Get Certbot

About Certbot

Certbot is meant to be run directly on a web server, normally by a system administrator. In most cases, running Certbot on your personal computer is not a useful option. The instructions below relate to installing and running Certbot on a server.

System administrators can use Certbot directly to request certificates; they should not allow unprivileged users to run arbitrary Certbot commands as root, because Certbot allows its user to specify arbitrary file locations and run arbitrary scripts.

Certbot is packaged for many common operating systems and web servers. Check whether certbot (or letsencrypt) is packaged for your web server’s OS by visiting certbot.eff.org, where you will also find the correct installation instructions for your system.

Note

Unless you have very specific requirements, we kindly suggest that you use the Certbot packages provided by your package manager (see certbot.eff.org). If such packages are not available, we recommend using certbot-auto, which automates the process of installing Certbot on your system.

System Requirements

Certbot currently requires Python 2.7 or 3.4+ running on a UNIX-like operating system. By default, it requires root access in order to write to /etc/letsencrypt, /var/log/letsencrypt, /var/lib/letsencrypt; to bind to port 80 (if you use the standalone plugin) and to read and modify webserver configurations (if you use the apache or nginx plugins). If none of these apply to you, it is theoretically possible to run without root privileges, but for most users who want to avoid running an ACME client as root, either letsencrypt-nosudo or simp_le are more appropriate choices.

The Apache plugin currently requires an OS with augeas version 1.0; currently it supports modern OSes based on Debian, Ubuntu, Fedora, SUSE, Gentoo and Darwin.

Additional integrity verification of certbot-auto script can be done by verifying its digital signature. This requires a local installation of gpg2, which comes packaged in many Linux distributions under name gnupg or gnupg2.

Installing with certbot-auto requires 512MB of RAM in order to build some of the dependencies. Installing from pre-built OS packages avoids this requirement. You can also temporarily set a swap file. See “Problems with Python virtual environment” below for details.

Alternate installation methods

If you are offline or your operating system doesn’t provide a package, you can use an alternate method for installing certbot.

Certbot-Auto

The certbot-auto wrapper script installs Certbot, obtaining some dependencies from your web server OS and putting others in a python virtual environment. You can download and run it as follows:

user@webserver:~$ wget https://dl.eff.org/certbot-auto
user@webserver:~$ sudo mv certbot-auto /usr/local/bin/certbot-auto
user@webserver:~$ sudo chown root /usr/local/bin/certbot-auto
user@webserver:~$ chmod 0755 /usr/local/bin/certbot-auto
user@webserver:~$ /usr/local/bin/certbot-auto --help

To check the integrity of the certbot-auto script, you can use these steps:

user@webserver:~$ wget -N https://dl.eff.org/certbot-auto.asc
user@webserver:~$ gpg2 --keyserver pool.sks-keyservers.net --recv-key A2CFB51FA275A7286234E7B24D17C995CD9775F2
user@webserver:~$ gpg2 --trusted-key 4D17C995CD9775F2 --verify certbot-auto.asc /usr/local/bin/certbot-auto

The output of the last command should look something like:

gpg: Signature made Wed 02 May 2018 05:29:12 AM IST
gpg:                using RSA key A2CFB51FA275A7286234E7B24D17C995CD9775F2
gpg: key 4D17C995CD9775F2 marked as ultimately trusted
gpg: checking the trustdb
gpg: marginals needed: 3  completes needed: 1  trust model: pgp
gpg: depth: 0  valid:   2  signed:   2  trust: 0-, 0q, 0n, 0m, 0f, 2u
gpg: depth: 1  valid:   2  signed:   0  trust: 2-, 0q, 0n, 0m, 0f, 0u
gpg: next trustdb check due at 2027-11-22
gpg: Good signature from "Let's Encrypt Client Team <letsencrypt-client@eff.org>" [ultimate]

The certbot-auto command updates to the latest client release automatically. Since certbot-auto is a wrapper to certbot, it accepts exactly the same command line flags and arguments. For more information, see Certbot command-line options.

For full command line help, you can type:

/usr/local/bin/certbot-auto --help all

Problems with Python virtual environment

On a low memory system such as VPS with less than 512MB of RAM, the required dependencies of Certbot will fail to build. This can be identified if the pip outputs contains something like internal compiler error: Killed (program cc1). You can workaround this restriction by creating a temporary swapfile:

user@webserver:~$ sudo fallocate -l 1G /tmp/swapfile
user@webserver:~$ sudo chmod 600 /tmp/swapfile
user@webserver:~$ sudo mkswap /tmp/swapfile
user@webserver:~$ sudo swapon /tmp/swapfile

Disable and remove the swapfile once the virtual environment is constructed:

user@webserver:~$ sudo swapoff /tmp/swapfile
user@webserver:~$ sudo rm /tmp/swapfile

Running with Docker

Docker is an amazingly simple and quick way to obtain a certificate. However, this mode of operation is unable to install certificates or configure your webserver, because our installer plugins cannot reach your webserver from inside the Docker container.

Most users should use the operating system packages (see instructions at certbot.eff.org) or, as a fallback, certbot-auto. You should only use Docker if you are sure you know what you are doing and have a good reason to do so.

