Merge pull request #2285 from rackerlabs/release-notes/v0.5.3

[Bot] docs: release notes for v0.5.3

Author: cardoe

changelog.d/20260902_131734_doug.goldstein.md

@@ -25,6 +25,60 @@ off for it rather than for the prose above:
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+<a id='changelog-v0.5.3'></a>
+## v0.5.3 — released 2026-09-02
+
+### Deploy repo changes
+
+`envoy-configs` gained knobs to scale the Envoy proxy pods behind a Gateway.
+Both `gateways.external` and `gateways.internal` now accept `envoyDeployment`
+and `externalTrafficPolicy`, in `envoy-configs/values.yaml`:
+
+```yaml title="envoy-configs/values.yaml"
+gateways:
+  external:
+    name: external-gateway
+    namespace: envoy-gateway
+    className: eg
+    envoyDeployment:
+      replicas: 3
+      container:
+        resources:
+          requests:
+            cpu: "250m"
+            memory: "256Mi"
+          limits:
+            cpu: "1"
+            memory: "512Mi"
+    externalTrafficPolicy: Local
+```
+
+This was added to give the shared external Gateway enough proxy replicas and
+headroom to absorb bursty traffic to nova's osapi, which routes through it
+alongside every other HTTP/TLS route. Both fields are optional; leaving them
+unset keeps Envoy Gateway's own defaults (a single replica, no resource
+requests or limits). See the
+[Gateway Schema reference](../operator-guide/gateway-api.md#gateway-schema)
+for the full set of fields.
+
+### Notes
+
+nova osapi (`nova_api_uwsgi`) was re-tuned to survive bursts of concurrent
+requests, which were filling the default 2-worker / 100-deep listen queue and
+causing connection refusals and liveness-probe restarts:
+
+- uWSGI `processes` raised from 2 to 8, and a `listen` backlog of 1024 was
+  added. Values above the node's `net.core.somaxconn` are silently capped, so
+  confirm that sysctl is at least 1024 on osapi nodes.
+- The osapi liveness probe was loosened (`initialDelaySeconds: 30`,
+  `periodSeconds: 15`, `timeoutSeconds: 10`, `failureThreshold: 6`) so a slow
+  response under load no longer triggers a destructive restart. Readiness
+  keeps a tighter probe so busy pods still drop out of rotation briefly.
+- Default osapi pod resources increased: requests from `256Mi`/none to
+  `512Mi`/`500m`, with new limits of `2Gi`/`4` CPU. This applies automatically
+  on the next resync -- confirm your cluster has the headroom before
+  upgrading, particularly if `pod.replicas.osapi` is scaled up.
+
 <a id='changelog-v0.5.0'></a>
 ## v0.5.0 — released 2026-08-19