# 4.4 多个客户端连接远端服务器 ## 4.4.1 多个Redis客户端连接远端服务器 在本节中,将新建三个Docker容器,以此模拟三台主机.在这三个Docker容器里,包含了一个Redis服务器、两个Redis客户端,并且两个Redis客户端会连接到Redis服务器上,以此模拟两台主机上的Redis客户端远程连接到Redis服务器上的效果.具体的效果图如下图示. 两台Redis客户端远程连接到Redis服务器的效果 ![两台Redis客户端远程连接到Redis服务器的效果](/files/2myfaaL977hKP2HAYETp) * step1. 创建表示redis-server的容器 ``` (base) root@yuanhong StudyRedisBaseOnDocker % docker run --name redis-server -d redis:latest 834148eedc13916828f2c1dc72a6b8df30cfcde01b91b128ab099617008035e4 ``` * step2. 创建并进入Redis客户端容器,在该容器内连接redis-server 创建并进入Redis客户端容器: ``` (base) root@yuanhong StudyRedisBaseOnDocker % docker run -it --name redis-client1 --link redis-server:server redis:latest /bin/bash root@b33298a59a78:/data# ``` 注:`--link`选项的含义: 在Docker的早期版本中,`--link`选项是用来在两个容器之间建立一个链接的.这意味着从一个容器可以安全地连接到另一个容器,而无需公开任何不必要的端口到宿主机.当您使用`--link`选项时,Docker会在两个容器之间建立一个私有网络连接,并将链接的容器的环境变量、主机名和其他相关信息传递给源容器.这使得源容器可以轻松地发现和连接到链接的容器. 语法:`--link 链接容器名称:源容器内的主机名` 连接redis-server: ``` root@b33298a59a78:/data# redis-cli -h server -p 6379 server:6379> ``` * step3. 尝试在客户端执行命令 ``` server:6379> SET name Peter OK ``` * step4. 再打开一个cmd窗口,再创建一个redis客户端容器 ``` (base) root@yuanhong StudyRedisBaseOnDocker % docker run -it --name redis-client2 --link redis-server:server redis:latest /bin/bash root@6945b1178f8c:/data# ``` ## 4.4.2 通过docker inspect命令观察IP地址 * step1. 检查redis-server容器的IP地址 ``` (base) root@yuanhong ~ % docker inspect redis-server|grep IPAddress "SecondaryIPAddresses": null, "IPAddress": "172.17.0.2", "IPAddress": "172.17.0.2", ``` 可以看到,名为`redis-server`的容器,其IP地址为`172.17.0.2` * step2. 检查redis-client1容器的IP地址 ``` (base) root@yuanhong ~ % docker inspect redis-client1|grep IPAddress "SecondaryIPAddresses": null, "IPAddress": "172.17.0.3", "IPAddress": "172.17.0.3", ``` 可以看到,名为`redis-client1`的容器,其IP地址为`172.17.0.3` * step3. 检查redis-client2容器的IP地址 ``` (base) root@yuanhong ~ % docker inspect redis-client2|grep IPAddress "SecondaryIPAddresses": null, "IPAddress": "172.17.0.4", "IPAddress": "172.17.0.4", ``` 可以看到,名为`redis-client2`的容器,其IP地址为`172.17.0.4` ## 4.4.3 实践客户端命令 在redis-client1容器中,查看连接到Redis服务器的所有客户端信息: ``` server:6379> CLIENT LIST id=3 addr=172.17.0.3:49948 laddr=172.17.0.2:6379 fd=8 name= age=724 idle=0 flags=N db=0 sub=0 psub=0 multi=-1 qbuf=26 qbuf-free=40928 argv-mem=10 obl=0 oll=0 omem=0 tot-mem=61466 events=r cmd=client user=default redir=-1 id=4 addr=172.17.0.4:39362 laddr=172.17.0.2:6379 fd=9 name= age=4 idle=4 flags=N db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 argv-mem=0 obl=0 oll=0 omem=0 tot-mem=20496 events=r cmd=command user=default redir=-1 ``` 从2个连接的`addr`和`laddr`属性可以看出,和上一小节中获取的容器IP地址是相同的 设置redis-client1的连接名为client1: ``` server:6379> CLIENT GETNAME (nil) server:6379> CLIENT SETNAME client1 OK server:6379> CLIENT GETNAME "client1" ``` 注:此时若在任意一个redis客户端上执行`SHUTDOWN`命令,则redis服务端和客户端都会关闭连接.该命令很容易造成生产事故! ## 4.4.4 通过info观察服务器状态 在redis-client2容器内连接redis-server后,查看服务器状态: ``` server:6379> INFO Stats # Stats total_connections_received:2 total_commands_processed:9 instantaneous_ops_per_sec:0 total_net_input_bytes:354 total_net_output_bytes:45639 instantaneous_input_kbps:0.00 instantaneous_output_kbps:0.00 rejected_connections:0 sync_full:0 sync_partial_ok:0 sync_partial_err:0 expired_keys:0 expired_stale_perc:0.00 expired_time_cap_reached_count:0 expire_cycle_cpu_milliseconds:39 evicted_keys:0 keyspace_hits:0 keyspace_misses:0 pubsub_channels:0 pubsub_patterns:0 latest_fork_usec:0 total_forks: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 tracking_total_keys:0 tracking_total_items:0 tracking_total_prefixes:0 unexpected_error_replies:0 total_error_replies:2 dump_payload_sanitizations:0 total_reads_processed:12 total_writes_processed:11 io_threaded_reads_processed:0 io_threaded_writes_processed:0 ``` 注:此处只查看了Stats部分的内容 在redis-client1容器中执行一些命令: ``` server:6379> SET salary 10000 OK server:6379> SET gender male OK ``` 再次在redis-client2容器中查看服务器状态: ``` server:6379> INFO Stats # Stats total_connections_received:2 total_commands_processed:12 instantaneous_ops_per_sec:0 total_net_input_bytes:450 total_net_output_bytes:46610 instantaneous_input_kbps:0.00 instantaneous_output_kbps:0.00 rejected_connections:0 sync_full:0 sync_partial_ok:0 sync_partial_err:0 expired_keys:0 expired_stale_perc:0.00 expired_time_cap_reached_count:0 expire_cycle_cpu_milliseconds:41 evicted_keys:0 keyspace_hits:0 keyspace_misses:0 pubsub_channels:0 pubsub_patterns:0 latest_fork_usec:0 total_forks: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 tracking_total_keys:0 tracking_total_items:0 tracking_total_prefixes:0 unexpected_error_replies:0 total_error_replies:2 dump_payload_sanitizations:0 total_reads_processed:15 total_writes_processed:14 io_threaded_reads_processed:0 io_threaded_writes_processed:0 ``` 可以看到`total_commands_processed`配置项发生了变化 --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://redis.sai.show/di-4-zhang-shi-jian-redis-fu-wu-qi-he-ke-hu-duan-de-cao-zuo/4.4-duo-ge-ke-hu-duan-lian-jie-yuan-duan-fu-wu-qi.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.