feat(collector): add hostAliases support to OpenTelemetryCollector and TargetAllocator (#4902)

Retr0-XD · swiatekm · web-flow · commit 97d13550f17f · 2026-04-02T08:40:42.000-04:00
* feat(collector): add hostAliases support to OpenTelemetryCollector and TargetAllocator Adds the `hostAliases` field to `OpenTelemetryCommonFields`, which is embedded by both `OpenTelemetryCollectorSpec` (via `OpenTelemetryCollectorSpec`) and `TargetAllocatorSpec` (v1alpha1). This allows operators to inject custom entries into a collector pod's `/etc/hosts` file, which is useful when DNS resolution for specific hostnames must be overridden within a cluster. The field maps directly to `corev1.HostAlias` (Kubernetes `hostAliases` on PodSpec) and is propagated in the Deployment, DaemonSet, and StatefulSet manifests for the collector, as well as the TargetAllocator Deployment. The `DeepCopyInto` method in `zz_generated.deepcopy.go` is updated to include a proper slice deep copy for the new field. Example usage: ```yaml spec: hostAliases: - ip: "10.0.0.1" hostnames: - "internal.registry.local" ``` Closes #986 Signed-off-by: Sakthi Harish <sakthi.harish@edgeverve.com> * chore: add hostAliases to collector CRD schema Signed-off-by: Retr0-XD <sakthi.harish@edgeverve.com> * chore: add hostAliases to targetallocator CRD schema Signed-off-by: Retr0-XD <sakthi.harish@edgeverve.com> * test: add TestDeploymentHostAliases for collector deployment Signed-off-by: Retr0-XD <sakthi.harish@edgeverve.com> * test: add TestDaemonsetHostAliases for collector daemonset Signed-off-by: Retr0-XD <sakthi.harish@edgeverve.com> * test: add TestStatefulSetHostAliases for collector statefulset Signed-off-by: Retr0-XD <sakthi.harish@edgeverve.com> * test: add TestDeploymentHostAliases for targetallocator deployment Signed-off-by: Retr0-XD <sakthi.harish@edgeverve.com> * Enhance support for hostAliases in pods Added support for hostAliases in OpenTelemetryCollector and TargetAllocator pods. * Fix formatting of HostAliases assignment * Fix formatting of HostAliases assignment * Add x-kubernetes-list-type to hostnames field * Add x-kubernetes-list-type to collectors YAML * Add x-kubernetes-list-type to targetallocators.yaml * lint fixes * supression for newMetrics --------- Signed-off-by: Sakthi Harish <sakthi.harish@edgeverve.com> Signed-off-by: Retr0-XD <sakthi.harish@edgeverve.com> Co-authored-by: Mikołaj Świątek <mail+sumo@mikolajswiatek.com>
diff --git a/.chloggen/feat_add-hostaliases.yaml b/.chloggen/feat_add-hostaliases.yaml
@@ -0,0 +1,4 @@
+change_type: enhancement
+component: operator
+note: Added hostAliases support for OpenTelemetryCollector and TargetAllocator pods
+issues: [896]
diff --git a/apis/v1beta1/common.go b/apis/v1beta1/common.go
@@ -244,6 +244,11 @@ type OpenTelemetryCommonFields struct {
 	// HostUsers isolates pod processes in a separate user namespace, reducing the risk of privilege escalation.
 	// +optional
 	HostUsers *bool `json:"hostUsers,omitempty"`
+	// HostAliases is an optional list of hosts and IPs that will be injected into the pod's hosts file if specified.
+	// This is only valid for non-hostNetwork pods and is not supported on Windows.
+	// +optional
+	// +listType=atomic
+	HostAliases []v1.HostAlias `json:"hostAliases,omitempty"`
 }
 
 type StatefulSetCommonFields struct {
diff --git a/apis/v1beta1/zz_generated.deepcopy.go b/apis/v1beta1/zz_generated.deepcopy.go
diff --git a/bundle/community/manifests/opentelemetry.io_opentelemetrycollectors.yaml b/bundle/community/manifests/opentelemetry.io_opentelemetrycollectors.yaml
@@ -6303,6 +6303,21 @@ spec:
                       x-kubernetes-map-type: atomic
                   type: object
                 type: array
+              hostAliases:
+                items:
+                  properties:
+                    hostnames:
+                      items:
+                        type: string
+                      type: array
+                      x-kubernetes-list-type: atomic
+                    ip:
+                      type: string
+                  required:
+                  - ip
+                  type: object
+                type: array
+                x-kubernetes-list-type: atomic
               hostNetwork:
                 type: boolean
               hostPID:
diff --git a/bundle/community/manifests/opentelemetry.io_targetallocators.yaml b/bundle/community/manifests/opentelemetry.io_targetallocators.yaml
@@ -1333,6 +1333,21 @@ spec:
                 type: string
               global:
                 type: object
+              hostAliases:
+                items:
+                  properties:
+                    hostnames:
+                      items:
+                        type: string
+                      type: array
+                      x-kubernetes-list-type: atomic
+                    ip:
+                      type: string
+                  required:
+                  - ip
+                  type: object
+                type: array
+                x-kubernetes-list-type: atomic
               hostNetwork:
                 type: boolean
               hostPID:
diff --git a/bundle/openshift/manifests/opentelemetry.io_opentelemetrycollectors.yaml b/bundle/openshift/manifests/opentelemetry.io_opentelemetrycollectors.yaml
@@ -6302,6 +6302,21 @@ spec:
                       x-kubernetes-map-type: atomic
                   type: object
                 type: array
+              hostAliases:
+                items:
+                  properties:
+                    hostnames:
+                      items:
+                        type: string
+                      type: array
+                      x-kubernetes-list-type: atomic
+                    ip:
+                      type: string
+                  required:
+                  - ip
+                  type: object
+                type: array
+                x-kubernetes-list-type: atomic
               hostNetwork:
                 type: boolean
               hostPID:
diff --git a/bundle/openshift/manifests/opentelemetry.io_targetallocators.yaml b/bundle/openshift/manifests/opentelemetry.io_targetallocators.yaml
@@ -1333,6 +1333,21 @@ spec:
                 type: string
               global:
                 type: object
+              hostAliases:
+                items:
+                  properties:
+                    hostnames:
+                      items:
+                        type: string
+                      type: array
+                      x-kubernetes-list-type: atomic
+                    ip:
+                      type: string
+                  required:
+                  - ip
+                  type: object
+                type: array
+                x-kubernetes-list-type: atomic
               hostNetwork:
                 type: boolean
               hostPID:
diff --git a/config/crd/bases/opentelemetry.io_opentelemetrycollectors.yaml b/config/crd/bases/opentelemetry.io_opentelemetrycollectors.yaml
@@ -6289,6 +6289,21 @@ spec:
                       x-kubernetes-map-type: atomic
                   type: object
                 type: array
+              hostAliases:
+                items:
+                  properties:
+                    hostnames:
+                      items:
+                        type: string
+                      type: array
+                      x-kubernetes-list-type: atomic
+                    ip:
+                      type: string
+                  required:
+                  - ip
+                  type: object
+                type: array
+                x-kubernetes-list-type: atomic
               hostNetwork:
                 type: boolean
               hostPID:
diff --git a/config/crd/bases/opentelemetry.io_targetallocators.yaml b/config/crd/bases/opentelemetry.io_targetallocators.yaml
@@ -1331,6 +1331,21 @@ spec:
                 type: string
               global:
                 type: object
+              hostAliases:
+                items:
+                  properties:
+                    hostnames:
+                      items:
+                        type: string
+                      type: array
+                      x-kubernetes-list-type: atomic
+                    ip:
+                      type: string
+                  required:
+                  - ip
+                  type: object
+                type: array
+                x-kubernetes-list-type: atomic
               hostNetwork:
                 type: boolean
               hostPID:
diff --git a/docs/api/opentelemetrycollectors.md b/docs/api/opentelemetrycollectors.md
@@ -20243,6 +20243,14 @@ This is only applicable to Deployment mode.<br/>
           List of sources to populate environment variables on the generated pods.<br/>
         </td>
         <td>false</td>
+      </tr><tr>
+        <td><b><a href="#opentelemetrycollectorspechostaliasesindex">hostAliases</a></b></td>
+        <td>[]object</td>
+        <td>
+          HostAliases is an optional list of hosts and IPs that will be injected into the pod's hosts file if specified.
+This is only valid for non-hostNetwork pods and is not supported on Windows.<br/>
+        </td>
+        <td>false</td>
       </tr><tr>
         <td><b>hostNetwork</b></td>
         <td>boolean</td>
@@ -26716,6 +26724,41 @@ More info: https://kubernetes.io/docs/concepts/overview/working-with-objects/nam
 </table>
 
