lib/promscrape/discovery/kubernetes: add __meta_kubernetes_pod_container_image label in the same way as Prometheus 2.38 does

See https://github.com/prometheus/prometheus/pull/11034

docs/CHANGELOG.md

@@ -20,6 +20,7 @@ The following tip changes can be tested by building VictoriaMetrics components f
 * FEATURE: [VictoriaMetrics cluster](https://docs.victoriametrics.com/Cluster-VictoriaMetrics.html): improve performance for heavy queries on systems with many CPU cores.
 * FEATURE: [vmagent](https://docs.victoriametrics.com/vmagent.html): add support for MX record types in [dns_sd_configs](https://docs.victoriametrics.com/sd_configs.html#dns_sd_configs) in the same way as Prometheus 2.38 [does](https://github.com/prometheus/prometheus/pull/10099).
 * FEATURE: [vmagent](https://docs.victoriametrics.com/vmagent.html): add `__meta_kubernetes_service_port_number` meta-label for `role: service` in [kubernetes_sd_configs](https://docs.victoriametrics.com/sd_configs.html#kubernetes_sd_configs) in the same way as Prometheus 2.38 [does](https://github.com/prometheus/prometheus/pull/11002).
+* FEATURE: [vmagent](https://docs.victoriametrics.com/vmagent.html): add `__meta_kubernetes_pod_container_image` meta-label for `role: pod` in [kubernetes_sd_configs](https://docs.victoriametrics.com/sd_configs.html#kubernetes_sd_configs) in the same way as Prometheus 2.38 [does](https://github.com/prometheus/prometheus/pull/11034).
 * FEATURE: [vmalert](https://docs.victoriametrics.com/vmalert.html): add `toTime()` template function in the same way as Prometheus 2.38 [does](https://github.com/prometheus/prometheus/pull/10993). See [these docs](https://prometheus.io/docs/prometheus/latest/configuration/template_reference/#numbers).
 
 * BUGFIX: prevent from excess CPU usage when the storage enters [read-only mode](https://docs.victoriametrics.com/Cluster-VictoriaMetrics.html#readonly-mode).

docs/sd_configs.md

@@ -776,6 +776,7 @@ One of the following `role` types can be configured to discover targets:
   * `__meta_kubernetes_pod_annotation_<annotationname>`: Each annotation from the pod object.
   * `__meta_kubernetes_pod_annotationpresent_<annotationname>`: "true" for each annotation from the pod object.
   * `__meta_kubernetes_pod_container_init`: "true" if the container is an InitContainer
+  * `__meta_kubernetes_pod_container_image`: Container image the target address points to.
   * `__meta_kubernetes_pod_container_name`: Name of the container the target address points to.
   * `__meta_kubernetes_pod_container_port_name`: Name of the container port.
   * `__meta_kubernetes_pod_container_port_number`: Number of the container port.

lib/promscrape/discovery/kubernetes/endpoints_test.go

@@ -184,7 +184,11 @@ func TestGetEndpointsLabels(t *testing.T) {
 			},
 		}
 		for cn, ports := range args.containerPorts {
-			pod.Spec.Containers = append(pod.Spec.Containers, Container{Name: cn, Ports: ports})
+			pod.Spec.Containers = append(pod.Spec.Containers, Container{
+				Name:  cn,
+				Image: "test-image",
+				Ports: ports,
+			})
 		}
 		var gw groupWatcher
 		gw.m = map[string]*urlWatcher{
@@ -298,6 +302,7 @@ func TestGetEndpointsLabels(t *testing.T) {
 				"__meta_kubernetes_node_label_node_label":        "xyz",
 				"__meta_kubernetes_node_labelpresent_node_label": "true",
 				"__meta_kubernetes_node_name":                    "test-node",
+				"__meta_kubernetes_pod_container_image":          "test-image",
 				"__meta_kubernetes_pod_container_name":           "metrics",
 				"__meta_kubernetes_pod_container_port_name":      "http-metrics",
 				"__meta_kubernetes_pod_container_port_number":    "8428",
@@ -343,6 +348,7 @@ func TestGetEndpointsLabels(t *testing.T) {
 				"__meta_kubernetes_node_label_node_label":        "xyz",
 				"__meta_kubernetes_node_labelpresent_node_label": "true",
 				"__meta_kubernetes_node_name":                    "test-node",
+				"__meta_kubernetes_pod_container_image":          "test-image",
 				"__meta_kubernetes_pod_container_name":           "metrics",
 				"__meta_kubernetes_pod_container_port_name":      "web",
 				"__meta_kubernetes_pod_container_port_number":    "8428",

