EAI-7889 Add pod anti-affinity for SeaweedFS and fix keycloak-old CNPG topology

[silokimmo]

Related:

• EAI-7854 Spread CNPG instances across distinct nodes #802
• EAI-7854 Pin aiwb-infra-cnpg to one instance on small profile #801
• https://amd.atlassian.net/browse/EAI-7889

Companion to #802 (CNPG topology fix) and #801 (small profile pin). This PR
covers the remaining anti-affinity work from EAI-7889 that those PRs do not
address.

Problem

SeaweedFS — master, volume, and filer have zero anti-affinity. In large
clusters (3 master replicas, 3 volume replicas) all pods can land on one node.
Losing that node takes down the entire S3 storage layer.

keycloak-old CNPG — #802 fixed keycloak-config but the active Keycloak
chart is keycloak-old (root/values.yaml maps keycloak to
path: keycloak-old). The keycloak-old CNPG cluster still hardcodes
topology.kubernetes.io/zone, which is a no-op on bare-metal.

Large profile CNPG instance counts — AIRM and Keycloak CNPG run 1 instance
even on large clusters (6+ nodes). A single database instance means no
automatic failover; losing the node requires pod rescheduling and WAL recovery.

Change

SeaweedFS anti-affinity

Add preferredDuringSchedulingIgnoredDuringExecution pod anti-affinity for
master, volume, and filer components in the Seaweed CR template. Topology key
is configurable via seaweed.affinity.topologyKey (default
kubernetes.io/hostname).

Component	Large replicas	Anti-affinity
master	3	soft, weight 100
volume	3	soft, weight 100
filer	1	soft, weight 100 (future-proofing)

Soft anti-affinity ensures single-node and medium clusters still schedule all
pods without anything sitting Pending.

keycloak-old CNPG topology fix

Same pattern as #802 — expose podAntiAffinityType and topologyKey as
values, defaulting to preferred and kubernetes.io/hostname. Consistent with
the AIRM and AIWB CNPG charts from #802.

Large profile instance counts

App	Before	After	Reason
AIRM CNPG	1	2	Primary + hot standby for automatic failover
Keycloak CNPG	1	2	Auth DB failover in seconds instead of minutes

AIWB CNPG already has 3 instances — no change needed.

Files touched:

• sources/seaweedfs-config/templates/seaweedfs-seaweed.yaml — anti-affinity blocks
• sources/seaweedfs-config/values.yaml — affinity defaults
• sources/keycloak-old/templates/keycloak-cnpg.yaml — templatize topology
• sources/keycloak-old/values.yaml — topology defaults
• root/values_large.yaml — AIRM and Keycloak CNPG instances: 2

Testing

• Deploy on single-node ephemeral VM (medium profile) — verify no scheduling failures
• Deploy on multi-node cluster (3+ CP nodes) — verify SeaweedFS and CNPG pods spread across nodes
• helm template ./root on all four profiles

[oskarasbrink]

once testing steps are done, this is great