 
+### OpenTelemetryCollector.spec.hostAliases[index]
+<sup><sup>[↩ Parent](#opentelemetrycollectorspec-1)</sup></sup>
+
+
+
+HostAlias holds the mapping between IP and hostnames that will be injected as an entry in the
+pod's hosts file.
+
+<table>
+    <thead>
+        <tr>
+            <th>Name</th>
+            <th>Type</th>
+            <th>Description</th>
+            <th>Required</th>
+        </tr>
+    </thead>
+    <tbody><tr>
+        <td><b>ip</b></td>
+        <td>string</td>
+        <td>
+          IP address of the host file entry.<br/>
+        </td>
+        <td>true</td>
+      </tr><tr>
+        <td><b>hostnames</b></td>
+        <td>[]string</td>
+        <td>
+          Hostnames for the above IP address.<br/>
+        </td>
+        <td>false</td>
+      </tr></tbody>
+</table>
+
+
 ### OpenTelemetryCollector.spec.ingress
 <sup><sup>[↩ Parent](#opentelemetrycollectorspec-1)</sup></sup>
 
diff --git a/docs/api/targetallocators.md b/docs/api/targetallocators.md
@@ -178,6 +178,14 @@ The default is relabel-config.<br/>
 For more info, see https://prometheus.io/docs/prometheus/latest/configuration/configuration/#configuration-file.<br/>
         </td>
         <td>false</td>
+      </tr><tr>
+        <td><b><a href="#targetallocatorspechostaliasesindex">hostAliases</a></b></td>
+        <td>[]object</td>
+        <td>
+          HostAliases is an optional list of hosts and IPs that will be injected into the pod's hosts file if specified.
+This is only valid for non-hostNetwork pods and is not supported on Windows.<br/>
+        </td>
+        <td>false</td>
       </tr><tr>
         <td><b>hostNetwork</b></td>
         <td>boolean</td>
@@ -5611,6 +5619,41 @@ More info: https://kubernetes.io/docs/concepts/overview/working-with-objects/nam
 </table>
 
 
+### TargetAllocator.spec.hostAliases[index]
+<sup><sup>[↩ Parent](#targetallocatorspec)</sup></sup>
+
+
+
+HostAlias holds the mapping between IP and hostnames that will be injected as an entry in the
+pod's hosts file.
+
+<table>
+    <thead>
+        <tr>
+            <th>Name</th>
+            <th>Type</th>
+            <th>Description</th>
+            <th>Required</th>
+        </tr>
+    </thead>
+    <tbody><tr>
+        <td><b>ip</b></td>
+        <td>string</td>
+        <td>
+          IP address of the host file entry.<br/>
+        </td>
+        <td>true</td>
+      </tr><tr>
+        <td><b>hostnames</b></td>
+        <td>[]string</td>
+        <td>
+          Hostnames for the above IP address.<br/>
+        </td>
+        <td>false</td>
+      </tr></tbody>
+</table>
+
+
 ### TargetAllocator.spec.initContainers[index]
 <sup><sup>[↩ Parent](#targetallocatorspec)</sup></sup>
 
diff --git a/internal/manifests/collector/daemonset.go b/internal/manifests/collector/daemonset.go
@@ -54,6 +54,7 @@ func DaemonSet(params manifests.Params) (*appsv1.DaemonSet, error) {
 					HostNetwork:                   params.OtelCol.Spec.HostNetwork,
 					HostPID:                       params.OtelCol.Spec.HostPID,
 					HostUsers:                     params.OtelCol.Spec.HostUsers,
+					HostAliases:                   params.OtelCol.Spec.HostAliases,
 					ShareProcessNamespace:         &params.OtelCol.Spec.ShareProcessNamespace,
 					DNSPolicy:                     manifestutils.GetDNSPolicy(params.OtelCol.Spec.HostNetwork, params.OtelCol.Spec.PodDNSConfig, params.OtelCol.Spec.DNSPolicy),
 					DNSConfig:                     &params.OtelCol.Spec.PodDNSConfig,
diff --git a/internal/manifests/collector/daemonset_test.go b/internal/manifests/collector/daemonset_test.go
@@ -182,6 +182,45 @@ func TestDaemonsetHostUsers(t *testing.T) {
 	assert.False(t, *d3.Spec.Template.Spec.HostUsers)
 }
 
