Add dns config support

api/openapi-spec/swagger.json

@@ -1123,6 +1123,10 @@
           "description": "Arguments contain the parameters and artifacts sent to the workflow entrypoint Parameters are referencable globally using the 'workflow' variable prefix. e.g. {{workflow.parameters.myparam}}",
           "$ref": "#/definitions/io.argoproj.workflow.v1alpha1.Arguments"
         },
+        "dnsConfig": {
+          "description": "PodDNSConfig defines the DNS parameters of a pod in addition to those generated from DNSPolicy.",
+          "$ref": "#/definitions/io.k8s.api.core.v1.PodDNSConfig"
+        },
         "dnsPolicy": {
           "description": "Set DNS policy for the pod. Defaults to \"ClusterFirst\". Valid values are 'ClusterFirstWithHostNet', 'ClusterFirst', 'Default' or 'None'. DNS parameters given in DNSConfig will be merged with the policy selected with DNSPolicy. To have DNS options set along with hostNetwork, you have to specify DNS policy explicitly to 'ClusterFirstWithHostNet'.",
           "type": "string"

examples/dns-config.yaml

@@ -0,0 +1,22 @@
+apiVersion: argoproj.io/v1alpha1
+kind: Workflow                  # new type of k8s spec
+metadata:
+  generateName: test-dns-config-    # name of the workflow spec
+spec:
+  entrypoint: whalesay          # invoke the whalesay template
+  templates:
+  - name: whalesay              # name of the template
+    container:
+      image: docker/whalesay
+      command: [cowsay]
+      args: ["hello world"]
+      resources:                # limit the resources
+        limits:
+          memory: 32Mi
+          cpu: 100m
+  dnsConfig:
+    nameservers:
+      - 1.2.3.4
+    options:
+     - name: ndots
+       value: "2"

pkg/apis/workflow/v1alpha1/types.go

@@ -129,6 +129,10 @@ type WorkflowSpec struct {
 	// explicitly to 'ClusterFirstWithHostNet'.
 	DNSPolicy *apiv1.DNSPolicy `json:"dnsPolicy,omitempty"`
 
+	// PodDNSConfig defines the DNS parameters of a pod in addition to
+	// those generated from DNSPolicy.
+	DNSConfig *apiv1.PodDNSConfig `json:"dnsConfig,omitempty"`
+
 	// OnExit is a template reference which is invoked at the end of the
 	// workflow, irrespective of the success, failure, or error of the
 	// primary workflow.

workflow/controller/workflowpod.go

@@ -124,6 +124,10 @@ func (woc *wfOperationCtx) createWorkflowPod(nodeName string, mainCtr apiv1.Cont
 		pod.Spec.DNSPolicy = *woc.wf.Spec.DNSPolicy
 	}
 
+	if woc.wf.Spec.DNSConfig != nil {
+		pod.Spec.DNSConfig = woc.wf.Spec.DNSConfig
+	}
+
 	if woc.controller.Config.InstanceID != "" {
 		pod.ObjectMeta.Labels[common.LabelKeyControllerInstanceID] = woc.controller.Config.InstanceID
 	}