Docker 容器互连 --link
作者：互联网
一、启动两个容器测试
1.创建容器：
# 启动第一个容器
[root@yang ~]# docker run -it -d --name tomcat1 tomcat
# 启动第二个容器
[root@yang ~]# docker run -it -d --name tomcat2 tomcat
[root@yang ~]# docker ps -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES fcdd4c02da9c tomcat "catalina.sh run" 2 hours ago Up 2 hours 8080/tcp tomcat2 346962a1d73b tomcat "catalina.sh run" 5 hours ago Up 5 hours 8080/tcp tomcat1
2.测试两个容器间连通性
[root@yang ~]# docker exec -it tomcat1 ping tomcat2 ping: tomcat2: No address associated with hostname
以上显示两个容器之前ping不通！
思考：怎么做才能让两个容器之间ping通呢？
二、具体演示
1.创建容器：
# 启动第一个容器 [root@yang ~]# docker run -it -d --name tomcat3 --link tomcat2 tomcat
--link # 在hosts配置中，指定某容器的映射
2.测试
[root@yang ~]# docker exec -it tomcat3 ping tomcat2 PING tomcat2 (172.17.0.9) 56(84) bytes of data. 64 bytes from tomcat2 (172.17.0.9): icmp_seq=1 ttl=64 time=0.247 ms 64 bytes from tomcat2 (172.17.0.9): icmp_seq=2 ttl=64 time=0.089 ms 64 bytes from tomcat2 (172.17.0.9): icmp_seq=3 ttl=64 time=0.105 ms
查看tomcat3中配置：
[root@yang ~]# docker inspect tomcat3
[
{
"Id": "ee6a1fd2ba6708fe79f3708489e44e8aa00f9404640c585ae1d2ea5bd2395cdf",
"Created": "2021-01-29T09:06:20.640610921Z",
"Path": "catalina.sh",
"Args": [
"run"
],
"State": {
"Status": "running",
"Running": true,
"Paused": false,
"Restarting": false,
"OOMKilled": false,
"Dead": false,
"Pid": 7964,
"ExitCode": 0,
"Error": "",
"StartedAt": "2021-01-29T09:06:21.625013975Z",
"FinishedAt": "0001-01-01T00:00:00Z"
},
"Image": "sha256:345867df0879186da623555494dcf5f4561e5bf0b8d2e4276a71947f30bdca0d",
"ResolvConfPath": "/var/lib/docker/containers/ee6a1fd2ba6708fe79f3708489e44e8aa00f9404640c585ae1d2ea5bd2395cdf/resolv.conf",
"HostnamePath": "/var/lib/docker/containers/ee6a1fd2ba6708fe79f3708489e44e8aa00f9404640c585ae1d2ea5bd2395cdf/hostname",
"HostsPath": "/var/lib/docker/containers/ee6a1fd2ba6708fe79f3708489e44e8aa00f9404640c585ae1d2ea5bd2395cdf/hosts",
"LogPath": "/var/lib/docker/containers/ee6a1fd2ba6708fe79f3708489e44e8aa00f9404640c585ae1d2ea5bd2395cdf/ee6a1fd2ba6708fe79f3708489e44e8aa00f9404640c585ae1d2ea5bd2395cdf-json.log",
"Name": "/tomcat3",
"RestartCount": 0,
"Driver": "overlay2",
"Platform": "linux",
"MountLabel": "",
"ProcessLabel": "",
"AppArmorProfile": "",
"ExecIDs": null,
"HostConfig": {
"Binds": null,
"ContainerIDFile": "",
"LogConfig": {
"Type": "json-file",
"Config": {}
},
"NetworkMode": "default",
"PortBindings": {},
"RestartPolicy": {
"Name": "no",
"MaximumRetryCount": 0
},
"AutoRemove": false,
"VolumeDriver": "",
"VolumesFrom": null,
"CapAdd": null,
"CapDrop": null,
"Capabilities": null,
"Dns": [],
"DnsOptions": [],
"DnsSearch": [],
"ExtraHosts": null,
"GroupAdd": null,
"IpcMode": "private",
"Cgroup": "",
"Links": [
"/tomcat2:/tomcat3/tomcat2"
],
以上links位置显示，tomcat3绑定了tomcat2！
3.通过进入容器查看：
# 查看 hosts 配置，发现已经绑定！
[root@yang ~]# docker exec -it tomcat3 cat /etc/hosts 127.0.0.1 localhost ::1 localhost ip6-localhost ip6-loopback fe00::0 ip6-localnet ff00::0 ip6-mcastprefix ff02::1 ip6-allnodes ff02::2 ip6-allrouters 172.17.0.9 tomcat2 fcdd4c02da9c 172.17.0.10 ee6a1fd2ba67
其实tomcat3在本地就已经配置了tomcat2的配置了。
结论：
1.两个容器间互相通信使用--link，可以实现互通。
2.docker0 不支持容器名连接访问。
建议：
docker官方已不推荐使用docker run --link来链接2个容器互相通信，随后的版本中会删除--link，但了解其原理，对如何使2个容器之间互相通信还是有帮助。
标签：容器,--,link,tomcat2,tomcat3,docker,root,Docker 来源： https://www.cnblogs.com/yangzp/p/14346317.html