You should definitely read the Where are my certificates? section, in order to know how to manage the certs manually. Our ciphersuites page provides some information about recommended ciphersuites. If none of these make much sense to you, you should definitely use the certbot-auto method, which enables you to use installer plugins that cover both of those hard topics.

If you’re still not convinced and have decided to use this method, from the server that the domain you’re requesting a certficate for resolves to, install Docker, then issue a command like the one found below. If you are using Certbot with the Standalone plugin, you will need to make the port it uses accessible from outside of the container by including something like -p 80:80 or -p 443:443 on the command line before certbot/certbot.

sudo docker run -it --rm --name certbot \
            -v "/etc/letsencrypt:/etc/letsencrypt" \
            -v "/var/lib/letsencrypt:/var/lib/letsencrypt" \
            certbot/certbot certonly

Running Certbot with the certonly command will obtain a certificate and place it in the directory /etc/letsencrypt/live on your system. Because Certonly cannot install the certificate from within Docker, you must install the certificate manually according to the procedure recommended by the provider of your webserver.

There are also Docker images for each of Certbot’s DNS plugins available at https://hub.docker.com/u/certbot which automate doing domain validation over DNS for popular providers. To use one, just replace certbot/certbot in the command above with the name of the image you want to use. For example, to use Certbot’s plugin for Amazon Route 53, you’d use certbot/dns-route53. You may also need to add flags to Certbot and/or mount additional directories to provide access to your DNS API credentials as specified in the DNS plugin documentation. If you would like to obtain a wildcard certificate from Let’s Encrypt’s ACMEv2 server, you’ll need to include --server https://acme-v02.api.letsencrypt.org/directory on the command line as well.

For more information about the layout of the /etc/letsencrypt directory, see Where are my certificates?.

Operating System Packages

Arch Linux

sudo pacman -S certbot

Debian

If you run Debian Buster or Debian testing/Sid, you can easily install certbot packages through commands like:

sudo apt-get update
sudo apt-get install certbot

If you run Debian Stretch, we recommend you use the packages in Debian backports repository. First you’ll have to follow the instructions at https://backports.debian.org/Instructions/ to enable the Stretch backports repo, if you have not already done so. Then run:

sudo apt-get install certbot -t stretch-backports

In all of these cases, there also packages available to help Certbot integrate with Apache, nginx, or various DNS services. If you are using Apache or nginx, we strongly recommend that you install the python-certbot-apache or python-certbot-nginx package so that Certbot can fully automate HTTPS configuration for your server. A full list of these packages can be found through a command like:

apt search 'python-certbot*'

They can be installed by running the same installation command above but replacing certbot with the name of the desired package.

There are no Certbot packages available for Debian Jessie and Jessie users should instead use certbot-auto.

Ubuntu

If you run Ubuntu Trusty, Xenial, or Bionic, certbot is available through the official PPA, that can be installed as followed:

sudo apt-get update
sudo apt-get install software-properties-common
sudo add-apt-repository universe
sudo add-apt-repository ppa:certbot/certbot
sudo apt-get update

Then, certbot can be installed using:

sudo apt-get install certbot

Optionally to install the Certbot Apache plugin, you can use:

sudo apt-get install python-certbot-apache

Fedora

sudo dnf install certbot python2-certbot-apache

FreeBSD

  • Port: cd /usr/ports/security/py-certbot && make install clean
  • Package: pkg install py27-certbot

Gentoo

The official Certbot client is available in Gentoo Portage. If you want to use the Apache plugin, it has to be installed separately:

emerge -av app-crypt/certbot
emerge -av app-crypt/certbot-apache

When using the Apache plugin, you will run into a “cannot find an SSLCertificateFile directive” or “cannot find an SSLCertificateKeyFile directive for certificate” error if you’re sporting the default Gentoo httpd.conf. You can fix this by commenting out two lines in /etc/apache2/httpd.conf as follows:

Change

<IfDefine SSL>
LoadModule ssl_module modules/mod_ssl.so
</IfDefine>

to

#<IfDefine SSL>
LoadModule ssl_module modules/mod_ssl.so
#</IfDefine>

For the time being, this is the only way for the Apache plugin to recognise the appropriate directives when installing the certificate. Note: this change is not required for the other plugins.

NetBSD

  • Build from source: cd /usr/pkgsrc/security/py-certbot && make install clean
  • Install pre-compiled package: pkg_add py27-certbot

OpenBSD

  • Port: cd /usr/ports/security/letsencrypt/client && make install clean
  • Package: pkg_add letsencrypt

Other Operating Systems

OS packaging is an ongoing effort. If you’d like to package Certbot for your distribution of choice please have a look at the Packaging Guide.

Installing from source

Installation from source is only supported for developers and the whole process is described in the Developer Guide.

Warning

Please do not use python setup.py install, python pip install ., or easy_install .. Please do not attempt the installation commands as superuser/root and/or without virtual environment, e.g. sudo python setup.py install, sudo pip install, sudo ./venv/bin/.... These modes of operation might corrupt your operating system and are not supported by the Certbot team!