NOTE: The feature list is not completely implemented yet!
When version 2 is released of b9, all features listed here can be expected to work.
Quick-Start
Mission Statement
B9 is an executable and a Haskell library, that consumes a Haskell term describing
the generation of VM-Images.
A few core data
types form an EDSL, and B9
contains functions to read
and show
then.
Such a term can then be stored into a text file and is interpreted by a command line invokation.
Installation
Installation on NixOS
-
As command line utility in current directory:
$ nix-build -E 'import (fetchTarball https://github.com/sheyll/b9-vm-image-builder/archive/1.0.0.tar.gz) {}'
Now the executable b9c
is in ./result/bin/
:
$ result/bin/b9c
Runtime dependencies
To be able to use B9 install:
- Linux
- qemu
- ext4 tools
- genisoimage
- mtools
- vfat tools
- ssh
- rsync
- bash
- wget
- sudo (optional)
LibVirtLXC
support
- lxc
- libvirt with lxc support (libvirt-driver-lxc, libvirt-daemon-lxc,...)
- virsh
B9 has been tested with libvirt version 1.2.12.
Make sure that all neccessary daemons, e.g. libvirtd.service
, lxc.service
,..
are active, that SELinux is configured correctly and that the nbd
kernel
module is loaded.
If neccessary create a libvirt network configuration, e.g. by using
the GUI front-endvirt-manager
.
Depending upon the libvirt and lxc configuration of the system it might be
nessary to allow the user, that will execute b9c
, password-less sudo
for
these commands:
For SystemdNspawn
support
For Podman
support
For Docker
support
After installing B9 (either from a binary package or by building from source)
all its glory is availbe through a single executable called b9c
.
When b9c
is started for the first time, it creates a configuration file in
the users home directory called ~/.b9/b9.conf
. The path to that file can be
changed using command line arguments. Execute:
b9c -h
for a list of command line parameters and commands.
b9c
command line arguments always follow this pattern:
b9c <global-options> <command> <command-options> -- <build-script-extra-args>
To enable B9 to work correctly on your machine edit the config file and make
necessary adaptions.
General Overview
Use B9 to compile your software into a deployable set of Linux-VM- or
configuration images, from a set of scripts and input files and templates.
The main goal of this tool is to provide a build tool to increase automation and
reduce redundancy when creating configured, ready-to-run VM-images.
One big thing is that it can produce many machines and cloud-configs from a
single build file, because build files can describe concrete as well as
parameterized generators. It can create parameterized VM-Images by uploading
(e.g. system-)files assembled by syntax aware template application and
combination, all statically checked by during the build.
This sets B9 apart from e.g. cloud-init or other configuration management
systems that provide configuration through user provided dynamic script-programs,
which rely on the user to contain correct error handling.
The general idea is the same as in statically type programming languages: catch
errors as early as possible without relying on the user to create a covering set
of tests/error checks.
Certain sacrifies were made; there might be a steep laerning curve, but you will
eventually get there. The tool at hand works stable and reliable.
All builds happen in isolation, i.e. by default in random build directories, and
are cleaned on failure.
Also, B9 does not modify cached images.
Work on VM-Images is always done on a copy of an image, and to speed
things up, it is possible to explicitly use copy-on-write images.
B9 creates bootable virtual machine images, without necessarily using
virtualization itself.
In essence B9 is a tool for creation, configuration and sharing of VM images and
all peripheral artifacts, it creates:
- VMDK/QCOW2/Raw VM images
- Converted, extracted and resized copies of existing vm images
- Empty VM images with extended 4 file system
- Cloud-Config Images
- Text files from template files with variable interpolation
- Erlang OTP sys.config files
Make VM Disk Images
- Extract partitions from MRB Partitioned images
- Create, resuse, resize EXT-4 on Qcow2, vmdk or raw Images
- Run commands on images to create new image, similar to what docker build does,
- Using libvirt-lxc
- Using docker
- Using systemd-nspawn
Manage Disk Images
- Cache images locally
- Distribute cached images via SCP
Assemble Cloud-init Configuration
- Merge YAML Expressions
- Merge Erlang Terms
- Load local files
- Load files from HTTP servers
- Support
${identifier}
variable interpolation
- Create cloud-init
- ISO images
- Floppy images
- yaml files
The input files can be in:
- DHALL format
- Haskell values interpreted by the
Read
instances.
Usage as Library
Configuration
B9 uses a .ini
- style configuration file.
Incremental Builds
B9 uses shake
so some degree of incremental build is available.
B9 build files
If you really need to write these file, you are basically f'ed.
For now, look at existing config files and read the sources, if anything,
make sure to read at least the chapter Anger-Management before throwing stuff
around.
More documentation is comming soon!
General Structure
A B9 configuration describes a single ArtifactGenerator
. It generates files
belonging to a VM, such as qcow2/raw/vmdk-image file(s) and e.g. cloud-init ISO
image files.
Just to recap: a something.b9
build file is always ever only a mere
ArtifactGenerator
literal, no matter how many Let
, Each
, Artifacts
,
etc... you see flying around there.
