4.3.2.1. 前言
本主题主要说明在 swarm 服务集群中的 overlay 网络的使用。关于单主机容器网络配置见 bridge 网络配置。
本节主要包括四个部分。
默认 overlay 网络 展示当初始化或加入一个
swarm集群后 Docker 如何自动配置默认的overlay网络。该overlay网络不建议在 线上使用。自定义 overlay 网络 展示如何创建一个
overlay及服务如何加入该网络。推荐在线上使用自定义的overlay网络。在独立容器中使用 overlay 网络 展示如何使用
overlay网络在不同 Docker 守护程序（即 Docker 服务器）上的独立容器之间进行通信。
4.3.2.2. 准备工作
本节需要准备3台主机或者虚拟机也可以。Docker 版本最低要求是 v17.03。三台主机中一个管理节点、两个工作节点，当然管理节点本身也是一个工作节点。
- 管理节点：
192.168.1.9 - 工作节点1：
192.168.1.10 - 工作节点2：
192.168.1.12
4.3.2.3. 默认 overlay 网络
在之前先看一个三台主机的网络：
管理节点：
$ docker network ls
NETWORK ID NAME DRIVER SCOPE
bf92b17490fe bridge bridge local
666c50c30e70 host host local
4e6d7e6c3103 none null local
另外，两个工作节点中的网络与管理节点也是一样的，这里只是列出来号进行后续比较。
4.3.2.3.1. 创建 swarm
- 在管理节点上，初始化
swarm。如果你的主机只有一个网络接口，可以使用--advertise-addr进行指定 IP 地址：
$ docker swarm init --advertise-addr=<IP-ADDRESS-OF-MANAGER>
$ docker swarm init --advertise-addr=192.168.1.9
Swarm initialized: current node (4ccar9aqotyetbi5sde86q5z5) is now a manager.
To add a worker to this swarm, run the following command:
docker swarm join --token SWMTKN-1-2wnbo5bdf4rs92nde2hb2qrh5gjb1rry46bpkh7rkrr4nu61do-c71ufntkr69tf0h5fmnb2ffpe 192.168.1.9:2377
To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.
- 在管理节点初始化完成后，加入工作节点。同样的，如果工作节点没有也只有一个网络接口，需要使用
--advertise-addr参数进行进行指定 IP 地址：
$ docker swarm join --token <TOKEN> \
--advertise-addr <IP-ADDRESS-OF-WORKER-1> \
<IP-ADDRESS-OF-MANAGER>:2377
在工作1节点加入 swarm：
$ docker swarm join --token SWMTKN-1-2wnbo5bdf4rs92nde2hb2qrh5gjb1rry46bpkh7rkrr4nu61do-c71ufntkr69tf0h5fmnb2ffpe 192.168.1.9:2377 --advertise-addr=192.168.1.10
This node joined a swarm as a worker.
- 在工作2节点同样加入
swarm后，在管理节点上列出所有的节点，该命令只能在管理节点上运行。
$ docker node ls
ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS ENGINE VERSION
4f6g7ym3ph4ndc04z93k7zi1w 192.168.1.10 Ready Active 18.09.0
m8hmrxxdnazrjk1e9wkerqtkq * 192.168.1.9 Ready Active Leader 18.09.0
vzi7hibq5mfp5a9bktwiop4cs 192.168.1.12 Ready Active 18.09.0
另外，也可以使用 --filter 标识进行过滤
$ docker node ls --filter role=manager
ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS ENGINE VERSION
4ccar9aqotyetbi5sde86q5z5 * 192.168.1.9 Ready Active Leader 18.09.0
$ docker node ls --filter role=worker
ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS ENGINE VERSION
4f6g7ym3ph4ndc04z93k7zi1w 192.168.1.10 Ready Active 18.09.0
vzi7hibq5mfp5a9bktwiop4cs 192.168.1.12 Ready Active 18.09.0
- 在管理节点和工作节点分别列出网络，看到相比之前分别多了一个属于
overlay名为ingress的网络和一个属于bridge名为docker_gwbridge的网络。
$ docker network ls
NETWORK ID NAME DRIVER SCOPE
bf92b17490fe bridge bridge local
6480b7bc0dd3 docker_gwbridge bridge local
666c50c30e70 host host local
344gz56pl2l3 ingress overlay swarm
4e6d7e6c3103 none null local
docker_gwbridge 网络将 ingress 网络连接到 Docker主机的网络接口，以便在管理节点与工作节点之间进行通信。如果你创建一个 swarm 集群服务，
而没有指定网络，将会默认连接到 ingress 网络。因此建议为可以协同工作的每个应用程序或应用程序组使用单独的 overlay 网络。
