Question: I would like to use Python3.8.x on Google Cloud Compute Engine. First, I created an instance with gcloud command. gcloud compute instances create \ pegasus-test \ --zone=asia-northeast1-b \ --machine-type=n1-highmem-8 \ --boot-disk-size=500GB \ --image-project=ml-images \ --image-family=tf-1-15 \ --maintenance-policy TERMINATE --restart-on-failure  In default, Python version is 3.5.3. python3 -V Python 3.5.3  Therefore, I upgraded Python. I followed this instruction. (google cloud compute engine change to python 3.6) cd /tmp wget https://www.python.org/ftp/python/3.8.3/Python-3.8.3.tgz tar -xvf Python-3.8.3.tgz cd Python-3.8.3 ./configure sudo apt-get install zlib1g-dev sudo make sudo make install  I got no error message. Now, I have Python3.8.3. python3 -V Python 3.8.3  Next, I would like to use PEGASUS. (https://github.com/google-research/pegasus) git clone https://github.com/google-research/pegasus cd pegasus export PYTHONPATH=. pip3 install -r requirements.txt  Then, I got an error message. WARNING: pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available. Collecting absl-py (from -r requirements.txt (line 1)) WARNING: Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(" Can't connect to HTTPS URL because the SSL module is not available.")': /simple/absl-py/ WARNING: Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(" Can't connect to HTTPS URL because the SSL module is not available.")': /simple/absl-py/ WARNING: Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(" Can't connect to HTTPS URL because the SSL module is not available.")': /simple/absl-py/ WARNING: Retrying (Retry(total=1, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(" Can't connect to HTTPS URL because the SSL module is not available.")': /simple/absl-py/ WARNING: Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(" Can't connect to HTTPS URL because the SSL module is not available.")': /simple/absl-py/ Could not fetch URL https://pypi.org/simple/absl-py/: There was a problem confirming the ssl certificate: HTTPSConnectionPool( host='pypi.org', port=443): Max retries exceeded with url: /simple/absl-py/ (Caused by SSLError("Can't connect to HTTPS URL beca use the SSL module is not available.")) - skipping ERROR: Could not find a version that satisfies the requirement absl-py (from -r requirements.txt (line 1)) (from versions: non e) ERROR: No matching distribution found for absl-py (from -r requirements.txt (line 1)) WARNING: pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available. Could not fetch URL https://pypi.org/simple/pip/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host=' pypi.org', port=443): Max retries exceeded with url: /simple/pip/ (Caused by SSLError("Can't connect to HTTPS URL because the SS L module is not available.")) - skipping  I checked pip's version. pip3 -V pip 19.2.3 from /usr/local/lib/python3.8/site-packages/pip (python 3.8)  So, I tried to upgrade pip. pip3 install --upgrade pip Then, I got this error message. WARNING: pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available. WARNING: Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError("Ca n't connect to HTTPS URL because the SSL module is not available.")': /simple/pip/ WARNING: Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError("Ca n't connect to HTTPS URL because the SSL module is not available.")': /simple/pip/ WARNING: Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError("Ca n't connect to HTTPS URL because the SSL module is not available.")': /simple/pip/ WARNING: Retrying (Retry(total=1, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError("Ca n't connect to HTTPS URL because the SSL module is not available.")': /simple/pip/ WARNING: Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError("Ca n't connect to HTTPS URL because the SSL module is not available.")': /simple/pip/ Could not fetch URL https://pypi.org/simple/pip/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host=' pypi.org', port=443): Max retries exceeded with url: /simple/pip/ (Caused by SSLError("Can't connect to HTTPS URL because the SS L module is not available.")) - skipping Requirement already up-to-date: pip in /usr/local/lib/python3.8/site-packages (19.2.3) WARNING: pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available. Could not fetch URL https://pypi.org/simple/pip/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host=' pypi.org', port=443): Max retries exceeded with url: /simple/pip/ (Caused by SSLError("Can't connect to HTTPS URL because the SS L module is not available.")) - skipping  So, next I used pip instead of pip3. I input pip install -r requirements.txt This is the result. Defaulting to user installation because normal site-packages is not writeable Requirement already satisfied: absl-py in /usr/local/lib/python2.7/dist-packages (from -r requirements.txt (line 1)) (0.9.0) Requirement already satisfied: mock in /usr/local/lib/python2.7/dist-packages (from -r requirements.txt (line 2)) (3.0.5) Requirement already satisfied: numpy in /usr/local/lib/python2.7/dist-packages (from -r requirements.txt (line 3)) (1.16.6) Collecting rouge-score Downloading rouge_score-0.0.4-py2.py3-none-any.whl (22 kB) Collecting sacrebleu Downloading sacrebleu-1.3.7.tar.gz (26 kB) ERROR: Command errored out with exit status 1: command: /usr/bin/python -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-HCHhuX/sacrebleu/setup.p y'"'"'; __file__='"'"'/tmp/pip-install-HCHhuX/sacrebleu/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f .read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base /tmp/ pip-install-HCHhuX/sacrebleu/pip-egg-info cwd: /tmp/pip-install-HCHhuX/sacrebleu/ Complete output (7 lines): Traceback (most recent call last): File "<string>", line 1, in <module> File "/tmp/pip-install-HCHhuX/sacrebleu/setup.py", line 65, in <module> version = get_version(), File "/tmp/pip-install-HCHhuX/sacrebleu/setup.py", line 56, in get_version with open(os.path.join(os.path.dirname(__file__), 'sacrebleu.py'), encoding='utf-8') as fin: TypeError: 'encoding' is an invalid keyword argument for this function ---------------------------------------- ERROR: Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output. WARNING: You are using pip version 20.0.2; however, version 20.1.1 is available. You should consider upgrading via the '/usr/bin/python -m pip install --upgrade pip' command.  How can I realize pip3 install -r requirements.txt? Could you give me any advice, please?

Answer: I had the same issue and had to spend a few days to tackle. After exploring many different solutions, this worked for the pip ssl issue.