diff --git a/tools/functional-tester/tester/cluster.go b/tools/functional-tester/tester/cluster.go
index f258b8c16..a1d6f22f8 100644
--- a/tools/functional-tester/tester/cluster.go
+++ b/tools/functional-tester/tester/cluster.go
@@ -293,7 +293,10 @@ func (clus *Cluster) updateFailures() {
 				clus.lg.Info("no failpoints found!", zap.Error(fperr))
 			}
 			clus.failures = append(clus.failures, fpFailures...)
-		case "NO_FAIL":
+		case "NO_FAIL_WITH_STRESS":
+			clus.failures = append(clus.failures, newFailureNoOp())
+		case "NO_FAIL_WITH_NO_STRESS_FOR_LIVENESS":
+			// TODO
 			clus.failures = append(clus.failures, newFailureNoOp())
 		case "EXTERNAL":
 			clus.failures = append(clus.failures, newFailureExternal(clus.Tester.ExternalExecPath))
diff --git a/tools/functional-tester/tester/cluster_test.go b/tools/functional-tester/tester/cluster_test.go
index a6ac44c21..2653544b0 100644
--- a/tools/functional-tester/tester/cluster_test.go
+++ b/tools/functional-tester/tester/cluster_test.go
@@ -131,6 +131,8 @@ func Test_newCluster(t *testing.T) {
 				"DELAY_PEER_PORT_TX_RX_ONE_FOLLOWER",
 				"DELAY_PEER_PORT_TX_RX_LEADER",
 				"DELAY_PEER_PORT_TX_RX_ALL",
+				"NO_FAIL_WITH_STRESS",
+				"NO_FAIL_WITH_NO_STRESS_FOR_LIVENESS",
 			},
 			FailureShuffle:          true,
 			FailpointCommands:       []string{`panic("etcd-tester")`},
@@ -142,6 +144,7 @@ func Test_newCluster(t *testing.T) {
 			StressKeySuffixRange:    250000,
 			StressKeySuffixRangeTxn: 100,
 			StressKeyTxnOps:         10,
+			StressClients:           100,
 			StressQPS:               1000,
 		},
 	}
diff --git a/tools/functional-tester/tester/cluster_tester.go b/tools/functional-tester/tester/cluster_tester.go
index 9d6928ce8..e657f0dba 100644
--- a/tools/functional-tester/tester/cluster_tester.go
+++ b/tools/functional-tester/tester/cluster_tester.go
@@ -116,30 +116,34 @@ func (clus *Cluster) doRound() error {
 		zap.Int("round", clus.rd),
 		zap.Strings("failures", clus.failureStrings()),
 	)
-	for i, f := range clus.failures {
+
+	for i, fa := range clus.failures {
 		clus.cs = i
 
-		caseTotalCounter.WithLabelValues(f.Desc()).Inc()
+		caseTotalCounter.WithLabelValues(fa.Desc()).Inc()
 
 		clus.lg.Info("wait health before injecting failures")
 		if err := clus.WaitHealth(); err != nil {
 			return fmt.Errorf("wait full health error: %v", err)
 		}
 
+		// TODO: "NO_FAIL_WITH_STRESS"
+		// TODO: "NO_FAIL_WITH_NO_STRESS_FOR_LIVENESS"
+
 		clus.lg.Info(
 			"injecting failure",
 			zap.Int("round", clus.rd),
 			zap.Int("case", clus.cs),
-			zap.String("desc", f.Desc()),
+			zap.String("desc", fa.Desc()),
 		)
-		if err := f.Inject(clus); err != nil {
+		if err := fa.Inject(clus); err != nil {
 			return fmt.Errorf("injection error: %v", err)
 		}
 		clus.lg.Info(
 			"injected failure",
 			zap.Int("round", clus.rd),
 			zap.Int("case", clus.cs),
-			zap.String("desc", f.Desc()),
+			zap.String("desc", fa.Desc()),
 		)
 