4.3.2.3.2. 创建服务
- 在管理节点上，创建一个名为
nginx-net的overlay网络。
$ docker network create -d overlay nginx-net
该命令不需要再工作节点上进行再次创建，在管理节点上创建一个网络后，当在节点上启动服务后工作节点会自动的创建该网络。
在管理节点上将网络列出，看是否有名为 nginx-net 的 overlay 类型网络。
$ docker network ls
NETWORK ID NAME DRIVER SCOPE
bf92b17490fe bridge bridge local
6480b7bc0dd3 docker_gwbridge bridge local
666c50c30e70 host host local
344gz56pl2l3 ingress overlay swarm
lknuq2ejwia6 nginx-net overlay swarm
4e6d7e6c3103 none null local
- 在管理节点上，创建一个
Nginx服务的五个实例，向外部暴露80端口，这样所有服务任务容器都可以相互通信而无需打开任何端口。
$ docker service create \
--name my-nginx \
--publish target=80,published=80 \
--replicas=5 \
--network nginx-net \
nginx
zgekieqpk946o00sonf13g1g6
overall progress: 5 out of 5 tasks
1/5: running [==================================================>]
2/5: running [==================================================>]
3/5: running [==================================================>]
4/5: running [==================================================>]
5/5: running [==================================================>]
verify: Service converged
当你没有使用 --publish 标识进行指定模式时，会默认使用 ingress 模式发布。意思是，当你在管理节点或者在两个工作节点访问 80 端口时，你将会
在5个服务任务之一上连接到端口80，即使你浏览到的节点上当前没有任何任务正在运行。如果你想要使用 host 模式进行发布，你可以将 mode=host 加入
到 --publish 进行输出。不过，在这种情况下，你还需要使用 --mode global 而不是 --replicas = 5，因为只有一个服务任务可以绑定给定节点
上的给定端口。
- 在管理节点运行
docker service ls命令进行查看服务是否起来
$ docker service ls
ID NAME MODE REPLICAS IMAGE PORTS
zgekieqpk946 my-nginx replicated 5/5 nginx:latest *:80->80/tcp
另外，之前说。在管理节点创建 overlay 网络后，不需要再在工作节点上再次创建，因为当运行服务后会在工作节点上自动创建，现在在工作节点上查看下
nginx-net 网络是否自动创建：
# 192.168.1.10 工作节点
$ docker network ls
NETWORK ID NAME DRIVER SCOPE
8f29fbe91663 bridge bridge local
b2da9e66dfb0 docker_gwbridge bridge local
1006fa4fcdc1 host host local
344gz56pl2l3 ingress overlay swarm
lknuq2ejwia6 nginx-net overlay swarm
ad1bf137cf18 none null local
看到，以自动创建。
- 在管理、工作1和工作2节点上检查
nginx-net网络（注意，不需要再工作节点再次创建该网络，因为 Docker 会自动为你创建），输出会比较长。最需要 注意的时containers和peers部分。containers部分列出所有从该主机连接到overlay网络的服务任务（或独立容器）。
管理节点
$ docker network inspect nginx-net
[
{
"Name": "nginx-net",
"Id": "lknuq2ejwia6l3x8yjulrn5zu",
"Created": "2019-01-06T15:30:05.985792674+08:00",
"Scope": "swarm",
"Driver": "overlay",
"EnableIPv6": false,
"IPAM": {
"Driver": "default",
"Options": null,
"Config": [
{
"Subnet": "10.0.0.0/24",
"Gateway": "10.0.0.1"
}
]
},
"Internal": false,
"Attachable": false,
"Ingress": false,
"ConfigFrom": {
"Network": ""
},
"ConfigOnly": false,
"Containers": {
"68b867162f66dab0afc3f79ef7f8c6074744d01e6d03e4452d94e3be59fc958d": {
"Name": "my-nginx.2.yb03otxoqryiylq6pf77ytlig",
"EndpointID": "04155448b30f6bd8bb8d57c8c2bbde97f3c3b153995c95575ea784cec1d3ade2",
"MacAddress": "02:42:0a:00:00:04",
"IPv4Address": "10.0.0.4/24",
"IPv6Address": ""
},
"lb-nginx-net": {
"Name": "nginx-net-endpoint",
