 master - 0 1528705604149 1 connected 5462-10922 f45f9109f2297a83b1ac36f9e1db5e70bbc174ab 172.17.0.4:6379@16379 master - 0 1528705603545 0 connected 10923-16383 ae86224a3bc29c4854719c83979cb7506f37787a 172.17.0.7:6379@16379 slave f45f9109f2297a83b1ac36f9e1db5e70bbc174ab 0 1528705603144 5 connected 98aebcfe42d8aaa8a3375e4a16707107dc9da683 172.17.0.6:6379@16379 slave 54cb5c2eb8e5f5aed2d2f7843f75a9284ef6785c 0 1528705603000 4 connected 0bbdc4176884ef0e3bb9b2e7d03d91b0e7e11f44 172.17.0.5:6379@16379 slave 760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 0 1528705603000 3 connected 760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 172.17.0.2:6379@16379 myself,master - 0 1528705602000 2 connected 0-5461
可以看到我们现在实现了三主三从的一个高可用集群。
6.高可用测试——故障转移
查看当前运行状态:
192.168.10.52:6379> CLUSTER NODES 54cb5c2eb8e5f5aed2d2f7843f75a9284ef6785c 172.17.0.3:6379@16379 master - 0 1528705604149 1 connected 5462-10922 f45f9109f2297a83b1ac36f9e1db5e70bbc174ab 172.17.0.4:6379@16379 master - 0 1528705603545 0 connected 10923-16383 ae86224a3bc29c4854719c83979cb7506f37787a 172.17.0.7:6379@16379 slave f45f9109f2297a83b1ac36f9e1db5e70bbc174ab 0 1528705603144 5 connected 98aebcfe42d8aaa8a3375e4a16707107dc9da683 172.17.0.6:6379@16379 slave 54cb5c2eb8e5f5aed2d2f7843f75a9284ef6785c 0 1528705603000 4 connected 0bbdc4176884ef0e3bb9b2e7d03d91b0e7e11f44 172.17.0.5:6379@16379 slave 760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 0 1528705603000 3 connected 760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 172.17.0.2:6379@16379 myself,master - 0 1528705602000 2 connected 0-5461
以上,运行正常
尝试关闭一个master,选择端口为6380的容器,停掉之后:
192.168.10.52:6379> CLUSTER NODES 54cb5c2eb8e5f5aed2d2f7843f75a9284ef6785c 172.17.0.3:6379@16379 master,fail - 1528706408935 1528706408000 1 connected 5462-10922 f45f9109f2297a83b1ac36f9e1db5e70bbc174ab 172.17.0.4:6379@16379 master - 0 1528706463000 0 connected 10923-16383 ae86224a3bc29c4854719c83979cb7506f37787a 172.17.0.7:6379@16379 slave f45f9109f2297a83b1ac36f9e1db5e70bbc174ab 0 1528706462980 5 connected 98aebcfe42d8aaa8a3375e4a16707107dc9da683 172.17.0.6:6379@16379 slave 54cb5c2eb8e5f5aed2d2f7843f75a9284ef6785c 0 1528706463000 4 connected 0bbdc4176884ef0e3bb9b2e7d03d91b0e7e11f44 172.17.0.5:6379@16379 slave 760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 0 1528706463985 3 connected 760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 172.17.0.2:6379@16379 myself,master - 0 1528706462000 2 connected 0-5461 192.168.10.52:6379> 192.168.10.52:6379> CLUSTER INFO cluster_state:fail cluster_slots_assigned:16384 cluster_slots_ok:10923 cluster_slots_pfail:0 cluster_slots_fail:5461 cluster_known_nodes:6 cluster_size:3 cluster_current_epoch:5 cluster_my_epoch:2 cluster_stats_messages_ping_sent:275112 cluster_stats_messages_pong_sent:274819 cluster_stats_messages_meet_sent:10 cluster_stats_messages_fail_sent:5 cluster_stats_messages_sent:549946 cluster_stats_messages_ping_received:274818 cluster_stats_messages_pong_received:275004 cluster_stats_messages_meet_received:1 cluster_stats_messages_fail_received:1 cluster_stats_messages_received:549824
以上,发现整个集群都失败了,从节点没有自动升级为主节点,怎么回事??
重启停掉的容器,经排查日志信息 [root@df6ebce6f12a /]# tail -f /var/log/redis/redis-server.log :
1:S 11 Jun 09:57:46.712 # Cluster state changed: ok 1:S 11 Jun 09:57:46.718 * (Non critical) Master does not understand REPLCONF listening-port: -NOAUTH Authentication required. 1:S 11 Jun 09:57:46.718 * (Non critical) Master does not understand REPLCONF capa: -NOAUTH Authentication required. 1:S 11 Jun 09:57:46.719 * Partial resynchronization not possible (no cached master) 1:S 11 Jun 09:57:46.719 # Unexpected reply to PSYNC from master: -NOAUTH Authentication required. 1:S 11 Jun 09:57:46.719 * Retrying with SYNC... 1:S 11 Jun 09:57:46.719 # MASTER aborted replication with an error: NOAUTH Authentication required. 1:S 11 Jun 09:57:46.782 * Connecting to MASTER 172.17.0.6:6379 1:S 11 Jun 09:57:46.782 * MASTER <-> SLAVE sync started 1:S 11 Jun 09:57:46.782 * Non blocking connect for SYNC fired the event.
