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Project CentOS boot tier-1 and cloud agents

The tier-0 and tier-1 images today do not contain any special hypervisor-specific agents. The following specifically are not included for example:

  • cloud-init
  • vmware-guest-agent
  • google-guest-agent
  • qemu-guest-agent
  • ignition
  • afterburn


Unnecessary on bare metal

For deployment to bare metal using e.g. Anaconda or bootc install, none of these are necessary.

Unnecessary for “immutable infrastructure” on hypervisors

A model we aim to emphasize is having the container image define the “source of truth” for system state. This conflicts with using e.g. cloud-init and having it fetch instance metadata and raises questions around changes to the instance metadata and when they apply.

Related to this, vmware-guest-agent includes a full “backdoor” mechanism to log into the OS.

Should be containerized anyways

In general particularly for e.g. vmware-guest-agent, it makes more sense to containerize it.

Easy to install afterward

Many of these (particularly the first ones mentioned) are easy to install in a custom image.

You can build your own derived image that includes e.g. vmware-guest-agent if required alongside all other desired customizations.

Fully supported if installed

It is supported to include these agents in your image if desired (whether as part of the base image or containerized).

What about Ignition

Ignition as shipped by CoreOS Container Linux derivatives has a lot of advantages in providing a model that works smoothly across both bare metal and virtualized scenarios.

It also has some compelling advantages over cloud-init at a technical level.

However, there is also significant overlap between a container-focused model of the world and an Ignition-focused model.

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