consul: avoid triggering unnecessary sync when removing workload

There are bits of logic in callers of RemoveWorkload on group/task
cleanup hooks which call RemoveWorkload with the "Canary" version
of the workload, in case the alloc is marked as a Canary. This logic
triggers an extra sync with Consul, and also doesn't do the intended
behavior - for which no special casing is necessary anyway. When the
workload is marked for removal, all associated services and checks
will be removed regardless of the Canary status, because the service
and check IDs do not incorporate the canary-ness in the first place.

The only place where canary-ness matters is when updating a workload,
where we need to compute the hash of the services and checks to determine
whether they have been modified, the Canary flag of which is a part of
that.

Fixes #10842

.changelog/10842.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+consul: remove ineffective edge case handling on service deregistration
+```

client/allocrunner/alloc_runner_unix_test.go

@@ -120,12 +120,12 @@ func TestAllocRunner_Restore_RunningTerminal(t *testing.T) {
 	require.Error(t, logmonProc.Signal(syscall.Signal(0)))
 
 	// Assert consul was cleaned up:
-	//   2 removals (canary+noncanary) during prekill
-	//   2 removals (canary+noncanary) during exited
-	//   2 removals (canary+noncanary) during stop
-	//   2 removals (canary+noncanary) group during stop
+	//   1 removal during prekill
+	//   1 removal during exited
+	//   1 removal during stop
+	//   1 removal group during stop
 	consulOps := conf2.Consul.(*consul.MockConsulServiceClient).GetOps()
-	require.Len(t, consulOps, 8)
+	require.Len(t, consulOps, 4)
 	for _, op := range consulOps {
 		require.Equal(t, "remove", op.Op)
 	}

client/allocrunner/groupservice_hook.go

@@ -208,11 +208,6 @@ func (h *groupServiceHook) deregister() {
 	if len(h.services) > 0 {
 		workloadServices := h.getWorkloadServices()
 		h.consulClient.RemoveWorkload(workloadServices)
-
-		// Canary flag may be getting flipped when the alloc is being
-		// destroyed, so remove both variations of the service
-		workloadServices.Canary = !workloadServices.Canary
-		h.consulClient.RemoveWorkload(workloadServices)
 	}
 }
 

client/allocrunner/groupservice_hook_test.go

@@ -54,14 +54,12 @@ func TestGroupServiceHook_NoGroupServices(t *testing.T) {
 	require.NoError(t, h.PreTaskRestart())
 
 	ops := consulClient.GetOps()
-	require.Len(t, ops, 7)
+	require.Len(t, ops, 5)
 	require.Equal(t, "add", ops[0].Op)    // Prerun
 	require.Equal(t, "update", ops[1].Op) // Update
-	require.Equal(t, "remove", ops[2].Op) // Postrun (1st)
-	require.Equal(t, "remove", ops[3].Op) // Postrun (2nd)
-	require.Equal(t, "remove", ops[4].Op) // Restart -> preKill (1st)
-	require.Equal(t, "remove", ops[5].Op) // Restart -> preKill (2nd)
-	require.Equal(t, "add", ops[6].Op)    // Restart -> preRun
+	require.Equal(t, "remove", ops[2].Op) // Postrun
+	require.Equal(t, "remove", ops[3].Op) // Restart -> preKill
+	require.Equal(t, "add", ops[4].Op)    // Restart -> preRun
 }
 
 // TestGroupServiceHook_ShutdownDelayUpdate asserts calling group service hooks
@@ -127,14 +125,12 @@ func TestGroupServiceHook_GroupServices(t *testing.T) {
 	require.NoError(t, h.PreTaskRestart())
 
 	ops := consulClient.GetOps()
-	require.Len(t, ops, 7)
+	require.Len(t, ops, 5)
 	require.Equal(t, "add", ops[0].Op)    // Prerun
 	require.Equal(t, "update", ops[1].Op) // Update
-	require.Equal(t, "remove", ops[2].Op) // Postrun (1st)
-	require.Equal(t, "remove", ops[3].Op) // Postrun (2nd)
-	require.Equal(t, "remove", ops[4].Op) // Restart -> preKill (1st)
-	require.Equal(t, "remove", ops[5].Op) // Restart -> preKill (2nd)
-	require.Equal(t, "add", ops[6].Op)    // Restart -> preRun
+	require.Equal(t, "remove", ops[2].Op) // Postrun
+	require.Equal(t, "remove", ops[3].Op) // Restart -> preKill
+	require.Equal(t, "add", ops[4].Op)    // Restart -> preRun
 }
 
 // TestGroupServiceHook_Error asserts group service hooks with group
@@ -175,14 +171,12 @@ func TestGroupServiceHook_NoNetwork(t *testing.T) {
 	require.NoError(t, h.PreTaskRestart())
 
 	ops := consulClient.GetOps()
-	require.Len(t, ops, 7)
+	require.Len(t, ops, 5)
 	require.Equal(t, "add", ops[0].Op)    // Prerun
 	require.Equal(t, "update", ops[1].Op) // Update
-	require.Equal(t, "remove", ops[2].Op) // Postrun (1st)
-	require.Equal(t, "remove", ops[3].Op) // Postrun (2nd)
-	require.Equal(t, "remove", ops[4].Op) // Restart -> preKill (1st)
-	require.Equal(t, "remove", ops[5].Op) // Restart -> preKill (2nd)
-	require.Equal(t, "add", ops[6].Op)    // Restart -> preRun
+	require.Equal(t, "remove", ops[2].Op) // Postrun
+	require.Equal(t, "remove", ops[3].Op) // Restart -> preKill
+	require.Equal(t, "add", ops[4].Op)    // Restart -> preRun
 }
 
 func TestGroupServiceHook_getWorkloadServices(t *testing.T) {

client/allocrunner/taskrunner/service_hook.go

@@ -171,13 +171,10 @@ func (h *serviceHook) Exited(context.Context, *interfaces.TaskExitedRequest, *in
 
