OpenVPN container image

Minimal and secure Alpine Linux based Docker image with OpenVPN client.

Security

init

Tini is used by the container as an init process. It protects the system from process table being filled up, which can prevent the system from spawning any new processes, by reaping zombie processes.

In addtion to reaping zombies Tini also performs signal forwarding.

Firewall

Container uses iptables to configure packet filtering rules in the Linux kernel and therefore CAP_NET_ADMIN capability is required to run the container.

Outbound IPv4 network traffic is only allowed using the protocol, address(es) and port(s) defined in the OpenVPN configuration file. All outbound traffic that is routed through the VPN tunnel is allowed.

All IPv6 traffic is blocked.

Configuration

Host user mapping

Host user and group can be mapped to a container by defining HOST_UID and HOST_GID environment variables. If the variables are left undefined the container will execute its command with a random UID/GID combination.

SELinux

To use this container on a host that has SELinux enabled use the provided docker-openvpn.te policy module or create your own if it doesn't work. To compile and install the policy module run the following commands.

$ checkmodule -M -m docker-openvpn.te -o /tmp/docker-openvpn.mod
$ semodule_package -m /tmp/docker-openvpn.mod -o /tmp/docker-openvpn.pp
# semodule -i /tmp/docker-openvpn.pp

Logging

Container is compatible with docker logs command although logging is disabled by default if the container is started with docker-compose command. To find out more about logging see the command reference.

Debug log

To print out a trace of commands executed by container-entrypoint script, set DEBUG environment variable to any non-null value.

License

This project is licensed under the MIT License.