Merge pull request #4365 from hashicorp/b-consul-server-resync

Fix consul server resync when server and client point to the same Consul agent

Author: Preetha

client/task_runner_test.go

@@ -143,7 +143,7 @@ func testTaskRunnerFromAlloc(t *testing.T, restarts bool, alloc *structs.Allocat
 
 	vclient := vaultclient.NewMockVaultClient()
 	cclient := consul.NewMockAgent()
-	serviceClient := consul.NewServiceClient(cclient, logger)
+	serviceClient := consul.NewServiceClient(cclient, logger, true)
 	go serviceClient.Run()
 	tr := NewTaskRunner(logger, conf, db, upd.Update, taskDir, alloc, task, vclient, serviceClient)
 	if !restarts {
@@ -1860,7 +1860,7 @@ func TestTaskRunner_CheckWatcher_Restart(t *testing.T) {
 	// backed by a mock consul whose checks are always unhealthy.
 	consulAgent := consul.NewMockAgent()
 	consulAgent.SetStatus("critical")
-	consulClient := consul.NewServiceClient(consulAgent, ctx.tr.logger)
+	consulClient := consul.NewServiceClient(consulAgent, ctx.tr.logger, true)
 	go consulClient.Run()
 	defer consulClient.Shutdown()
 

command/agent/agent.go

@@ -958,7 +958,7 @@ func (a *Agent) setupConsul(consulConfig *config.ConsulConfig) error {
 	a.consulCatalog = client.Catalog()
 
 	// Create Consul Service client for service advertisement and checks.
-	a.consulService = consul.NewServiceClient(client.Agent(), a.logger)
+	a.consulService = consul.NewServiceClient(client.Agent(), a.logger, a.Client() != nil)
 
 	// Run the Consul service client's sync'ing main loop
 	go a.consulService.Run()

command/agent/consul/client.go

@@ -232,11 +232,17 @@ type ServiceClient struct {
 
 	// checkWatcher restarts checks that are unhealthy.
 	checkWatcher *checkWatcher
+
+	// isClientAgent specifies whether this Consul client is being used
+	// by a Nomad client.
+	isClientAgent bool
 }
 
 // NewServiceClient creates a new Consul ServiceClient from an existing Consul API
-// Client and logger.
-func NewServiceClient(consulClient AgentAPI, logger *log.Logger) *ServiceClient {
+// Client, logger and takes whether the client is being used by a Nomad Client agent.
+// When being used by a Nomad client, this Consul client reconciles all services and
+// checks created by Nomad on behalf of running tasks.
+func NewServiceClient(consulClient AgentAPI, logger *log.Logger, isNomadClient bool) *ServiceClient {
 	return &ServiceClient{
 		client:             consulClient,
 		logger:             logger,
@@ -255,6 +261,7 @@ func NewServiceClient(consulClient AgentAPI, logger *log.Logger) *ServiceClient
 		agentServices:      make(map[string]struct{}),
 		agentChecks:        make(map[string]struct{}),
 		checkWatcher:       newCheckWatcher(logger, consulClient),
+		isClientAgent:      isNomadClient,
 	}
 }
 
@@ -433,7 +440,12 @@ func (c *ServiceClient) sync() error {
 			// Known service, skip
 			continue
 		}
-		if !isNomadService(id) {
+
+		// Ignore if this is not a Nomad managed service. Also ignore
+		// Nomad managed services if this is not a client agent.
+		// This is to prevent server agents from removing services
+		// registered by client agents
+		if !isNomadService(id) || !c.isClientAgent {
 			// Not managed by Nomad, skip
 			continue
 		}
@@ -470,7 +482,12 @@ func (c *ServiceClient) sync() error {
 			// Known check, leave it
 			continue
 		}
-		if !isNomadService(check.ServiceID) {
+
+		// Ignore if this is not a Nomad managed check. Also ignore
+		// Nomad managed checks if this is not a client agent.
+		// This is to prevent server agents from removing checks
+		// registered by client agents
+		if !isNomadService(check.ServiceID) || !c.isClientAgent {
 			// Service not managed by Nomad, skip
 			continue
 		}

command/agent/consul/int_test.go

@@ -142,7 +142,7 @@ func TestConsul_Integration(t *testing.T) {
 	consulClient, err := consulapi.NewClient(consulConfig)
 	assert.Nil(err)
 
-	serviceClient := consul.NewServiceClient(consulClient.Agent(), logger)
+	serviceClient := consul.NewServiceClient(consulClient.Agent(), logger, true)
 	defer serviceClient.Shutdown() // just-in-case cleanup
 	consulRan := make(chan struct{})
 	go func() {

command/agent/consul/unit_test.go

@@ -117,7 +117,7 @@ func setupFake(t *testing.T) *testFakeCtx {
 	fc := NewMockAgent()
 	tt := testTask()
 	return &testFakeCtx{
-		ServiceClient: NewServiceClient(fc, testlog.Logger(t)),
+		ServiceClient: NewServiceClient(fc, testlog.Logger(t), true),
 		FakeConsul:    fc,
 		Task:          tt,
 		MockExec:      tt.DriverExec.(*mockExec),