Boom is a boot manager for Linux systems using boot loaders that support the BootLoader Specification for boot entry configuration. It is based on the boot manager design discussed in the Boot-to-snapshot design v0.6 document.
Boom requires a BLS compatible boot loader to function: either the
systemd-boot project, or Grub2 with the bls patch (Red Hat
Grub2 builds include this support in both Red Hat Enterprise Linux 7
and Fedora).
Boom allows for flexible boot configuration and simplifies the creation of new or modified boot entries: for example to boot snapshot images of the system created using LVM2 or BTRFS.
Boom does not modify the existing boot loader configuration (other than to insert the additional entries managed by boom - see Grub2 Integration): the existing boot configuration is maintained and any distribution integration (e.g. kernel installation and update scripts) will continue to function as before.
- Boom
Boom aims to be a simple and extensible, and to be able to create boot configurations for a wide range of Linux system configurations and boot parameters.
This project is hosted at:
For the latest version, to contribute, and for more information, please visit the project pages or join the mailing list.
To clone the current master (development) branch run:
git clone git://github.com/bmr-cymru/boom.git
Please report bugs via the mailing list or by opening an issue in the GitHub Issue Tracker
The dm-devel is the mailing list for any boom-related questions and discussion. Patch submissions and reviews are welcome too.
A setuptools based build script is provided: local installations and
package builds can be performed by running python setup.py and a
setup command. See python setup.py --help for detailed information on
the available options and commands.
Binary packages for Fedora and Red Hat Enterprise Linux are available from the copr repository. These builds use the RPM spec file distributed in the git repository and include all the necessary library modules, binaries, and configuration files needed to install and use boom.
To enable the repository on Fedora, run:
# dnf copr enable bmr/boom
The python2 and python3 versions of boom may be installed by running:
# dnf -y install python2-boom python3-boom
Note that although both python 2 and 3 versions of the library are
provided only one package contains the boom binary, depending on
the system default python runtime for that distribution version.
The boom command is the main interface to the boom boot manager.
It is able to create, delete, edit and display boot entries and
operating system profiles and provides reports showing the available
profiles and entries, and their configurations.
All boom commands operate on either an OsProfile or a BootEntry:
# boom profile <command> <options> # `OsProfile` command
# boom [entry] <command> <options> # `BootEntry` command
If no command type is given entry is assumed.
The two main object types in boom are the OsProfile and BootEntry.
Boom stores boot loader entries (BootEntry) in the system BLS loader
directory - normally /boot/loader/entries.
Boom OsProfile files are stored in the boom configuration directory,
/boot/boom/profiles.
The location of the boot file system may be overridden using the
--boot-dir command line option and the location of both the boot
file system and boom configuration directory may be overridden by
calling the boom.set_boot_path() and boom.set_boom_path()
functions.
These options are primarily of use for testing, or for working with boom data from a system other than the running host.
Boom configuration data is stored in the /boot file system to permit
the tool to be run from any booted instance of any installed operating
system.
An OsProfile stores identity information and templates used to write
bootloader configurations for an instance of an operating system. The
identity is based on values from the /etc/os-release file, and the
available templates allow customisation of the kernel and initramfs
images, kernel options and other properties required to boot an instance
of that OS.
A set of OsProfile files can be pre-installed with boom, or generated
using the command line tool.
An OsProfile is uniquely identified by its OS Identifier, or
os_id, a SHA2 hash computed on the OsProfile identity fields.
All SHA identifiers are displayed by default using the minimum width
necessary to ensure uniqueness: all command line arguments accepting
an identifier also accept any unique prefix of a valid identifier.
The template properties of an OsProfile (kernel pattern, initramfs
pattern, LVM2 and BTRFS root options and kernel command line options)
may include format strings that are expanded when creating a new
BootEntry.
The available keys are:
%{version}- the kernel version%{lvm_root_lv}- the LVM2 logical volume containing the root file system invg/lvnotation.%{btrfs_subvol_id}- the BTRFS subvolume identifier to use.%{btrfs_subvol_path}- the BTRFS subvolume path to use.%{root_device}- The system root device, relative to/.%{options}- Kernel command line options, including the root device specification and options.
Default template values are supplied when creating a new OsProfile;
these can be overridden by specifying alternate values on the command
line. The defaults are suitable for most Linux operating systems but
can be customised to allow for particular OS requirements, or to set
custom behaviours.
A BootEntry is an individual bootloader entry for one instance of an
operating system. It includes all the parameters required for the
boot loader to load the OS, and for the kernel and user space to
boot the environment (including configuration of LVM2 logical volumes
and BTRFS subvolumes).
The BootEntry stored on-disk is generated from the templates stored
in an associated OsProfile and boot parameters configuration provided
by command line arguments.
Boom uses BLS0 notation as the canonical format for the boot entry store.
An BootEntry is uniquely identified by its Boot Identifier, or
boot_id, a SHA2 hash computed on the BootEntry boot parameter
fields (note that this means that changing the parameters of an
existing BootEntry will also change its boot_id. All SHA
identifiers are displayed by default using the minimum width
necessary to ensure uniqueness: all command line arguments
accepting an identifier also accept any unique prefix of a valid
identifier.
For each type, boom provides six subcommands:
createdelete --profile OS_ID | --boot-id BOOT_ID [...]clone --profile OS_ID | --boot-id BOOT_ID [...]showlistedit
Create a new OsProfile or BootEntry using the values entered on
the command line.
Delete the specified OsProfile or BootEntry.
Create a new OsProfile or BootEntry by cloning an existing object
and modifying its properties. A boot_id or os_id must be used
to select the object to clone. Any remaining command line options
modify the newly created object.
Display the specified objects in human readable format.
List objects matching selection criteria as a tabular report.
Modify an existing OsProfile or BootEntry by changing one or
more of its attributes.
It is not possible to change the name, short name, version, or
version identifier of an OsProfile using this command, since these
fields form the OsProfile identifier: to modify one of these
fields use the clone command to create a new profile specifying
the attribute to be changed.
When editing a BootEntry, the boot_id will change: this is
because the options that define an entry form the entry's identity.
The new boot_id is written to the terminal on success.
The boom entry list and boom profile list commands generate a
tabular report as output. To control the list of displayed fields
use the -o/--options FIELDS argument:
boom list -oboot_id,version
BootId Version
fb3286f 3.10-1.el7.fc24.x86_64
1031ab0 3.10-23.el7
a559d3a 2.6.32-232.el6
a559d3a 2.6.32-232.el6
2c89556 2.2.2-2.fc24.x86_64
e79db6a 1.1.1-1.fc24.x86_64
d85f2c3 3.10.1-1.el7
2fc3f4f 4.1.1-100.fc24
d85f2c3 3.10.1-1.el7
To add extra fields to the default selection, prefix the field list
with the + character:
boom list -o+kernel,initramfs
BootID Version OsID Name OsVersion Kernel Initramfs
fb3286f 3.10-1.el7.fc24.x86_64 3fc389b Red Hat Enterprise Linux Server 7.2 (Maipo) /boot/vmlinuz-3.10-1.el7.fc24.x86_64 /boot/initramfs-3.10-1.el7.fc24.x86_64.img
1031ab0 3.10-23.el7 3fc389b Red Hat Enterprise Linux Server 7.2 (Maipo) /boot/vmlinuz-3.10-23.el7 /boot/initramfs-3.10-23.el7.img
a559d3a 2.6.32-232.el6 98c3edb Red Hat Enterprise Linux Server 6 (Server) /boot/kernel-2.6.32-232.el6 /boot/initramfs-2.6.32-232.el6.img
a559d3a 2.6.32-232.el6 98c3edb Red Hat Enterprise Linux Server 6 (Server) /boot/kernel-2.6.32-232.el6 /boot/initramfs-2.6.32-232.el6.img
d85f2c3 3.10.1-1.el7 3fc389b Red Hat Enterprise Linux Server 7.2 (Maipo) /boot/vmlinuz-3.10.1-1.el7 /boot/initramfs-3.10.1-1.el7.img
d85f2c3 3.10.1-1.el7 3fc389b Red Hat Enterprise Linux Server 7.2 (Maipo) /boot/vmlinuz-3.10.1-1.el7 /boot/initramfs-3.10.1-1.el7.img
e19586b 7.7.7 3fc389b Red Hat Enterprise Linux Server 7.2 (Maipo) /boot/vmlinuz-7.7.7 /boot/initramfs-7.7.7.img
To display the available fields for either report use the field
name help.
