Docker containers not connecting to the configured default bridge

Question

I have configured the default docker bridge dockerO using the daemon.json as follows:

{
  "bip": "192.168.1.5/24",
  "fixed-cidr": "192.168.1.5/25"
}

But my containers are not connecting to the bridge, I am not using any user-defined bridges.

$ docker network inspect bridge
[
    {
        "Name": "bridge",
        "Id": "0af71606024f88dd7ef5f14b9298d2aff76a6e5016e8a67745ceb401820949cb",
        "Created": "2019-12-31T09:56:41.626771723Z",
        "Scope": "local",
        "Driver": "bridge",
        "EnableIPv6": false,
        "IPAM": {
            "Driver": "default",
            "Options": null,
            "Config": [
                {
                    "Subnet": "192.168.1.5/24",
                    "IPRange": "192.168.1.0/25",
                    "Gateway": "192.168.1.5"
                }
            ]
        },
        "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": {}
    }
]

Also, my docker status shows the container ip in the default 172.xxx range.

CGroup: /system.slice/docker.service
           |-3243 /usr/bin/dockerd
           |-3252 docker-containerd --config /var/run/docker/containerd/containerd.toml
           |-3350 /usr/bin/docker-proxy -proto tcp -host-ip 0.0.0.0 -host-port 9000 -container-ip 172.18.0.2 -container-port 9000
           |-3363 /usr/bin/docker-proxy -proto tcp -host-ip 0.0.0.0 -host-port 8500 -container-ip 172.18.0.2 -container-port 8100
           |-3374 /usr/bin/docker-proxy -proto tcp -host-ip 0.0.0.0 -host-port 514 -container-ip 172.18.0.2 -container-port 514
           |-3387 /usr/bin/docker-proxy -proto udp -host-ip 0.0.0.0 -host-port 514 -container-ip 172.18.0.2 -container-port 514
           `-3395 docker-containerd-shim -namespace moby -workdir /var/lib/docker/containerd/daemon/io.containerd.runtime.v1.linux/moby/92e91d6994d0ea9d6f44cd2b3956397db5bc0942f202b79cf86439c10ba92f5f -add...

Do I need to change anything else for the containers to connect to this bridge?

Answer 1

My container was using another user-configured network. To change that I followed the below steps:

1. Disconnect docker containers connected to the network and remove the network.

    docker network disconnect <network-name> <container> docker network rm <network-name>

2. Re-create the network with the desired subnet and gateway.

    docker network create --subnet=192.168.1.0/24 --gateway=192.168.1.1 <network-name>

3. Connect the docker containers to the newly created network.

    docker network connect <network-name> <container>