通过
zookeeper的watcher机制联想到了这个同步机制，当在容器1与容器2自动通信,原理是etcd（分布式数据库）存能互相访问的ip及端口通过overlay网络，记录一下
环境准备
1.俩台能ping通的docker环境
2.通过weget下载好etcd
3.在docker-node1上
vagrant@docker-node1:~$ wget [https://github.com/coreos/etcd/releases/download/v3.0.12/etcd-v3.0.12-linux-amd64.tar.gz](https://github.com/coreos/etcd/releases/download/v3.0.12/etcd-v3.0.12-linux-amd64.tar.gz)
vagrant@docker-node1:~$ tar zxvf etcd-v3.0.12-linux-amd64.tar.gz
vagrant@docker-node1:~$ cd etcd-v3.0.12-linux-amd64
vagrant@docker-node1:~$ nohup ./etcd --name docker-node1 --initial-advertise-peer-urls [http://192.168.59.2:2380](http://192.168.59.2:2380/)\
--listen-peer-urls [http://192.168.59.2:2380](http://192.168.59.2:2380/)\
--listen-client-urls [http://192.168.59.2:2379,http://127.0.0.1:2379](http://192.168.59.2:2379,http://127.0.0.1:2379)\
--advertise-client-urls [http://192.168.59.2:2379](http://192.168.59.2:2379/)\
--initial-cluster-token etcd-cluster \
--initial-cluster docker-node1=[http://192.168.59.2:2380,docker-node2=http://192.168.59.3:2380](http://192.168.59.2:2380,docker-node2=http://192.168.59.3:2380)\
--initial-cluster-state new&
4.在docker-node2上
vagrant@docker-node2:~$ wget [https://github.com/coreos/etcd/releases/download/v3.0.12/etcd-v3.0.12-linux-amd64.tar.gz](https://github.com/coreos/etcd/releases/download/v3.0.12/etcd-v3.0.12-linux-amd64.tar.gz)
vagrant@docker-node2:~$ tar zxvf etcd-v3.0.12-linux-amd64.tar.gz
vagrant@docker-node2:~$ cd etcd-v3.0.12-linux-amd64/
vagrant@docker-node2:~$ nohup ./etcd --name docker-node2 --initial-advertise-peer-urls [http://192.168.59.3:2380](http://192.168.59.3:2380/)\
--listen-peer-urls [http://192.168.59.3:2380](http://192.168.59.3:2380/)\
--listen-client-urls [http://192.168.59.3:2379,http://127.0.0.1:2379](http://192.168.59.3:2379,http://127.0.0.1:2379)\
--advertise-client-urls [http://192.168.59.3:2379](http://192.168.59.3:2379/)\
--initial-cluster-token etcd-cluster \
--initial-cluster docker-node1=[http://192.168.59.2:2380,docker-node2=http://192.168.59.3:2380](http://192.168.59.2:2380,docker-node2=http://192.168.59.3:2380)\
--initial-cluster-state new&
检查cluster状态
vagrant@docker-node2:~/etcd-v3.0.12-linux-amd64$ ./etcdctl cluster-health
member 21eca106efe4caee is healthy: got healthy result from [http://192.168.59.2:2379](http://192.168.59.2:2379/)
member 8614974c83d1cc6d is healthy: got healthy result from [http://192.168.59.3:2379](http://192.168.59.3:2379/)
cluster is healthy
以上结果如图
image.png
在docker-node1上
$ sudo service docker stop
$ sudo /usr/bin/dockerd -H [tcp://0.0.0.0:2375](tcp://0.0.0.0:2375)-H unix:///var/run/docker.sock --cluster-store=[etcd://192.168.59.2:2379](etcd://192.168.59.2:2379)--cluster-advertise=192.168.59.2:2375&
在docker-node2上
$ sudo service docker stop
$ sudo /usr/bin/dockerd -H [tcp://0.0.0.0:2375](tcp://0.0.0.0:2375)-H unix:///var/run/docker.sock --cluster-store=[etcd://192.168.59.3:2379](etcd://192.168.59.3:2379)--cluster-advertise=192.168.59.3:2375&
效果如图(错误忽略)
image.png
创建overlay network
在docker-node1上创建一个demo_huey的overlay network
image.png
node2上可看到demo_huey overlay网络
image.png
通过查看etcd的key-value, 我们获取到，这个demo的network是通过etcd从node1同步到node2的(命令看截图)
image.png
创建连接demo网络的容器
在docker-node1上
