monitoring: keep VictoriaMetrics on Pi 5 workers

services/monitoring/helmrelease.yaml

@@ -108,6 +108,13 @@ spec:
                     operator: In
                     values:
                       - "true"
+                  # VictoriaMetrics is too memory- and CPU-heavy for the Pi 4
+                  # workers. A hard Pi 5 requirement also moves old placements
+                  # instead of leaving them on a previously selected Pi 4.
+                  - key: hardware
+                    operator: In
+                    values:
+                      - rpi5
                   - key: kubernetes.io/hostname
                     operator: NotIn
                     values:
@@ -120,20 +127,6 @@ spec:
                       - titan-22
                       - titan-24
           preferredDuringSchedulingIgnoredDuringExecution:
-            - weight: 100
-              preference:
-                matchExpressions:
-                  - key: hardware
-                    operator: In
-                    values:
-                      - rpi5
-            - weight: 50
-              preference:
-                matchExpressions:
-                  - key: hardware
-                    operator: In
-                    values:
-                      - rpi4
             - weight: 25
               preference:
                 matchExpressions: