Environment creation
Grid'5000 provides bare-metal as a service for experimenting on distributed computers, thanks to the kadeploy service. While kadeploy handles the efficient deployment of a user's customized system (also named environment in the Grid'5000 terminology) on many nodes, companion tools allow building such custom systems environments. Hence, this page describes the Grid'5000 environment creation processes, with the several methods for doing it, and helpful tools.
Introduction: the several ways for preparing a custom system environment
There are different ways to prepare a system environment for experiments:
(1)
A first way consists in deploying a provided environment, e.g. Grid'5000 supporteddebian10-x64-big
, and adding software and custom configurations to it after the initial deployment. That every time a new experiment is run (new deploy job). While it can be relevant, it has an obvious bias: the post-deployment setup is not factorized and must be redone every time and on all nodes.(2)
A second way consists in building a master system environment with all the wanted customizations, then deploying that pre-built environment on the experiment nodes. This way, the environment preparation is only done once for all times and all nodes: it is factorized.
Once again, building such a customized master system environment can be achieved in different ways:
(2-a)
A first way consists in deploying an already provided environment (such as one of the Grid'5000 supported reference environments) on one node, doing some customizations on that node, then finally saving the operating system of the node as a master environment image, to later allow deploying it on all the nodes of an experiment. This usually involves thetgz-g5k
command to create the master environment image (tarball).(2-b)
A second way consists in building the master environment to deploy on all the nodes of an experiment from a recipe which describes the whole system environment construction process (possibly from scratch). This obviously allows for the reconstructibility and sharing of the environment, hence it helps the reproducibility of the experiment. This involves the same build process that is used to produce the Grid'5000 reference environments, using thekameleon
tool (Grid'5000 environment recipes are written in the kameleon recipe and Puppet languages).
In the remaining of this page, (1)
will not be detailed: it is let to the user to choose a tool to deploy software and configurations on running systems, such as clush
, taktuk
, ansible
, etc.
About Grid'5000 supported environments
While building a system environment from scratch (only taking a generic OS installation media as a base) may be doable, it is technically extremely difficult (see the last section of this page). Most Grid'5000 users should rather create customized environments on top of existing works, already done for Grid'5000.
The Grid'5000 technical team provides several reference environments, which a user's customized environment can be built on top of.
Of course, a user can also build a new customized environment on top of another user's customized environment.
The next sections give detailed technical howtos for customizing existing Grid'5000 environments, first following way (2-a)
, then way (2-b)
.
Creating an environment images using tgz-g5k
In this section, following the (2-a)
way described above, we explain how to extend an existing Grid'5000 environment by first deploying it on a machine with kadeploy3
, then bringing customization to that machine, and finally archiving the operating system of the machine with tgz-g5k
to create a new environment image.
Note that this method allows building environment in the format to be deployed with kadeploy3
, not VM image to use for instance with qemu
(but qcow2
VM disk image can be modified in place). Also note that the next section shows how to build a VM disk image from a recipe using kameleon
.
1: deploy the existing environment on a machine
First, we have to create the deploy job, to reserve a machine on which we will deploy the existing environment of our choice, which our customized environment will be based on.
Note | |
---|---|
At this stage, it is wise choosing a Grid'5000 site and cluster that is not too loaded, furthermore using rather old hardware is of special interest because newer hardware usually has significantly longer boot time → see the Hardware page. |
We do an interactive job (-I
), of the deploy type (-t deploy
), on only one machine (-l host=1
). We will give ourselves 3 hours with -l walltime=3
.
The interactive job opens a new shell on the frontend (careful: the job ends when exiting that shell).
Since the hostname of the reserved machine is stored in the $OAR_FILE_NODES
file, we can deploy the reference environment of our choice (or another user's environment that we would like to extend) with kadeploy3
:
(if the chosen environment is not registered in kaenv3
, see the -a
option of kadeploy3
to point to a environment description file).
2: customize the environment
Once the deployment has run successfully, we can connect to the machine using ssh
as root without password, and do any customization using shell commands.
You can therefore update your environment (to add any missing library you need, remove any package that you don't need in order to sizes down the image and possibly speeds up the deployment process, etc.)
Note: When you are done with the customization, mind clearing temporary files or caches to save disk space.
