Document bridge interfaces on-device

[chrisys]

Copied from: https://github.com/balena-os/meta-balena/issues/1578

eth0 / wlan0 resin-dns resin-vpn balena0 supervisor0 br-xxxxxxxxx

Documentation would cover:

how interface is created (links to source if possible) what services use the interface for what purposes

User also asks for documentation around the IP ranges used internally in order to avoid conflicts, e.g. in the case that the address range 172.18.0.0/16 as used internally is also used externally on the LAN. https://jel.ly.fish/inbox/2680eacb-60fb-4406-b1ec-cd7b0521e67e

[jellyfish-bot]

[chrisys] This issue has attached support thread https://jel.ly.fish/2680eacb-60fb-4406-b1ec-cd7b0521e67e

[JaccovdS]

@chrisys is there already some documentation on this topic?

[chrisys]

I don't think any progress has been made on this one, @vipulgupta2048 may know more.

[vipulgupta2048]

Not any that I know off @chrisys

[pdcastro]

Compiled from a couple of sources (restricted access: FD, JF)

• resin-dns - A bridge network interface used to provide DNS resolution to service containers. It is created by balenaOS in the balena-net-config script with a hardcoded IP address/subnet of 10.114.102.1/24.
• balena0 (renamed from docker0) - A bridge network interface used for connecting the virtual Ethernet interfaces of service containers to the host networking namespace. It is created by balenaEngine (balena's IoT-optimized derivative of Moby/Docker). Its IP address and subnet are configured with --bip=10.114.101.1/24 --fixed-cidr=10.114.101.0/25 when the balenaEngine service starts.
• supervisor0 - A bridge network interface with the same purpose as balena0, but used only by the balena_supervisor container. It is created by the balenaSupervisor (the on-device manager of service containers) with IP address/subnet 10.114.104.0/25 in network-manager.ts.

[jellyfish-bot]

[maggie0002] This has attached https://jel.ly.fish/969f5482-5d5b-4c82-b44b-0717df248ee5