---
description: Enabling AppArmor in Docker
keywords: AppArmor, security, docker, documentation
title: AppArmor security profiles for Docker
---
AppArmor (Application Armor) is a Linux security module that protects an
operating system and its applications from security threats. To use it, a system
administrator associates an AppArmor security profile with each program. Docker
expects to find an AppArmor policy loaded and enforced.
Docker automatically generates and loads a default profile for containers named
`docker-default`. The Docker binary generates this profile in `tmpfs` and then
loads it into the kernel.
> [!NOTE]
>
> This profile is used on containers, not on the Docker daemon.
A profile for the Docker Engine daemon exists but it is not currently installed
with the `deb` packages. If you are interested in the source for the daemon
profile, it is located in
[contrib/apparmor](https://github.com/moby/moby/tree/master/contrib/apparmor)
in the Docker Engine source repository.
## Understand the policies
The `docker-default` profile is the default for running containers. It is
moderately protective while providing wide application compatibility. The
profile is generated from the following
[template](https://github.com/moby/moby/blob/master/profiles/apparmor/template.go).
When you run a container, it uses the `docker-default` policy unless you
override it with the `security-opt` option. For example, the following
explicitly specifies the default policy:
```console
$ docker run --rm -it --security-opt apparmor=docker-default hello-world
```
## Load and unload profiles
To load a new profile into AppArmor for use with containers:
```console
$ apparmor_parser -r -W /path/to/your_profile
```
Then, run the custom profile with `--security-opt`:
```console
$ docker run --rm -it --security-opt apparmor=your_profile hello-world
```
To unload a profile from AppArmor:
```console
# unload the profile
$ apparmor_parser -R /path/to/profile
```
### Resources for writing profiles
The syntax for file globbing in AppArmor is a bit different than some other
globbing implementations. It is highly suggested you take a look at some of the
below resources with regard to AppArmor profile syntax.
- [Quick Profile Language](https://gitlab.com/apparmor/apparmor/wikis/QuickProfileLanguage)
- [Globbing Syntax](https://gitlab.com/apparmor/apparmor/wikis/AppArmor_Core_Policy_Reference#AppArmor_globbing_syntax)
## Nginx example profile
In this example, you create a custom AppArmor profile for Nginx. Below is the
custom profile.
```c
#include <tunables/global>
profile docker-nginx flags=(attach_disconnected,mediate_deleted) {
#include <abstractions/base>
network inet tcp,
network inet udp,
network inet icmp,
deny network raw,
deny network packet,
file,
umount,
deny /bin/** wl,
deny /boot/** wl,
deny /dev/** wl,
deny /etc/** wl,
deny /home/** wl,
deny /lib/** wl,
deny /lib64/** wl,
deny /media/** wl,
deny /mnt/** wl,
deny /opt/** wl,
deny /proc/** wl,
deny /root/** wl,
deny /sbin/** wl,
deny /srv/** wl,
deny /tmp/** wl,
deny /sys/** wl,
deny /usr/** wl,
audit /** w,
/var/run/nginx.pid w,
/usr/sbin/nginx ix,
deny /bin/dash mrwklx,
deny /bin/sh mrwklx,
deny /usr/bin/top mrwklx,
capability chown,
capability dac_override,
capability setuid,
capability setgid,
capability net_bind_service,
deny @{PROC}/* w, # deny write for all files directly in /proc (not in a subdir)
# deny write to files not in /proc/<number>/** or /proc/sys/**
deny @{PROC}/{[^1-9],[^1-9][^0-9],[^1-9s][^0-9y][^0-9s],[^1-9][^0-9][^0-9][^0-9]*}/** w,
deny @{PROC}/sys/[^k]** w, # deny /proc/sys except /proc/sys/k* (effectively /proc/sys/kernel)
deny @{PROC}/sys/kernel/{?,??,[^s][^h][^m]**} w, # deny everything except shm* in /proc/sys/kernel/
deny @{PROC}/sysrq-trigger rwklx,
deny @{PROC}/mem rwklx,
deny @{PROC}/kmem rwklx,
deny @{PROC}/kcore rwklx,
deny mount,
deny /sys/[^f]*/** wklx,
deny /sys/f[^s]*/** wklx,
deny /sys/fs/[^c]*/** wklx,
deny /sys/fs/c[^g]*/** wklx,
deny /sys/fs/cg[^r]*/** wklx,
deny /sys/firmware/** rwklx,
deny /sys/kernel/security/** rwklx,
}
```
1. Save the custom profile to disk in the
`/etc/apparmor.d/containers/docker-nginx` file.