"EndpointID": "9cdc6b75bb7195bc5583b3dd2f542127d4e404ba68d28363cad69c37a6caea7e",
"MacAddress": "02:42:0a:00:00:0a",
"IPv4Address": "10.0.0.10/24",
"IPv6Address": ""
}
},
"Options": {
"com.docker.network.driver.overlay.vxlanid_list": "4097"
},
"Labels": {},
"Peers": [
{
"Name": "a4037138043d",
"IP": "192.168.1.9"
},
{
"Name": "746de4a0435c",
"IP": "192.168.1.12"
},
{
"Name": "b4d8838fb56f",
"IP": "192.168.1.10"
}
]
}
]
工作1节点
$ docker network inspect nginx-net
[
{
"Name": "nginx-net",
"Id": "lknuq2ejwia6l3x8yjulrn5zu",
"Created": "2019-01-06T15:30:05.988961101+08:00",
"Scope": "swarm",
"Driver": "overlay",
"EnableIPv6": false,
"IPAM": {
"Driver": "default",
"Options": null,
"Config": [
{
"Subnet": "10.0.0.0/24",
"Gateway": "10.0.0.1"
}
]
},
"Internal": false,
"Attachable": false,
"Ingress": false,
"ConfigFrom": {
"Network": ""
},
"ConfigOnly": false,
"Containers": {
"2ee96a8062c5fb38149040b4df044a9c8db3083ab9fb41cc2dc5b0dcc5e8cf47": {
"Name": "my-nginx.5.lf2qcvi39r28yaw88w3ohuoz7",
"EndpointID": "f688acbf0810b2a064958046eca99b37c82041929b3143dabdc2d599c9d48497",
"MacAddress": "02:42:0a:00:00:07",
"IPv4Address": "10.0.0.7/24",
"IPv6Address": ""
},
"cc474c0ea3235ef36f490953ad9f5a82b924cf9ad0896f0663c901c1f5a7f2cb": {
"Name": "my-nginx.3.jo2s51nhqrlkx59sqw1yo26ux",
"EndpointID": "7ccdf91c7d0ffeafb391d9e06dd86e819df04c64037426d730524fddd2bb6ff0",
"MacAddress": "02:42:0a:00:00:05",
"IPv4Address": "10.0.0.5/24",
"IPv6Address": ""
},
"lb-nginx-net": {
"Name": "nginx-net-endpoint",
"EndpointID": "be82c7735413e3b8af331d811014d58b6e94fedb970c0c9faa8629bc32fe6b48",
"MacAddress": "02:42:0a:00:00:08",
"IPv4Address": "10.0.0.8/24",
"IPv6Address": ""
}
},
"Options": {
"com.docker.network.driver.overlay.vxlanid_list": "4097"
},
"Labels": {},
"Peers": [
{
"Name": "b4d8838fb56f",
"IP": "192.168.1.10"
},
{
"Name": "a4037138043d",
"IP": "192.168.1.9"
},
{
"Name": "746de4a0435c",
"IP": "192.168.1.12"
}
]
}
]
工作2节点
$ docker network inspect nginx-net
[
{
"Name": "nginx-net",
"Id": "lknuq2ejwia6l3x8yjulrn5zu",
"Created": "2019-01-06T15:30:05.989094312+08:00",
"Scope": "swarm",
"Driver": "overlay",
"EnableIPv6": false,
"IPAM": {
"Driver": "default",
"Options": null,
"Config": [
{
"Subnet": "10.0.0.0/24",
"Gateway": "10.0.0.1"
}
]
},
"Internal": false,
"Attachable": false,
"Ingress": false,
"ConfigFrom": {
"Network": ""
},
"ConfigOnly": false,
"Containers": {
"5c26f1464c684c33b8c94a923919ec3fc80f0da98def214ce261bbf32a34eeed": {
"Name": "my-nginx.1.uoim3lrc76ipbxvw07yzq0euk",
"EndpointID": "ce2133c8c7c9a7b7a1b6a7374a9c3c6a613a0742753a94aebe88404727acbedc",
"MacAddress": "02:42:0a:00:00:03",
"IPv4Address": "10.0.0.3/24",
"IPv6Address": ""
},
"fe198907032c11ad5488921d222d87c7305d7ab3bb885668c69ac88d1652df51": {
"Name": "my-nginx.4.5p03u0z7n2b3qqlmrx4dgb5ls",
"EndpointID": "7898c659a2e8217ae4f346bc93497a194493f8a5122dc89282d57df8afa290bb",
