Container is pausing with no apparent reason

[fspegni]

Hi,

I'm experimenting with your container (thanks for the nice job). I've some problem to understand why the following docker-compose configuration starts a container that is paused after a few seconds:

...
  rsync:
    image: eeacms/rsync
    command: [ "client" ]
...

This is what I get filtering the output of docker ps command:

$ user@host:~/git/project$ docker ps | grep rsync
a5af0b17883a        eeacms/rsync             "/docker-entrypoint.…"   20 seconds ago      Up 18 seconds                                                     project_rsync_1
...
$ user@host:~/git/project$ docker ps | grep rsync
a5af0b17883a        eeacms/rsync             "/docker-entrypoint.…"   41 seconds ago      Up 40 seconds (Paused)                                                 project_rsync_1

You can see that while the container project_rsync_1 is created just fine, but it goes to a (Paused) state without me doing nothing. By checking the container log I can only see the usual SSH key output:

user@host:~/git/project$ docker logs project_rsync_1 
ssh-keygen: generating new host keys: RSA DSA ECDSA ED25519 
Please add this ssh key to your server /home/user/.ssh/authorized_keys        
================================================================================
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABgQDRmI7wc61m4gaDnaJQVq2TfS2Rj/avt0Oxw1ZRmvDYkzVXmkBJIUt0aycLcqJSrcu9oaVg0m/t5oFwTxX7rGCl1JObhCiibSn8FI+X30VZRxPmMt4fKybGgFAcTSY9C1TsIny9+jbLo+lO24dUWP05wlD6UPFxWhUyFxLIXbk8HT03Z+GI/1gLZ7cjS3jhYtrCxP5MO6T//jRksRj0qYyGtGWt84fRptFCMd9/HFVa09m95N9ASteHTLAz+t8TKaxqrt0otpsTPAAbMFHy/lmIIW9QCjvRfE56nVYvwd9vak6sR6GLhLdW62vVr3EF/qQP64cmgvygnOWqCQH4asajb9i2e3Jxn1xJ91O5ZbX8UMLplnFArIh//lPRClR7zRMvGNzKo/f6BwsEUE5Of4vGH6Xkwj9bk0FCQp8IbQAydSRaPNxuBeEczXtBi9GdWZYAsONJW1Oie5x5kXWPW5jZI6ZU+fe45kieVCjDeES8n4wMG8nm6lRSErfw8UY5KzU= root@a5af0b17883a
================================================================================

If I (manually) unpause the container and check the running processes within the container, I can see the following:

$ docker-compose exec rsync ash
... (enter the container) ...
Mem: 14428704K used, 1373116K free, 936804K shrd, 952276K buff, 5104148K cached
CPU:   2% usr   4% sys   0% nic  91% idle   0% io   0% irq   1% sirq
Load average: 1.20 1.36 1.43 2/1716 20
  PID  PPID USER     STAT   VSZ %VSZ CPU %CPU COMMAND
   15     0 root     S     1624   0%   1   0% ash
   20    15 root     R     1560   0%   3   0% top
    1     0 root     S     1552   0%   4   0% /usr/sbin/crond -f

The container crontab -l is actually empty, because I did not set the variable CRON_TASK_1, but the same problem happens if I set such variable.

Is it a problem or is it supposed to work that way? Do I miss something obvious?

Thanks