kube-vip: optional Prometheus metrics (default port 2112) (#13229)

Add kube_vip_metrics_enabled and kube_vip_metrics_port; wire
prometheus_server and container port in the static pod manifest.
Default metrics port to 2112 to match kube-vip upstream. Document
and sample inventory updated.

docs/ingress/kube-vip.md

@@ -86,3 +86,12 @@ kube_vip_leaseduration: 30
 kube_vip_renewdeadline: 20
 kube_vip_retryperiod: 4
 ```
+
+To expose [Prometheus metrics](https://kube-vip.io/docs/installation/flags/#environment-variables) from the kube-vip static pod, set `kube_vip_metrics_enabled`. `kube_vip_metrics_port` is an integer; the manifest sets `prometheus_server` to `:PORT` because kube-vip passes that value to Go's HTTP listen address (see [`servePrometheusHTTPServer` in kube-vip](https://github.com/kube-vip/kube-vip/blob/main/cmd/kube-vip.go)). The manifest `ports` entry uses the same number for tooling that reads the pod spec.
+
+Kubespray defaults `kube_vip_metrics_port` to `2112`, matching upstream kube-vip's `--prometheusHTTPServer` default. Override it if your scrape config expects another port.
+
+```yaml
+kube_vip_metrics_enabled: true
+# kube_vip_metrics_port: 2112
+```

inventory/sample/group_vars/k8s_cluster/addons.yml

@@ -201,6 +201,8 @@ kube_vip_enabled: false
 # kube_vip_lb_fwdmethod: local
 # kube_vip_bgp_sourceip:
 # kube_vip_bgp_sourceif:
+# kube_vip_metrics_enabled: false
+# kube_vip_metrics_port: 2112
 
 # Node Feature Discovery
 node_feature_discovery_enabled: false

roles/kubernetes/node/defaults/main.yml

@@ -88,6 +88,9 @@ kube_vip_retryperiod: 1
 kube_vip_enable_node_labeling: false
 kube_vip_bgp_sourceip:
 kube_vip_bgp_sourceif:
+kube_vip_metrics_enabled: false
+# TCP port for kube-vip Prometheus metrics; manifest sets prometheus_server to :PORT (same as kube-vip upstream default, see cmd/kube-vip.go).
+kube_vip_metrics_port: 2112
 
 # Requests for load balancer app
 loadbalancer_apiserver_memory_requests: 32M

roles/kubernetes/node/templates/manifests/kube-vip.manifest.j2

@@ -109,11 +109,21 @@ spec:
 {% if kube_vip_lb_fwdmethod %}
     - name: lb_fwdmethod
       value: {{ kube_vip_lb_fwdmethod | string | to_json }}
+{% endif %}
+{% if kube_vip_metrics_enabled %}
+    - name: prometheus_server
+      value: {{ (':' ~ (kube_vip_metrics_port | string)) | to_json }}
 {% endif %}
     image: {{ kube_vip_image_repo }}:{{ kube_vip_image_tag }}
     imagePullPolicy: {{ k8s_image_pull_policy }}
     name: kube-vip
     resources: {}
+{% if kube_vip_metrics_enabled %}
+    ports:
+    - name: metrics
+      containerPort: {{ kube_vip_metrics_port }}
+      protocol: TCP
+{% endif %}
 {% if kube_vip_lb_fwdmethod == "masquerade" %}
     securityContext:
       privileged: true