 		// if run local, recovering server may conflict
@@ -149,16 +153,16 @@ func (clus *Cluster) doRound() error {
 			"recovering failure",
 			zap.Int("round", clus.rd),
 			zap.Int("case", clus.cs),
-			zap.String("desc", f.Desc()),
+			zap.String("desc", fa.Desc()),
 		)
-		if err := f.Recover(clus); err != nil {
+		if err := fa.Recover(clus); err != nil {
 			return fmt.Errorf("recovery error: %v", err)
 		}
 		clus.lg.Info(
 			"recovered failure",
 			zap.Int("round", clus.rd),
 			zap.Int("case", clus.cs),
-			zap.String("desc", f.Desc()),
+			zap.String("desc", fa.Desc()),
 		)
 
 		clus.lg.Info("pausing stresser after failure recovery, before wait health")
@@ -168,6 +172,7 @@ func (clus *Cluster) doRound() error {
 		if err := clus.WaitHealth(); err != nil {
 			return fmt.Errorf("wait full health error: %v", err)
 		}
+
 		clus.lg.Info("check consistency after recovering failures")
 		if err := clus.checkConsistency(); err != nil {
 			return fmt.Errorf("tt.checkConsistency error (%v)", err)
@@ -177,7 +182,7 @@ func (clus *Cluster) doRound() error {
 			"failure case passed",
 			zap.Int("round", clus.rd),
 			zap.Int("case", clus.cs),
-			zap.String("desc", f.Desc()),
+			zap.String("desc", fa.Desc()),
 		)
 	}
 
@@ -186,6 +191,7 @@ func (clus *Cluster) doRound() error {
 		zap.Int("round", clus.rd),
 		zap.Strings("failures", clus.failureStrings()),
 	)
+
 	return nil
 }
 
diff --git a/tools/functional-tester/tester/local-test.yaml b/tools/functional-tester/tester/local-test.yaml
index 4104691d4..09f631cfc 100644
--- a/tools/functional-tester/tester/local-test.yaml
+++ b/tools/functional-tester/tester/local-test.yaml
@@ -97,6 +97,8 @@ tester-config:
   - DELAY_PEER_PORT_TX_RX_ONE_FOLLOWER
   - DELAY_PEER_PORT_TX_RX_LEADER
   - DELAY_PEER_PORT_TX_RX_ALL
+  - NO_FAIL_WITH_STRESS
+  - NO_FAIL_WITH_NO_STRESS_FOR_LIVENESS
 
   failure-shuffle: true
   failpoint-commands:
@@ -110,7 +112,6 @@ tester-config:
   stress-types:
   - KV
   - LEASE
-  # - NO_STRESS
   # - ELECTION_RUNNER
   # - WATCH_RUNNER
   # - LOCK_RACER_RUNNER
@@ -121,4 +122,6 @@ tester-config:
   stress-key-suffix-range: 250000
   stress-key-suffix-range-txn: 100
   stress-key-txn-ops: 10
+
+  stress-clients: 100
   stress-qps: 1000
diff --git a/tools/functional-tester/tester/stress_key.go b/tools/functional-tester/tester/stress_key.go
index e3868c2ae..2359e87e1 100644
--- a/tools/functional-tester/tester/stress_key.go
+++ b/tools/functional-tester/tester/stress_key.go
@@ -44,14 +44,15 @@ type keyStresser struct {
 	keyTxnSuffixRange int
 	keyTxnOps         int
 
-	N int
-
 	rateLimiter *rate.Limiter
 
-	wg sync.WaitGroup
+	wg       sync.WaitGroup
+	clientsN int
 
+	ctx    context.Context
 	cancel func()
 	cli    *clientv3.Client
+
 	// atomicModifiedKeys records the number of keys created and deleted by the stresser.
 	atomicModifiedKeys int64
 
@@ -59,40 +60,37 @@ type keyStresser struct {
 }
 
 func (s *keyStresser) Stress() error {
-	// TODO: add backoff option
-	cli, err := s.m.CreateEtcdClient()
+	var err error
+	s.cli, err = s.m.CreateEtcdClient(grpc.WithBackoffMaxDelay(1 * time.Second))
 	if err != nil {
 		return fmt.Errorf("%v (%q)", err, s.m.EtcdClientEndpoint)
 	}
-	ctx, cancel := context.WithCancel(context.Background())
-
-	s.wg.Add(s.N)
-	s.cli = cli
-	s.cancel = cancel
+	s.ctx, s.cancel = context.WithCancel(context.Background())
 