BootEntry fields:
boom list -o help
Boot loader entries Fields
--------------------------
bootid - Boot identifier [sha]
title - Entry title [str]
options - Kernel options [str]
kernel - Kernel image [str]
initramfs - Initramfs image [str]
machineid - Machine identifier [sha]
OS profiles Fields
------------------
osid - OS identifier [sha]
osname - OS name [str]
osshortname - OS short name [str]
osversion - OS version [str]
osversion_id - Version identifier [str]
unamepattern - UTS name pattern [str]
kernelpattern - Kernel image pattern [str]
initrdpattern - Initrd pattern [str]
lvm2opts - LVM2 options [str]
btrfsopts - BTRFS options [str]
options - Kernel options [str]
Boot parameters Fields
----------------------
version - Kernel version [str]
rootdev - Root device [str]
rootlv - Root logical volume [str]
subvolpath - BTRFS subvolume path [str]
subvolid - BTRFS subvolume ID [num]
OsProfile fields:
boom profile list -o help
OS profiles Fields
------------------
osid - OS identifier [sha]
osname - OS name [str]
osshortname - OS short name [str]
osversion - OS version [str]
osversion_id - Version identifier [str]
unamepattern - UTS name pattern [str]
kernelpattern - Kernel image pattern [str]
initrdpattern - Initrd pattern [str]
lvm2opts - LVM2 options [str]
btrfsopts - BTRFS options [str]
options - Kernel options [str]
Help is available for the boom command and each command line option.
Run the command with --help to display the full usage message:
# boom --help
To automatically generate boot configuration Boom needs an Operating System Profile for the system(s) for which it will create entries.
And OsProfile is a collection of attributes that describe the OS identity and provide templates for boot loader entries.
The identity information comprising an OsProfile is taken from the
os-release file for the distribution. Additional properties,
such as the UTS release pattern to match for the distribution,
are either provided on the boom command line or are set to default
values.
To create an OsProfile for the running system, use the
-H/--from-host' command line option:
# boom profile create --from-host --uname-pattern fc26
Created profile with os_id d4439b7:
OS ID: "d4439b7d2f928c39f1160c0b0291407e5990b9e0",
Name: "Fedora", Short name: "fedora",
Version: "26 (Workstation Edition)", Version ID: "26",
UTS release pattern: "fc26",
Kernel pattern: "/kernel-%{version}", Initramfs pattern: "/initramfs-%{version}.img",
Root options (LVM2): "rd.lvm.lv=%{lvm_root_lv}",
Root options (BTRFS): "rootflags=%{btrfs_subvolume}",
Options: "root=%{root_device} ro %{root_opts}"
The --uname-pattern OsProfile property is an otional but recommended
pattern (regular expression) that should match the UTS release (uname)
strings reported by the operating system.
The uname pattern is used when an on-disk boot loader entry is found that does not contain an OS identifier (for e.g. a manually edited entry, or one created by a different program).
To create a new boot entry using an existing OsProfile, use the
boom create command, specifying the OsProfile using its assigned
identifier:
# boom profile list --short-name rhel
OsID Name OsVersion
3fc389b Red Hat Enterprise Linux Server 7.2 (Maipo)
98c3edb Red Hat Enterprise Linux Server 6 (Server)
c0b921e Red Hat Enterprise Linux Server 7 (Server)
# boom create --profile 3fc389b --title "RHEL7 snapshot" --version 3.10-272.el7 --root-lv vg00/lvol0-snap
Created entry with boot_id a5aef11:
title RHEL7 snapshot
machine-id 611f38fd887d41dea7eb3403b2730a76
version 3.10-272.el7
linux /boot/vmlinuz-3.10-272.el7
initrd /boot/initramfs-3.10-272.el7.img
options root=/dev/vg00/lvol0-snap ro rd.lvm.lv=vg00/lvol0-snap rhgb quiet
Once the entry has been created it will appear in the boot loader menu as configured:
Red Hat Enterprise Linux Server (3.10.0-327.el7.x86_64) 7.2 (Maipo)
Red Hat Enterprise Linux Server (3.10.0-272.el7.x86_64) 7.2 (Maipo)
RHEL7 Snapshot
Use the ↑ and ↓ keys to change the selection.
