cluster-autoscaler-with-capi/docs/decisions.md

Decisions

Every direction chosen, rejected or reversed, newest at the bottom. Rows are never rewritten: a reversal is a new row, and the old row's status becomes superseded by #N. Status is active, proposed (not yet confirmed by lab work) or superseded by #N.

Rows 1–9 were back-filled on 2026-09-26 from the README, versions.md, the phase docs and the image-builder fixes log; their dates are when the decision was recorded, not necessarily made.

#	Date	Decision	Alternatives considered	Why	Status
1	2026-09-24	Pin CAPI core to 1.12.x (versions.md)	latest CAPI 1.14.x	CAPMOX v0.9.x is only tested against CAPI 1.11/1.12; caps workload Kubernetes and cluster-autoscaler at 1.35	active
2	2026-09-24	Management cluster is k3s on a Proxmox VM	kind on a workstation	CAPI controllers and the autoscaler must run permanently	active
3	2026-09-24	Node images built with kubernetes-sigs/image-builder (Ubuntu 24.04, Proxmox builder)	—	upstream-maintained CAPI images	active
4	2026-09-24	image-builder overrides go in a PACKER_VAR_FILES JSON	PACKER_FLAGS	flags were silently lost when PACKER_FLAGS was re-exported (fixes log #4)	active
5	2026-09-24	Cilium installed by Helm with ipam.mode=kubernetes, pod CIDR 10.244.0.0/16	ClusterResourceSet CNI flavors; pod CIDR 192.168.0.0/16	keeps the CNI version under our control; 192.168.0.0/16 overlaps the lab LAN	active
6	2026-09-24	Scale-from-zero via capacity.cluster-autoscaler.kubernetes.io/* annotations on the MachineDeployment	infrastructure provider publishing status.capacity	CAPMOX does not publish status.capacity on ProxmoxMachineTemplate	active
7	2026-09-24	Template only on pv1-1, ALLOWED_NODES=[pv1-1]	template on every node; shared storage	local-lvm is node-local and there is no shared storage yet	active
8	2026-09-26	Phase 2: spike CAPLV first; own provider if insufficient; KubeVirt as fallback (phase-2)	CAPK + KubeVirt, Metal3, own provider from the start	CAPLV shares CAPI 1.12 with CAPMOX and fits plain libvirt hosts directly	proposed
9	2026-09-26	Phases 2 and 3 are independent and can be done in either order	strict sequence	no technical dependency between the KVM provider and hosted control planes	active
10	2026-09-26	Keep project history in the repo: plans, execution logs, session notes, decisions, prompts, reviews, changelog (session)	chat history only; raw transcripts committed	research repo, reasoning must outlive sessions; transcripts are noisy and may contain secrets	active
11	2026-09-27	Cluster inspection by agents only via read-only ServiceAccount kubeconfigs minted by .claude/cluster-inspector/make-kubeconfig.sh (short-lived TokenRequest tokens, gitignored)	admin kubeconfig + permission allowlist; long-lived SA token Secret; RBAC under configs/	RBAC (view, no Secrets) enforces read-only regardless of which kubectl verb an agent runs — also closes the kubectl get secret gap from the history-conventions session; short-lived tokens limit leak impact	active
12	2026-09-27	Management cluster built by one idempotent Ansible playbook, ansible/mgmt.yml, run from the laptop (plan)	cloud-init + k3s auto-deploy manifests; bash scripts with guards; OpenTofu + Helm	owner's choice; idempotent modules, one tool; only ansible.builtin, charts through k3s's helm-controller so nothing extra on the VM	active
13	2026-09-27	CAPI providers installed by cluster-api-operator 0.28.0 (Provider CRs), cert-manager v1.21.2 pre-installed	guarded clusterctl init	declarative; re-apply is a no-op; upgrade = spec.version bump; 0.28.0 built against CAPI 1.12.10. Consequence: no clusterctl init/upgrade/move/delete	active
14	2026-09-27	Management VM created by the playbook from the pinned Ubuntu 24.04 cloud image (VM 201, 192.168.4.21)	hand-made VM; the image-builder node template	reproducible from the repo; the image-builder template is a kubeadm node image, not meant for k3s	active