Enable TCP port 2375 for external connection to Docker

docker-api-port.md

Enable TCP port 2375 for external connection to Docker

See this issue.
Docker best practise to Control and configure Docker with systemd.

1. Create daemon.json file in /etc/docker:

    {"hosts": ["tcp://0.0.0.0:2375", "unix:///var/run/docker.sock"]}
   

2. Add /etc/systemd/system/docker.service.d/override.conf

    [Service]
    ExecStart=
    ExecStart=/usr/bin/dockerd
   

3. Reload the systemd daemon:

    systemctl daemon-reload
   

4. Restart docker:

    systemctl restart docker.service
   

Sorry @honue , I don't know as I don't use proxies. Maybe Synology doesn't support those options. They are also using a slightly older version of docker. v20.10.23, build 876964a

ExecStart=
ExecStart=/usr/bin/dockerd --config-file /etc/docker/daemon.json

Thank you. This override.conf trick worked nicely for me. I used daemon.json to supply my TLS configuration as well as listen on 2376. Giving it nothing except a reference to daemon.json feels like a hack to avoid the hosts conflict.. but it works. Thanks again @webzakimbo

root@mnretrogamer029:~# cat /etc/docker/daemon.json
{
"data-root": "/mnt/dietpi_userdata/docker-data",
"log-driver": "journald",
"log-level": "warn",
"debug": false,
"hosts": ["unix:///var/run/docker.sock", "tcp://0.0.0.0:2376"],
"tlscacert": "/etc/docker/certs.d/ca.pem",
"tlscert": "/etc/docker/certs.d/server-cert.pem",
"tlskey": "/etc/docker/certs.d/server-key.pem",
"tlsverify": true
}

what if I don't have systemd? ie. Unraid/Slackware

on Ubuntu 22.04.3 couldn't get it to work with these instructions... do this:

Update Docker Configuration:
Edit the Docker daemon configuration file. The configuration file is typically located at /etc/docker/daemon.json. If it doesn't exist, you can create it.

sudo nano /etc/docker/daemon.json

Add the following content to the file:

{
"hosts": ["unix:///var/run/docker.sock", "tcp://0.0.0.0:2375"]
}

This configuration tells Docker to listen on both the UNIX socket and a TCP socket on all available network interfaces (0.0.0.0) on port 2375.

Restart Docker:
After making changes to the Docker daemon configuration, you need to restart the Docker daemon for the changes to take effect.

sudo systemctl restart docker

Adjust Firewall Rules (if necessary):
If you have a firewall enabled on your Ubuntu server, make sure to allow traffic on the Docker daemon port (default is 2375). You can use ufw (Uncomplicated Firewall) to do this:

bash

sudo ufw allow 2375

For Synology NAS (I am using DS923+) I found an easier way.
In your compose file for Homepage make sure to have the following listed under 'volumes'
- /var/run/docker.sock:/var/run/docker.sock

Then in your Homepage docker.yaml file, uncomment only this part:

# my-docker:
#   socket: /var/run/docker.sock

Once I did this it's working. Didn't have to mess with anything else.

Thanks for your gist! It works great for me, with special case where I use Windows 10 & WSL2!

thanks, it worked for me