From 9ab046eb9e8a9d8cb13d0392542a149a800085f5 Mon Sep 17 00:00:00 2001
From: Aleksei Sviridkin <f@lex.la>
Date: Sat, 4 Jul 2026 13:57:38 +0300
Subject: [PATCH] fix(seaweedfs): soften master anti-affinity for small
 clusters

The vendored subchart pins the master to a hard hostname anti-affinity
(requiredDuringSchedulingIgnoredDuringExecution). With the master
StatefulSet at three replicas, the surplus Pods stay Pending forever on
clusters with fewer than three nodes, so `helm install --wait` never
returns and the S3 stack never comes up.

Soften the term to a strong preference (weight 100) so the masters still
spread across distinct nodes when the cluster has them, while single-
and dual-node clusters can bring the master up. Mirrors the posture
already used for the s3 component. Selector and topologyKey are
unchanged; only required -> preferred.

Assisted-By: Claude <noreply@anthropic.com>
Signed-off-by: Aleksei Sviridkin <f@lex.la>
---
 .../seaweedfs/tests/master_affinity_test.yaml | 33 +++++++++++++++++++
 packages/system/seaweedfs/values.yaml         | 22 +++++++++++++
 2 files changed, 55 insertions(+)
 create mode 100644 packages/system/seaweedfs/tests/master_affinity_test.yaml

diff --git a/packages/system/seaweedfs/tests/master_affinity_test.yaml b/packages/system/seaweedfs/tests/master_affinity_test.yaml
new file mode 100644
index 000000000..8fd4eaba5
--- /dev/null
+++ b/packages/system/seaweedfs/tests/master_affinity_test.yaml
@@ -0,0 +1,33 @@
+suite: seaweedfs master anti-affinity
+
+# Pins the master anti-affinity override that keeps the 3-replica master
+# StatefulSet schedulable on clusters with fewer than three nodes. The upstream
+# subchart ships a HARD hostname anti-affinity
+# (requiredDuringSchedulingIgnoredDuringExecution); with three replicas that
+# leaves the surplus master Pods Pending forever on a single- or dual-node
+# cluster, so `helm install --wait` never returns. The overlay softens it to a
+# strong preference (weight 100) so the masters still spread across distinct
+# nodes when the cluster has them. This guards against a subchart bump silently
+# re-hardening the term back to required.
+
+templates:
+  - charts/seaweedfs/templates/master/master-statefulset.yaml
+
+release:
+  name: seaweedfs
+  namespace: cozy-seaweedfs
+
+tests:
+  - it: softens the master hostname anti-affinity to a preference
+    asserts:
+      - notExists:
+          path: spec.template.spec.affinity.podAntiAffinity.requiredDuringSchedulingIgnoredDuringExecution
+      - equal:
+          path: spec.template.spec.affinity.podAntiAffinity.preferredDuringSchedulingIgnoredDuringExecution[0].weight
+          value: 100
+      - equal:
+          path: spec.template.spec.affinity.podAntiAffinity.preferredDuringSchedulingIgnoredDuringExecution[0].podAffinityTerm.topologyKey
+          value: kubernetes.io/hostname
+      - equal:
+          path: spec.template.spec.affinity.podAntiAffinity.preferredDuringSchedulingIgnoredDuringExecution[0].podAffinityTerm.labelSelector.matchLabels["app.kubernetes.io/component"]
+          value: master
diff --git a/packages/system/seaweedfs/values.yaml b/packages/system/seaweedfs/values.yaml
index 488fca098..c363dc3ed 100644
--- a/packages/system/seaweedfs/values.yaml
+++ b/packages/system/seaweedfs/values.yaml
@@ -45,6 +45,28 @@ seaweedfs:
       timeoutSeconds: 30
     readinessProbe:
       timeoutSeconds: 30
+    # The upstream subchart pins the master to a HARD hostname anti-affinity
+    # (requiredDuringSchedulingIgnoredDuringExecution). With the 3-replica
+    # StatefulSet above, that makes the master unschedulable on clusters with
+    # fewer than three nodes: the surplus master Pods stay Pending forever, so
+    # `helm install --wait` never returns and Flux loops install/uninstall —
+    # the whole S3 stack never comes up. Soften it to a strong preference
+    # (weight 100) so the masters still spread across distinct nodes whenever
+    # the cluster has them, while single- and dual-node clusters can still
+    # bring the master up. Same posture already used for the s3 component
+    # below. Selector and topologyKey are unchanged from the subchart default;
+    # only required -> preferred.
+    affinity: |
+      podAntiAffinity:
+        preferredDuringSchedulingIgnoredDuringExecution:
+          - weight: 100
+            podAffinityTerm:
+              labelSelector:
+                matchLabels:
+                  app.kubernetes.io/name: {{ template "seaweedfs.name" . }}
+                  app.kubernetes.io/instance: {{ .Release.Name }}
+                  app.kubernetes.io/component: master
+              topologyKey: kubernetes.io/hostname
   volume:
     replicas: 2
     resizeHook: