diff --git a/.gitignore b/.gitignore
index 78fe8261e..f5c83426c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 cover/cover
 socks/proxy
 socks/image.tar
+runner/runner
diff --git a/README.md b/README.md
index ad801aa00..85fdfeb39 100644
--- a/README.md
+++ b/README.md
@@ -1,12 +1,36 @@
-# Weaveworks Tools
+# Weaveworks Build Tools
 
 Included in this repo are tools shared by weave.git and scope.git.  They include
 
-- ```cover```: a tool which merges overlapping coverage reports generated by go test
-- ```lint```: a script to lint Go project; runs various tools like golint, go vet, errcheck etc
-- ```rebuild-image```: a script to rebuild docker images when their input files change; useful
-  when you using docker images to build your software, but you don't want to build the
-  image every time.
-- ```socks```: a simple, dockerised SOCKS proxy for getting your laptop onto the Weave network
-- ```test```: a script to run all go unit tests in subdirectories, gather the coverage results,
-  and merge them into a single report.
+- ```cover```: a tool which merges overlapping coverage reports generated by go
+  test
+- ```lint```: a script to lint Go project; runs various tools like golint, go
+  vet, errcheck etc
+- ```rebuild-image```: a script to rebuild docker images when their input files
+  change; useful when you using docker images to build your software, but you
+  don't want to build the image every time.
+- ```socks```: a simple, dockerised SOCKS proxy for getting your laptop onto
+  the Weave network
+- ```test```: a script to run all go unit tests in subdirectories, gather the
+  coverage results, and merge them into a single report.
+- ```runner```: a tool for running tests in parallel; given each test is
+  suffixed with the number of hosts it requires, and the hosts available are
+  contained in the environment variable HOSTS, the tool will run tests in
+  parallel, on different hosts.
+
+## Using build-tools.git
+
+To allow you to tie your code to a specific version of build-tools.git, such
+that future changes don't break you, we recommendation that you [`git subtree`]()
+this repository into your own repository:
+
+[`git subtree`]: http://blogs.atlassian.com/2013/05/alternatives-to-git-submodule-git-subtree/
+
+```
+git subtree add --prefix tools https://github.com/weaveworks/build-tools.git master --squash
+````
+
+To update the code in build-tools.git, the process is therefore:
+- PR into build-tools.git, go through normal review process etc.
+- Do `git subtree pull --prefix tools https://github.com/weaveworks/build-tools.git master --squash`
+  in your repo, and PR that.
diff --git a/circle.yml b/circle.yml
index b79465799..0c1ebddb1 100644
--- a/circle.yml
+++ b/circle.yml
@@ -19,4 +19,5 @@ test:
     - cd $SRCDIR; ./lint .
     - cd $SRCDIR/cover; make
     - cd $SRCDIR/socks; make
+    - cd $SRCDIR/runner; make
 
diff --git a/runner/Makefile b/runner/Makefile
new file mode 100644
index 000000000..f19bcc7d8
--- /dev/null
+++ b/runner/Makefile
@@ -0,0 +1,11 @@
+.PHONY: all clean
+
+all: runner
+
+runner: *.go
+	go get -tags netgo ./$(@D)
+	go build -ldflags "-extldflags \"-static\" -linkmode=external" -tags netgo -o $@ ./$(@D)
+
+clean:
+	rm -rf runner
+	go clean ./...
