diff --git a/configs/core.py b/configs/core.py
index 42e17a1..1f751a1 100644
--- a/configs/core.py
+++ b/configs/core.py
@@ -84,18 +84,24 @@
   def FindAll(self, **kwargs):
     return [i for i in self if i.Match(**kwargs)]
 
-  def FindOne(self, **kwargs):
+  def _FindOne(self, **kwargs):
     l = self.FindAll(**kwargs)
     if l:
       return l[0]
 
+  def FindOne(self, **kwargs):
+    v = self._FindOne(**kwargs)
+    if v is None:
+      raise KeyError(kwargs)
+    return v
+
   def FindOrAdd(self, **kwargs):
-    h = self.FindOne(**kwargs)
+    h = self._FindOne(**kwargs)
     if not h:
       h = Host(**kwargs)
       self.append(h)
     if not h.name:
-      h.name = h.ether or h.ip or h.ip6
+      h.name = h.ether or h.serialno or h.ip or h.ip6
     return h
 
   def Query(self, mincount=None, maxcount=None, randomize=False, **kwargs):
diff --git a/rinstall b/rinstall
new file mode 100755
index 0000000..906aac7
--- /dev/null
+++ b/rinstall
@@ -0,0 +1,90 @@
+#!/bin/sh
+#
+# Upgrade multiple bruno devices at once.  Returns 0 if they were all
+# successful.
+#
+mydir=$(dirname "$0")
+imgfile=$1
+imgbase=$(basename "$imgfile" .gi)
+shift
+hosts="$*"
+
+log()
+{
+  printf '\x1b[1m%s\x1b[m\n' "$*" >&2
+}
+
+
+die()
+{
+  log "FAILED"
+  exit 1
+}
+
+
+run()
+{
+  "$mydir/run" $hosts -- "$@" || die
+}
+
+
+if [ ! -e "$imgfile" ] || [ -z "$hosts" ]; then
+  log "Usage: $0 <filename.gi> [hostnames...]"
+  exit 1
+fi
+
+log "Checking running versions..."
+versions=$(run ssh root@\$ip cat /etc/version) || die
+echo "$versions"
+newhosts=$(
+  echo "$versions" |
+  while IFS=': ' read name version; do
+    if [ "$version" != "$imgbase" ]; then
+      echo "$name"
+    else
+      log "'$name' is up to date; skipping."
+    fi
+  done
+)
+if [ -z "$newhosts" ]; then
+  log "No upgrades needed."
+  exit 0
+fi
+log "Will upgrade:" $newhosts
+hosts=$newhosts
+
+log "Copying image files..."
+imgfile=$imgfile run 'scp "$imgfile" root@$ip:/tmp/img.gi && echo ok'
+
+log "Installing..."
+run 'ssh root@$ip ginstall -t /tmp/img.gi -p other && echo ok'
+
+log "Rebooting..."
+run ssh root@\$ip '(sleep 2; reboot) &'
+sleep 5
+
+log "Waiting for hosts to come back up..."
+run '
+  for i in $(seq 5 5 90); do
+    if ping -c1 -w5 $ip >/dev/null; then
+      echo "ok!"
+      sleep 5
+      exit 0
+    fi
+  done
+  exit 1
+'
+
+log "Checking running versions (expect: $imgbase)..."
+versions=$(run ssh root@\$ip cat /etc/version) || die
+echo "$versions"
+echo "$versions" | (
+  rv=0
+  while IFS=': ' read name version; do
+    if [ "$version" != "$imgbase" ]; then
+      log "$name: failed to upgrade!"
+      rv=1
+    fi
+  done
+  exit $rv
+) || die
diff --git a/run b/run
new file mode 120000
index 0000000..e56fbdd
--- /dev/null
+++ b/run
@@ -0,0 +1 @@
+run.py
\ No newline at end of file
diff --git a/run.py b/run.py
new file mode 100755
index 0000000..b0e5088
--- /dev/null
+++ b/run.py
@@ -0,0 +1,122 @@
+#!/usr/bin/python
+# Copyright 2012 Google Inc. All Rights Reserved.
+#
+"""Run the given shell command for each of the given hosts."""
+
+import os
+import re
+import select
+import subprocess
+import sys
+import config
+from portsh import options
+
+__author__ = 'Avery Pennarun (apenwarr@google.com)'
+
+
+optspec = """
+run [options...] <hosts> -- <command string...>
+--
+r,raw           Raw output (don't prefix with the host's name)
+q,quiet         Quiet: don't print to stderr for nonzero exit codes
+"""
+
+
+def _FixNull(s):
+  if s is None:
+    return ''
+  return str(s)
+
+
+def _ArgSub(argv, host):
+  for arg in argv:
+    argout = []
+    for part in re.split(r'(\$\w+)', arg):
+      if part.startswith('$'):
+        for var in config.Host.__slots__:
+          if part[1:] == var:
+            part = _FixNull(getattr(host, var))
+            break
+      argout.append(part)
+    yield ''.join(argout)
+
+
+class Handler(object):
+  def __init__(self, prefix, fileobj, raw):
+    self.prefix = prefix
+    self.fileobj = fileobj
+    self.raw = raw
+
+  def fileno(self):  #gpylint: disable-msg=C6409
+    return self.fileobj.fileno()
+
+  def Run(self):
+    """Read from this handler and write its results to stdout."""
+    buf = os.read(self.fileobj.fileno(), 65536)
+    if buf:
+      if self.raw:
+        sys.stdout.write(buf)
+      else:
+        if not buf.endswith('\n'):
+          buf += '\n'
+        lines = buf.split('\n')[:-1]
+        for line in lines:
+          print '%s: %s' % (self.prefix, line)
+    return buf
+
+
+def main():
+  o = options.Options(optspec)
+  args = []
+  cmd = []
+  for i in range(1, len(sys.argv)):
+    if sys.argv[i] == '--':
+      args = sys.argv[1:i]
+      cmd = sys.argv[i+1:]
+      break
+  opt, _, hostnames = o.parse(args)
+  if not hostnames or not cmd:
+    o.fatal('you must specify hosts, --, and a command string')
+
+  try:
+    hosts = [config.hosts.FindOne(name=i) for i in hostnames]
+  except KeyError, e:
+    o.fatal('host not configured: %s' % e)
+
+  procs = []
+  handlers = []
+  for host in hosts:
+    env = dict(os.environ)
+    env.update(dict((key, _FixNull(getattr(host, key)))
+                    for key in config.Host.__slots__))
+    if len(cmd) > 1:
+      argv = list(_ArgSub(cmd, host))
+      shell = False
+    else:
+      argv = cmd[0]
+      shell = True
+    p = subprocess.Popen(argv, env=env, shell=shell,
+                         stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    procs.append((host, p))
+    handlers.append(Handler(host.name, p.stdout, opt.raw))
+    handlers.append(Handler(host.name, p.stderr, opt.raw))
+
+  while handlers:
+    r, _, _ = select.select(handlers, [], [])
+    for handler in r:
+      if not handler.Run():
+        handlers.remove(handler)
+
+  final_rv = 0
+  for host, p in procs:
+    rv = p.wait()
+    if rv != 0:
+      if not opt.quiet:
+        sys.stderr.write('-- %s: exited with error code %d\n'
+                         % (host.name, rv))
+      final_rv = 1
+  return final_rv
+
+
+if __name__ == '__main__':
+  sys.exit(main())