[OTAGENT-920] Set DD_OTELCOLLECTOR_INSTALLATION_METHOD on otel-agent container (#2846)

* Set DD_OTELCOLLECTOR_INSTALLATION_METHOD=kubernetes on otel-agent container

* Update tests

* Add env var for gateway

Author: liustanley

internal/controller/datadogagent/feature/otelcollector/envvar.go

@@ -10,4 +10,5 @@ const (
 	DDOtelCollectorCoreConfigExtensionURL     = "DD_OTELCOLLECTOR_EXTENSION_URL"
 	DDOtelCollectorCoreConfigExtensionTimeout = "DD_OTELCOLLECTOR_EXTENSION_TIMEOUT"
 	DDOtelCollectorConverterFeatures          = "DD_OTELCOLLECTOR_CONVERTER_FEATURES"
+	DDOtelCollectorInstallationMethod         = "DD_OTELCOLLECTOR_INSTALLATION_METHOD"
 )

internal/controller/datadogagent/feature/otelcollector/feature.go

@@ -399,6 +399,11 @@ func (o *otelCollectorFeature) ManageNodeAgent(managers feature.PodTemplateManag
 		})
 	}
 
+	managers.EnvVar().AddEnvVarToContainers([]apicommon.AgentContainerName{apicommon.OtelAgent}, &corev1.EnvVar{
+		Name:  DDOtelCollectorInstallationMethod,
+		Value: "kubernetes",
+	})
+
 	return nil
 }
 

internal/controller/datadogagent/feature/otelcollector/feature_test.go

@@ -29,12 +29,13 @@ type expectedPorts struct {
 }
 
 type expectedEnvVars struct {
-	agent_ipc_port     expectedEnvVar
-	agent_ipc_refresh  expectedEnvVar
-	enabled            expectedEnvVar
-	extension_timeout  expectedEnvVar
-	extension_url      expectedEnvVar
-	converter_features expectedEnvVar
+	agent_ipc_port      expectedEnvVar
+	agent_ipc_refresh   expectedEnvVar
+	enabled             expectedEnvVar
+	extension_timeout   expectedEnvVar
+	extension_url       expectedEnvVar
+	converter_features  expectedEnvVar
+	installation_method expectedEnvVar
 }
 
 type expectedEnvVar struct {
@@ -64,6 +65,10 @@ var (
 		extension_timeout:  expectedEnvVar{},
 		extension_url:      expectedEnvVar{},
 		converter_features: expectedEnvVar{},
+		installation_method: expectedEnvVar{
+			present: true,
+			value:   "kubernetes",
+		},
 	}
 
 	onlyIpcEnvVars = expectedEnvVars{
@@ -75,6 +80,10 @@ var (
 			present: true,
 			value:   "60",
 		},
+		installation_method: expectedEnvVar{
+			present: true,
+			value:   "kubernetes",
+		},
 	}
 	defaultVolumeMounts = []corev1.VolumeMount{
 		{
@@ -234,6 +243,10 @@ func Test_otelCollectorFeature_Configure(t *testing.T) {
 						present: true,
 						value:   "health_check,zpages,pprof,ddflare",
 					},
+					installation_method: expectedEnvVar{
+						present: true,
+						value:   "kubernetes",
+					},
 				},
 				map[string]string{"checksum/otel_agent-custom-config": "b4ea5ecc5c7901d3b48c58622379ecfb"},
 				defaultVolumeMounts,
@@ -272,6 +285,10 @@ func Test_otelCollectorFeature_Configure(t *testing.T) {
 						present: true,
 						value:   "health_check,zpages,pprof,ddflare",
 					},
+					installation_method: expectedEnvVar{
+						present: true,
+						value:   "kubernetes",
+					},
 				},
 				map[string]string{"checksum/otel_agent-custom-config": "d9c73c9017a4fcb811da0e51f5044b3c"},
 				defaultVolumeMounts,
@@ -321,6 +338,10 @@ func Test_otelCollectorFeature_Configure(t *testing.T) {
 					present: true,
 					value:   "13",
 				},
+				installation_method: expectedEnvVar{
+					present: true,
+					value:   "kubernetes",
+				},
 			},
 				defaultAnnotations,
 				defaultVolumeMounts,
@@ -348,6 +369,10 @@ func Test_otelCollectorFeature_Configure(t *testing.T) {
 					present: true,
 					value:   "https://localhost:1234",
 				},
+				installation_method: expectedEnvVar{
+					present: true,
+					value:   "kubernetes",
+				},
 			},
 				defaultAnnotations,
 				defaultVolumeMounts,
@@ -384,6 +409,10 @@ func Test_otelCollectorFeature_Configure(t *testing.T) {
 					present: true,
 					value:   "true",
 				},
+				installation_method: expectedEnvVar{
+					present: true,
+					value:   "kubernetes",
+				},
 			},
 				defaultAnnotations,
 				defaultVolumeMounts,
@@ -547,6 +576,13 @@ func testExpectedAgent(
 				})
 			}
 
+			if expectedEnvVars.installation_method.present {
+				wantEnvVarsOTel = append(wantEnvVarsOTel, &corev1.EnvVar{
+					Name:  DDOtelCollectorInstallationMethod,
+					Value: expectedEnvVars.installation_method.value,
+				})
+			}
+
 			if len(wantEnvVars) == 0 {
 				wantEnvVars = nil
 			}

internal/controller/datadogagent/global/otelagentgateway.go

@@ -35,6 +35,11 @@ func applyOtelAgentGatewayResources(manager feature.PodTemplateManagers, ddaSpec
 		Value: "true",
 	})
 
+	manager.EnvVar().AddEnvVarToContainer(apicommon.OtelAgent, &corev1.EnvVar{
+		Name:  "DD_OTELCOLLECTOR_INSTALLATION_METHOD",
+		Value: "kubernetes",
+	})
+
 	// Enable gateway mode
 	manager.EnvVar().AddEnvVarToContainer(apicommon.OtelAgent, &corev1.EnvVar{
 		Name:  "DD_OTELCOLLECTOR_GATEWAY_MODE",