Docker跨服务器通信Overlay解决方案之Consul单实例
任务：容器可以不在同一台服务器上，互相调用
思路：
想要实现Overlay网络，需要引入一个K-V数据库，来保存网络状态信息，
想
包括 Network、Endpoint、IP 等。Consul、Etcd 和 ZooKeeper 都是 Docker 支持的K-V数据库
我们这里使用 Consul，相比其它K-V数据库，Consul提供的界面化方便管理，所以这里使用Consul实现Overlay
通过让每个服务器的Docker daemon将自己的IP注册到Consul中，来共享Docker内网，这里共享的内网是
Overlay网络模式的，也只有在注册的Docker环境下使用同overlay网络的容器，才能互相通讯
创建完成后，不使用overlay网络的跨服务器容器，不能ping通*
| 服务器OS | 主机IP | Docker版本 | 网卡名 |
| --------- | ---------- | ---------- | ------ |
| centos7.9 | 10.0.54.21 | 23.0.3 | ens33 |
| centos7.9 | 10.0.54.22 | 18.09.7 | ens33 |
| centos7.9 | 10.0.54.23 | 18.09.7 | ens33 |
注意事项：
高版本不能使用 cluster-store与cluster-advertise，请降到适当的版本进行实验
#分别设置3台
1、每台运行docker的主机都不能同hostname，可以使用
hostnamectl set-hostname docker-zh54-1
hostnamectl set-hostname docker-zh54-2
hostnamectl set-hostname docker-zh54-3
2、关闭selinux
setenforce 0
3、关闭防火墙
systemctl disable firewalld && systemctl stop firewalld
拉取consul的镜像
[root@docker-zh54-1 ~]# docker pull consul:1.5.2
1.5.2: Pulling from library/consul
e7c96db7181b: Pull complete
2967157a1cec: Pull complete
89eac26c7594: Pull complete
fed432a284a5: Pull complete
eff914b7f5d7: Pull complete
0c1d0a78f0c3: Pull complete
Digest: sha256:b31edc821d5e3deae8ce9f9a2070dc3fbaa72f5e1746a85a91ebe551ed8fb17f
Status: Downloaded newer image for consul:1.5.2
docker.io/library/consul:1.5.2
consul服务器建立
[root@docker-zh54-1 ~]# docker run -d --network host -h consul --name consule --restart always -e CONSUL_BIND_INTERFACE=ens33 consul:1.5.2
1b293c1d4f86f16da502487d815584b3e91d4ad994e2d93201f8d2bf0e22ea64
测试：
10.0.54.21:8500
其他两台测试机器配置集群地址：
[root@docker-zh54-2 ~]# cat /etc/docker/daemon.json
{
"cluster-store": "consul://10.0.54.21:8500",
"cluster-advertise": "ens33:2375"
}
[root@docker-zh54-2 ~]# scp /etc/docker/daemon.json root@10.0.54.23:/etc/docker/
[root@docker-zh54-2 ~]# systemctl restart docker
[root@docker-zh54-3 ~]# systemctl restart docker
测试:
1、新建一个overlay网络
[root@docker-zh54-2 ~]# docker network create --driver overlay zh54
313b6f3af43631a704cfb38847977fcf00603814b33ae0ebd822493b61daad35
[root@docker-zh54-2 ~]# docker network list
NETWORK ID NAME DRIVER SCOPE
6ff8ce0771b7 bridge bridge local
accfd32f1830 host host local
46b450ace1d9 none null local
313b6f3af436 zh54 overlay global
#可以看到docker2创建的zh54网络被同步到了docker3中
[root@docker-zh54-3 ~]# docker network list
NETWORK ID NAME DRIVER SCOPE
477b71be1af9 bridge bridge local
accfd32f1830 host host local
46b450ace1d9 none null local
313b6f3af436 zh54 overlay global
2、在两台服务器上分别新建两个busybox的容器，我们刚才创建的网络zh54使用overlay
[root@docker-zh54-2 ~]# docker run -it --name zh1 --network zh54 busybox
[root@docker-zh54-3 ~]# docker run -it --name zh2 --network zh54 busybox
测试连通性
[root@docker-zh54-2 ~]# docker exec -it zh1 sh
/ # ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
7: eth0@if8: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1450 qdisc noqueue
link/ether 02:42:0a:00:01:02 brd ff:ff:ff:ff:ff:ff
inet 10.0.1.2/24 brd 10.0.1.255 scope global eth0
valid_lft forever preferred_lft forever
10: eth1@if11: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue
link/ether 02:42:ac:12:00:02 brd ff:ff:ff:ff:ff:ff
inet 172.18.0.2/16 brd 172.18.255.255 scope global eth1
valid_lft forever preferred_lft forever
/ # ping 10.0.1.3
PING 10.0.1.3 (10.0.1.3): 56 data bytes
64 bytes from 10.0.1.3: seq=0 ttl=64 time=0.409 ms
64 bytes from 10.0.1.3: seq=1 ttl=64 time=1.379 ms
^C
--- 10.0.1.3 ping statistics ---
2 packets transmitted, 2 packets received, 0% packet loss
round-trip min/avg/max = 0.409/0.894/1.379 ms
/ # ping zh2
PING zh2 (10.0.1.3): 56 data bytes
64 bytes from 10.0.1.3: seq=0 ttl=64 time=0.546 ms
64 bytes from 10.0.1.3: seq=1 ttl=64 time=1.956 ms
^C
--- zh2 ping statistics ---
2 packets transmitted, 2 packets received, 0% packet loss
round-trip min/avg/max = 0.546/1.251/1.956 ms
[root@docker-zh54-3 ~]# docker exec -it zh2 sh
/ # ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
7: eth0@if8: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1450 qdisc noqueue
link/ether 02:42:0a:00:01:03 brd ff:ff:ff:ff:ff:ff
inet 10.0.1.3/24 brd 10.0.1.255 scope global eth0
valid_lft forever preferred_lft forever
10: eth1@if11: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue
link/ether 02:42:ac:12:00:02 brd ff:ff:ff:ff:ff:ff
inet 172.18.0.2/16 brd 172.18.255.255 scope global eth1
valid_lft forever preferred_lft forever
/ # ping 10.0.1.2
PING 10.0.1.2 (10.0.1.2): 56 data bytes
64 bytes from 10.0.1.2: seq=0 ttl=64 time=0.397 ms
^C
--- 10.0.1.2 ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss
round-trip min/avg/max = 0.397/0.397/0.397 ms
/ # ping zh1
PING zh1 (10.0.1.2): 56 data bytes
64 bytes from 10.0.1.2: seq=0 ttl=64 time=0.378 ms
64 bytes from 10.0.1.2: seq=1 ttl=64 time=2.291 ms
^C
--- zh1 ping statistics ---
2 packets transmitted, 2 packets received, 0% packet loss
round-trip min/avg/max = 0.378/1.334/2.291 ms
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