lib/promscrape/discovery/kubernetes/endpointslice_test.go

@@ -304,7 +304,11 @@ func TestGetEndpointsliceLabels(t *testing.T) {
 			},
 		}
 		for cn, ports := range args.containerPorts {
-			pod.Spec.Containers = append(pod.Spec.Containers, Container{Name: cn, Ports: ports})
+			pod.Spec.Containers = append(pod.Spec.Containers, Container{
+				Name:  cn,
+				Image: "test-image",
+				Ports: ports,
+			})
 		}
 		var gw groupWatcher
 		gw.m = map[string]*urlWatcher{
@@ -432,6 +436,7 @@ func TestGetEndpointsliceLabels(t *testing.T) {
 				"__meta_kubernetes_node_label_node_label":        "xyz",
 				"__meta_kubernetes_node_labelpresent_node_label": "true",
 				"__meta_kubernetes_node_name":                    "test-node",
+				"__meta_kubernetes_pod_container_image":          "test-image",
 				"__meta_kubernetes_pod_container_name":           "metrics",
 				"__meta_kubernetes_pod_container_port_name":      "http-metrics",
 				"__meta_kubernetes_pod_container_port_number":    "8428",
@@ -484,6 +489,7 @@ func TestGetEndpointsliceLabels(t *testing.T) {
 				"__meta_kubernetes_node_label_node_label":                                 "xyz",
 				"__meta_kubernetes_node_labelpresent_node_label":                          "true",
 				"__meta_kubernetes_node_name":                                             "test-node",
+				"__meta_kubernetes_pod_container_image":                                   "test-image",
 				"__meta_kubernetes_pod_container_name":                                    "metrics",
 				"__meta_kubernetes_pod_container_port_name":                               "web",
 				"__meta_kubernetes_pod_container_port_number":                             "8428",

lib/promscrape/discovery/kubernetes/pod.go

@@ -66,6 +66,7 @@ type PodSpec struct {
 // See https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.17/#container-v1-core
 type Container struct {
 	Name  string
+	Image string
 	Ports []ContainerPort
 }
 
@@ -135,6 +136,7 @@ func appendPodLabelsInternal(ms []map[string]string, gw *groupWatcher, p *Pod, c
 }
 
 func (p *Pod) appendContainerLabels(m map[string]string, c Container, cp *ContainerPort) {
+	m["__meta_kubernetes_pod_container_image"] = c.Image
 	m["__meta_kubernetes_pod_container_name"] = c.Name
 	if cp != nil {
 		m["__meta_kubernetes_pod_container_port_name"] = cp.Name

lib/promscrape/discovery/kubernetes/pod_test.go

@@ -249,6 +249,7 @@ func TestParsePodListSuccess(t *testing.T) {
 			"__meta_kubernetes_node_name":                    "test-node",
 			"__meta_kubernetes_pod_name":                     "etcd-m01",
 			"__meta_kubernetes_pod_ip":                       "172.17.0.2",
+			"__meta_kubernetes_pod_container_image":          "k8s.gcr.io/etcd:3.4.3-0",
 			"__meta_kubernetes_pod_container_name":           "etcd",
 			"__meta_kubernetes_pod_container_port_name":      "foobar",
 			"__meta_kubernetes_pod_container_port_number":    "1234",