[api] Add NetworkStatus to allocation response

.changelog/17280.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+api: add missing field NetworkStatus for Allocation
+```

api/allocations.go

@@ -270,6 +270,7 @@ type Allocation struct {
 	PreviousAllocation    string
 	NextAllocation        string
 	RescheduleTracker     *RescheduleTracker
+	NetworkStatus         *AllocNetworkStatus
 	PreemptedAllocations  []string
 	PreemptedByAllocation string
 	CreateIndex           uint64
@@ -400,6 +401,15 @@ type AllocDeploymentStatus struct {
 	ModifyIndex uint64
 }
 
+// AllocNetworkStatus captures the status of an allocation's network during runtime.
+// Depending on the network mode, an allocation's address may need to be known to other
+// systems in Nomad such as service registration.
+type AllocNetworkStatus struct {
+	InterfaceName string
+	Address       string
+	DNS           *DNSConfig
+}
+
 type AllocatedResources struct {
 	Tasks  map[string]*AllocatedTaskResources
 	Shared AllocatedSharedResources

api/allocations_test.go

@@ -161,6 +161,46 @@ func TestAllocations_CreateIndexSort(t *testing.T) {
 	must.Eq(t, allocs, expect)
 }
 
+func TestAllocations_Info(t *testing.T) {
+	testutil.RequireRoot(t)
+	testutil.Parallel(t)
+
+	c, s := makeClient(t, nil, func(c *testutil.TestServerConfig) {
+		c.DevMode = true
+	})
+	defer s.Stop()
+	a := c.Allocations()
+
+	// wait for node
+	_ = oneNodeFromNodeList(t, c.Nodes())
+
+	// Create a job and attempt to register it
+	job := testJob()
+	resp, wm, err := c.Jobs().Register(job, nil)
+	must.NoError(t, err)
+	must.NotNil(t, resp)
+	must.UUIDv4(t, resp.EvalID)
+	assertWriteMeta(t, wm)
+
+	// List allocations.
+	qo := &QueryOptions{
+		WaitIndex: wm.LastIndex,
+	}
+	allocs, qm, err := a.List(qo)
+	must.NoError(t, err)
+	must.NonZero(t, qm.LastIndex)
+
+	// Check that we got one allocation.
+	must.Len(t, 1, allocs)
+	must.Eq(t, resp.EvalID, allocs[0].EvalID)
+
+	// Fetch alloc info.
+	qo.WaitIndex = qm.LastIndex
+	alloc, _, err := a.Info(allocs[0].ID, qo)
+
+	must.NotNil(t, alloc.NetworkStatus)
+}
+
 func TestAllocations_RescheduleInfo(t *testing.T) {
 	testutil.Parallel(t)