fullofentropy / docker-pxe

A virtualized implementation of PXE supported by DNSMasq

Dockerized PXE

A Docker image serving as a standalone PXE (running Dnsmasq). This server can be placed in an existing network infrastructure with an already configured DHCP server or in a network without any DHCP server.

This PXE currently serves:

• MemTest86+

Dependencies

These are the dependencies required to build and run the box:

• Docker 1.12+

How to run

The ENTRYPOINT of this image is set to run dnsmasq in no-daemon mode. Add your desired dhcp-ranges as command line options (see dnsmasq documentation for details). Note that you can specify more than one range by adding multiple dhcp-range options.

The easiest way to use instances of this image to provide a PXE in an existing network is to run a container based on it with the --net=host option.

To sum up: docker run -it --rm --net=host ferrarimarco/pxe

If you want to inspect the container just run it overwriting the entrypoint: --entrypoint=/bin/sh

Integrated DHCP server

If you want to enable the integrated DHCP server for a given IP address range add a dhcp-range option: dhcp-range=x.x.x.x,y.y.y.y,z.z.z.z where x.x.x.x is the start of the range, y.y.y.y is the end and z.z.z.z is the subnet mask.

Standalone DHCP server

If you want to use an existing DHCP server and let dnsmasq handle only the PXE, add a dhcp-range option: dhcp-range=x.x.x.x,proxy where x.x.x.x is the IP address of the server running dnsmasq.

How to modify the configuration

All the configuration files can be modified at will. Just look at the Dockerfile to see where they are (mainly in /etc and /var/lib/tftpboot) and overwrite them with your own (mounting volumes from the Docker host or rebuilding the image).

Additional PXE Boot Menu Entries

If you just want to add additional menu entries to the boot menu, just overwrite the contents of /var/lib/tftpboot/pxelinux.cfg/additional_menu_entries file. The syntax for this file is described in the syslinux documentation.

Example: 2nd Memtest86+ plus Ubuntu 16.04 Boot Options

Here is an additional_menu_entries file to include (along with the default Memtest86+) two additional boot options: a customized Memtest86+ and Ubuntu 16.04.

LABEL memtest86-2
  MENU LABEL Memtest86+ 2nd entry
  KERNEL /memtest/memtest86+
LABEL ubuntu-16-04-amd64
  MENU LABEL Ubuntu 16.04 amd64
  KERNEL /ubuntu/16.04/16.04.2-server-amd64/install/netboot/ubuntu-installer/amd64/linux
  APPEND /install/vmlinuz auto=true interface=eth0 hostname=cluster domain=home url=tftp://<pxe-container-ip>/preseed/16.04/preseed.cfg initrd=ubuntu/16.04/16.04.2-server-amd64/install/netboot/ubuntu-installer/amd64/initrd.gz debian-installer=en_US locale=en_US kbd-chooser/method=us keyboard-configuration/modelcode=SKIP keyboard-configuration/layout=USA keyboard-configuration/variant=USA console-setup/ask_detect=false --

Testing and validating the setup

Dependencies

1. Virtualbox 5.1.16+
2. Vagrant 1.9.3+

How to run

After running the container with a suitable DHCP configuration (see above for instructions) and the --net=host option, you can run vagrant up from the root of the project. A Virtualbox VM (with a NATed network adapter) will boot from the given PXE.

Note that you should check the IP address ranged configured by the Virtualbox DHCP server (if enabled) and configure your dhcp-range and /var/lib/tftpboot/pxelinux.cfg/default accordingly.

Example

Virtualbox runs a DHCP server by default in each virtual network. If you want to test the PXE feature you have to run a container based on this image with DNSMasq as a DHCP proxy (see Standalone Mode) and with the host network stack (see the --net=host option) so you know in advance the IP address of the container running DNSMasq: it's the same as the Docker host!

If Virtualbox DHCP server assigns addresses in the 192.168.56.0/24 subnet (check the virtual network configuration of the Host-only network assigned to a VM to know this), then the dhcp-range could be: dhcp-range=192.168.56.2,proxy, where 192.168.56.2 is the address assigned to the Docker host running the container based on this image in "host network" mode. Remember to also update any IP address in /var/lib/tftpboot/pxelinux.cfg/default you may have configured, if you serve any content from the TFTP server (like a preseed.cfg for example) to point to the IP address of the container running this PXE. For this reason it could be useful to manually assign (or reserve) IP addresses (or better, hostnames!) for containers running this PXE.

Contributions

If you have suggestions, please create a new GitHub issue or a pull request.