You can run Zerotier in a container on CHR.
I've had success with this one:
https://github.com/zyclonite/zerotier-docker
Instead of using a seperate subnet for the veth interface needed for Docker I just added the veth interface to the existing bridge.
Probably not good practice but it works! Change IP, Bridge names, interface name and disk to suit:
/interface/veth/add name=veth1 address=10.13.0.2/24 gateway=10.13.0.1
/interface/bridge/port add bridge=bridge1 interface=veth1
/container/envs/add key=net name=zt value=host
/container/envs/add key=cap-add name=zt value=NET_ADMIN
/container/envs/add key=device name=zt value=/dev/net/tun
/container/config/set registry-url=https://registry-1.docker.io tmpdir=disk1/pull
/container/add remote-image=zyclonite/zerotier:latest interface=veth1 root-dir=disk1/zerotier envlist=zt
Then shell into your container and join your Zerotier Network.
You can use the IP address of the Zerotier network as a gateway to the networks attached or accessible to your CHR.