"MacAddress": "02:42:0a:00:00:06",
"IPv4Address": "10.0.0.6/24",
"IPv6Address": ""
},
"lb-nginx-net": {
"Name": "nginx-net-endpoint",
"EndpointID": "d39c4b74a39c8c45d44c071c1836fabf2ee2c3162226e5655fa8470898b4caa0",
"MacAddress": "02:42:0a:00:00:09",
"IPv4Address": "10.0.0.9/24",
"IPv6Address": ""
}
},
"Options": {
"com.docker.network.driver.overlay.vxlanid_list": "4097"
},
"Labels": {},
"Peers": [
{
"Name": "746de4a0435c",
"IP": "192.168.1.12"
},
{
"Name": "a4037138043d",
"IP": "192.168.1.9"
},
{
"Name": "b4d8838fb56f",
"IP": "192.168.1.10"
}
]
}
]
- 在管理节点上使用
docker service inspect my-nginx命令检查服务，需要注意有关服务的端口和端点信息
$ docker service inspect my-nginx
[
{
"ID": "zgekieqpk946o00sonf13g1g6",
"Version": {
"Index": 24
},
"CreatedAt": "2019-01-06T07:30:05.803235091Z",
"UpdatedAt": "2019-01-06T07:30:05.804887452Z",
"Spec": {
"Name": "my-nginx",
"Labels": {},
"TaskTemplate": {
"ContainerSpec": {
"Image": "nginx:latest@sha256:b543f6d0983fbc25b9874e22f4fe257a567111da96fd1d8f1b44315f1236398c",
"Init": false,
"StopGracePeriod": 10000000000,
"DNSConfig": {},
"Isolation": "default"
},
"Resources": {
"Limits": {},
"Reservations": {}
},
"RestartPolicy": {
"Condition": "any",
"Delay": 5000000000,
"MaxAttempts": 0
},
"Placement": {
"Platforms": [
{
"Architecture": "amd64",
"OS": "linux"
},
{
"OS": "linux"
},
{
"Architecture": "arm64",
"OS": "linux"
},
{
"Architecture": "386",
"OS": "linux"
},
{
"Architecture": "ppc64le",
"OS": "linux"
},
{
"Architecture": "s390x",
"OS": "linux"
}
]
},
"Networks": [
{
"Target": "lknuq2ejwia6l3x8yjulrn5zu"
}
],
"ForceUpdate": 0,
"Runtime": "container"
},
"Mode": {
"Replicated": {
"Replicas": 5
}
},
"UpdateConfig": {
"Parallelism": 1,
"FailureAction": "pause",
"Monitor": 5000000000,
"MaxFailureRatio": 0,
"Order": "stop-first"
},
"RollbackConfig": {
"Parallelism": 1,
"FailureAction": "pause",
"Monitor": 5000000000,
"MaxFailureRatio": 0,
"Order": "stop-first"
},
"EndpointSpec": {
"Mode": "vip",
"Ports": [
{
"Protocol": "tcp",
"TargetPort": 80,
"PublishedPort": 80,
"PublishMode": "ingress"
}
]
}
},
"Endpoint": {
"Spec": {
"Mode": "vip",
"Ports": [
{
"Protocol": "tcp",
"TargetPort": 80,
"PublishedPort": 80,
"PublishMode": "ingress"
}
]
},
"Ports": [
{
"Protocol": "tcp",
"TargetPort": 80,
"PublishedPort": 80,
"PublishMode": "ingress"
}
],
"VirtualIPs": [
{
"NetworkID": "344gz56pl2l3rhpxu9ykibwb1",
"Addr": "10.255.0.5/16"
},
{
"NetworkID": "lknuq2ejwia6l3x8yjulrn5zu",
"Addr": "10.0.0.2/24"
}
]
}
}
]
- 在管理节点上创建
nginx-net-2overlay网络，并代替服务的nginx-net网络
$ docker network create -d overlay nginx-net-2
lg6urfk7yt2856xvlj565dho0
$ docker network ls
NETWORK ID NAME DRIVER SCOPE
bf92b17490fe bridge bridge local
6480b7bc0dd3 docker_gwbridge bridge local
666c50c30e70 host host local
344gz56pl2l3 ingress overlay swarm
lknuq2ejwia6 nginx-net overlay swarm
