Docker generates an apparmor profile on the fly under /etc/apparmor.d/docker.
This profile gets overwritten on every docker daemon start.
This profile allows processes to ptrace themselves. This is required by
circus (python process manager) for reasons unknown to me. It floods the logs
with
audit[7623]: <audit-1400> apparmor="DENIED" operation="ptrace" profile="docker-default" pid=7623 comm="python3.4" requested_mask="trace" denied_mask="trace" peer="docker-default"
This is easily tested using:
docker run -it cloudron/base:0.3.3 /bin/bash
a) now do ps
b) journalctl should show error log as above
docker run --security-opt=apparmor:docker-cloudron-app -it cloudron/base:0.3.3 /bin/bash
a) now do ps
b) no error!
Note that despite this, the process may not have ability to ptrace since it does not
have CAP_PTRACE. Also, security-opt is the profile name (inside the apparmor config file)
and not the filename.
References:
https://groups.google.com/forum/#!topic/docker-user/xvxpaceTCywhttps://github.com/docker/docker/issues/7276https://bugs.launchpad.net/ubuntu/+source/docker.io/+bug/1320869
This is an infra update because we need to recreate containers to get the right profile.
Fixes#492
