systemd cgroup driver is unsupported

[ziggythehamster]

Some third-party work was started on this (aws/amazon-ecs-agent#1140), but never completed. I'm using CentOS 8 and would really rather use the systemd cgroup driver. I've also submitted an AWS support ticket for this feature request, but the support engineer requested I remove the ticket number.

[taylorb-syd]

In addition for support for the systemd cgroup driver, it would also be useful to be able to provide an alternative parent. Right now tasks in ECS cannot have a parent specified.

[ziggythehamster]

Docker 20.01 is out now, which defaults to the systemd cgroup driver. The ECS agent will require changing the default to cgroupfs in order to work on Docker 20.01.

[tianon]

It should be opportunistic based on whether the systemd driver is available/works: moby/moby#40846

(So if it isn't, it should automatically fall back appropriately and work just like 19.03)

[ziggythehamster]

I think that aws/amazon-ecs-agent#3161 getting merged makes this work now, because I am able to get ECS to work correctly with native.cgroupdriver set to systemd, and the ECS slice shows up as expected.