Press 'e' to edit the selected item, or 'c' for a command prompt.
If creating an entry for the currently running kernel version, and the OsProfile of the running host, these options can be omitted from the create command:
# boom create --title "Fedora 26 snapshot (4.13.5-200.fc26.x86_64)" --root-lv vg_hex/root-snap-f26
Created entry with boot_id d12c177:
title Fedora 26 snapshot (4.13.5-200.fc26.x86_64)
machine-id 611f38fd887d41dea7eb3403b2730a76
version 4.13.5-200.fc26.x86_64
linux /kernel-4.13.5-200.fc26.x86_64
initrd /initramfs-4.13.5-200.fc26.x86_64.img
options root=/dev/vg_hex/root-snap-f26 ro rd.lvm.lv=vg_hex/root-snap-f26
Red Hat Enterprise Linux Server (3.10.0-327.el7.x86_64) 7.2 (Maipo)
Red Hat Enterprise Linux Server (3.10.0-272.el7.x86_64) 7.2 (Maipo)
Fedora 26 snapshot (4.13.5-200.fc26.x86_64)
RHEL7 Snapshot
Use the ↑ and ↓ keys to change the selection.
Press 'e' to edit the selected item, or 'c' for a command prompt.
Boom includes scripts to integrate with versions of grub2 that support
the BLS extension (including the builds of Grub shipped with Fedora and
Red Hat Enterprise Linux).
The scripts support optionally placing all boom-managed entries into a separate named submenu.
To place all boom-managed boot entries into a separate submenu edit the
file /etc/default/boom and set the BOOM_USE_SUBMENU variable to yes:
BOOM_USE_SUBMENU="yes"
To change the name of the submenu modify the BOOM_SUBMENU_NAME variable:
BOOM_SUBMENU_NAME="Snapshots"
After modifying the file run the grub2-mkconfig program to update the
Grub boot loader configuration.
If submenu support is enabled a new entry (named Snapshots in this
example) will appear at the bottom of the main Grub2 menu:
Red Hat Enterprise Linux Server (3.10.0-327.el7.x86_64) 7.2 (Maipo)
Red Hat Enterprise Linux Server (3.10.0-272.el7.x86_64) 7.2 (Maipo)
Snapshots
Use the ↑ and ↓ keys to change the selection.
Press 'e' to edit the selected item, or 'c' for a command prompt.
Hitting enter on the submenu item will display the available boom
boot entries:
RHEL7 Snapshot (3.10.0-327.el7.x86_64) 2017-10-10
RHEL7 Snapshot (3.10.0-327.el7.x86_64) 2017-10-01
RHEL7 Snapshot (3.10.0-272.el7.x86_64) 2017-09-20
RHEL7 Snapshot (3.10.0-272.el7.x86_64) 2017-08-13
Fedora 24 (4.11.12-100.fc24.x86_64)
Use the ↑ and ↓ keys to change the selection.
Press 'e' to edit the selected item, or 'c' for a command prompt.
Press Escape to return to the previous menu.
Boom also supports programatic use via a Python API. The API is flexible and allows greater customisation than is possible using the command line tool.
Two interfaces are provided: a procedural command-driven interface that
closely mimics the command line tool (the boom CLI is implemented using
this interface), and a native object interface that provides complete
access to boom's capabilities and full control over boom OsProfile
BootEntry, and BootParams objects. User-defined tabular reports
may also be created using the boom.report module.
The command API is implemented in the boom.command sub-module. Programs
wishing to use the command API can just import this module:
import boom.command
The command API is documented at readthedocs.org.
The object API is implemented in several boom sub-modules:
boomboom.bootloaderboom.osprofileboom.report
Applications using the object API need only import the sub-modules that contain the needed interfaces.
The object API is documented at readthedocs.org.
Patches can be submitted via the mailing list or as GitHub pull requests. If
using GitHub please make sure your branch applies to the current master as a
'fast forward' merge (i.e. without creating a merge commit). Use the git rebase command to update your branch to the current master if necessary.
API documentation is automatically generated using Sphinx and Read the Docs.
Installation and user documentation will be added in a future update.