Creating artifacts
To get any real artifact out of an artifact generator use the Artifact
constructor. It takes 2 parameters an arbitrary id and a describtion of what
the artifact consists of:
Artifact (IID "some_instance_id")
(VmImages ... | CloudInit ...)
An artifact can either be a (set of) VM-disk-image(s) likely in combination
with some shell script to install software, etc or a static collection of
files put on a cloud-init image(VFAT or ISO or directory).
Defining artifact generators that produce vm image files
To produce vm image files, e.g. with some software installed use the VmImages
artifact generator. It has only 2 parameters:
VmImages
[ ... disk image targets ... ]
( ... installation script ...)
Of course it must be wrapped in an Artifact
definition, so we get this structure:
Artifact (IID "my_first_image")
(VmImages [...] (...))
ImageTargets
The first argument to VmImages
is a list of ImageTarget
. Each describes
a single VM-disk-image. The syntax is:
ImageTarget
ImageDestination
ImageSource
MountPoint
- An
ImageDestination
specifies if/where to put the output image.
- An
ImageSource
specifies how the image is created or from where it is taken.
- A
MountPoint
specifies where to mount the image during the execution of an
optional VmBuild
-script.
Parameterized artifact generators
B9 supports $varnam
variable interpolation in all strings anywhere in an
ArtifactGenerator
:
- All filenames and paths
- All id strings and names
- Template files included via e.g.
Template
- In every string in
VmScript
s (e.g. in Run "${cmd}" ["${world}"]
)
- Also in all included template files (e.g. included via
Template
)
Parameters can be defined using Let
, Each
and special command line
arguments.
To pass parameters via the command line, append them after the argument delimiter
option --
which ends the list of regular b9c arguments:
b9c -v build -f file1.b9 .. -- arg_1 arg_2 ...
The parameters are bound to ${arg_1}
, ${arg_2}
, that is variables indicating
the corresponding position on the command line.
To define variables using Let
, write:
Let [key-value-pairs, ...]
[artifactgenerators, ...]
All key-value bindings defined in the first list are available in every artifact
generator contained in the second list (body).
A key-value binding, e.g. ("hostname", "www.acme.org")
, consist of two strings
on parens seperated by a ,
(comma). The left string is the key, and the right
string is the value.
This ("webserver", "www.${domainname}")
is an example to show that the value
may also contain a variable reference. (Of course, only to variabled defined
before)
Anger-Management
B9 build files contain a single literal ArtifactGenerator
value
in Haskell syntax. B9 currently 'parses' the config file without any
error checking, so writing config files is VERY frustrating without
some tricks:
Trick 1
Start with a working file and run
b9c reformat -f <filename>
after each modification. The reformat
command only parses and - hence the
name - (re-) formats/pretty-prints the files passed with -f
options.
You will immediately know if a modification broke the file.
NOTE: If your build file refers to any ${arg_...}
positional arguments pass
them to reformat
using --
followed by the argument list.
Trick 2
Obtain and build the sources of B9, start an interactive haskell shell with the
B9 code loaded and try to paste the contents of the config file to see if ghci
accepts it. Use the ghci macros :{
and :}
to begin and end a multi-line input
and paste the raw contents of the config file in question in between.
$ cabal install
$ cabal repl
... (many lines omitted) ...
*B9> :{
*B9| Artifact (IID "filer")
*B9| (VmImages [ ImageTarget
*B9| (LocalFile (Image "EXPORT/machines/filer/disks/0.vmdk" Vmdk Ext4)
*B9| KeepSize)
*B9| (From "fedora-20-prod" KeepSize)
*B9| (MountPoint "/")
*B9| , ImageTarget
*B9| (LocalFile (Image "EXPORT/machines/filer/disks/1.vmdk" Vmdk Ext4)
*B9| KeepSize)
*B9| (EmptyImage "audio_files" Ext4 Raw (ImageSize 64 GB))
*B9| (MountPoint "/export/lb/audio")
*B9| ]
*B9| (VmScript X86_64
*B9| [ SharedDirectoryRO "./filer" (MountPoint "/mnt/build_root")
*B9| , SharedDirectoryRO "../_common/upload" (MountPoint "/mnt/common")]
*B9| (Begin
*B9| [ Run "dhclient" []
*B9| , In "/mnt/build_root" [ Run "./machine-" [] ]
*B9| , In "/mnt/common" [ Run "./post_export.sh" [] ]
*B9| ])))
*B9| :}
Artifact (IID "filer") (VmImages
[ImageTarget (LocalFile (Image "EXPORT/machines/filer/disks/0.vmdk" Vmdk Ext4) KeepSize)
(From "fedora-20-prod" KeepSize) (MountPoint "/"),ImageTarget
(LocalFile (Image "EXPORT/machines/filer/disks/1.vmdk" Vmdk Ext4) KeepSize)
(EmptyImage "audio_files" Ext4 Raw (ImageSize 64 GB)) (MountPoint "/export/lb/audio")]
(VmScript X86_64
[SharedDirectoryRO "./filer" (MountPoint "/mnt/build_root"),
SharedDirectoryRO "../_common/upload" (MountPoint "/mnt/common")]
(Begin [Run "dhclient" [],In "/mnt/build_root" [Run "./machine-" []],In
"/mnt/common" [Run "./post_export.sh" []]])))
B9 Config File Reference
This is an example of a B9 configuration file, by default found in
~/.b9/b9.conf
and uses the ini-file format.
