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Docker : Docker Network2023/06/22

 
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
11b02877db72   bridge         bridge    local
7e5fccb8cd81   host           host      local
a58e9ea6ddae   none           null      local
e9c682aa11d5   root_default   bridge    local

# display details of [bridge]

root@dlp:~#
docker network inspect bridge

[
    {
        "Name": "bridge",
        "Id": "11b02877db7276c9f302ec6211591ee67e674efda4f34637125191d58fe82d4f",
        "Created": "2023-06-22T01:56:04.398417557-05:00",
        "Scope": "local",
        "Driver": "bridge",
        "EnableIPv6": false,
        "IPAM": {
            "Driver": "default",
            "Options": null,
            "Config": [
                {
                    "Subnet": "172.17.0.0/16"
                }
            ]
        },
        "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 debian /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|head -2|tail -1|awk '{print $1}') srv.world/debian-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

5a736efe2fc4abcc70fd27198bf48a384fb854ea0422bf111b6c28bfa719931c

root@dlp:~#
docker network ls

NETWORK ID     NAME           DRIVER    SCOPE
11b02877db72   bridge         bridge    local
7e5fccb8cd81   host           host      local
5a736efe2fc4   network01      bridge    local
a58e9ea6ddae   none           null      local
e9c682aa11d5   root_default   bridge    local

# run a container with specifying [network01]

root@dlp:~#
docker run --net network01 srv.world/debian-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
752707cb6701   srv.world/debian-nginx   "/usr/sbin/nginx -g …"   8 seconds ago   Up 7 seconds   0.0.0.0:8081->80/tcp, :::8081->80/tcp   friendly_williams

root@dlp:~#
docker exec 752707cb6701 /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 752707cb6701
root@dlp:~#
docker exec 752707cb6701 /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 752707cb6701

root@dlp:~#
docker exec 752707cb6701 /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
11b02877db72   bridge         bridge    local
7e5fccb8cd81   host           host      local
5a736efe2fc4   network01      bridge    local
a58e9ea6ddae   none           null      local
e9c682aa11d5   root_default   bridge    local

# remove [network01]

root@dlp:~#
docker network rm network01

network01
[4] To connect to Host network, set like follows.
root@dlp:~#
docker network ls

NETWORK ID     NAME           DRIVER    SCOPE
11b02877db72   bridge         bridge    local
7e5fccb8cd81   host           host      local
a58e9ea6ddae   none           null      local
e9c682aa11d5   root_default   bridge    local

root@dlp:~#
docker images

REPOSITORY                 TAG       IMAGE ID       CREATED          SIZE
srv.world/debian-iproute   latest    2b1c5b7c483d   5 minutes ago    151MB
root_web                   latest    d2928f1806c2   22 minutes ago   252MB
srv.world/debian-apache2   latest    431c51e7819a   48 minutes ago   252MB
srv.world/debian-nginx     latest    5a202ab0ab76   53 minutes ago   153MB
mariadb                    latest    99833200524a   6 days ago       403MB
debian                     latest    49081a1edb0b   9 days ago       116MB

# run a container with [host] network

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

63b4e21a4647a1a9ec3ed9eb9baace67b61e3a49db9ca4e5314a7d3f9c4efa9d

root@dlp:~#
docker ps

CONTAINER ID   IMAGE                      COMMAND                  CREATED          STATUS         PORTS     NAMES
63b4e21a4647   srv.world/debian-apache2   "/usr/sbin/apachectl…"   10 seconds ago   Up 9 seconds             nice_sinoussi

# 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=15703,fd=4),("apache2",pid=15702,fd=4),("apache2",pid=15701,fd=4))

root@dlp:~#
curl localhost

index.html on Aapche2
Matched Content