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)