diff --git a/metropolis/node/core/curator/BUILD.bazel b/metropolis/node/core/curator/BUILD.bazel
index 24c2d97..dc39f38 100644
--- a/metropolis/node/core/curator/BUILD.bazel
+++ b/metropolis/node/core/curator/BUILD.bazel
@@ -79,7 +79,9 @@
         "@io_etcd_go_etcd_client_v3//:client",
         "@io_etcd_go_etcd_tests_v3//integration",
         "@org_golang_google_grpc//:go_default_library",
+        "@org_golang_google_grpc//grpclog",
         "@org_golang_google_grpc//test/bufconn",
         "@org_golang_google_protobuf//proto",
+        "@org_uber_go_zap//:zap",
     ],
 )
diff --git a/metropolis/node/core/curator/curator_test.go b/metropolis/node/core/curator/curator_test.go
index e9674f5..c4ae80a 100644
--- a/metropolis/node/core/curator/curator_test.go
+++ b/metropolis/node/core/curator/curator_test.go
@@ -9,11 +9,14 @@
 
 	clientv3 "go.etcd.io/etcd/client/v3"
 	"go.etcd.io/etcd/tests/v3/integration"
+	"go.uber.org/zap"
+	"google.golang.org/grpc/grpclog"
 
 	"source.monogon.dev/metropolis/node/core/consensus"
 	"source.monogon.dev/metropolis/node/core/identity"
 	"source.monogon.dev/metropolis/node/core/rpc"
 	"source.monogon.dev/metropolis/pkg/event"
+	"source.monogon.dev/metropolis/pkg/logtree"
 	"source.monogon.dev/metropolis/pkg/supervisor"
 )
 
@@ -44,7 +47,7 @@
 
 // newDut creates a new dut harness for a curator instance, connected to a given
 // etcd endpoint.
-func newDut(ctx context.Context, t *testing.T, endpoint string, n *identity.NodeCredentials) *dut {
+func newDut(ctx context.Context, lt *logtree.LogTree, t *testing.T, endpoint string, n *identity.NodeCredentials) *dut {
 	t.Helper()
 	// Create new etcd client to the given endpoint.
 	cli, err := clientv3.New(clientv3.Config{
@@ -53,6 +56,7 @@
 		DialKeepAliveTime:    1 * time.Second,
 		DialKeepAliveTimeout: 1 * time.Second,
 		Context:              ctx,
+		Logger:               logtree.Zapify(lt.MustLeveledFor("client"), zap.WarnLevel),
 	})
 	if err != nil {
 		t.Fatalf("clientv3.New: %v", err)
@@ -175,12 +179,20 @@
 // of them respond correctly to election, partitioning and subsequent
 // re-election.
 func TestLeaderElectionStatus(t *testing.T) {
+	lt := logtree.New()
+	logtree.PipeAllToTest(t, lt)
+
 	ctx, ctxC := context.WithCancel(context.Background())
 	cfg := integration.ClusterConfig{
 		Size:                 3,
 		GRPCKeepAliveMinTime: time.Millisecond,
+		LoggerBuilder: func(memberName string) *zap.Logger {
+			dn := logtree.DN("etcd." + memberName)
+			return logtree.Zapify(lt.MustLeveledFor(dn), zap.WarnLevel)
+		},
 	}
 	integration.BeforeTestExternal(t)
+	grpclog.SetLoggerV2(logtree.GRPCify(lt.MustLeveledFor("grpc")))
 	cluster = integration.NewClusterV3(t, &cfg)
 	t.Cleanup(func() {
 		ctxC()
@@ -208,7 +220,7 @@
 	dutC := make(chan *dut)
 	supervisor.TestHarness(t, func(ctx context.Context) error {
 		for e, n := range endpointToNum {
-			dutC <- newDut(ctx, t, e, ephemeral.Nodes[n])
+			dutC <- newDut(ctx, lt, t, e, ephemeral.Nodes[n])
 		}
 		close(dutC)
 		supervisor.Signal(ctx, supervisor.SignalHealthy)
diff --git a/metropolis/node/core/curator/impl_leader_test.go b/metropolis/node/core/curator/impl_leader_test.go
index b5b46de..5063fef 100644
--- a/metropolis/node/core/curator/impl_leader_test.go
+++ b/metropolis/node/core/curator/impl_leader_test.go
@@ -15,7 +15,9 @@
 	"time"
 
 	"go.etcd.io/etcd/tests/v3/integration"
+	"go.uber.org/zap"
 	"google.golang.org/grpc"
+	"google.golang.org/grpc/grpclog"
 	"google.golang.org/grpc/test/bufconn"
 	"google.golang.org/protobuf/proto"
 
