Is it possible to use environment variables inside docker daemon configuration file

background:

We are using registry_mirrors & insecure_registries options in docker daemon.json file. We would like to stop setting the location of the mirrors hard-coded.

Question

Is it possible to use env variable inside daemon.json? So instead of writing ip X.Y.Z.W:PORT one would write ${REPO1}. Hopefully it will be possible to change REPO1 var without restarting the daemon

Remarks

The solution must allow to change the repo location without restarting the daemon

EDIT

it is not possible to use the following inside daemon.json
1. ${VAR_NAME}

Possible workaround

Use custom hostname and redefine it in /etc/hosts. This allows to change repo ip without restarting the daemon. But it does not allow to change the port or the protocol

Possible workaround 2

Some options can be reconfigured when the daemon is running without requiring to restart the process. We use the SIGHUP signal in Linux to reload, and a global event in Windows with the key Globaldocker-daemon-config-$PID. The options can be modified in the configuration file but still will check for conflicts with the provided flags. The daemon fails to reconfigure itself if there are conflicts, but it won’t stop executionsource

So one can edit the registry and do sudo systemctl reload docker or sudo kill -SIGHUP $(pidof dockerd). This does not restart the existing containers nor the daemon itself

Source: StackOverflow