diff --git a/runner/runner.go b/runner/runner.go
new file mode 100644
index 000000000..bfac9c58b
--- /dev/null
+++ b/runner/runner.go
@@ -0,0 +1,275 @@
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+	"os"
+	"os/exec"
+	"sort"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/docker/docker/pkg/mflag"
+	"github.com/mgutz/ansi"
+)
+
+const (
+	defaultSchedulerHost = "positive-cocoa-90213.appspot.com"
+	jsonContentType      = "application/json"
+)
+
+var (
+	start = ansi.ColorCode("black+ub")
+	fail  = ansi.ColorCode("red+b")
+	succ  = ansi.ColorCode("green+b")
+	reset = ansi.ColorCode("reset")
+
+	schedulerHost = defaultSchedulerHost
+	useScheduler  = false
+	runParallel   = false
+	verbose       = false
+
+	consoleLock = sync.Mutex{}
+)
+
+type test struct {
+	name  string
+	hosts int
+}
+
+type schedule struct {
+	Tests []string `json:"tests"`
+}
+
+type result struct {
+	test
+	errored bool
+	hosts   []string
+}
+
+type tests []test
+
+func (ts tests) Len() int      { return len(ts) }
+func (ts tests) Swap(i, j int) { ts[i], ts[j] = ts[j], ts[i] }
+func (ts tests) Less(i, j int) bool {
+	if ts[i].hosts != ts[j].hosts {
+		return ts[i].hosts < ts[j].hosts
+	}
+	return ts[i].name < ts[j].name
+}
+
+func (ts *tests) pick(availible int) (test, bool) {
+	// pick the first test that fits in the availible hosts
+	for i, test := range *ts {
+		if test.hosts <= availible {
+			*ts = append((*ts)[:i], (*ts)[i+1:]...)
+			return test, true
+		}
+	}
+
+	return test{}, false
+}
+
+func (t test) run(hosts []string) bool {
+	consoleLock.Lock()
+	fmt.Printf("%s>>> Running %s on %s%s\n", start, t.name, hosts, reset)
+	consoleLock.Unlock()
+
+	var out bytes.Buffer
+
+	cmd := exec.Command(t.name)
+	cmd.Env = os.Environ()
+	cmd.Stdout = &out
+	cmd.Stderr = &out
+
+	// replace HOSTS in env
+	for i, env := range cmd.Env {
+		if strings.HasPrefix(env, "HOSTS") {
+			cmd.Env[i] = fmt.Sprintf("HOSTS=%s", strings.Join(hosts, " "))
+			break
+		}
+	}
+
+	start := time.Now()
+	err := cmd.Run()
+	duration := float64(time.Now().Sub(start)) / float64(time.Second)
+
+	consoleLock.Lock()
+	if err != nil {
+		fmt.Printf("%s>>> Test %s finished after %0.1f secs with error: %v%s\n", fail, t.name, duration, err, reset)
+	} else {
+		fmt.Printf("%s>>> Test %s finished with success after %0.1f secs%s\n", succ, t.name, duration, reset)
+	}
+	if err != nil || verbose {
+		fmt.Print(out.String())
+		fmt.Println()
+	}
+	consoleLock.Unlock()
+
+	if err != nil && useScheduler {
+		updateScheduler(t.name, duration)
+	}
+
+	return err != nil
+}
+
+func updateScheduler(test string, duration float64) {
+	req := &http.Request{
+		Method: "POST",
+		Host:   schedulerHost,
+		URL: &url.URL{
+			Opaque: fmt.Sprintf("/record/%s/%0.2f", url.QueryEscape(test), duration),
+			Scheme: "http",
+			Host:   schedulerHost,
+		},
+		Close: true,
+	}
+	if resp, err := http.DefaultClient.Do(req); err != nil {
+		fmt.Printf("Error updating scheduler: %v\n", err)
+	} else {
+		resp.Body.Close()
+	}
+}
+
+func getSchedule(tests []string) ([]string, error) {
+	var (
+		testRun     = "integration-" + os.Getenv("CIRCLE_BUILD_NUM")
+		shardCount  = os.Getenv("CIRCLE_NODE_TOTAL")
+		shardID     = os.Getenv("CIRCLE_NODE_INDEX")
+		requestBody = &bytes.Buffer{}
+	)
+	if err := json.NewEncoder(requestBody).Encode(schedule{tests}); err != nil {