@@ -52,8 +54,13 @@
 
 	// Start a single-node etcd cluster.
 	integration.BeforeTestExternal(t)
+	grpclog.SetLoggerV2(logtree.GRPCify(lt.MustLeveledFor("grpc")))
 	cluster := integration.NewClusterV3(t, &integration.ClusterConfig{
 		Size: 1,
+		LoggerBuilder: func(memberName string) *zap.Logger {
+			dn := logtree.DN("etcd." + memberName)
+			return logtree.Zapify(lt.MustLeveledFor(dn), zap.WarnLevel)
+		},
 	})
 	// Clean up the etcd cluster and cancel the context on test end. We don't just
 	// use a context because we need the cluster to terminate synchronously before
diff --git a/metropolis/pkg/event/etcd/BUILD.bazel b/metropolis/pkg/event/etcd/BUILD.bazel
index 51ad5c1..37df147 100644
--- a/metropolis/pkg/event/etcd/BUILD.bazel
+++ b/metropolis/pkg/event/etcd/BUILD.bazel
@@ -20,10 +20,13 @@
     deps = [
         "//metropolis/node/core/consensus/client",
         "//metropolis/pkg/event",
+        "//metropolis/pkg/logtree",
         "@io_etcd_go_etcd_api_v3//v3rpc/rpctypes",
         "@io_etcd_go_etcd_client_pkg_v3//testutil",
         "@io_etcd_go_etcd_client_v3//:client",
         "@io_etcd_go_etcd_tests_v3//integration",
         "@org_golang_google_grpc//codes",
+        "@org_golang_google_grpc//grpclog",
+        "@org_uber_go_zap//:zap",
     ],
 )
diff --git a/metropolis/pkg/event/etcd/etcd_test.go b/metropolis/pkg/event/etcd/etcd_test.go
index 81aee51..e7e1227 100644
--- a/metropolis/pkg/event/etcd/etcd_test.go
+++ b/metropolis/pkg/event/etcd/etcd_test.go
@@ -16,10 +16,13 @@
 	"go.etcd.io/etcd/client/pkg/v3/testutil"
 	clientv3 "go.etcd.io/etcd/client/v3"
 	"go.etcd.io/etcd/tests/v3/integration"
+	"go.uber.org/zap"
 	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/grpclog"
 
 	"source.monogon.dev/metropolis/node/core/consensus/client"
 	"source.monogon.dev/metropolis/pkg/event"
+	"source.monogon.dev/metropolis/pkg/logtree"
 )
 
 var (
@@ -29,14 +32,22 @@
 
 // TestMain brings up a 3 node etcd cluster for tests to use.
 func TestMain(m *testing.M) {
+	// This logtree's data is not output anywhere.
+	lt := logtree.New()
+
 	cfg := integration.ClusterConfig{
 		Size:                 3,
 		GRPCKeepAliveMinTime: time.Millisecond,
+		LoggerBuilder: func(memberName string) *zap.Logger {
+			dn := logtree.DN("etcd." + memberName)
+			return logtree.Zapify(lt.MustLeveledFor(dn), zap.WarnLevel)
+		},
 	}
 	tb, cancel := testutil.NewTestingTBProthesis("curator")
 	defer cancel()
 	flag.Parse()
 	integration.BeforeTestExternal(tb)
+	grpclog.SetLoggerV2(logtree.GRPCify(lt.MustLeveledFor("grpc")))
 	cluster = integration.NewClusterV3(tb, &cfg)
 	endpoints = make([]string, 3)
 	for i := range endpoints {
diff --git a/metropolis/pkg/pki/BUILD.bazel b/metropolis/pkg/pki/BUILD.bazel
index ec3babe..97e7fb1 100644
--- a/metropolis/pkg/pki/BUILD.bazel
+++ b/metropolis/pkg/pki/BUILD.bazel
@@ -28,7 +28,9 @@
     embed = [":pki"],
     deps = [
         "//metropolis/node/core/consensus/client",
+        "//metropolis/pkg/logtree",
         "@io_etcd_go_etcd_client_pkg_v3//testutil",
         "@io_etcd_go_etcd_tests_v3//integration",
+        "@org_uber_go_zap//:zap",
     ],
 )
diff --git a/metropolis/pkg/pki/certificate_test.go b/metropolis/pkg/pki/certificate_test.go
index d38b559..19baf94 100644
--- a/metropolis/pkg/pki/certificate_test.go
+++ b/metropolis/pkg/pki/certificate_test.go
@@ -10,15 +10,24 @@
 
 	"go.etcd.io/etcd/client/pkg/v3/testutil"
 	"go.etcd.io/etcd/tests/v3/integration"
+	"go.uber.org/zap"
+
+	"source.monogon.dev/metropolis/pkg/logtree"
 )
 