+func TestDaemonsetHostAliases(t *testing.T) {
+	params1 := manifests.Params{
+		Config: config.New(),
+		OtelCol: v1beta1.OpenTelemetryCollector{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      "my-instance",
+				Namespace: "my-namespace",
+			},
+			Spec: v1beta1.OpenTelemetryCollectorSpec{},
+		},
+		Log: testLogger,
+	}
+	// test default (unset)
+	d1, err := DaemonSet(params1)
+	require.NoError(t, err)
+	assert.Empty(t, d1.Spec.Template.Spec.HostAliases)
+
+	// verify hostAliases set
+	aliases := []v1.HostAlias{{IP: "1.2.3.4", Hostnames: []string{"host.local"}}}
+	params2 := manifests.Params{
+		Config: config.New(),
+		OtelCol: v1beta1.OpenTelemetryCollector{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      "my-instance",
+				Namespace: "my-namespace",
+			},
+			Spec: v1beta1.OpenTelemetryCollectorSpec{
+				OpenTelemetryCommonFields: v1beta1.OpenTelemetryCommonFields{
+					HostAliases: aliases,
+				},
+			},
+		},
+		Log: testLogger,
+	}
+	d2, err := DaemonSet(params2)
+	require.NoError(t, err)
+	assert.Equal(t, aliases, d2.Spec.Template.Spec.HostAliases)
+}
+
 func TestDaemonsetDNSPolicy(t *testing.T) {
 	params1 := manifests.Params{
 		Config: config.New(),
diff --git a/internal/manifests/collector/deployment.go b/internal/manifests/collector/deployment.go
@@ -55,6 +55,7 @@ func Deployment(params manifests.Params) (*appsv1.Deployment, error) {
 					HostNetwork:                   params.OtelCol.Spec.HostNetwork,
 					HostPID:                       params.OtelCol.Spec.HostPID,
 					HostUsers:                     params.OtelCol.Spec.HostUsers,
+					HostAliases:                   params.OtelCol.Spec.HostAliases,
 					ShareProcessNamespace:         &params.OtelCol.Spec.ShareProcessNamespace,
 					Tolerations:                   params.OtelCol.Spec.Tolerations,
 					NodeSelector:                  params.OtelCol.Spec.NodeSelector,
diff --git a/internal/manifests/collector/deployment_test.go b/internal/manifests/collector/deployment_test.go
@@ -350,6 +350,50 @@ func TestDeploymentHostUsers(t *testing.T) {
 	assert.False(t, *d3.Spec.Template.Spec.HostUsers)
 }
 
+func TestDeploymentHostAliases(t *testing.T) {
+	// Test default (unset)
+	otelcol1 := v1beta1.OpenTelemetryCollector{
+		ObjectMeta: metav1.ObjectMeta{
+			Name: "my-instance",
+		},
+	}
+
+	cfg := config.New()
+
+	params1 := manifests.Params{
+		Config:  cfg,
+		OtelCol: otelcol1,
+		Log:     testLogger,
+	}
+
+	d1, err := Deployment(params1)
+	require.NoError(t, err)
+	assert.Empty(t, d1.Spec.Template.Spec.HostAliases)
+
+	// Test hostAliases set
+	aliases := []v1.HostAlias{{IP: "1.2.3.4", Hostnames: []string{"host.local"}}}
+	otelcol2 := v1beta1.OpenTelemetryCollector{
+		ObjectMeta: metav1.ObjectMeta{
+			Name: "my-instance-hostaliases",
+		},
+		Spec: v1beta1.OpenTelemetryCollectorSpec{
+			OpenTelemetryCommonFields: v1beta1.OpenTelemetryCommonFields{
+				HostAliases: aliases,
+			},
+		},
+	}
+
+	params2 := manifests.Params{
+		Config:  cfg,
+		OtelCol: otelcol2,
+		Log:     testLogger,
+	}
+
+	d2, err := Deployment(params2)
+	require.NoError(t, err)
+	assert.Equal(t, aliases, d2.Spec.Template.Spec.HostAliases)
+}
+
 func TestDeploymentDNSPolicy(t *testing.T) {
 	otelcol1 := v1beta1.OpenTelemetryCollector{
 		ObjectMeta: metav1.ObjectMeta{
diff --git a/internal/manifests/collector/statefulset.go b/internal/manifests/collector/statefulset.go
@@ -65,6 +65,7 @@ func StatefulSet(params manifests.Params) (*appsv1.StatefulSet, error) {
 					HostNetwork:                   params.OtelCol.Spec.HostNetwork,
 					HostPID:                       params.OtelCol.Spec.HostPID,
 					HostUsers:                     params.OtelCol.Spec.HostUsers,
+					HostAliases:                   params.OtelCol.Spec.HostAliases,
 					ShareProcessNamespace:         &params.OtelCol.Spec.ShareProcessNamespace,
 					Tolerations:                   params.OtelCol.Spec.Tolerations,
 					NodeSelector:                  params.OtelCol.Spec.NodeSelector,
diff --git a/internal/manifests/collector/statefulset_test.go b/internal/manifests/collector/statefulset_test.go
diff --git a/internal/manifests/targetallocator/deployment.go b/internal/manifests/targetallocator/deployment.go
diff --git a/internal/manifests/targetallocator/deployment_test.go b/internal/manifests/targetallocator/deployment_test.go
