diff --git a/cmd/captured/filterexpr.go b/cmd/captured/filterexpr.go
index 5dc1448..f05b4a6 100644
--- a/cmd/captured/filterexpr.go
+++ b/cmd/captured/filterexpr.go
@@ -21,11 +21,11 @@ import (
 	"fmt"
 	"go/format"
 	"io"
-	"io/ioutil"
 	"log"
 
 	"github.com/google/gopacket/layers"
 	"github.com/google/gopacket/pcap"
+	"github.com/google/renameio"
 )
 
 // udp and (port 67 or port 68)   # dhcpv4
@@ -57,7 +57,7 @@ func main() {
 	if err != nil {
 		log.Fatal(err)
 	}
-	if err := ioutil.WriteFile("GENERATED_filterexpr.go", gofmt, 0644); err != nil {
+	if err := renameio.WriteFile("GENERATED_filterexpr.go", gofmt, 0644); err != nil {
 		log.Fatal(err)
 	}
 }
diff --git a/cmd/dhcp4/dhcp4.go b/cmd/dhcp4/dhcp4.go
index de7b277..ea71b1a 100644
--- a/cmd/dhcp4/dhcp4.go
+++ b/cmd/dhcp4/dhcp4.go
@@ -30,6 +30,7 @@ import (
 
 	"github.com/google/gopacket"
 	"github.com/google/gopacket/layers"
+	"github.com/google/renameio"
 	"github.com/jpillora/backoff"
 	"github.com/rtr7/router7/internal/dhcp4"
 	"github.com/rtr7/router7/internal/notify"
@@ -83,7 +84,7 @@ func logic() error {
 		if err != nil {
 			return err
 		}
-		if err := ioutil.WriteFile(leasePath, b, 0644); err != nil {
+		if err := renameio.WriteFile(leasePath, b, 0644); err != nil {
 			return fmt.Errorf("persisting lease to %s: %v", leasePath, err)
 		}
 		buf := gopacket.NewSerializeBuffer()
@@ -94,7 +95,7 @@ func logic() error {
 			},
 			c.Ack,
 		)
-		if err := ioutil.WriteFile(ackFn, buf.Bytes(), 0644); err != nil {
+		if err := renameio.WriteFile(ackFn, buf.Bytes(), 0644); err != nil {
 			return fmt.Errorf("persisting DHCPACK to %s: %v", ackFn, err)
 		}
 		if err := notify.Process("/user/netconfigd", syscall.SIGUSR1); err != nil {
diff --git a/cmd/dhcp4d/dhcp4d.go b/cmd/dhcp4d/dhcp4d.go
index 6c6e553..10fdb14 100644
--- a/cmd/dhcp4d/dhcp4d.go
+++ b/cmd/dhcp4d/dhcp4d.go
@@ -27,6 +27,7 @@ import (
 	"time"
 
 	"github.com/gokrazy/gokrazy"
+	"github.com/google/renameio"
 	"github.com/krolaw/dhcp4"
 	"github.com/krolaw/dhcp4/conn"
 	"github.com/prometheus/client_golang/prometheus"
@@ -125,8 +126,7 @@ func logic() error {
 			errs <- err
 			return
 		}
-		// TODO: write atomically
-		if err := ioutil.WriteFile("/perm/dhcp4d/leases.json", b, 0644); err != nil {
+		if err := renameio.WriteFile("/perm/dhcp4d/leases.json", b, 0644); err != nil {
 			errs <- err
 		}
 		updateNonExpired(leases)
diff --git a/cmd/dhcp6/dhcp6.go b/cmd/dhcp6/dhcp6.go
index d5f0f14..1fad918 100644
--- a/cmd/dhcp6/dhcp6.go
+++ b/cmd/dhcp6/dhcp6.go
@@ -26,6 +26,7 @@ import (
 	"syscall"
 	"time"
 
+	"github.com/google/renameio"
 	"github.com/rtr7/router7/internal/dhcp6"
 	"github.com/rtr7/router7/internal/notify"
 	"github.com/rtr7/router7/internal/teelogger"
@@ -34,8 +35,8 @@ import (
 var log = teelogger.NewConsole()
 
 func logic() error {
-	const configPath = "/perm/dhcp6/wire/lease.json"
-	if err := os.MkdirAll(filepath.Dir(configPath), 0755); err != nil {
+	const leasePath = "/perm/dhcp6/wire/lease.json"
+	if err := os.MkdirAll(filepath.Dir(leasePath), 0755); err != nil {
 		return err
 	}
 
@@ -64,7 +65,7 @@ func logic() error {
 		if err != nil {
 			return err
 		}
-		if err := ioutil.WriteFile(configPath, b, 0644); err != nil {
+		if err := renameio.WriteFile(leasePath, b, 0644); err != nil {
 			return err
 		}
 		if err := notify.Process("/user/netconfigd", syscall.SIGUSR1); err != nil {
diff --git a/internal/netconfig/netconfig.go b/internal/netconfig/netconfig.go
index c23a5db..8cb8f5b 100644
--- a/internal/netconfig/netconfig.go
+++ b/internal/netconfig/netconfig.go
@@ -30,6 +30,7 @@ import (
 	"github.com/google/nftables"
 	"github.com/google/nftables/binaryutil"
 	"github.com/google/nftables/expr"
+	"github.com/google/renameio"
 	"github.com/vishvananda/netlink"
 	"golang.org/x/sys/unix"
 
@@ -287,7 +288,7 @@ func applyInterfaces(dir, root string) error {
 				if err := os.Remove(fn); err != nil && !os.IsNotExist(err) {
 					return err
 				}
-				if err := ioutil.WriteFile(fn, b, 0644); err != nil {
+				if err := renameio.WriteFile(fn, b, 0644); err != nil {
 					return err
 				}
 			}