 // deregister services from Consul.
 func (h *serviceHook) deregister() {
-	workloadServices := h.getWorkloadServices()
-	h.consulServices.RemoveWorkload(workloadServices)
-
-	// Canary flag may be getting flipped when the alloc is being
-	// destroyed, so remove both variations of the service
-	workloadServices.Canary = !workloadServices.Canary
-	h.consulServices.RemoveWorkload(workloadServices)
+	if len(h.services) > 0 {
+		workloadServices := h.getWorkloadServices()
+		h.consulServices.RemoveWorkload(workloadServices)
+	}
 	h.initialRegistration = false
 }
 

client/allocrunner/taskrunner/service_hook_test.go

@@ -39,16 +39,15 @@ func TestUpdate_beforePoststart(t *testing.T) {
 	// so Update should again wait on Poststart.
 
 	require.NoError(t, hook.Exited(context.Background(), &interfaces.TaskExitedRequest{}, &interfaces.TaskExitedResponse{}))
-	require.Len(t, c.GetOps(), 4)
+	require.Len(t, c.GetOps(), 3)
 	require.NoError(t, hook.Update(context.Background(), &interfaces.TaskUpdateRequest{Alloc: alloc}, &interfaces.TaskUpdateResponse{}))
-	require.Len(t, c.GetOps(), 4)
+	require.Len(t, c.GetOps(), 3)
 	require.NoError(t, hook.Poststart(context.Background(), &interfaces.TaskPoststartRequest{}, &interfaces.TaskPoststartResponse{}))
-	require.Len(t, c.GetOps(), 5)
+	require.Len(t, c.GetOps(), 4)
 	require.NoError(t, hook.Update(context.Background(), &interfaces.TaskUpdateRequest{Alloc: alloc}, &interfaces.TaskUpdateResponse{}))
-	require.Len(t, c.GetOps(), 6)
+	require.Len(t, c.GetOps(), 5)
 	require.NoError(t, hook.PreKilling(context.Background(), &interfaces.TaskPreKillRequest{}, &interfaces.TaskPreKillResponse{}))
-	require.Len(t, c.GetOps(), 8)
+	require.Len(t, c.GetOps(), 6)
 	require.NoError(t, hook.Update(context.Background(), &interfaces.TaskUpdateRequest{Alloc: alloc}, &interfaces.TaskUpdateResponse{}))
-	require.Len(t, c.GetOps(), 8)
-
+	require.Len(t, c.GetOps(), 6)
 }

client/allocrunner/taskrunner/task_runner_test.go

@@ -957,17 +957,16 @@ func TestTaskRunner_ShutdownDelay(t *testing.T) {
 		assert.NoError(t, tr.Kill(context.Background(), structs.NewTaskEvent("test")))
 	}()
 
-	// Wait for *2* deregistration calls (due to needing to remove both
-	// canary tag variants)
+	// Wait for *1* de-registration calls (all [non-]canary variants removed).
+
 WAIT:
 	for {
 		ops := mockConsul.GetOps()
 		switch n := len(ops); n {
-		case 1, 2:
-			// Waiting for both deregistration calls
-		case 3:
+		case 1:
+			// Waiting for single de-registration call.
+		case 2:
 			require.Equalf(t, "remove", ops[1].Op, "expected deregistration but found: %#v", ops[1])
-			require.Equalf(t, "remove", ops[2].Op, "expected deregistration but found: %#v", ops[2])
 			break WAIT
 		default:
 			// ?!
@@ -2401,25 +2400,22 @@ func TestTaskRunner_UnregisterConsul_Retries(t *testing.T) {
 
 	consul := conf.Consul.(*consulapi.MockConsulServiceClient)
 	consulOps := consul.GetOps()
-	require.Len(t, consulOps, 8)
+	require.Len(t, consulOps, 5)
 
 	// Initial add
 	require.Equal(t, "add", consulOps[0].Op)
 
-	// Removing canary and non-canary entries on first exit
+	// Removing entries on first exit
 	require.Equal(t, "remove", consulOps[1].Op)
-	require.Equal(t, "remove", consulOps[2].Op)
 
 	// Second add on retry
-	require.Equal(t, "add", consulOps[3].Op)
+	require.Equal(t, "add", consulOps[2].Op)
 
-	// Removing canary and non-canary entries on retry
-	require.Equal(t, "remove", consulOps[4].Op)
-	require.Equal(t, "remove", consulOps[5].Op)
+	// Removing entries on retry
+	require.Equal(t, "remove", consulOps[3].Op)
 
-	// Removing canary and non-canary entries on stop
-	require.Equal(t, "remove", consulOps[6].Op)
-	require.Equal(t, "remove", consulOps[7].Op)
+	// Removing entries on stop
+	require.Equal(t, "remove", consulOps[4].Op)
 }
 
 // testWaitForTaskToStart waits for the task to be running or fails the test