Tailscale (in a container, host wide)

Official site

Inspiration

version: "3.3"
services:
  tailscale:
    container_name: tailscale
    hostname: yourhostname
    network_mode: "host"   # mandatory if you want it system wide
    image: tailscale/tailscale:stable
    volumes:
      - ./Tailscale:/var/lib # State data will be stored in this directory
      - /dev/net/tun:/dev/net/tun # Required for tailscale to work
    cap_add: # Required for tailscale to work
      - net_admin
      - sys_module
    command: tailscaled
    privileged: true
    restart: unless-stopped

Then to login, shell into the container, or enter the container's console in Portainer, and type 

tailscale up

You'll get a link. Follow the link to add the machine to your Tailscale account.