Guix Machines

• Repository Structure
  • User Supplied Files Required for Push Based Deployment
  • Guix Channel Files
    • Updating guix channels used for deployment
  • guix-machines the Guix Channel
• Push Deployment with guix deploy
• Pull Based Deployment
• Footnotes

Guix configurations for all Guix powered systems privately managed by the author. This includes all virtual machines for my home network, cloud/vps instances, as well as personal computers. Due to the variety of types of systems managed via this repository, two mutable deployment methodologies are supported:

1. A push based model, using guix deploy¹ to remotely deploy changes (useful for example from ci/cd).
2. A pull based model, using guix along with this repository directly from the target machine.

Immutable deployment is not yet supported, but is certainly possible given Guix's ability to build an operating-system configuration into a image.

Repository Structure

channels*.scm

Guix channel files

deploy/

Folder containing all guix deploy configurations

.gitignore

Files ignored by git

.guix/

Guix channel directory

.guix-authorizations

Guix authorizations file²

.guix-channel

Guix channel file³

.pub-keys/

Folder containing public key files used by Guix configurations

README.org

Org-mode⁴ documentation

TODO.org

Org-mode todo's, known issues and future aspirations

unguix/

Docker/docker-compose files used on deployed instances, managed outside of guix. Once better support for running docker/docker-compose via shepherd, specified declaratively via Guix configuration has been implemented, this directory and all files within it should be able to be removed.

User Supplied Files Required for Push Based Deployment

.deploy-key

Folder expected to contain two files (a public and private ssh key, named key.pub and key respectively).

Guix Channel Files

Guix channels⁵ allow for Guix to be customized and extended. They are also critical for replicating a Guix system⁶. As mentioned above, there are two primary classes of deployments that are managed using this repository, push based and pull based. In both cases, what specific versions of software that will be installed during deployment depends on the guix channels in use. To ensure reproducibility, channel*.scm files are provided in this repository that are expected to be used during deployment. However, multiple channel files are provided as it makes sense to lock software versions across different sets of machines in varying ways. For example, there is value in using the same channel file (and thus, same software versions) across all virtual machines running on my home hypervisor cluster, but there is no reason to explicitly lock my personal machines to the same software versions. Further, cases could arise where my personal computer configuration/s or server configuration/s need to be pinned to a specific set of software versions, and thus require a individual channel file.

Though supporting a channel file per machine is possible, it would cause additional maintenance overhead. So instead, two channel files are provided, that correspond to the two classes of machines that are managed.

channels-vms.scm

Channel file used for push based deployments to vm's running on my home hypervisor cluster

~channels.scm

Channel file used for pull based deployments of personal computers

If for some reason channels need to be pinned for a specific deployment, a new channel file named channels-<hostname>.scm can be created and used in place of normally used channel file.

TODO Updating guix channels used for deployment

This doesn't work right unless your channels match what is expected by this repository.

  guix time-machine -- describe -f channels > channels-vms.scm

guix-machines the Guix Channel

This repository is itself a Guix channel, which facilitates CI, allowing for changes to it to be evaluated by Cuirass at https://guix-ci.home.rekahsoft.ca (only available in my internal home-network). This channel is not intended to be used directly from guix systems as it doesn't provide any packages.

At a later date, this also will allow for building of machine images for immutable deployment, bootstrapping and more.

Push Deployment with guix deploy

Push based mutable deployment is the default deployment methodology for the majority of systems managed by this repository. This is particularity safe because Guix changes are done as transactions, and thus can easily be rolled back.

  guix time-machine -C channels-vms.scm -- deploy -L ./.guix deploy/<vm-hostname>.scm

Pull Based Deployment

Pull based mutable deployment is the default deployment methodology for personal computers, where using a push based method doesn't make sense. It also serves as a secondary deployment mechanism for systems normally maintained using the push deployment model; for example, this becomes necessary when facing guix deploy bugs.

To manually deploy from the target, first the contents of this repository must be transferred to the target machine. The easiest way to do this is via git, from the target like so.

  git clone https://git.home.rekahsoft.ca/rekahsoft-public/guix-machines.git

Once this repository is on the target, pull the appropriate channels as root.

  sudo -i guix pull -C $(realpath channels-<vms|manual>.scm)

Once channels have been updated successfully, use the following to reconfigure the system.

  sudo -i guix system reconfigure -L $(realpath .guix) -e '(@ (rekahsoft guix-config <vms|manual> <target>) system)'

Alternatively, the same effect can be achieved without first pulling the appropriate channels by instead using guix time-machine as follows.

  sudo -i guix time-machine -C $(realpath channels-<vms|manual>.scm) -- system reconfigure -L $(realpath .guix) -e '(@ (rekahsoft guix-config <vms|manual> <target>) system)'

Footnotes

---

¹

https://guix.gnu.org/manual/en/html_node/Invoking-guix-deploy.html

²

https://guix.gnu.org/manual/en/html_node/Channel-Authentication.html

³

https://guix.gnu.org/manual/en/html_node/Package-Modules-in-a-Sub_002ddirectory.html

⁴

https://orgmode.org/

⁵

https://guix.gnu.org/manual/en/html_node/Channels.html

⁶

https://guix.gnu.org/manual/en/html_node/Replicating-Guix.html