"stderr": "Exception:\nTraceback (most recent call last):\n  File \"/tmp/tmpOcni_I/pip.zip/pip/basecommand.py\", line 215, in main\n    status = self.run(options, ar
gs)\n  File \"/tmp/tmpOcni_I/pip.zip/pip/commands/install.py\", line 335, in run\n    wb.build(autobuilding=True)\n  File \"/tmp/tmpOcni_I/pip.zip/pip/wheel.py\", line 7
49, in build\n    self.requirement_set.prepare_files(self.finder)\n  File \"/tmp/tmpOcni_I/pip.zip/pip/req/req_set.py\", line 380, in prepare_files\n    ignore_dependenc
ies=self.ignore_dependencies))\n  File \"/tmp/tmpOcni_I/pip.zip/pip/req/req_set.py\", line 487, in _prepare_file\n    req_to_install, finder)\n  File \"/tmp/tmpOcni_I/pi
p.zip/pip/req/req_set.py\", line 428, in _check_skip_installed\n    req_to_install, upgrade_allowed)\n  File \"/tmp/tmpOcni_I/pip.zip/pip/index.py\", line 465, in find_r
equirement\n    all_candidates = self.find_all_candidates(req.name)\n  File \"/tmp/tmpOcni_I/pip.zip/pip/index.py\", line 423, in find_all_candidates\n    for page in se
lf._get_pages(url_locations, project_name):\n  File \"/tmp/tmpOcni_I/pip.zip/pip/index.py\", line 568, in _get_pages\n    page = self._get_page(location)\n  File \"/tmp/
tmpOcni_I/pip.zip/pip/index.py\", line 683, in _get_page\n    return HTMLPage.get_page(link, session=self.session)\n  File \"/tmp/tmpOcni_I/pip.zip/pip/index.py\", line
792, in get_page\n    \"Cache-Control\": \"max-age=600\",\n  File \"/tmp/tmpOcni_I/pip.zip/pip/_vendor/requests/sessions.py\", line 488, in get\n    return self.request(
'GET', url, **kwargs)\n  File \"/tmp/tmpOcni_I/pip.zip/pip/download.py\", line 386, in request\n    return super(PipSession, self).request(method, url, *args, **kwargs)\
n  File \"/tmp/tmpOcni_I/pip.zip/pip/_vendor/requests/sessions.py\", line 475, in request\n    resp = self.send(prep, **send_kwargs)\n  File \"/tmp/tmpOcni_I/pip.zip/pip
/_vendor/requests/sessions.py\", line 596, in send\n    r = adapter.send(request, **kwargs)\n  File \"/tmp/tmpOcni_I/pip.zip/pip/_vendor/requests/adapters.py\", line 482
, in send\n    raise RetryError(e, request=request)\nRetryError: HTTPConnectionPool(host='172.29.236.11', port=8181): Max retries exceeded with url: /os-releases/16.0.0/
centos-7.4-x86_64/ (Caused by ResponseError('too many 503 error responses',))",