With the "Preserve user defined networks" disabled, my custom network was retained after docker restart or server restart. The help message for the setting states the followings:

Quote

 

User created networks are networks created by the user outside of the GUI. By default user created networks are removed from Docker. This is done to prevent potential conflicts with the automatic generation of custom networks.

Change this setting to preserve user defined networks, but it is the responsibility of the user to ensure these entries work correctly and are conflict free.

 

 

Did my custom network survive after Docker/Server restart because there are containers that are referencing the custom network?

 

The "Preserve user defined networks" option in Unraid is designed to ensure that any networks you've configured manually (outside of Unraid's default network setup) are retained across reboots and system updates. This feature is particularly useful if you've set up custom Docker networks or complex network configurations that you need to persist without having to redefine them after each system update or restart.

 

What It Affects

Docker Networks: If you use Docker on Unraid and have created custom networks via Docker CLI or Docker Compose, this setting ensures those networks aren't wiped or reset when you reboot or upgrade Unraid.

Other Custom Network Configurations: Any other network configurations that are not part of the standard Unraid network management but are defined at the system level can also be preserved with this setting.

The theres more on template editing and authing for those programming docker temples to the community.

Example:
if you have a template acquired, download, made, etc and shared that template. But the template is set to use bond0 but your default network settings and config uses br0 this will keep and maintain the templates docker network settings.

*Sometime useful in testing maintain or checking networking related things with docker. its fine to have it enabled, it doesn't hurt anything. More noticeable when moving docker network around when a buch a network are deployed on a different docker network.

But Mainly in adding other networks to survive a reboot.
*This also give use the ability to make docker networks and use docker networks made outside unraids default configurations.

So I want to make a docker bridge network or another macvlan network or add ipvaln network to seperate some docker services... this option should be enabled.

Edited December 9, 20241 yr by bmartino1
data - typo