Some of the options can also be specified on the command line
and in environment variables.
A path to an alternative config file can given on the command lines.
When the default config file does not exist, b9c
will create it from
default values.
This example is the current default configuration:
[global]
build_dir_root: Nothing
keep_temp_dirs: False
log_file: Nothing
max_cached_shared_images: Just 2
repository: Nothing
repository_cache: Just (InB9UserDir "repo-cache")
unique_build_dirs: True
verbosity: Just LogInfo
[libvirt-lxc]
connection: lxc:///
emulator_path: Just "/usr/lib/libvirt/libvirt_lxc"
guest_capabilities: [CAP_MKNOD,CAP_SYS_ADMIN,CAP_SYS_CHROOT,CAP_SETGID,CAP_SETUID,CAP_NET_BIND_SERVICE,CAP_SETPCAP,CAP_SYS_PTRACE,CAP_SYS_MODULE]
guest_ram_size: RamSize 1 GB
network: Nothing
use_sudo: True
[podman]
guest_capabilities: [CAP_MKNOD,CAP_SYS_ADMIN,CAP_SYS_CHROOT,CAP_SETGID,CAP_SETUID,CAP_NET_BIND_SERVICE,CAP_SETPCAP,CAP_SYS_PTRACE,CAP_SYS_MODULE]
network: Nothing
[systemdNspawn]
console: read-only
executable: Nothing
extra_args: Nothing
guest_capabilities: [CAP_MKNOD,CAP_SYS_ADMIN,CAP_SYS_CHROOT,CAP_SETGID,CAP_SETUID,CAP_NET_BIND_SERVICE,CAP_SETPCAP,CAP_SYS_PTRACE,CAP_SYS_MODULE]
max_lifetime_seconds: Just 14400
use_sudo: True
[docker]
guest_capabilities: [CAP_MKNOD,CAP_SYS_ADMIN,CAP_SYS_CHROOT,CAP_SETGID,CAP_SETUID,CAP_NET_BIND_SERVICE,CAP_SETPCAP,CAP_SYS_PTRACE,CAP_SYS_MODULE]
network: Nothing
The [global]
Section
build_dir_root
:
TODO document this option.
keep_temp_dirs
:
TODO document this option.
log_file
:
TODO document this option.
max_cached_shared_images
:
TODO document this option.
repository
:
TODO document this option.
repository_cache
:
- Default:
Just (InB9UserDir "repo-cache")
TODO document this option.
unique_build_dirs
:
TODO document this option.
verbosity
:
TODO document this option.
The [libvirt-lxc]
Section
connection
TODO document this option.
emulator_path
- Default:
Just "/usr/lib/libvirt/libvirt_lxc"
TODO document this option.
guest_capabilities
- Default:
[CAP_MKNOD,CAP_SYS_ADMIN,CAP_SYS_CHROOT,CAP_SETGID,CAP_SETUID,CAP_NET_BIND_SERVICE,CAP_SETPCAP,CAP_SYS_PTRACE,CAP_SYS_MODULE]
TODO document this option.
guest_ram_size
TODO document this option.
network
TODO document this option.
use_sudo
TODO document this option.
The [podman]
Section
Since: 1.0.0
guest_capabilities
- Default:
[CAP_MKNOD,CAP_SYS_ADMIN,CAP_SYS_CHROOT,CAP_SETGID,CAP_SETUID,CAP_NET_BIND_SERVICE,CAP_SETPCAP,CAP_SYS_PTRACE,CAP_SYS_MODULE]
TODO document this option.
network
TODO document this option.
The [systemdNspawn]
Section
Since: 1.0.0
console
- Default:
read-only
- Valid Values:
read-only
interactive
passive
pipe
This corresponds to the --console=<...>
parameter to systemd-nspawn
.
If the value is set to interactive
the execution of
any VmScript
s through systemd-nspawn
will be interactive
by using stdin
, stdout
and stderr
of the b9c
process.
executable
TODO document this option.
TODO document this option.
guest_capabilities
- Default:
[CAP_MKNOD,CAP_SYS_ADMIN,CAP_SYS_CHROOT,CAP_SETGID,CAP_SETUID,CAP_NET_BIND_SERVICE,CAP_SETPCAP,CAP_SYS_PTRACE,CAP_SYS_MODULE]
TODO document this option.
max_lifetime_seconds
TODO document this option.
use_sudo
TODO document this option.
The [docker]
Section
Since: 1.0.0
guest_capabilities
- Default:
[CAP_MKNOD,CAP_SYS_ADMIN,CAP_SYS_CHROOT,CAP_SETGID,CAP_SETUID,CAP_NET_BIND_SERVICE,CAP_SETPCAP,CAP_SYS_PTRACE,CAP_SYS_MODULE]
TODO document this option.
network
TODO document this option.