lg6urfk7yt28 nginx-net-2 overlay swarm
4e6d7e6c3103 none null local
$ docker service update \
--network-add nginx-net-2 \
--network-rm nginx-net \
my-nginx
my-nginx
overall progress: 5 out of 5 tasks
1/5: running [==================================================>]
2/5: running [==================================================>]
3/5: running [==================================================>]
4/5: running [==================================================>]
5/5: running [==================================================>]
verify: Service converged
- 运行
docker service ls命令验证服务是否已经被更新以及任务是否已被重新部署。运行docker network inspect nginx-net命令验证当前已 经没有容器连接该网络，运行同样的命令检查nginx-net-2网络看是不是所有的容器都要已经连接到了该网络。
$ docker service ls
ID NAME MODE REPLICAS IMAGE PORTS
zgekieqpk946 my-nginx replicated 5/5 nginx:latest *:80->80/tcp
$ docker network inspect nginx-net
[
{
"Name": "nginx-net",
"Id": "lknuq2ejwia6l3x8yjulrn5zu",
"Created": "2019-01-06T15:30:05.985792674+08:00",
"Scope": "swarm",
"Driver": "overlay",
"EnableIPv6": false,
"IPAM": {
"Driver": "default",
"Options": null,
"Config": [
{
"Subnet": "10.0.0.0/24",
"Gateway": "10.0.0.1"
}
]
},
"Internal": false,
"Attachable": false,
"Ingress": false,
"ConfigFrom": {
"Network": ""
},
"ConfigOnly": false,
"Containers": {
"lb-nginx-net": {
"Name": "nginx-net-endpoint",
"EndpointID": "9cdc6b75bb7195bc5583b3dd2f542127d4e404ba68d28363cad69c37a6caea7e",
"MacAddress": "02:42:0a:00:00:0a",
"IPv4Address": "10.0.0.10/24",
"IPv6Address": ""
}
},
"Options": {
"com.docker.network.driver.overlay.vxlanid_list": "4097"
},
"Labels": {},
"Peers": [
{
"Name": "a4037138043d",
"IP": "192.168.1.9"
},
{
"Name": "746de4a0435c",
"IP": "192.168.1.12"
},
{
"Name": "b4d8838fb56f",
"IP": "192.168.1.10"
}
]
}
]
$ docker network inspect nginx-net-2
[
{
"Name": "nginx-net-2",
"Id": "lg6urfk7yt2856xvlj565dho0",
"Created": "2019-01-06T16:09:52.066700394+08:00",
"Scope": "swarm",
"Driver": "overlay",
"EnableIPv6": false,
"IPAM": {
"Driver": "default",
"Options": null,
"Config": [
{
"Subnet": "10.0.1.0/24",
"Gateway": "10.0.1.1"
}
]
},
"Internal": false,
"Attachable": false,
"Ingress": false,
"ConfigFrom": {
"Network": ""
},
"ConfigOnly": false,
"Containers": {
"f4675b26411e3178bbe2860b8da39ae95df7be695c6cd04a3d5cfbcfa3ba1bd0": {
"Name": "my-nginx.4.farkvlh3jrswsu3uwedjslk8t",
"EndpointID": "2c629c9e91b843eebb64c2e4920a44653368cf9f62fe60d428d42d0e33666c36",
"MacAddress": "02:42:0a:00:01:03",
"IPv4Address": "10.0.1.3/24",
"IPv6Address": ""
},
"lb-nginx-net-2": {
"Name": "nginx-net-2-endpoint",
"EndpointID": "6c8735bec6a432754ed37e1da75f3d9eb71b4ef7cc7a92b9e8900c4723454b81",
"MacAddress": "02:42:0a:00:01:04",
"IPv4Address": "10.0.1.4/24",
"IPv6Address": ""
}
},
"Options": {
"com.docker.network.driver.overlay.vxlanid_list": "4098"
},
"Labels": {},
"Peers": [
{
"Name": "a4037138043d",
