[systemd-devel] systemd-nspawn and shared private network

[Igor Bukanov]

Hello,

I am trying to see how to implement with systemd-nspawn a version of
docker's pod when a group of very lightweight containers use a
loopback interface or unix sockets to communicate with each other and
a shared network interface to communicate with the outside world.
Otherwise the containers are isolated and do not share process and
other namespaces.

My impression from the documentation is that I should create a version
of systemd-nspawn at .service that uses JoinsNamespaceOf to join the
namespace of the main service for the pod. That main service should
configures container networking, expose ports to host etc. For that I
plan to use systemd-nspawn --network-veth  ...

The problem I do not see how to pass the name of the main service
created with systemd-nspawn to that template. Obviously I can create
own unit for the main service that contains PrivateNetwork=true, but
then I cannot use --network-veth with nspawn as that configures the
namespace that nspawn creates, not the one from the unit.

Any suggestions?