add HostAliases field to PodSpec to support adding entries into hosts file

pkg/api/types.go

@@ -2099,6 +2099,17 @@ type PodSpec struct {
 	// If specified, the pod's tolerations.
 	// +optional
 	Tolerations []Toleration
+	// 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.
+	// +optional
+	HostAliases []HostAlias
+}
+
+// HostAlias holds the mapping between IP and hostnames that will be injected as an entry in the
+// pod's hosts file.
+type HostAlias struct {
+	IP        string
+	Hostnames []string
 }
 
 // Sysctl defines a kernel parameter to be set