Ubuntu 23.04
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Docker : Docker Network2023/04/27

 
This is the basic usage to configure Docker Network.
[1] When running containers without specifying network, default [bridge] network is assigned.
# display network list

root@dlp:~#
docker network ls

NETWORK ID     NAME           DRIVER    SCOPE
d5180938b0a8   bridge         bridge    local
6760b95b1dd1   host           host      local
ff57b05d9bdc   none           null      local
9d6424d9014d   root_default   bridge    local

# display details of [bridge]

root@dlp:~#
docker network inspect bridge

[
    {
        "Name": "bridge",
        "Id": "d5180938b0a88bd697e26e2e0456688aec577d6670cd43fa59a0b45d0b5063f3",
        "Created": "2023-04-27T01:47:23.332133453Z",
        "Scope": "local",
        "Driver": "bridge",
        "EnableIPv6": false,
        "IPAM": {
            "Driver": "default",
            "Options": null,
            "Config": [
                {
                    "Subnet": "172.17.0.0/16",
                    "Gateway": "172.17.0.1"
                }
            ]
        },
        "Internal": false,
        "Attachable": false,
        "Ingress": false,
        "ConfigFrom": {
            "Network": ""
        },
        "ConfigOnly": false,
        "Containers": {},
        "Options": {
            "com.docker.network.bridge.default_bridge": "true",
            "com.docker.network.bridge.enable_icc": "true",
            "com.docker.network.bridge.enable_ip_masquerade": "true",
            "com.docker.network.bridge.host_binding_ipv4": "0.0.0.0",
            "com.docker.network.bridge.name": "docker0",
            "com.docker.network.driver.mtu": "1500"
        },
        "Labels": {}
    }
]

# [bridge] is assigned as container network by default

root@dlp:~#
docker run ubuntu /bin/bash -c "apt-get update; apt-get -y install iproute2; /usr/sbin/ip route"

.....
.....
default via 172.17.0.1 dev eth0
172.17.0.0/16 dev eth0 proto kernel scope link src 172.17.0.2

root@dlp:~#
docker commit $(docker ps -a | sed -n 2p | awk '{print $1}') srv.world/ubuntu-iproute

[2] If you'd like to assign another network, set like follows.
# create network [network01] with [192.168.100.0/24] subnet

root@dlp:~#
docker network create --subnet 192.168.100.0/24 network01

e3328bd35135bd534a5d2bafafd7455d666a8d389224b881327c6a3520b17d60

root@dlp:~#
docker network ls

NETWORK ID     NAME           DRIVER    SCOPE
d5180938b0a8   bridge         bridge    local
6760b95b1dd1   host           host      local
e3328bd35135   network01      bridge    local
ff57b05d9bdc   none           null      local
9d6424d9014d   root_default   bridge    local

# run a container with specifying [network01]

root@dlp:~#
docker run --net network01 srv.world/ubuntu-iproute /usr/sbin/ip route

default via 192.168.100.1 dev eth0
192.168.100.0/24 dev eth0 proto kernel scope link src 192.168.100.2

# to attach the network to existing running container, set like follows

root@dlp:~#
docker ps

CONTAINER ID   IMAGE                    COMMAND                  CREATED         STATUS         PORTS                                   NAMES
7e737a6fd180   srv.world/ubuntu-nginx   "/usr/sbin/nginx -g …"   8 seconds ago   Up 8 seconds   0.0.0.0:8081->80/tcp, :::8081->80/tcp   agitated_pascal

root@dlp:~#
docker exec 7e737a6fd180 /usr/sbin/ip route

default via 172.17.0.1 dev eth0
172.17.0.0/16 dev eth0 proto kernel scope link src 172.17.0.2

# attach network to specify an IP address in the subnet

root@dlp:~#
docker network connect --ip 192.168.100.10 network01 7e737a6fd180
root@dlp:~#
docker exec 7e737a6fd180 /usr/sbin/ip route

default via 172.17.0.1 dev eth0
172.17.0.0/16 dev eth0 proto kernel scope link src 172.17.0.2
192.168.100.0/24 dev eth1 proto kernel scope link src 192.168.100.10

# to disconnect the network, set like follows

root@dlp:~#
docker network disconnect network01 7e737a6fd180

root@dlp:~#
docker exec 7e737a6fd180 /usr/sbin/ip route

default via 172.17.0.1 dev eth0
172.17.0.0/16 dev eth0 proto kernel scope link src 172.17.0.2
[3] To remove docker networks, set like follows.
root@dlp:~#
docker network ls

NETWORK ID     NAME           DRIVER    SCOPE
d5180938b0a8   bridge         bridge    local
6760b95b1dd1   host           host      local
e3328bd35135   network01      bridge    local
ff57b05d9bdc   none           null      local
9d6424d9014d   root_default   bridge    local

# remove [network01]

root@dlp:~#
docker network rm network01

network01
[4] To connect to Host network, not bridge, set like follows.
root@dlp:~#
docker network ls

NETWORK ID     NAME           DRIVER    SCOPE
d5180938b0a8   bridge         bridge    local
6760b95b1dd1   host           host      local
ff57b05d9bdc   none           null      local
9d6424d9014d   root_default   bridge    local

root@dlp:~#
docker images

REPOSITORY                  TAG           IMAGE ID       CREATED             SIZE
srv.world/ubuntu-iproute    latest        a52d4a7663a0   5 minutes ago       126MB
root_web                    latest        75ab1e6bff3e   37 minutes ago      235MB
srv.world/ubuntu-apache2    latest        886e2f7307a1   58 minutes ago      235MB
srv.world/ubuntu-nginx      latest        df0287c5017d   About an hour ago   177MB
mariadb                     latest        4a632f970181   5 weeks ago         401MB
dlp.srv.world:5000/ubuntu   my-registry   08d22c0ceb15   7 weeks ago         77.8MB
ubuntu                      latest        08d22c0ceb15   7 weeks ago         77.8MB

# run a container with [host] network

root@dlp:~#
docker run -d --net host srv.world/ubuntu-apache2

a0e60a616d6ad4ab9a9f471cc350d2d6d817984abe780de8d8888083e1fb961b

root@dlp:~#
docker ps

CONTAINER ID   IMAGE                      COMMAND                  CREATED          STATUS         PORTS     NAMES
a0e60a616d6a   srv.world/ubuntu-apache2   "/usr/sbin/apachectl…"   10 seconds ago   Up 9 seconds             frosty_chatterjee

# the port [apache2] service listens on container is used on Host network

root@dlp:~#
ss -napt

State     Recv-Q    Send-Q       Local Address:Port        Peer Address:Port
.....
.....
LISTEN    0         511                      *:80                     *:*        users:(("apache2",pid=14363,fd=4),("apache2",pid=14362,fd=4),("apache2",pid=14361,fd=4))

root@dlp:~#
curl localhost

index.html on Aapche2
Matched Content