Change configuration of Docker daemon in Rancher Desktop

I switched recently from Docker Desktop on my MacBook to Rancher Desktop . The most important reason for me to do it, was possibility to gently switch between docker and containerd runtimes.

There’s still one feature that I miss on Rancher Desktop - possibility to change Docker daemon configuration. I used to enable experimental features¹ and BuildKit². Sadly, there’s no easy way to do it on Rancher… But there’s a magical way³.

You have to enter to the running Rancher Desktop virtual machine. As machine is created during first run and usually not changed untile next upgrade, it’s good enough solution. Also if you reset the machine (to regain free space), the whole config is gone too.

Enter the Rancher

$ LIMA_HOME="$HOME/Library/Application Support/rancher-desktop/lima" "/Applications/Rancher Desktop.app/Contents/Resources/resources/darwin/lima/bin/limactl" shell 0

Then, you have to switch to root:

Provide the config

sudo su -
cat <<EOF > /etc/docker/daemon.json
{
  "features": {
    "buildkit" : true
  },
  "experimental": true
}
EOF

Now restart the Rancher Desktop (turn it off and on again) and voilà! Custom config loaded.