ConnectionRefusedErrorです。[Errno 111] 接続が拒否されました。

pip3 install --upgrade pip

//result
Exception:
Traceback (most recent call last):
  File "/usr/share/python-wheels/urllib3-1.19.1-py2.py3-none-any.whl/urllib3/connection.py", line 138, in _new_conn
    (self.host, self.port), self.timeout, **extra_kw)
  File "/usr/share/python-wheels/urllib3-1.19.1-py2.py3-none-any.whl/urllib3/util/connection.py", line 98, in create_connection
    raise err
  File "/usr/share/python-wheels/urllib3-1.19.1-py2.py3-none-any.whl/urllib3/util/connection.py", line 88, in create_connection
    sock.connect(sa)
ConnectionRefusedError: [Errno 111] Connection refused

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/share/python-wheels/urllib3-1.19.1-py2.py3-none-any.whl/urllib3/connectionpool.py", line 594, in urlopen
    chunked=chunked)
  File "/usr/share/python-wheels/urllib3-1.19.1-py2.py3-none-any.whl/urllib3/connectionpool.py", line 350, in _make_request
    self._validate_conn(conn)
  File "/usr/share/python-wheels/urllib3-1.19.1-py2.py3-none-any.whl/urllib3/connectionpool.py", line 837, in _validate_conn
    conn.connect()
  File "/usr/share/python-wheels/urllib3-1.19.1-py2.py3-none-any.whl/urllib3/connection.py", line 281, in connect
    conn = self._new_conn()
  File "/usr/share/python-wheels/urllib3-1.19.1-py2.py3-none-any.whl/urllib3/connection.py", line 147, in _new_conn
    self, "Failed to establish a new connection: %s" % e)
Requests.packages.urllib3.exceptions.NewConnectionError: <requests.packages.urllib3.connection.VerifiedHTTPSConnection object at 0x7f10def4b160>: Failed to establish a new connection: [Errno 111] Connection rejected

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/pip/basecommand.py", line 215, in main
    status = self.run(options, args)
  File "/usr/lib/python3/dist-packages/pip/commands/install.py", line 353, in run
    wb.build(autobuilding=True)
  File "/usr/lib/python3/dist-packages/pip/wheel.py", line 749, in build
    self.requirement_set.prepare_files(self.finder)
  File "/usr/lib/python3/dist-packages/pip/req/req_set.py", line 380, in prepare_files
    ignore_dependencies=self.ignore_dependencies))
  File "/usr/lib/python3/dist-packages/pip/req/req_set.py", line 487, in _prepare_file
    req_to_install, finder)
  File "/usr/lib/python3/dist-packages/pip/req/req_set.py", line 428, in _check_skip_installed
    req_to_install, upgrade_allowed)
  File "/usr/lib/python3/dist-packages/pip/index.py", line 465, in find_requirement
    all_candidates = self.find_all_candidates(req.name)
  File "/usr/lib/python3/dist-packages/pip/index.py", line 423, in find_all_candidates
    for page in self._get_pages(url_locations, project_name):
  File "/usr/lib/python3/dist-packages/pip/index.py", line 568, in _get_pages
    page = self._get_page(location)
  File "/usr/lib/python3/dist-packages/pip/index.py", line 683, in _get_page
    return HTMLPage.get_page(link, session=self.session)
  File "/usr/lib/python3/dist-packages/pip/index.py", line 792, in get_page
    "Cache-Control": "max-age=600",
  File "/usr/share/python-wheels/requests-2.12.4-py2.py3-none-any.whl/requests/sessions.py", line 501, in get
    return self.request('GET', url, **kwargs)
  File "/usr/lib/python3/dist-packages/pip/download.py", line 386, in request
    return super(PipSession, self).request(method, url, *args, **kwargs)
  File "/usr/share/python-wheels/requests-2.12.4-py2.py3-none-any.whl/requests/sessions.py", line 488, in request
    resp = self.send(prep, **send_kwargs)
  File "/usr/share/python-wheels/requests-2.12.4-py2.py3-none-any.whl/requests/sessions.py", line 609, in send
    r = adapter.send(request, **kwargs)
  File "/usr/share/python-wheels/CacheControl-0.11.7-py2.py3-none-any.whl/cachecontrol/adapter.py", line 47, in send
    resp = super(CacheControlAdapter, self).send(request, **kw)
  File "/usr/share/python-wheels/requests-2.12.4-py2.py3-none-any.whl/requests/adapters.py", line 423, in send
    timeout=timeout
  File "/usr/share/python-wheels/urllib3-1.19.1-py2.py3-none-any.whl/urllib3/connectionpool.py", line 643, in urlopen
    _stacktrace=sys.exc_info()[2])
  File "/usr/share/python-wheels/urllib3-1.19.1-py2.py3-none-any.whl/urllib3/util/retry.py", line 315, in increment
    total -= 1
TypeError: unsupported operand type(s) for -=: 'Retry' and 'int'

原因：ネットワーク接続の問題。

回避策、ソースを変更する。

mkdir ~/.pip

cat >~/.pip/pip.conf << EOF
[global]
trusted-host=mirrors.aliyun.com
index-url=http://mirrors.aliyun.com/pypi/simple/
EOF


pip3 install --upgrade pip

OK