diff --git a/dashboard/retrybuilds/retrybuilds.go b/dashboard/retrybuilds/retrybuilds.go
new file mode 100644
index 0000000000..a2d97df0de
--- /dev/null
+++ b/dashboard/retrybuilds/retrybuilds.go
@@ -0,0 +1,228 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// The retrybuilds command clears build failures from the build.golang.org dashboard
+// to force them to be rebuilt.
+//
+// Valid usage modes:
+//
+//   retrybuilds -loghash=f45f0eb8
+//   retrybuilds -builder=openbsd-amd64
+//   retrybuilds -builder=openbsd-amd64 -hash=6fecb7
+//   retrybuilds -redo-flaky
+//   retrybuilds -redo-flaky -builder=linux-amd64-clang
+package main
+
+import (
+	"bytes"
+	"crypto/hmac"
+	"crypto/md5"
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"net/url"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+)
+
+var (
+	masterKeyFile = flag.String("masterkey", filepath.Join(os.Getenv("HOME"), "keys", "gobuilder-master.key"), "path to Go builder master key. If present, the key argument is not necessary")
+	keyFile       = flag.String("key", "", "path to key file")
+	builder       = flag.String("builder", "", "builder to wipe a result for.")
+	hash          = flag.String("hash", "", "Hash to wipe. If empty, all will be wiped.")
+	redoFlaky     = flag.Bool("redo-flaky", false, "Reset all flaky builds. If builder is empty, the master key is required.")
+	builderPrefix = flag.String("builder-prefix", "https://build.golang.org", "builder URL prefix")
+	logHash       = flag.String("loghash", "", "If non-empty, clear the build that failed with this loghash prefix")
+)
+
+type Failure struct {
+	Builder string
+	Hash    string
+	LogURL  string
+}
+
+func main() {
+	flag.Parse()
+	*builderPrefix = strings.TrimSuffix(*builderPrefix, "/")
+	if *logHash != "" {
+		substr := "/log/" + *logHash
+		for _, f := range failures() {
+			if strings.Contains(f.LogURL, substr) {
+				wipe(f.Builder, f.Hash)
+			}
+		}
+		return
+	}
+	if *redoFlaky {
+		fixTheFlakes()
+		return
+	}
+	if *builder == "" {
+		log.Fatalf("Missing -builder, -redo-flaky, or -loghash flag.")
+	}
+	wipe(*builder, fullHash(*hash))
+}
+
+func fixTheFlakes() {
+	gate := make(chan bool, 50)
+	var wg sync.WaitGroup
+	for _, f := range failures() {
+		f := f
+		if *builder != "" && f.Builder != *builder {
+			continue
+		}
+		gate <- true
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			defer func() { <-gate }()
+			res, err := http.Get(f.LogURL)
+			if err != nil {
+				log.Fatalf("Error fetching %s: %v", f.LogURL, err)
+			}
+			defer res.Body.Close()
+			failLog, err := ioutil.ReadAll(res.Body)
+			if err != nil {
+				log.Fatalf("Error reading %s: %v", f.LogURL, err)
+			}
+			if isFlaky(string(failLog)) {
+				log.Printf("Restarting flaky %+v", f)
+				wipe(f.Builder, f.Hash)
+			}
+		}()
+	}
+	wg.Wait()
+}
+
+var flakePhrases = []string{
+	"No space left on device",
+	"fatal error: error in backend: IO failure on output stream",
+	"Boffset: unknown state 0",
+	"Bseek: unknown state 0",
+	"error exporting repository: exit status",
+	"remote error: User Is Over Quota",
+}
+
+func isFlaky(failLog string) bool {
+	if strings.HasPrefix(failLog, "exit status ") {
+		return true
+	}
+	for _, phrase := range flakePhrases {
+		if strings.Contains(failLog, phrase) {
+			return true
+		}
+	}
+	numLines := strings.Count(failLog, "\n")
+	if numLines < 20 && strings.Contains(failLog, "error: exit status") {
+		return true
+	}
+	return false
+}
+
+func fullHash(h string) string {
+	if h == "" || len(h) == 40 {
+		return h
+	}
+	for _, f := range failures() {
+		if strings.HasPrefix(f.Hash, h) {
+			return f.Hash
+		}
+	}
+	log.Fatalf("invalid hash %q; failed to finds its full hash. Not a recent failure?", h)
+	panic("unreachable")
+}
+
+// hash may be empty
+func wipe(builder, hash string) {
+	if hash != "" {
+		log.Printf("Clearing %s, hash %s", builder, hash)
+	} else {
+		log.Printf("Clearing all builds for %s", builder)
+	}
+	vals := url.Values{
+		"builder": {builder},
+		"hash":    {hash},
+		"key":     {builderKey(builder)},
+	}
+	res, err := http.PostForm(*builderPrefix+"/clear-results?"+vals.Encode(), nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer res.Body.Close()
+	if res.StatusCode != 200 {
+		log.Fatalf("Error clearing %v hash %q: %v", builder, hash, res.Status)
+	}
+}
+
+func builderKey(builder string) string {
+	if v, ok := builderKeyFromMaster(builder); ok {
+		return v
+	}
+	if *keyFile == "" {
+		log.Fatalf("No --key specified for builder %s", builder)
+	}
+	slurp, err := ioutil.ReadFile(*keyFile)
+	if err != nil {
+		log.Fatalf("Error reading builder key %s: %v", builder, err)
+	}
+	return strings.TrimSpace(string(slurp))
+}
+
+func builderKeyFromMaster(builder string) (key string, ok bool) {
+	if *masterKeyFile == "" {
+		return
+	}
+	slurp, err := ioutil.ReadFile(*masterKeyFile)
+	if err != nil {
+		return
+	}
+	h := hmac.New(md5.New, bytes.TrimSpace(slurp))
+	h.Write([]byte(builder))
+	return fmt.Sprintf("%x", h.Sum(nil)), true
+}
+
+var (
+	failMu    sync.Mutex
+	failCache []Failure
+)
+
+func failures() (ret []Failure) {
+	failMu.Lock()
+	ret = failCache
+	failMu.Unlock()
+	if ret != nil {
+		return
+	}
+	ret = []Failure{} // non-nil
+
+	res, err := http.Get(*builderPrefix + "/?mode=failures")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer res.Body.Close()
+	slurp, err := ioutil.ReadAll(res.Body)
+	if err != nil {
+		log.Fatal(err)
+	}
+	body := string(slurp)
+	for _, line := range strings.Split(body, "\n") {
+		f := strings.Fields(line)
+		if len(f) == 3 {
+			ret = append(ret, Failure{
+				Hash:    f[0],
+				Builder: f[1],
+				LogURL:  f[2],
+			})
+		}
+	}
+
+	failMu.Lock()
+	failCache = ret
+	failMu.Unlock()
+	return ret
+}