Build linux (debian) root filesystems / vmdk / disks
On a 16.04 (ubuntu) system, ensure you have ruby installed (as well as rake)
Running rake -T will list out all the tasks you can run
akshay@host:~/diskbot$ rake -T
rake build:cache # Build debootstrap package cache (supports some env vars)
rake build:device:bios # Build a bootable BIOS device using the debootstrap rootfs
rake build:device:uefi # Build a bootable UEFI device using the debootstrap rootfs
rake build:iso # Build (live cd) ISO using the debootstrap rootfs
rake build:rootfs # Build basic rootfs using debootstrap (supports some env vars)
rake build:vmdk:bios # Build a bootable BIOS vmdk disk using the debootstrap rootfs
rake build:vmdk:uefi # Build a bootable UEFI vmdk disk using the debootstrap rootfs
rake clean:cache # Clean the debootstrap rootfs file
rake clean:disks # Clean all disk files
rake clean:iso # Clean the ISO file
rake clean:rootfs # Clean the debootstrap rootfs file
rake clean:vmdk_bios # Clean the BIOS disk file
rake clean:vmdk_uefi # Clean the UEFI disk file
rake prereqs:check # Check if prerequisite software is present
The build set of tasks build stuff. Subtasks under here can build one of:
- rootfs
- vmdk (uefi or bios boot)
- disks (block device) (uefi or bios boot)
The clean set of tasks cleans up the corresponding build artifacts.
The prereqs:check tasks runs a check for all the necessary software/tools that
are needed for all the tasks to succeed.
Most of the build tasks will need sudo permission. Most will run sudo date
once in the beginning to force the password prompt once, and then rely on the
fact that sudo won't prompt you for your password for subsequent invocations
till a given timeout.
Assuming the prereqs:check task has found all the tools to be present, lets
go ahead and build the rootfs. By default it will build a ubuntu rootfs for
the xenial distribution. You can change that by modifying the Rakefile (use
the @distro variable to control what gets built - debian or ubuntu).
akshay@host:~/diskbot$ rake build:rootfs \
CUSTOMIZE_PKGS=customize/<additional_pkgs_file> \
OVERLAY_ROOTFS=<optional_overlay_dir> \
CUSTOMIZE_SCRIPT=customize/modify_rootfs.sh
The above invocation will begin the build of a rootfs. The additional args are optional and can be used to control the following:
- CUSTOMIZE_PKGS - this file (newline sep, csv or json) contains additional packages you want included in the rootfs.
- OVERLAY_ROOTFS - this dir is copied into the rootfs after it is prepared, but before the customize_script is run.
- CUSTOMIZE_SCRIPT - script that is executed in the rootfs to modify it before it is saved. Use this to create additional dirs/users/files etc. You can also modify the permissions and ownership of dirs copied from the overlay_dir here.
Et viola, the rootfs should be ready at the end of this. You can use this as a baseimage for docker containers, or to boot on physical/virtual hardware.
If you'd like to create a virtual disk using this rootfs, use the build:vmdk
tasks to create the virtual media that can be used with virtualbox. There are
two flavors of disks you can build - UEFI and BIOS, depending on the type of
virtual hardware you wish to run.
If you'd like create a bootable physical disk using, use the build:device
target(s) and specify a dev env var (e.g. dev=/dev/loop0 or dev=/dev/sdb).
When creating bootable media (physical or virtual, using dev or vmdk) you
can specify the partition layout for how you'd like the disk to be parted
using the PARTITION_LAYOUT env var. The file specified via this env var is
expected to be a JSON file describing the partition layout as an Array of json
objects. For example, run:
akshay@host:~diskbot$ rake build:vmdk:bios \
PARTITION_LAYOUT=customize/PART_LAYOUT_flat.json
Some PARTITION_LAYOUT examples are provided in the customize dir for you to
get started. Note that the layout must always contain at least one partition
marked as "os": true. You can also specify that LVM be used (see the sample
layout file named accordingly).