How to solved certbot-auto no supported python package available to install. aborting bootstrap! (Let'sencrypt)

If you get an error like this on CentOS 6 or CentOS 7 :

Bootstrapping dependencies for RedHat-based OSes that will use Python3... (you can skip this with --no-bootstrap)
yum is /usr/bin/yum
No supported Python package available to install. Aborting bootstrap!

You can following this command :

If CentOS 6 :
create CentOS-Base.repo

# nano /etc/yum.repos.d/CentOS-Base.repo

# CentOS-Base.repo
#
# The mirror system uses the connecting IP address of the client and the
# update status of each mirror to pick mirrors that are updated to and
# geographically close to the client.  You should use this for CentOS updates
# unless you are manually picking other mirrors.
#
# If the mirrorlist= does not work for you, as a fall back you can try the
# remarked out baseurl= line instead.
#
#

[base]
name=CentOS-$releasever - Base
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
#baseurl=http://mirror.centos.org/centos/$releasever/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6

#released updates
[updates]
name=CentOS-$releasever - Updates
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates
#baseurl=http://mirror.centos.org/centos/$releasever/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6

#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras
#baseurl=http://mirror.centos.org/centos/$releasever/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6

#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus
#baseurl=http://mirror.centos.org/centos/$releasever/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6

#contrib - packages by Centos Users
[contrib]
name=CentOS-$releasever - Contrib
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=contrib
#baseurl=http://mirror.centos.org/centos/$releasever/contrib/$basearch/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6

And add repo rhscl-centos-release-scl-epel-6.repo.

# sudo yum-config-manager --add-repo=https://copr.fedoraproject.org/coprs/rhscl/centos-release-scl/repo/epel-6/rhscl-centos-release-scl-epel-6.repo

Make sure there are centos-release-scl.noarch version 10:7-4.el6.centos, with this command :

# yum list centos-release-scl

[root@arie ~]# yum list centos-release-scl
Loaded plugins: presto, replace, security
gitlab_gitlab-ce/signature                                                                                                                         |  836 B     00:00     
gitlab_gitlab-ce/signature                                                                                                                         | 1.0 kB     00:00 ... 
gitlab_gitlab-ce-source/signature                                                                                                                  |  836 B     00:00     
gitlab_gitlab-ce-source/signature                                                                                                                  |  951 B     00:00 ... 
varnishcache_varnish41/signature                                                                                                                   |  833 B     00:00     
varnishcache_varnish41/signature                                                                                                                   | 1.0 kB     00:00 ... 
varnishcache_varnish41-source/signature                                                                                                            |  833 B     00:00     
varnishcache_varnish41-source/signature                                                                                                            | 1.0 kB     00:00 ... 
Installed Packages
centos-release-scl.noarch                                    10:7-4.el6.centos                                     @extras                                                
Available Packages
centos-release-scl.noarch                                    10:6-8.el6                                            copr:copr.fedorainfracloud.org:rhscl:centos-release-scl
centos-release-scl.noarch                                    10:7-3.el6.centos                                     extras                                                 
centos-release-scl.noarch                                    10:7-4.el6.centos                                     extras                                                 

# sudo yum install centos-release-scl




If Centos 7 :

sudo yum-config-manager --add-repo=https://copr.fedoraproject.org/coprs/rhscl/centos-release-scl/repo/epel-7/rhscl-centos-release-scl-epel-7.repo

sudo yum install centos-release-scl

Save the day !!!!