[8.18](backport #7011) fix: set gateway k8s replicas spec

changelog/fragments/1740492672-set-replicas-for-gateway-collector.yaml

@@ -0,0 +1,32 @@
+# Kind can be one of:
+# - breaking-change: a change to previously-documented behavior
+# - deprecation: functionality that is being removed in a later release
+# - bug-fix: fixes a problem in a previous version
+# - enhancement: extends functionality but does not break or fix existing behavior
+# - feature: new functionality
+# - known-issue: problems that we are aware of in a given version
+# - security: impacts on the security of a product or a user’s deployment.
+# - upgrade: important information for someone upgrading from a prior version
+# - other: does not fit into any of the other categories
+kind: feature
+
+# Change summary; a 80ish characters long description of the change.
+summary: set replicas for gateway collector
+
+# Long description; in case the summary is not enough to describe the change
+# this field accommodate a description without length limits.
+# NOTE: This field will be rendered only for breaking-change and known-issue kinds at the moment.
+#description:
+
+# Affected component; usually one of "elastic-agent", "fleet-server", "filebeat", "metricbeat", "auditbeat", "all", etc.
+component: "elastic-agent"
+
+# PR URL; optional; the PR number that added the changeset.
+# If not present is automatically filled by the tooling finding the PR where this changelog fragment has been added.
+# NOTE: the tooling supports backports, so it's able to fill the original PR number instead of the backport PR number.
+# Please provide it if you are adding a fragment for a different PR.
+pr: https://github.com/elastic/elastic-agent/pull/7011
+
+# Issue URL; optional; the GitHub issue related to this changeset (either closes or is part of).
+# If not present is automatically filled by the tooling with the issue linked to the PR number.
+#issue: https://github.com/owner/repo/1234

deploy/helm/edot-collector/kube-stack/managed_otlp/values.yaml

@@ -526,6 +526,7 @@ collectors:
   #  forwarding telemetry to an Elasticsearch endpoint.
   gateway:
     suffix: gateway
+    replicas: 2
     autoscaler:
       minReplicas: 2 # Start with at least 2 replicas for better availability.
       maxReplicas: 5 # Allow more scale-out if needed.

testing/integration/otel_helm_test.go

@@ -109,9 +109,9 @@ func TestOtelKubeStackHelm(t *testing.T) {
 				// (1 EDOT collector pod per node)
 				// - A Cluster wide Deployment to collect K8s metrics and
 				// events (1 EDOT collector pod per cluster)
-				// - One Gateway pod to collect, aggregate and forward
+				// - Two Gateway replicas to collect, aggregate and forward
 				// telemetry.
-				k8sStepCheckRunningPods("app.kubernetes.io/managed-by=opentelemetry-operator", 3, "otc-container"),
+				k8sStepCheckRunningPods("app.kubernetes.io/managed-by=opentelemetry-operator", 4, "otc-container"),
 			},
 		},
 	}