3: archive the environment image
We can now archive the customized environment, using tgz-g5k
to create a Grid'5000 environment image from the filesystem of the machine. The environment image is a tarball of the filesystem of the OS with some adaptations.
This will create a file named environment_image.tgz
in your home directory on the frontend
.
4: create the environment description file
The new environment image cannot be deployed directly: the image is only one part of an environment. An environment is described by a YAML document. To use the new image, it must be referred by an environment description, so that deploying that environment uses the new image. Note that the environment includes also other information such as the postinstall script and the kernel command line for instance, which can be changed independently from changing the environment image.
The easiest way to create a description for your new environment is to modify the description of the environment it is based on.
Since we used the debian10-x64-base
reference environment, we can retrieve its description using the kaenv3
command and save it to a file. Then we'll use it as a base for the description of our customized environment.
We now edit the file to change the environment name
, version
, description
, author
, and so on. The image file
entry must of course be changed to point to our new environment image tarball file. Since it is stored locally in our home directory, the path can be a simple absolute path (remove the server://
prefix). Finally, the visibility
line should be removed or its value changed to shared
or private
.
---
name: my-debian
version: 1
description: my customized environment based on debian 10 (buster) - base
author: john@doe.org
visibility: shared
destructive: false
os: linux
image:
file: /home/jdoe/environment_image.tgz
kind: tar
compression: gzip
postinstalls:
- archive: server:///grid5000/postinstalls/g5k-postinstall.tgz
compression: gzip
script: g5k-postinstall --net debian
boot:
kernel: "/vmlinuz"
initrd: "/initrd.img"
kernel_params:
filesystem: ext4
partition_type: 131
multipart: false
Once this is done, our customized environment is ready to be deployed (in a deploy job) using:
(This kind of deployment is called anonymous deployment because the description is not yet in the Kadeploy3 environment registry. It is particularly useful when working by iteration on the environment, thus having to recreate the environment image several times. Otherwise, since registered environments are checksummed, changing the image file requires updating the registration every time with kaenv3
)
Once your customized environment is ready, it's optionally the time to add it to the Kadeploy3 environment registry:
Assuming you set the name field in the environment description to "my-debian", it will then be deployable using the following command:
If the visibility
is set to shared
, your environment will show up in the list of available registered environment for any user, using kaenv3 -l -u
your_username
.
Creating an environment from a recipe using kameleon
In this section, following the (2-b)
way described above, we explain how to build environments from recipes describing the whole creation process, rather than doing interactive modifications in command-line then use tgz-g5k
to export the system to an image. With the method, all steps requested to build the environment are written, which helps traceability, reconstructability, and sharing.
There are actually different ways of writing recipes. The recipes of the Grid'5000 reference environment for instance describe the whole process of installation of the operating system from scratch using the installer of the target Linux distribution. Also, the Debian stable environments which are provided in several variants use Puppet for most of the configuration of the system. However, while building from scratch and using Puppet may look very nice, it is also complex and longer to execute.
As a result, we present a method in this documentation that is simpler and closer to what is actually done when using tgz-g5k:
- The recipe will first retrieve the operating system image (tarball) of an existing Grid'5000 environment and run it a VM. That's bootstrap stage.
- Then, the recipe will allow any customizations of the VM's operating system in the setup stage.
- Finally, the export stage will create a new environment from the customized operating system, ready to be consumed by kadeploy.
Recipes are written for and processed by a tool named kameleon, that do the actual build of the environment. Kameleon is a powerful utility to generate operating system images or environments in the Grid'5000 context from recipes.
A kameleon recipe is composed of a main YAML file: the recipe. That recipe possibly depends on other YAML files: some recipes it extends and some macro steps. It also depends on various other files: data, helper scripts,....
Kameleon provides features such as context isolation and interactive breakpoints. Context isolation means that kameleon can run a build process without altering the operating system from where the tool is called itself (kameleon typically uses qemu VMs for the build). Kameleon does not need to run as root.
See the Kameleon website for more information, notably a description of the recipe syntax (language) used in the YAML files.
Preparing the workspace to use kameleon
For the work with kameleon, we suggest creating a fresh directory that will contain our recipes and all dependencies. Optionally, that directory can of course be versioned in a new git project, in order to keep track of any changes made.
First we create an interactive job to reserve a node where to run the kameleon commands:
Kameleon is preinstalled on the nodes.
