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Templates are stopped VM instances that the runner clones from for each scenario run. Each template is a Debian 12 base image pre-provisioned with specific software. Cloning is fast (a few seconds); provisioning only happens once, when the template is first created. Template instances are named template-{name} in incus/lima (e.g. template-debian-docker).

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Available Templates

TemplatevCPUsRAMDescription
debian-base11 GBDebian 12 with basic tools (curl, wget, python3, vim, git)
debian-docker12 GBDebian 12 with Docker CE pre-installed
debian-podman12 GBDebian 12 with Podman pre-installed (rootful, cgroupfs)
debian-k3s22 GBDebian 12 with k3s (lightweight Kubernetes) pre-installed
debian-localstack12 GBDebian 12 with AWS CLI v2 and moto server on port 4566
All templates use a 10 GB disk.

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Auto-Initialization

Templates are created automatically the first time a scenario references them. When the runner starts and a referenced template doesn’t exist as a stopped instance, it:
  1. Boots a fresh VM from the Debian 12 cloud image
  2. Runs the provisioning playbooks (installs Docker, k3s, etc.)
  3. Stops and saves the VM as template-{name}
This happens once per template per machine. Subsequent runs clone from the existing template and start in seconds.

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Listing Templates

Check which templates have been initialized: 
incus list template-

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Deleting a Template

Delete a template to force re-initialization on the next run. Useful if a template becomes stale or you want to pick up a newer base image. 
incus delete template-debian-docker
Deleting a template does not affect existing VM clones. The next run that references the deleted template will re-provision it from scratch, which takes a few minutes.

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Purging Stale Clones

If a run or sandbox prepare session is interrupted, clone VMs may be left behind. Use purge-vms to clean them up. Template instances are never touched. 
2501-runner sandbox purge-vms [-m incus|lima]
If -m is omitted, both providers are tried.