docker-compose does not set CPU limit – Debian

I want to set a CPU limit on a container in a docker-compose file.

When I execute the following:

docker run -d --rm --cpus 0.3 --name aaa progrium/stress -c 8 -t 20s

The container is taking 30% of a core according to docker stats:

CONTAINER ID   NAME                                               CPU %     MEM USAGE / LIMIT     MEM %     NET I/O           BLOCK I/O         PIDS
d6be318a85e6   aaa                                                29.01%    1.328MiB / 3.805GiB   0.03%     806B / 0B         0B / 0B           9

And the limit is set according to docker inspect:

$ docker inspect aaa | grep -i cpu
            "CpuShares": 0,
            "NanoCpus": 300000000,
            "CpuPeriod": 0,
            "CpuQuota": 0,
            "CpuRealtimePeriod": 0,
            "CpuRealtimeRuntime": 0,
            "CpusetCpus": "",
            "CpusetMems": "",
            "CpuCount": 0,
            "CpuPercent": 0,

This is expected behavior. But when I write the following docker-compose.yml file:

version: '3'
services:
  aaa:
    image: progrium/stress
    command: -c 8 -t 20s
    deploy:
      resources:
        limits:
          memory: 100M
          cpus: '0.3'

And start the project with docker-compose up -d ; I got the following stats output:

CONTAINER ID   NAME                                               CPU %     MEM USAGE / LIMIT     MEM %     NET I/O           BLOCK I/O         PIDS
a94118f4a5f7   docker-aaa-1                                       87.74%    1.359MiB / 100MiB     1.36%     806B / 0B         1.91MB / 0B       9

And the limit is not set in the inspect output. I expected to see a CPU limit:

$ docker inspect docker-aaa-1 | grep -i cpu
            "CpuShares": 0,
            "NanoCpus": 0,
            "CpuPeriod": 0,
            "CpuQuota": 0,
            "CpuRealtimePeriod": 0,
            "CpuRealtimeRuntime": 0,
            "CpusetCpus": "",
            "CpusetMems": "",
            "CpuCount": 0,
            "CpuPercent": 0,

My conclusions are:

• My docker engine is able to set cpu limits
• The limits in the docker-compose.yml file are read (docker stats explicitly show memory limit
• docker-compose fails to set limit

I tried to set cpu limit the old way (as mentioned in the compose file documentation).

version: '2'
services:
  aaa:
    image: progrium/stress
    command: -c 8 -t 20s
    cpus: 0.3

The result is the same (no limit on CPU). And no error message from docker-compose.

CONTAINER ID   NAME                                               CPU %     MEM USAGE / LIMIT     MEM %     NET I/O           BLOCK I/O         PIDS
8658bc78c795   docker-aaa-1                                       180.75%   1.367MiB / 3.805GiB   0.04%     1.18kB / 0B       0B / 0B           9

How can I ask docker-compose to set the CPU limit? What documentation or configuration lines did I miss?

Thanks for your help!

Versions:

$ docker-compose -v
Docker Compose version v2.4.1
$ docker -v
Docker version 20.10.21, build baeda1f
$ uname -a
Linux hostname 5.10.0-18-amd64 #1 SMP Debian 5.10.140-1 (2022-09-02) x86_64 GNU/Linux
$ lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description:    Debian GNU/Linux 11 (bullseye)
Release:        11
Codename:       bullseye