We then install the repository of Grid'5000 recipes:
node :
|
kameleon repository add grid5000 https://gitlab.inria.fr/grid5000/environments-recipes.git |
In case you already installed the repository previously, you may want to update it. To do so, run the following command:
You can then list the available recipe templates with:
As explained above, we see here the templates for Debian stable (9, 10, and 11) with their different variants. We also see the templates for other distributions with only the min variant. Finally, we see the template to build from an existing Grid'5000 environment.
Create the new recipe
As explained above, we extend the grid5000/from_grid5000_environment/base
recipe. To do so, we run the following command:
We can now edit the new recipe file: my_custom_environment.yaml
, and look at the global section. A lot of comments are provided to help adapt the recipe to our needs. The most important information to provide in the recipe is what existing environment we want to base our recipe on. This information must be provided in the grid5000_environment_import_name global variable. It must be set to one of the environments that are shown when running kaenv3 -l
on a frontend. For instance we may choose to use debiantesting-x64-min
. Most other global variables are commented (line begin with a #) because default values may be just fine. However, we may want to change some of those variables for instance to specify the user and version for a specific environment.
## Environment to build from
grid5000_environment_import_name: "debiantesting-x64-min
"
#grid5000_environment_import_user: "deploy"
#grid5000_environment_import_version: ""
Once done, the important part is to bring our customization steps for the setup of our environment in the setup section (bootstrap and export should not require any changes).
For example, let's assume we want to install the ffmpeg package in our environement.
We add a new step to the recipe, which is just a sequence of actions to execute. This basically gives a setup section in our recipe as follows:
setup: - install_more_packages: - install_ffmpeg: - exec_in : apt-get update && apt-get install -y ffmpeg
exec_in
means that the command will be executed with bash in the VM of the build process. See the kameleon documation for other commands.install_more_packages
is a macrostep, it can group one or several microstepsinstall_ffmpeg
is a microstep
It is mandatory to define the 2 levels of steps (macrostep and microstep) and respect the format of a correct YAML document, to have a working recipe.
Optionnaly a macrostep and its microsteps can also be defined in a separate file. For instance, we can create the ~/my_recipes/steps/setup/
directory hierarchy and the steps/setup/install_more_packages.yaml
file inside, with the following content:
- install_ffmpeg: - exec_in : apt-get update && apt-get install -y ffmpeg
Then use it in the recipe with just:
setup: - install_more_packages
(no :
after install_more_packages
, since the macrostep is defined in a separate file).
You can find more information about the kameleon language in the kameleon documentation
To inpect our environment before launching the build:
- We can look at the information about the environment with
kameleon info
:
- We can look at what the build of the environment involves by running
kameleon dryrun
:
If any error is raised with those commands, it probably come from a bad syntax in the recipe (e.g. bad YAML formating).
Build and test
Once the recipe is written, we can launch the build. To do so, we just have to run following command:
We end up with a build
directory that contains the freshly build files we are interested in:
- File
build/my_custom_environment/my_custom_environment.dsc
- This is the description file of the new environment (this is a YAML file, the file extension does not really matter, be it
.dsc
,.env
or.yaml
) - It can be used either directly with kadeploy to run the deployment without registering the environment:
After creating a new job of type deploy, we run the following kadeploy command from the frontend:
- Or to register the environment with
kaenv3
, for later use with kadeploy.
- File
build/my_custom_environment/my_custom_environment.tar.zst
- This is the tarball of our new environment, referred to in the environment description (previously
debian11_custom.tgz
because the compression was formerly gzip) - It can also be used directly, for instance with
docker import
After installing docker on a reserved node with g5k-setup-docker
, run:
node :
|
zstdcat ~/my_recipe/build/my_custom_environment/my_custom_environment.tar.zst | docker import - debian11-x64-min |
Then run the docker container, for instance:
Of course, writing recipes, building the environment, and testing it may be a trial and error process requiring to loop over the different stages.
Please note that kameleon provides an interactive debugging of the recipe in case of errors or when breakpoints are inserted in the recipe. See comments in the recipes which give the syntax to add a breakpoint.
Other types of recipes
We present below more information about the recipes used to build the Grid'5000 reference environments.
Creating an environment by extending a Grid'5000 recipe using Puppet
We present here how to extend a Grid'5000 recipe and use Puppet to bring some customizations in a traceable way.
As a reminder, Puppet is only used in the Debian stable environment recipes of Grid'5000. We will extend one of those.
The names of the Debian stable (Debian 9, 10 and 11) recipe templates end by a word after a dash: that's the variant name. Variants are min
, base
, nfs
, xen
, big
, std
(see above in this page for more details). Puppet is in charge of configuring the environment operating system with regard to the chosen variant. All variants are defined as Puppet classes that include each others in the following order:
min ⊂ base ⊂ nfs ⊂ big ⊂ std
Additionnaly, the xen
class just includes the base
class, so that the xen
environment is just the base
environment with Xen hypervisor and tools added.
This means that for changes made in the min
class will affect all other variants. Changes made in the big
class will affect the builds of both the big
and std
variants.
In this example we will extend the min
environment recipe of Debian 11. To do so, we use the kameleon new
command as follows:
This creates the ~/my_recipes/debian11_custom.yaml
file which is our new recipe. Besides, kameleon took care of importing in the directory all the files for the new recipe depends on.
You can list the recipes which are present in your workspace using the list command:
You can see your new debian11_custom recipe along with the recipes that it extends directly or indirectly.
You can look at the steps involved in the build of the recipes using the kameleon dryrun
command:
We see that the setup section has setup and run steps for an orchestrator: what's the part that prepares everything to use Puppet in the recipe and run it.
Since we want to write our customization with the Puppet language, we do not have to modify the debian11_custom.yaml
recipe file much. We may just change the environment description by editing the recipe file ~/my_recipes/debian11_custom.yaml
, and changing the description field starting at line 4, for instance:
#============================================================================== # # DESCRIPTION: My Grid'5000 Debian Bullseye # #==============================================================================
Once done, we can close the file and look at the Puppet code.
Puppet is a software configuration management tool that includes its own declarative language to describe system configuration. It is a model-driven solution that requires limited programming knowledge to use.
The puppets modules used by the Grid'5000 reference environments are located in ~/my_recipes/grid5000/steps/data/setup/puppet/modules/env/manifests/
.
For our use case, we can look at the commonpackages.pp
file. This is a really simple file that requests packages to be installed.
We can install ffmpeg like this :
class env::commonpackages{ } ... class env::commonpackages::ffmpeg{ package{ 'ffmpeg': ensure => installed; } } ...
In this quite simple use case, but if you have a package like postfix which requires more configuration, it could be more complex! Puppet covers a lot of needs that we cannot describe in this documentation. To know more, please refer to the Puppet documentation.
Creating an environment by extending a Grid'5000 recipe without using Puppet
In this section, we will describe the customization of a Grid'5000 environment template using only the kameleon language, not Puppet. Thus the environment template that we extend is not limited to Debian stable.
We have two possibilities here for the method, using different recipe templates:
- Method
A
: either use thegrid5000/from_grid5000_environment/base.yaml
recipe template, which builds by starting from an Grid'5000 environment (to specified in the recipe), - Method
B
: or extend any of the recipes of the Grid'5000 environments.
We details in the next 2 paragraphs how to work for both methods.
Extending grid5000/from_grid5000_environment/base.yaml
Let's assume we choose to follow method A
and extend grid5000/from_grid5000_environment/base.yaml
: We run the following command:
With method A
, the environment to base work on is not given by the name of the recipe template we extend: the grid5000/from_grid5000_environment/base.yaml
template works with any environment as base. Thus the Grid'5000 environment to import the image tarbal from (and build on top of) has to be specified within the recipe. We edit the new recipe file: my_custom_environment.yaml
, and look at the global section. The required information to provide here is the grid5000_environment_import_name: it must be set to one of the environment that show when running kaenv3 -l
on a frontend. For instance we may choose to use debiantesting-x64-min
. We do not specify user and version since the default ones are just fine by default.
## Environment to build from
grid5000_environment_import_name: "debiantesting-x64-min
"
#grid5000_environment_import_user: "deploy"
#grid5000_environment_import_version: ""
Other lines of the global section can be modified as suggested by the comments in the recipe file itself. This is self-explanatory so we do not detail more here.
Once done, the important part is to bring your customization steps for the setup of your environment in the setup section. See below.
Extending a the recipe of a Grid'5000 environment
If we prefer building from scratch (following method B
) rather that starting from the image (tarball) of an existing environment, we can extend directly the recipe of one of the Grid'5000 reference environment. Let's say we want to extend grid5000/debiantesting-x64-min
. We run the following command:
(compared to method A
, we just change the template used).