The file path in this example is not a requirement. In production, you could
use another.
2. Load the profile.
```console
$ sudo apparmor_parser -r -W /etc/apparmor.d/containers/docker-nginx
```
3. Run a container with the profile.
To run nginx in detached mode:
```console
$ docker run --security-opt "apparmor=docker-nginx" \
-p 80:80 -d --name apparmor-nginx nginx
```
4. Exec into the running container.
```console
$ docker container exec -it apparmor-nginx bash
```
5. Try some operations to test the profile.
```console
root@6da5a2a930b9:~# ping 8.8.8.8
ping: Lacking privilege for raw socket.
root@6da5a2a930b9:/# top
bash: /usr/bin/top: Permission denied
root@6da5a2a930b9:~# touch ~/thing
touch: cannot touch 'thing': Permission denied
root@6da5a2a930b9:/# sh
bash: /bin/sh: Permission denied
root@6da5a2a930b9:/# dash
bash: /bin/dash: Permission denied
```
You just deployed a container secured with a custom apparmor profile.
## Debug AppArmor
You can use `dmesg` to debug problems and `aa-status` check the loaded profiles.
### Use dmesg
Here are some helpful tips for debugging any problems you might be facing with
regard to AppArmor.
AppArmor sends quite verbose messaging to `dmesg`. Usually an AppArmor line
looks like the following:
```text
[ 5442.864673] audit: type=1400 audit(1453830992.845:37): apparmor="ALLOWED" operation="open" profile="/usr/bin/docker" name="/home/jessie/docker/man/man1/docker-attach.1" pid=10923 comm="docker" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0
```
In the above example, you can see `profile=/usr/bin/docker`. This means the
user has the `docker-engine` (Docker Engine daemon) profile loaded.
Look at another log line:
```text
[ 3256.689120] type=1400 audit(1405454041.341:73): apparmor="DENIED" operation="ptrace" profile="docker-default" pid=17651 comm="docker" requested_mask="receive" denied_mask="receive"
```
This time the profile is `docker-default`, which is run on containers by
default unless in `privileged` mode. This line shows that apparmor has denied
`ptrace` in the container. This is exactly as expected.
### Use aa-status
If you need to check which profiles are loaded, you can use `aa-status`. The
output looks like:
```console
$ sudo aa-status
apparmor module is loaded.
14 profiles are loaded.
1 profiles are in enforce mode.
docker-default
13 profiles are in complain mode.
/usr/bin/docker
/usr/bin/docker///bin/cat
/usr/bin/docker///bin/ps
/usr/bin/docker///sbin/apparmor_parser
/usr/bin/docker///sbin/auplink
/usr/bin/docker///sbin/blkid
/usr/bin/docker///sbin/iptables
/usr/bin/docker///sbin/mke2fs
/usr/bin/docker///sbin/modprobe
/usr/bin/docker///sbin/tune2fs
/usr/bin/docker///sbin/xtables-multi
/usr/bin/docker///sbin/zfs
/usr/bin/docker///usr/bin/xz
38 processes have profiles defined.
37 processes are in enforce mode.
docker-default (6044)
...
docker-default (31899)
1 processes are in complain mode.
/usr/bin/docker (29756)
0 processes are unconfined but have a profile defined.
```
The above output shows that the `docker-default` profile running on various
container PIDs is in `enforce` mode. This means AppArmor is actively blocking
and auditing in `dmesg` anything outside the bounds of the `docker-default`
profile.
The output above also shows the `/usr/bin/docker` (Docker Engine daemon) profile
is running in `complain` mode. This means AppArmor only logs to `dmesg`
activity outside the bounds of the profile. (Except in the case of Ubuntu
Trusty, where some interesting behaviors are enforced.)
## Contribute to Docker's AppArmor code
Advanced users and package managers can find a profile for `/usr/bin/docker`
(Docker Engine daemon) underneath
[contrib/apparmor](https://github.com/moby/moby/tree/master/contrib/apparmor)
in the Docker Engine source repository.
The `docker-default` profile for containers lives in
[profiles/apparmor](https://github.com/moby/moby/tree/master/profiles/apparmor).