daisy_skate CQ failed:
https://uberchromegw.corp.google.com/i/chromeos/waterfall?builder=daisy_skate-paladin

Debug log:
https://pantheon.corp.google.com/storage/browser/chromeos-autotest-results/100519721-chromeos-test/chromeos4-row9-rack5-host9/debug

"""
02/10 09:44:02.135 ERROR|        dev_server:0427| Devserver call failed: "http://100.108.1.152:8082/check_health?", timeout: 2.0 seconds, Error: 
...

        500 Internal Server Error
        The server encountered an unexpected condition which prevented it from fulfilling the request.
        Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/cherrypy/_cprequest.py", line 656, in respond
    response.body = self.handler()
  File "/usr/lib/python2.7/dist-packages/cherrypy/lib/encoding.py", line 188, in __call__
    self.body = self.oldhandler(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/cherrypy/_cpdispatch.py", line 34, in __call__
    return self.callable(*self.args, **self.kwargs)
  File "/usr/local/google/home/chromeos-test/chromiumos/src/platform/dev/devserver.py", line 1510, in check_health
    apache_client_count = self._get_process_count('apache')
  File "/usr/local/google/home/chromeos-test/chromiumos/src/platform/dev/devserver.py", line 1489, in _get_process_count
    'pgrep -fc "%s"' % process_cmd_pattern, shell=True))
  File "/usr/lib/python2.7/subprocess.py", line 566, in check_output
    process = Popen(stdout=PIPE, *popenargs, **kwargs)
  File "/usr/lib/python2.7/subprocess.py", line 710, in __init__
    errread, errwrite)
  File "/usr/lib/python2.7/subprocess.py", line 1215, in _execute_child
    errpipe_read, errpipe_write = self.pipe_cloexec()
  File "/usr/lib/python2.7/subprocess.py", line 1167, in pipe_cloexec
    r, w = os.pipe()
OSError: [Errno 24] Too many open files
"""