AppArmor is a Linux kernel security module that provides mandatory access control (MAC) by enforcing per-application security profiles. These profiles strictly define what files, system resources, and operations a given program—including container runtimes like Docker—can access or perform.
Why this prevents containers from being shut down
AppArmor operates using security profiles that describe permitted actions for specific processes. If a Docker container or daemon attempts an operation not allowed by its profile—such as sending certain signals to stop or kill a container—the action is denied by the kernel, resulting in a “permission denied” error.
The issue most commonly arises when a container tries to execute system-level operations that the AppArmor profile for Docker does not explicitly permit, such as signaling, accessing files outside allowed paths, or modifying critical system resources. Hence, if a container tries to execute system-wide commands, it probably bugs out and cannot be stopped while being blocked by AppArmor.
This command removes all unknown entries from AppArmor
sudo aa-remove-unknownThe alternative option would be to stop AppArmor entirely and restart the container with the risk of unpermitted stuff happening. If nothing else works, it helps to restart the PC
sudo systemctl stop apparmor
docker rm -f synchronize-tenant-data
sudo systemctl start apparmor