+		return []string{}, err
+	}
+	url := fmt.Sprintf("http://%s/schedule/%s/%s/%s", schedulerHost, testRun, shardCount, shardID)
+	resp, err := http.Post(url, jsonContentType, requestBody)
+	if err != nil {
+		return []string{}, err
+	}
+	var sched schedule
+	if err := json.NewDecoder(resp.Body).Decode(&sched); err != nil {
+		return []string{}, err
+	}
+	return sched.Tests, nil
+}
+
+func getTests(testNames []string) (tests, error) {
+	var err error
+	if useScheduler {
+		testNames, err = getSchedule(testNames)
+		if err != nil {
+			return tests{}, err
+		}
+	}
+	tests := tests{}
+	for _, name := range testNames {
+		parts := strings.Split(strings.TrimSuffix(name, "_test.sh"), "_")
+		numHosts, err := strconv.Atoi(parts[len(parts)-1])
+		if err != nil {
+			numHosts = 1
+		}
+		tests = append(tests, test{name, numHosts})
+		fmt.Printf("Test %s needs %d hosts\n", name, numHosts)
+	}
+	return tests, nil
+}
+
+func summary(tests, failed tests) {
+	if len(failed) > 0 {
+		fmt.Printf("%s>>> Ran %d tests, %d failed%s\n", fail, len(tests), len(failed), reset)
+		for _, test := range failed {
+			fmt.Printf("%s>>> Fail %s%s\n", fail, test.name, reset)
+		}
+	} else {
+		fmt.Printf("%s>>> Ran %d tests, all succeeded%s\n", succ, len(tests), reset)
+	}
+}
+
+func parallel(ts tests, hosts []string) bool {
+	testsCopy := ts
+	sort.Sort(sort.Reverse(ts))
+	resultsChan := make(chan result)
+	outstanding := 0
+	failed := tests{}
+	for len(ts) > 0 || outstanding > 0 {
+		// While we have some free hosts, try and schedule
+		// a test on them
+		for len(hosts) > 0 {
+			test, ok := ts.pick(len(hosts))
+			if !ok {
+				break
+			}
+			testHosts := hosts[:test.hosts]
+			hosts = hosts[test.hosts:]
+
+			go func() {
+				errored := test.run(testHosts)
+				resultsChan <- result{test, errored, testHosts}
+			}()
+			outstanding++
+		}
+
+		// Otherwise, wait for the test to finish and return
+		// the hosts to the pool
+		result := <-resultsChan
+		hosts = append(hosts, result.hosts...)
+		outstanding--
+		if result.errored {
+			failed = append(failed, result.test)
+		}
+	}
+	summary(testsCopy, failed)
+	return len(failed) > 0
+}
+
+func sequential(ts tests, hosts []string) bool {
+	failed := tests{}
+	for _, test := range ts {
+		if test.run(hosts) {
+			failed = append(failed, test)
+		}
+	}
+	summary(ts, failed)
+	return len(failed) > 0
+}
+
+func main() {
+	mflag.BoolVar(&useScheduler, []string{"scheduler"}, false, "Use scheduler to distribute tests across shards")
+	mflag.BoolVar(&runParallel, []string{"parallel"}, false, "Run tests in parallel on hosts where possible")
+	mflag.BoolVar(&verbose, []string{"v"}, false, "Print output from all tests (Also enabled via DEBUG=1)")
+	mflag.StringVar(&schedulerHost, []string{"scheduler-host"}, defaultSchedulerHost, "Hostname of scheduler.")
+	mflag.Parse()
+
+	if len(os.Getenv("DEBUG")) > 0 {
+		verbose = true
+	}
+
+	tests, err := getTests(mflag.Args())
+	if err != nil {
+		fmt.Printf("Error parsing tests: %v\n", err)
+		os.Exit(1)
+	}
+
+	hosts := strings.Fields(os.Getenv("HOSTS"))
+	maxHosts := len(hosts)
+	if maxHosts == 0 {
+		fmt.Print("No HOSTS specified.\n")
+		os.Exit(1)
+	}
+
+	var errored bool
+	if runParallel {
+		errored = parallel(tests, hosts)
+	} else {
+		errored = sequential(tests, hosts)
+	}
+
+	if errored {
+		os.Exit(1)
+	}
+}