 // TestManaged ensures Managed Certificates work, including re-ensuring
 // certificates with the same data and issuing subordinate certificates.
 func TestManaged(t *testing.T) {
+	lt := logtree.New()
+	logtree.PipeAllToTest(t, lt)
 	tb, cancel := testutil.NewTestingTBProthesis("pki-managed")
 	defer cancel()
 	cluster := integration.NewClusterV3(tb, &integration.ClusterConfig{
 		Size: 1,
+		LoggerBuilder: func(memberName string) *zap.Logger {
+			dn := logtree.DN("etcd." + memberName)
+			return logtree.Zapify(lt.MustLeveledFor(dn), zap.WarnLevel)
+		},
 	})
 	cl := cluster.Client(0)
 	defer cluster.Terminate(tb)
@@ -103,10 +112,16 @@
 // re-Ensuring certificates with the same public key, and attempting to re-issue
 // the same certificate with a different public key (which should fail).
 func TestExternal(t *testing.T) {
+	lt := logtree.New()
+	logtree.PipeAllToTest(t, lt)
 	tb, cancel := testutil.NewTestingTBProthesis("pki-managed")
 	defer cancel()
 	cluster := integration.NewClusterV3(tb, &integration.ClusterConfig{
 		Size: 1,
+		LoggerBuilder: func(memberName string) *zap.Logger {
+			dn := logtree.DN("etcd." + memberName)
+			return logtree.Zapify(lt.MustLeveledFor(dn), zap.WarnLevel)
+		},
 	})
 	cl := cluster.Client(0)
 	defer cluster.Terminate(tb)
diff --git a/third_party/go/patches/etcd-integration-logging.patch b/third_party/go/patches/etcd-integration-logging.patch
new file mode 100644
index 0000000..9652524
--- /dev/null
+++ b/third_party/go/patches/etcd-integration-logging.patch
@@ -0,0 +1,44 @@
+Implement LoggerBuilder override in etcd integration library. That library is
+generally not designed to be consumed by outside code, and we should migrate
+off of it instead. But that's a future Monogon problem.
+
+diff -ur io_etcd_go_etcd_tests_v3.orig/integration/cluster.go io_etcd_go_etcd_tests_v3/integration/cluster.go
+--- io_etcd_go_etcd_tests_v3.orig/integration/cluster.go	2023-04-05 10:18:09.220532258 +0200
++++ io_etcd_go_etcd_tests_v3/integration/cluster.go	2023-04-05 10:26:36.870901710 +0200
+@@ -171,6 +170,7 @@
+ 
+ 	WatchProgressNotifyInterval time.Duration
+ 	CorruptCheckTime            time.Duration
++	LoggerBuilder func(memberName string) *zap.Logger
+ }
+ 
+ type cluster struct {
+@@ -334,6 +335,7 @@
+ 			leaseCheckpointInterval:     c.cfg.LeaseCheckpointInterval,
+ 			WatchProgressNotifyInterval: c.cfg.WatchProgressNotifyInterval,
+ 			CorruptCheckTime:            c.cfg.CorruptCheckTime,
++			LoggerBuilder:               c.cfg.LoggerBuilder,
+ 		})
+ 	m.DiscoveryURL = c.cfg.DiscoveryURL
+ 	if c.cfg.UseGRPC {
+@@ -638,6 +640,7 @@
+ 	leaseCheckpointPersist      bool
+ 	WatchProgressNotifyInterval time.Duration
+ 	CorruptCheckTime            time.Duration
++	LoggerBuilder               func(memberName string) *zap.Logger
+ }
+ 
+ // mustNewMember return an inited member with the given name. If peerTLS is
+@@ -747,7 +750,11 @@
+ 
+ 	m.V2Deprecation = config.V2_DEPR_DEFAULT
+ 	m.grpcServerRecorder = &grpc_testing.GrpcRecorder{}
+-	m.Logger = memberLogger(t, mcfg.name)
++	if mcfg.LoggerBuilder != nil {
++		m.Logger = mcfg.LoggerBuilder(mcfg.name)
++	} else {
++		m.Logger = memberLogger(t, mcfg.name)
++	}
+ 	t.Cleanup(func() {
+ 		// if we didn't cleanup the logger, the consecutive test
+ 		// might reuse this (t).
diff --git a/third_party/go/repositories.bzl b/third_party/go/repositories.bzl
index 2b780d7..b58c990 100644
--- a/third_party/go/repositories.bzl
+++ b/third_party/go/repositories.bzl
@@ -6198,6 +6198,10 @@
     go_repository(
         name = "io_etcd_go_etcd_tests_v3",
         importpath = "go.etcd.io/etcd/tests/v3",
+        patch_args = ["-p1"],
+        patches = [
+            "//third_party/go/patches:etcd-integration-logging.patch",
+        ],
         sum = "h1:wiYG8vbDwZO2UatQE9Z3GIv2z52jGg5DvEkTDXm090c=",
         version = "v3.5.4",
     )