"IP": "192.168.1.9"
},
{
"Name": "b4d8838fb56f",
"IP": "192.168.1.10"
},
{
"Name": "746de4a0435c",
"IP": "192.168.1.12"
}
]
}
]
[warning] 注意
虽然
orverlay网络会根据需要在工作节点上自动创建，但是不会自动删除。
- 在管理节点上运行下面命令将服务与网络进行删除。管理节点会自动引导工作节点删除网络。
$ docker service rm my-nginx
$ docker network rm nginx-net nginx-net-2
4.3.2.4. 自定义 overlay 网络
因为在之前的默认 overlay 的网络中已经演示了自定义的 overlay 网络，因此这里只简单的说下。
- 创建自定义
overlay网络
$ docker network create -d overlay my-overlay
- 使用自定义
overlay网络运行服务，并将80端口发布到 Docker 主机的8080端口。
$ docker service create \
--name my-nginx \
--network my-overlay \
--replicas 1 \
--publish published=8080,target=80 \
nginx:latest
xtoqr66jpj00wbqy1lwgc12v6
overall progress: 1 out of 1 tasks
1/1: running [==================================================>]
verify: Service converged
$ docker service ls
ID NAME MODE REPLICAS IMAGE PORTS
xtoqr66jpj00 my-nginx replicated 1/1 nginx:latest *:8080->80/tcp
- 运行
docker network inspect my-overlay命令验证my-nginx服务任务已经连接到了该网络，另外要注意下containers中的信息。
$ docker network inspect my-overlay
[
{
"Name": "my-overlay",
"Id": "kdj4cgpzgi3kgkp0q5o0ae6bk",
"Created": "2019-01-06T16:34:43.91033391+08:00",
"Scope": "swarm",
"Driver": "overlay",
"EnableIPv6": false,
"IPAM": {
"Driver": "default",
"Options": null,
"Config": [
{
"Subnet": "10.0.2.0/24",
"Gateway": "10.0.2.1"
}
]
},
"Internal": false,
"Attachable": false,
"Ingress": false,
"ConfigFrom": {
"Network": ""
},
"ConfigOnly": false,
"Containers": {
"70372391d37d27fba62b8add60687bd7c534c1e14444c3c2d33c4f2cd3314284": {
"Name": "my-nginx.1.akqwxtd6enefvlurqya06ta6t",
"EndpointID": "bbfe904f4b3297f5b31643931513404ca6e675ad92a3ac1ed8d8a0d4a59939e9",
"MacAddress": "02:42:0a:00:02:03",
"IPv4Address": "10.0.2.3/24",
"IPv6Address": ""
},
"lb-my-overlay": {
"Name": "my-overlay-endpoint",
"EndpointID": "be1a0ea5cb86a51031821bb39fdded9bc26e0d1ac43e48e4a15987ada20a3595",
"MacAddress": "02:42:0a:00:02:04",
"IPv4Address": "10.0.2.4/24",
"IPv6Address": ""
}
},
"Options": {
"com.docker.network.driver.overlay.vxlanid_list": "4099"
},
"Labels": {},
"Peers": [
{
"Name": "a4037138043d",
"IP": "192.168.1.9"
}
]
}
]
- 自定义的
overlay网络只到这里，具体见默认的overlay网络中的有关说明，下面叫服务与网络进行删除。
$ docker service rm my-nginx
$ docker network rm my-overlay
4.3.2.5. 在独立容器中使用 overlay 网络
本示例展示 DNS 容器的发现。准确来说，是在不同的 Docker 主机之间如何使用 overlay 网络实现独立容器的通信。具体步骤如下：
[success] 说明
以下步骤中：
host1：对应主机192.168.1.9host2：对应主机192.168.1.10
- 在
host1主机上，初始化一个swarm - 在
host2上加入该集群 - 在
host1主机上创建overlay网络test-net - 在
host1主机上，运行alpine容器（alpine1）并连接到test-net网络 - 在
host2主机上，运行alpine容器（alpine2）并连接到test-net网络 - 在
host1主机上的容器alpine1中pingalpine2
另外，在执行以下步骤是要保证已经开启如下端口：
- TCP port 2377
- TCP and UDP port 7946
- UDP port 4789
- 在
host1中初始化swarm（同样的，如果出现提示。需要使用--advertise-addr指定与群中其他主机通信的接口的IP地址）
$ docker swarm init
Swarm initialized: current node (z62948o72kv6yx9rjpcv1hc9a) is now a manager.