vagrant@docker-node1:~$ sudo docker run -d --name test1 --net demo busybox sh -c "while true; do sleep 3600; done"
Unable to find image 'busybox:latest' locally
latest: Pulling from library/busybox
56bec22e3559: Pull complete
Digest: sha256:29f5d56d12684887bdfa50dcd29fc31eea4aaf4ad3bec43daf19026a7ce69912
Status: Downloaded newer image for busybox:latest
a95a9466331dd9305f9f3c30e7330b5a41aae64afda78f038fc9e04900fcac54
vagrant@docker-node1:~$ sudo docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
a95a9466331d busybox "sh -c 'while true; d" 4 seconds ago Up 3 seconds test1
vagrant@docker-node1:~$ sudo docker exec test1 ifconfig
eth0 Link encap:Ethernet HWaddr 02:42:0A:00:00:02
inet addr:10.0.0.2 Bcast:0.0.0.0 Mask:255.255.255.0
inet6 addr: fe80::42:aff:fe00:2/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1450 Metric:1
RX packets:15 errors:0 dropped:0 overruns:0 frame:0
TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:1206 (1.1 KiB) TX bytes:648 (648.0 B)
eth1 Link encap:Ethernet HWaddr 02:42:AC:12:00:02
inet addr:172.18.0.2 Bcast:0.0.0.0 Mask:255.255.0.0
inet6 addr: fe80::42:acff:fe12:2/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:8 errors:0 dropped:0 overruns:0 frame:0
TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:648 (648.0 B) TX bytes:648 (648.0 B)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
vagrant@docker-node1:~$
在docker-node2上
vagrant@docker-node2:~$ sudo docker run -d --name test1 --net demo busybox sh -c "while true; do sleep 3600; done"
Unable to find image 'busybox:latest' locally
latest: Pulling from library/busybox
56bec22e3559: Pull complete
Digest: sha256:29f5d56d12684887bdfa50dcd29fc31eea4aaf4ad3bec43daf19026a7ce69912
Status: Downloaded newer image for busybox:latest
fad6dc6538a85d3dcc958e8ed7b1ec3810feee3e454c1d3f4e53ba25429b290b
docker: Error response from daemon: service endpoint with name test1 already exists.
vagrant@docker-node2:~$ sudo docker run -d --name test2 --net demo busybox sh -c "while true; do sleep 3600; done"
9d494a2f66a69e6b861961d0c6af2446265bec9b1d273d7e70d0e46eb2e98d20
验证连通性。
vagrant@docker-node2:~$ sudo docker exec -it test2 ifconfig
eth0 Link encap:Ethernet HWaddr 02:42:0A:00:00:03
inet addr:10.0.0.3 Bcast:0.0.0.0 Mask:255.255.255.0
inet6 addr: fe80::42:aff:fe00:3/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1450 Metric:1
RX packets:208 errors:0 dropped:0 overruns:0 frame:0
TX packets:201 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:20008 (19.5 KiB) TX bytes:19450 (18.9 KiB)
eth1 Link encap:Ethernet HWaddr 02:42:AC:12:00:02
inet addr:172.18.0.2 Bcast:0.0.0.0 Mask:255.255.0.0
inet6 addr: fe80::42:acff:fe12:2/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:8 errors:0 dropped:0 overruns:0 frame:0
TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:648 (648.0 B) TX bytes:648 (648.0 B)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
vagrant@docker-node1:~$ sudo docker exec test1 sh -c "ping 10.0.0.3"
PING 10.0.0.3 (10.0.0.3): 56 data bytes
64 bytes from 10.0.0.3: seq=0 ttl=64 time=0.579 ms
64 bytes from 10.0.0.3: seq=1 ttl=64 time=0.411 ms
64 bytes from 10.0.0.3: seq=2 ttl=64 time=0.483 ms
^C
vagrant@docker-node1:~$
总结
ping通即可，为研究k8s做准备
参考
官网：https://docs.docker.com
书籍：Docker技术入门与实战
网课： 推荐 慕课网 图灵学院 谷粒学院
