So we've been running devpi internall for a few weeks, 1.1 and now 1.2.  One thing we've seen occasionally is pip running into this SSLError below.  Apache Bench doesn't show any oddities when we try to hit devpi directly.  Our SSL settings are the same we use with all our internal sites.  It's fronted by nginx:
  ssl on;
  ssl_certificate ***;
  ssl_certificate_key ***;
  ssl_prefer_server_ciphers on;
  ssl_session_cache shared:SSL:10m;
  add_header Strict-Transport-Security max-age=86400;

Exception:

Traceback (most recent call last):

File "/home/travis/virtualenv/python2.7/local/lib/python2.7/site-packages/pip/basecommand.py", line 134, in main

status = self.run(options, args)

File "/home/travis/virtualenv/python2.7/local/lib/python2.7/site-packages/pip/commands/install.py", line 236, in run

requirement_set.prepare_files(finder, force_root_egg_info=self.bundle, bundle=self.bundle)

File "/home/travis/virtualenv/python2.7/local/lib/python2.7/site-packages/pip/req.py", line 1092, in prepare_files

self.unpack_url(url, location, self.is_download)

File "/home/travis/virtualenv/python2.7/local/lib/python2.7/site-packages/pip/req.py", line 1238, in unpack_url

retval = unpack_http_url(link, location, self.download_cache, self.download_dir)

File "/home/travis/virtualenv/python2.7/local/lib/python2.7/site-packages/pip/download.py", line 602, in unpack_http_url

resp = _get_response_from_url(target_url, link)

File "/home/travis/virtualenv/python2.7/local/lib/python2.7/site-packages/pip/download.py", line 638, in _get_response_from_url

resp = urlopen(target_url)

File "/home/travis/virtualenv/python2.7/local/lib/python2.7/site-packages/pip/download.py", line 176, in __call__

response = self.get_opener(scheme=scheme).open(url)

File "/usr/lib/python2.7/urllib2.py", line 400, in open

response = self._open(req, data)

File "/usr/lib/python2.7/urllib2.py", line 418, in _open

'_open', req)

File "/usr/lib/python2.7/urllib2.py", line 378, in _call_chain

result = func(*args)

File "/home/travis/virtualenv/python2.7/local/lib/python2.7/site-packages/pip/download.py", line 155, in https_open

return self.do_open(self.specialized_conn_class, req)

File "/usr/lib/python2.7/urllib2.py", line 1180, in do_open

r = h.getresponse(buffering=True)

File "/usr/lib/python2.7/httplib.py", line 1030, in getresponse

response.begin()

File "/usr/lib/python2.7/httplib.py", line 407, in begin

version, status, reason = self._read_status()

File "/usr/lib/python2.7/httplib.py", line 365, in _read_status

line = self.fp.readline()

File "/usr/lib/python2.7/socket.py", line 447, in readline

data = self._sock.recv(self._rbufsize)

File "/usr/lib/python2.7/ssl.py", line 241, in recv

return self.read(buflen)

File "/usr/lib/python2.7/ssl.py", line 160, in read

return self._sslobj.read(len)

SSLError: The read operation timed ou
t