+	s.wg.Add(s.clientsN)
 	var stressEntries = []stressEntry{
-		{weight: 0.7, f: newStressPut(cli, s.keySuffixRange, s.keySize)},
+		{weight: 0.7, f: newStressPut(s.cli, s.keySuffixRange, s.keySize)},
 		{
 			weight: 0.7 * float32(s.keySize) / float32(s.keyLargeSize),
-			f:      newStressPut(cli, s.keySuffixRange, s.keyLargeSize),
+			f:      newStressPut(s.cli, s.keySuffixRange, s.keyLargeSize),
 		},
-		{weight: 0.07, f: newStressRange(cli, s.keySuffixRange)},
-		{weight: 0.07, f: newStressRangeInterval(cli, s.keySuffixRange)},
-		{weight: 0.07, f: newStressDelete(cli, s.keySuffixRange)},
-		{weight: 0.07, f: newStressDeleteInterval(cli, s.keySuffixRange)},
+		{weight: 0.07, f: newStressRange(s.cli, s.keySuffixRange)},
+		{weight: 0.07, f: newStressRangeInterval(s.cli, s.keySuffixRange)},
+		{weight: 0.07, f: newStressDelete(s.cli, s.keySuffixRange)},
+		{weight: 0.07, f: newStressDeleteInterval(s.cli, s.keySuffixRange)},
 	}
 	if s.keyTxnSuffixRange > 0 {
 		// adjust to make up ±70% of workloads with writes
 		stressEntries[0].weight = 0.35
 		stressEntries = append(stressEntries, stressEntry{
 			weight: 0.35,
-			f:      newStressTxn(cli, s.keyTxnSuffixRange, s.keyTxnOps),
+			f:      newStressTxn(s.cli, s.keyTxnSuffixRange, s.keyTxnOps),
 		})
 	}
 	s.stressTable = createStressTable(stressEntries)
 
-	for i := 0; i < s.N; i++ {
-		go s.run(ctx)
+	for i := 0; i < s.clientsN; i++ {
+		go s.run()
 	}
 
 	s.lg.Info(
@@ -102,18 +100,18 @@ func (s *keyStresser) Stress() error {
 	return nil
 }
 
-func (s *keyStresser) run(ctx context.Context) {
+func (s *keyStresser) run() {
 	defer s.wg.Done()
 
 	for {
-		if err := s.rateLimiter.Wait(ctx); err == context.Canceled {
+		if err := s.rateLimiter.Wait(s.ctx); err == context.Canceled {
 			return
 		}
 
 		// TODO: 10-second is enough timeout to cover leader failure
 		// and immediate leader election. Find out what other cases this
 		// could be timed out.
-		sctx, scancel := context.WithTimeout(ctx, 10*time.Second)
+		sctx, scancel := context.WithTimeout(s.ctx, 10*time.Second)
 		err, modifiedKeys := s.stressTable.choose()(sctx)
 		scancel()
 		if err == nil {
diff --git a/tools/functional-tester/tester/stress_lease.go b/tools/functional-tester/tester/stress_lease.go
index 264f3ee99..ed65a9ec7 100644
--- a/tools/functional-tester/tester/stress_lease.go
+++ b/tools/functional-tester/tester/stress_lease.go
@@ -33,8 +33,8 @@ import (
 
 const (
 	// time to live for lease
-	TTL      = 120
-	TTLShort = 2
+	defaultTTL      = 120
+	defaultTTLShort = 2
 )
 
 type leaseStresser struct {
@@ -201,7 +201,7 @@ func (ls *leaseStresser) createAliveLeases() {
 		wg.Add(1)
 		go func() {
 			defer wg.Done()
-			leaseID, err := ls.createLeaseWithKeys(TTL)
+			leaseID, err := ls.createLeaseWithKeys(defaultTTL)
 			if err != nil {
 				ls.lg.Debug(
 					"createLeaseWithKeys failed",
@@ -228,7 +228,7 @@ func (ls *leaseStresser) createShortLivedLeases() {
 		wg.Add(1)
 		go func() {
 			defer wg.Done()
-			leaseID, err := ls.createLeaseWithKeys(TTLShort)
+			leaseID, err := ls.createLeaseWithKeys(defaultTTLShort)
 			if err != nil {
 				return
 			}
@@ -323,7 +323,7 @@ func (ls *leaseStresser) keepLeaseAlive(leaseID int64) {
 			// if it is renewed, this means that invariant checking have at least ttl/2 time before lease exipres which is long enough for the checking to finish.
 			// if it is not renewed, we remove the lease from the alive map so that the lease doesn't exipre during invariant checking
 			renewTime, ok := ls.aliveLeases.read(leaseID)
-			if ok && renewTime.Add(TTL/2*time.Second).Before(time.Now()) {
+			if ok && renewTime.Add(defaultTTL/2*time.Second).Before(time.Now()) {
 				ls.aliveLeases.remove(leaseID)
 				ls.lg.Debug(
 					"keepLeaseAlive lease has not been renewed, dropped it",