Our servers went through a few major system changes during the years:
- upgrade from Ubuntu 16.04
- update to python 3
- modules deployed for instrumentation and monitoring
and as a result different packages were not renewed automatically. One of them was the certbot application from Let’s Encrypt.Today we realized the auto update feature was failing. I logged in and tried a dry run, the result is shown below.
The error is a module named _cffi_backend. After a few google searches it seemed there were packages missing from certbot / python3 application.
This is what worked for us:
- python3 -m pip install cffi
python3 -m pip install certbot-nginx
then we checked the installation with a dry run
- sudo certbot renew –dry-run
The certificates were renewed and hopefully the next renewal will be without hiccups.