This creates the ~/my_recipes/my_custom_environment.yaml
file, which this time directly describes that it extends grid5000/debiantesting-x64-min
.
We can now edit the recipe file and look at comments inside it, that are self-explanatory.
Customize the environment in the setup section
Whatever template we choose to extend (following method A
or B
), our customization of the environment operating system is to be written in the setup section (bootstrap and export should not require any changes as long as we work on customizing the environment for Grid'5000).
For example, just like in the previous section with Puppet, we describe below how to install the ffmpeg package (but in the kameleon language this time).
We add a new step to the recipe, which is just a sequence of actions to execute. This basically gives a setup section in our recipe as follows:
setup: - "@base" - install_more_packages: - install_ffmpeg: - exec_in : apt-get update && apt-get install -y ffmpeg
"@base"
means that the steps from the environment we extend should be executed before our new steps (a bit like when using super() in a constructor of a class in Java or Ruby to call the constructor of the inherited class).exec_in
means that the command will be executed with bash in the VM of the build process. See the kameleon documation for other commands.install_more_packages
is a macrostep,install_ffmpeg
is a microstep: It is mandatory to define the 2 level of steps and respect the format of a correct YAML document.
Additionnaly, a macrostep and its microsteps can also be defined in a separate file. For instance, we can create the steps/setup/
directory hierarchy and the steps/setup/install_more_packages.yaml
file inside, with the following content:
- install_ffmpeg: - exec_in : apt-get update && apt-get install -y ffmpeg
Then use it in the recipe with just:
setup: - "@base" - install_more_packages
(no :
after install_more_packages
here).
You can find more information about the kameleon language in the kameleon documentation
To inpect our environment before launching the build:
- We can look at the information about the environment with
kameleon info
:
- We can look at what the build of the environment involves by running
kameleon dryrun
:
If any error is raised with those commands, it probably come from a bad syntax in the recipe (e.g. bad YAML formating).
Build and test
Once the recipe is written, we can launch the build. To do so, we just have to run following command:
We end up with a build
directory that contains the freshly build files we are interested in:
- File
build/my_custom_environment/my_custom_environment.dsc
- This is the description file of the new environment (this is a YAML file, the file extension does not really matter, be it
.dsc
,.env
or.yaml
) - It can be used either directly with kadeploy to run the deployment without registering the environment:
After creating a new job of type deploy, we run the following kadeploy command from the frontend:
- Or to register the environment with
kaenv3
, for later use with kadeploy.
- File
build/my_custom_environment/my_custom_environment.tar.zst
- This is the tarball of our new environment, referred to in the environment description (previously
debian11_custom.tgz
because the compression was formerly gzip) - It can also be used directly, for instance with
docker import
After installing docker on a reserved node with g5k-setup-docker
, run:
node :
|
zstdcat ~/my_recipe/build/my_custom_environment/my_custom_environment.tar.zst | docker import - debian11-x64-min |
Then run the docker container, for instance:
- File
build/my_custom_environment/my_custom_environment.qcow2
- It is a qcow2 version of the environment for use with
qemu
(as seen earlier, it is not built when extendinggrid5000/from_grid5000_environment/base
).
Just run Qemu on the image:
node :
|
qemu-system-x86_64 -enable-kvm -m 2048 -cpu host ~/my_recipe/build/my_custom_environment/my_custom_environment.qcow2 |
Of course, writing recipes, building the environment, and testing it may be a trial and error process requiring to loop over the different stages.
Please note that kameleon provides an interactive debugging of the recipe in case of errors or when breakpoints are inserted in the recipe. See comments in the recipes which give the syntax to add a breakpoint.
Creating an environment for an unsupported Operating System
Note | |
---|---|
This requires strong system administrator skills and a very good understanding of how the Grid'5000 bare metal deployment functions. |
If an Operating System is not provided as a Grid'5000 environment already, please mind that kameleon recipe allows installation from scratch of any Linux systems:
- boot the OS installer in a VM and do an unattended installation
- run some additional setup
- finally export the built system ready to be consumed by
kadeploy3
.
Therefore please mind using kameleon. Please get in touch with the Grid'50000 technical team to explain your motivation and ideas and possibly to get some help.