可以看到,主从之间访问需要auth,之前忘记了配置 redis.conf 中的 # masterauth ,所以导致主从之间无法通讯。修改配置之后,自动故障转移正常。
有时候需要实施人工故障转移:
登录6380端口的从节点:6383,执行 CLUSTER FAILOVER 命令:
192.168.10.52:6383> CLUSTER FAILOVER (error) ERR Master is down or failed, please use CLUSTER FAILOVER FORCE
发现因为master已经down了,所以我们需要执行强制转移
192.168.10.52:6383> CLUSTER FAILOVER FORCE OK
查看当前 cluster node 情况:
192.168.10.52:6383> CLUSTER NODES 0bbdc4176884ef0e3bb9b2e7d03d91b0e7e11f44 172.17.0.5:6379@16379 slave 760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 0 1528707535332 3 connected ae86224a3bc29c4854719c83979cb7506f37787a 172.17.0.7:6379@16379 slave f45f9109f2297a83b1ac36f9e1db5e70bbc174ab 0 1528707534829 5 connected f45f9109f2297a83b1ac36f9e1db5e70bbc174ab 172.17.0.4:6379@16379 master - 0 1528707534527 0 connected 10923-16383 98aebcfe42d8aaa8a3375e4a16707107dc9da683 172.17.0.6:6379@16379 myself,master - 0 1528707535000 6 connected 5462-10922 760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 172.17.0.2:6379@16379 master - 0 1528707535834 2 connected 0-5461 54cb5c2eb8e5f5aed2d2f7843f75a9284ef6785c 172.17.0.3:6379@16379 master,fail - 1528707472833 1528707472000 1 connected
从节点已经升级为master节点。这时候,我们尝试重启了,6380节点的redis(其实是重新启动停掉的容器):
192.168.10.52:6383> CLUSTER NODES 0bbdc4176884ef0e3bb9b2e7d03d91b0e7e11f44 172.17.0.5:6379@16379 slave 760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 0 1528707556044 3 connected ae86224a3bc29c4854719c83979cb7506f37787a 172.17.0.7:6379@16379 slave f45f9109f2297a83b1ac36f9e1db5e70bbc174ab 0 1528707555000 5 connected f45f9109f2297a83b1ac36f9e1db5e70bbc174ab 172.17.0.4:6379@16379 master - 0 1528707556000 0 connected 10923-16383 98aebcfe42d8aaa8a3375e4a16707107dc9da683 172.17.0.6:6379@16379 myself,master - 0 1528707556000 6 connected 5462-10922 760e4d0039c5ac13d04aa4791c9e6dc28544d7c7 172.17.0.2:6379@16379 master - 0 1528707556000 2 connected 0-5461 54cb5c2eb8e5f5aed2d2f7843f75a9284ef6785c 172.17.0.3:6379@16379 slave 98aebcfe42d8aaa8a3375e4a16707107dc9da683 0 1528707556547 6 connected
我们发现,6380节点反而变成了 6383节点的从节点。
现在集群应该是完整的了,所以,集群状态应该已经恢复了,我们查看下:
192.168.10.52:6383> CLUSTER INFO 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:6 cluster_stats_messages_ping_sent:19419 cluster_stats_messages_pong_sent:19443 cluster_stats_messages_meet_sent:1 cluster_stats_messages_auth-req_sent:5 cluster_stats_messages_update_sent:1 cluster_stats_messages_sent:38869 cluster_stats_messages_ping_received:19433 cluster_stats_messages_pong_received:19187 cluster_stats_messages_meet_received:5 cluster_stats_messages_fail_received:4 cluster_stats_messages_auth-ack_received:2 cluster_stats_messages_received:38631
OK,没有问题。
7.集群访问
客户端在初始化的时候只需要知道一个节点的地址即可,客户端会先尝试向这个节点执行命令,比如 get key ,如果key所在的slot刚好在该节点上,则能够直接执行成功。如果slot不在该节点,则节点会返回MOVED错误,同时把该slot对应的节点告诉客户端,客户端可以去该节点执行命令
192.168.10.52:6383> get hello (error) MOVED 866 172.17.0.2:6379 192.168.10.52:6379> set number 20004 (error) MOVED 7743 172.17.0.3:6379
另外,redis集群版只使用db0,select命令虽然能够支持select 0。其他的db都会返回错误。
192.168.10.52:6383> select 0 OK 192.168.10.52:6383> select 1 (error) ERR SELECT is not allowed in cluster mode
近期,有网友询问docker redis集群连接报错的问题,具体报错如下:
初步认为是,node节点没有全部添加进去,添加之后,依然有上述问题。想到是跨主机访问,应该是路由寻址不了导致的。当初写上述教程的时候,docker是以默认的网络模式bridge模式运行的,毕竟当初是以学习整理文档为主,主要是单机访问。但是,实际应用化场景中,多是公网跨主机访问,问题明朗了,想着集群这东西最好还是设置成共享主机公网ip比较好,于是解决如下:
- 在docker运行时,执行网络模式为:host。
- 端口冲突解决,毕竟host模式下,容器会占用宿主机的端口,于是,我们就从配置下手,在宿主机上生成配置redis-60001.conf,redis-60002.conf,redis-60003.conf...,有多少端口建多少个文件,最终运行一个容器,挂载一个配置到容器中用于覆盖主机中的配置。
最终的运行方式如下:
docker run -d --name redis-6380 --net host -v /tmp/redis.conf:/usr/local/redis/redis.conf hakimdstx/nodes-redis:4.0.1
至此,网络问题得到解决。
PS.生产环境需要注意防火墙问题,不然也是会报错的。