To add a worker to this swarm, run the following command:
docker swarm join --token SWMTKN-1-652zly2800j5tyxegghapcu6v5lr5qhqrssmk4q4572n70fnr5-3zmda20ogojaric5sm778zg53 192.168.1.9:2377
To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.
- 在
host2中加入swarm
$ docker swarm join --token SWMTKN-1-652zly2800j5tyxegghapcu6v5lr5qhqrssmk4q4572n70fnr5-3zmda20ogojaric5sm778zg53 192.168.1.9:2377
This node joined a swarm as a worker.
注意，在加入节点之前需要退出已加入的 swarm，使用如下命令强制退出
$ docker swarm leave --force
- 在
host1中，创建一个attachableoverlay网络test-net
$ docker network create --driver=overlay --attachable test-net
unpuqsxonmuf4oes6tohpjbk2
需要注意这个id，在连接 host2 时会再次看到该 ID。
- 在
host1中运行一个可交互（-it）的容器alpine1并连接到test-host网络
$ docker run -it --name alpine1 --network test-net alpine
/ #
- 在
host2中列出网络信息，确定没有test-net网络
$ docker network ls
NETWORK ID NAME DRIVER SCOPE
8f29fbe91663 bridge bridge local
0cde9a023dee docker_gwbridge bridge local
1006fa4fcdc1 host host local
pr4jkgpe6d2o ingress overlay swarm
ad1bf137cf18 none null local
- 在
host2中后台运行（-d）一个可交互式（-it）的容器alpine2，并连接到test-net网络。
$ docker run -dit --name alpine2 --network test-net alpine
6ac220e5010ed4b022d76c9cc69fde50d0b91a069c3ac06d34f7b55736efdc9d
自动DNS容器发现仅适用于唯一的容器名称。如果硬存在该容器名称将会提示如下错误：
$ docker run -dit --name alpine2 --network test-net alpine
docker: Error response from daemon: Conflict. The container name "/alpine2" is already in use by container "aa887162d56e47a2b9ec476ddd0a6cda025e2b73947f14acb434182375ba6dc7". You have to remove (or rename) that container to be able to reuse that name.
- 在
host2中验证test-net网络是否已自动创建，并且 ID 与之前相同。
$ docker network ls
NETWORK ID NAME DRIVER SCOPE
...
l1d3jpr0kpbc test-net overlay swarm
- 在
host1中，pingalpine2。看能否ping通。
/ # ping -c 3 alpine2
PING alpine2 (10.0.0.6): 56 data bytes
64 bytes from 10.0.0.6: seq=0 ttl=64 time=0.529 ms
64 bytes from 10.0.0.6: seq=1 ttl=64 time=0.592 ms
64 bytes from 10.0.0.6: seq=2 ttl=64 time=0.523 ms
--- alpine2 ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max = 0.523/0.548/0.592 ms
两个容器与连接两个主机的 overlay 网络通信。如果你在 host2 在运行另外一个 alpine 容器是不能分离的。你可以在 host2 ping alpine1。
$ docker run -it --rm --name alpine3 --network test-net alpine
/ # ping -c 3 alpine3
PING alpine3 (10.0.0.8): 56 data bytes
64 bytes from 10.0.0.8: seq=0 ttl=64 time=0.060 ms
64 bytes from 10.0.0.8: seq=1 ttl=64 time=0.070 ms
64 bytes from 10.0.0.8: seq=2 ttl=64 time=0.054 ms
--- alpine3 ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max = 0.054/0.061/0.070 ms
- 清楚容器和网络。在清楚之前，你必须要先停止容器。因为Docker守护进程独立运行，这些是独立的容器。你只需要删除
host1上的网络，因为当你在host2上停止alpine2时，test-net会消失。
在 host2 上停止 alpine2 检查 test-net 网络是否已自动移除。
$ docker container stop alpine2
$ docker network ls
NETWORK ID NAME DRIVER SCOPE
8f29fbe91663 bridge bridge local
46a1fa8aac76 docker_gwbridge bridge local
1006fa4fcdc1 host host local
kvizopvh3m8c ingress overlay swarm
ad1bf137cf18 none null local
$ docker container rm alpine2
在 host1 中，停止、移除 alpine1 和 test-net
$ docker container stop alpine1
$ docker container rm alpine1
$ docker network rm test-net