container_spec_memory_reservation_limit_bytes always Zero on cgroups_v2/docker_v25/al2023

[amcgilvray]

When using ECS with Docker v25 on Amazon Linux 2023, which uses cgroups v2, cadvisor is looking for the memory reservation in memory.min, but the location used by docker/ecs is memory.low.

Kubernetes seems to use both memory.low and memory.min according to this https://kubernetes.io/docs/concepts/configuration/manage-resources-containers/

It is specified on this line

cadvisor/container/common/helpers.go

Line 178 in 54dff2b

spec.Memory.Reservation = readUInt64(memoryRoot, "memory.min")

Exact versions I am using for testing:

Docker version 25.0.3, build 4debf41
Amazon Linux 2023.4.20240401
ecs-init-1.82.2-1.amzn2023.x86_64

Example:

$ pwd
/sys/fs/cgroup/ecstasks.slice/ecstasks-bf0cb7fdfabf43ecbe5ade8dedb8888d.slice/docker-5218493fe83a2248aa9a17d392433bce8f29182de06ff71dc62486cac7cafd5a.scope
$ cat memory.min
0
$ cat memory.low
201326592