I have a bridge device set up with systemd, br0, that replaces my primary ethernet eth0. With the br0 bridge device, Incus is able to create containers/VMs that have unique MAC addresses that are then assigned IP addresses by my DHCP server. (sudo incus profile device add <profileName> eth0 nic nictype=bridged parent=br0) Additionally, the containers/VMs can directly contact the host, unlike with MACVLAN.

With Docker, I can’t see a way to get the same feature-set with their options. I have MACVLAN working, but it is even shoddier than the Incus implementation as it can’t do DHCP without a poorly-maintained plugin. And the host cannot contact the container due to the MACVLAN method (precludes running a container like a DNS server that the host server would want to rely on).

Is there a way I’ve missed with the bridge driver to specify a specific parent device? Can I make another bridge device off of br0 and bind to that one host-like? Searching really fell apart when I got to this point.

Also, if someone knows how to match Incus’ networking capability with Podman, I would love to hear that. I’m eyeing trying to move to Podman Quadlets (with Debian 13) after I’ve got myself well-versed with Docker (and its vast support infrastructure to learn from).

Hoping someone has solved this and wants to share their powers. I can always put a Docker/podman inside of an Incus container, but I’d like to avoid onioning if possible.

  • glizzyguzzler@lemmy.blahaj.zoneOPEnglish
    0·
    3 days ago

    Thanks for taking the time to reply!

    The host setup has eth0 as the physical interface to the rest of the network, with br0 replacing it completely. br0 has the same MAC as the eth0 interface and eth0 just forwards to br0 which then does the bridging internally. br0 being a bridge means that incus is able to split it off without MACVLAN but rather its nic device in bridge mode which “Uses an existing bridge on the host (br0) and creates a virtual device pair to connect the host bridge to the instance.” That results in a network interface that has its own MAC and is assigned a local IP by the DHCP server on the network while also being able to talk to the host.

    Incus accomplishes the same goal as Proxmox (Proxmox has similar bridge network devices for its containers/VMs) just without Incus needing to be your OS/distro like Proxmox does, it’s just a package.

    As for the Docker, the parent interface is br0 which has supplanted eth0. MACVLAN is working as it is intended to in Docker, as far as I can tell. The container has a networking device with its own MAC address, and after supplying the MACVLAN network device with my network’s subnet and gateway and static IP address in the Docker compose file it works as expected. If I don’t supply a static IP in the Docker compose file, Docker just assigns it the first IP in the given subnet - no DHCP interaction. This docker-net-dhcp plugin (I linked to the issue about it not working on the latest version of Docker anymore) was made to give Docker network devices the ability to use DHCP to get an IP address, but it’s clearly not something to rely on.

    If I’m missing something about MACVLAN that makes DHCP work for Docker, let me know! Hardcoding an IP into a docker-compose file adds an extra step to remember compared to everything else being configured on the centralized DHCP server - hence the shoddy implementation claim for Docker.

    Thanks for the link to using another MACVLAN and routing around the host<-/->container connection issue inherent to MACVLAN. I’ll keep it in mind as an alternate to Incus container around another container! I do wish there could be something like Incus’ hassle-free solution for Docker or Podman.

    • MangoPenguin@lemmy.blahaj.zoneEnglish
      0·
      3 days ago

      What about using the default docker bridge networking instead of macvlan? You can access docker containers from the host, they can talk to each other if on the same bridge network, and there’s nothing hardcoded into the docker compose files.

      • glizzyguzzler@lemmy.blahaj.zoneOPEnglish
        0·
        3 days ago

        With the default Docker bridge networking the container won’t have a unique IP/MAC address on the local network, as far as I am aware. Communication with external clients will have to contact the host server’s IP at the port the container is tied to in order to interact. If there’s a way to specify a specific parent interface, let me know!