单向连接 --link

docker run -d --name centos-test-1

[ ~]# docker run -d --name centos-test-1 centos ping 114.114.114.114
bd4aa8b35c8d6e85dbf653574368ef2e2062648398ca36a1d8bcfdf4fb32ee91

[ ~]# docker run -d --name centos-test-2 --link centos-test-1 centos ping 114.114.114.114
4157e80f41850bf5babfc264d6d049ed51faa2d6a851b402532817eb6cc754e1

[ ~]# docker exec -it centos-test-2 bash
[ /]# ping centos-test-1
PING centos-test-1 (172.17.0.5) 56(84) bytes of data.
64 bytes from centos-test-1 (172.17.0.5): icmp_seq=1 ttl=64 time=0.113 ms
64 bytes from centos-test-1 (172.17.0.5): icmp_seq=2 ttl=64 time=0.168 ms
^C
--- centos-test-1 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1000ms
rtt min/avg/max/mdev = 0.113/0.140/0.168/0.029 ms
[ /]#

[ /]# ping centos-test-2
ping: centos-test-2: Name or service not known
[ /]#