Fixing Let's Encrypt Certbot prerequisite issues

Nov 30, 2021

I ran into an issue today when I could not install certbot-auto on a Linux machine running CentOS 6.10.

As it turns out that you need to enable EPEL package repository with yum package manager. The error I got during cert bot installation(prior to enabling the EPEL) was:

Package ca-certificates-2018.2.22-65.1.el6.noarch already installed and latest version
Package python-devel-2.6.6-68.el6_10.x86_64 already installed and latest version
No package python-virtualenv available.
Package python-tools-2.6.6-68.el6_10.x86_64 already installed and latest version
No package python-pip available.
Package 1:mod_ssl-2.2.15-69.el6.centos.x86_64 already installed and latest version
Nothing to do
Creating virtual environment...
Traceback (most recent call last):
  File "<stdin>", line 27, in <module>
  File "<stdin>", line 19, in create_venv
  File "/usr/lib64/python2.7/subprocess.py", line 185, in check_call
    retcode = call(*popenargs, **kwargs)
  File "/usr/lib64/python2.7/subprocess.py", line 172, in call
    return Popen(*popenargs, **kwargs).wait()
  File "/usr/lib64/python2.7/subprocess.py", line 394, in _init_
    errread, errwrite)
  File "/usr/lib64/python2.7/subprocess.py", line 1047, in _execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory

Let's focus on the line with No package python-pip available.. It turns out that python-pip & python-virtualenv are EPEL packages. These are the packages that caused the issue, because cert bot could not install them without EPEL enabled.

Solution/Fix

Install and enable EPEL:

yum update

Install EPEL

yum install epel-release -y

Open epel config

vim /etc/yum.repos.d/epel.repo

set enable=1

[EPEL]
...
#enabled=0
enable=1

Save & Exit the text editor. Update packages:

yum update

Verify that EPEL was enabled:

yum repolist | grep epel

If grep matches something similar:

# epel        Extra Packages for Enterprise Linux 6 - x86_64       12,568

then certbot prerequisites should be met. You can now continue with Encrypt's certbot installation.