feat(ansible): parameterise target groups so prod reuses the roles unchanged (R-ENV-02)

roles/k3s_server, roles/cilium and every node-host playbook hardcoded the dev group
names k3s_primary/k3s_secondary/k3s_servers, so the prod inventory groups could not be
selected at all. That broke the R-ENV-02 promise that prod reuses the SAME roles, and
blocked PROD-PROVISIONING.md §6 outright.

TWO KNOBS, deliberately separate — Ansible templates a play's `hosts:` BEFORE any host
context exists, so group_vars is unreadable there, while roles run WITH host context:
  * which hosts a play RUNS ON — k3s_hosts, k3s_primary_hosts/k3s_secondary_hosts
    (k3s.yml's split), vpn_egress_gateway_hosts; each `| default(<dev group>)`, set by -e
    only. Follows node-health.yml's established `<name>_hosts | default(dev)` pattern.
  * which group a ROLE means by "my primary"/"my servers" — k3s_primary_group,
    k3s_servers_group in group_vars/all.yml (dev), overridden in group_vars/k3s_prod.
    Follows the k3s_api_host convention already in this repo. No per-run flag.

DEV IS UNCHANGED — the key evidence. --list-hosts/--list-tasks/--syntax-check captured
for all 9 playbooks at HEAD and after: sorted host lists IDENTICAL for all 9, same
primary/secondary split, same 6-play site.yml. (Raw --list-hosts PRINT ORDER varies run
to run; proven to be Ansible's own set ordering by running UNMODIFIED HEAD cilium.yml
four times -> 3,1,2 / 1,3,2 / 1,2,3 / 1,2,3. Hence sorted comparison.) --list-tasks
differs in exactly two files, only by added TAGS annotations and one new assert; no task
reordered, renamed or removed. Var resolution verified per environment with -c local:
dev -> k3s_primary/192.168.1.50/sans .50,.49,127.0.0.1,.51,.52; prod ->
k3s_prod_primary/192.168.2.10/vip .9/sans .10,.9,127.0.0.1,.11,.12.

BREAKS THE SMARTMONTOOLS CIRCULAR DEPENDENCY. node_baseline tasks are now tagged
packages/system/disks, so the package install can run alone:
  ansible-playbook playbooks/node-baseline.yml -e k3s_hosts=k3s_prod --tags packages
Skipping is the guard — no disks-tagged task is selected, so the
BLOCKED-pending-disk-decision paths are never templated, let alone passed to mkfs.
Belt-and-braces, a new disks-tagged assert fires first in a FULL run and names §2
explicitly instead of failing obscurely at mkfs. `tags: never` was deliberately NOT used
(it would change the default run).

FOOTGUN FOUND AND FIXED: roles/cilium, cluster_verify and flux_bootstrap all hardcoded
.cache/dev.kubeconfig — the exact file infra/devcontainer/dev.sh exports as $KUBECONFIG.
Once prod became targetable, a prod cilium/verify run would have SILENTLY OVERWRITTEN it,
leaving the operator's kubectl quietly answering from PROD. Now cluster_kubeconfig_name
(dev.kubeconfig -> prod.kubeconfig). Dev path byte-identical.

KNOWN, DOCUMENTED, NOT FIXED HERE: flux-bootstrap.yml retargets but roles/flux_bootstrap
shells out to bootstrap/flux/bootstrap.sh with a hardcoded --path=clusters/dev — a
bootstrap/ subtree change, not a target-group change (§6, cross-referenced to §7).
vpn.egress.gateway.yml is parameterised but prod has no egress group yet and would need
its own vaulted PIA credentials. --check against prod is still impossible until the prod
vault exists — even the packages-only run needs it.

Nothing was run against the dev cluster: --list-hosts/--list-tasks/--syntax-check, plus
debug/assert with -c local, only.

Serves: R-ENV-01, R-ENV-02, R-ENV-03. Task: T-7.1.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

infra/ansible/inventory/hosts.ini

@@ -66,19 +66,21 @@ proxmox ansible_host=192.168.2.102 ansible_port=22 ansible_user=root ansible_ssh
 # `ansible_port` is the node's own real sshd (22). See group_vars/k3s_prod/vars.yml for
 # the k3s_api_host override that reflects this directly-reachable topology.
 #
-# GAP flagged for the PM, NOT fixed in this pass (inventory/group_vars only): the
-# k3s_server role hardcodes the LITERAL group names `k3s_primary` / `k3s_secondary` /
-# `k3s_servers` in roles/k3s_server/defaults/main.yml (tls-san SAN list) and
-# roles/k3s_server/tasks/main.yml (node-token delegate_to), and every node-host
-# playbook (node-baseline.yml, k3s.yml, cilium.yml, kube-vip.yml, verify.yml,
-# flux-bootstrap.yml) declares `hosts: k3s_servers` / `k3s_primary` / `k3s_secondary`
-# literally. Naming prod's groups k3s_prod_primary/k3s_prod_secondary — as this
-# checklist and PROD-PROVISIONING.md §6 both call for — means those existing
-# playbooks will NOT select prod hosts as they stand today. That's harmless right now
-# (nothing can accidentally run against prod), but it means actually reusing the dev
-# playbooks against prod later (the R-ENV-02 promise) needs either parametrizing the
-# group name they target or some other mechanism — not yet designed, tracked here so
-# it isn't lost before §6 is attempted for real.
+# GROUP-NAME GAP: CLOSED 2026-08-31. The roles and playbooks used to hardcode the
+# LITERAL dev groups (`hosts: k3s_servers` / `k3s_primary` / `k3s_secondary`, and
+# `groups['k3s_primary']` inside roles/k3s_server + roles/cilium), so nothing could
+# select the k3s_prod_* groups below. Both halves are now variables, deliberately kept
+# separate because Ansible resolves them at different times:
+#   * WHICH HOSTS A PLAY RUNS ON — `k3s_hosts` (whole-cluster plays), `k3s_primary_hosts`
+#     / `k3s_secondary_hosts` (k3s.yml's split), each defaulting to the dev group.
+#     EXTRA VARS ONLY: a play's `hosts:` is templated before any host exists, so
+#     group_vars cannot be read there. Prod: `-e k3s_hosts=k3s_prod` etc.
+#   * WHICH GROUP A ROLE MEANS BY "MY PRIMARY"/"MY SERVERS" — `k3s_primary_group` /
+#     `k3s_servers_group`, set in group_vars/all.yml (dev) and group_vars/k3s_prod/vars.yml
+#     (prod), so roles resolve their own environment with NO per-run flag — the same
+#     mechanism k3s_api_host already used.
+# Running with no extra vars is byte-for-byte the dev behaviour it always had. See
+# infra/ansible/README.md "Targeting prod" and PROD-PROVISIONING.md §6.
 # =============================================================================
 
 [k3s_prod_primary]