This is ACME client implementation in Python based on https://github.com/diafygi/acme-tiny code. It's written in pure Python depends on pyOpenSSL and pycrypto and the only binary it calls is ps to determine nginx master process id to send SIGHUP to it during challenge completion.
As you may not trust this script feel free to check source code, it's under 400 lines.
Script should be run as root on host with running nginx. Domain for which you request certificate should point to that host's IP and port 80 should be available from outside. Script can generate all keys for you if you don't set them in command line. Keys are RSA with length of 2048 bytes. You can specify as many alternative domain names as you wish. The result PEM file is a certificate chain containing your signed certificate and letsencrypt signed chain. You can use it with nginx.
Should work with Python >= 2.6
Please be informed that the quickiest and easiest way of installation is to use your OS installation way because Python way includes compilation of dependencies that may take much time and CPU resources and may require you to install all build dependencies.
Automatically
pip install acme-nginx
or manually
git clone https://github.com/kshcherban/acme-nginx
cd acme-nginx
python setup.py install
sudo apt-get install -y python-openssl python-crypto
sudo python setup.py install
sudo yum install -y pyOpenSSL python-crypto
sudo python setup.py install
Simplest scenario: you have neither letsencrypt account key nor domain key and want to generate certificate for example.com and www.example.com
sudo acme-nginx -d example.com -d www.example.com
You will see output similar to this:
Oct 12 23:42:17 Can not open key /etc/ssl/private/letsencrypt-account.key, generating new
Oct 12 23:42:17 Can not open key /etc/ssl/private/letsencrypt-domain.key, generating new
Oct 12 23:42:17 Trying to register account key
Oct 12 23:42:18 Registered!
Oct 12 23:42:18 Requesting challenge
Oct 12 23:42:19 Adding nginx virtual host and completing challenge
Oct 12 23:42:19 Creating file /etc/nginx/sites-enabled/letsencrypt
Oct 12 23:42:21 example.com verified!
Oct 12 23:42:21 Requesting challenge
Oct 12 23:42:21 Adding nginx virtual host and completing challenge
Oct 12 23:42:21 Creating file /etc/nginx/sites-enabled/letsencrypt
Oct 12 23:42:23 www.example.com verified!
Oct 12 23:42:23 Signing certificate
Oct 12 23:42:23 Certificate signed!
Oct 12 23:42:23 Writing result file in /etc/ssl/private/letsencrypt-domain.pem
Oct 12 23:42:23 Removing /etc/nginx/sites-enabled/letsencrypt and sending HUP to nginx
Certificate was generated into /etc/ssl/private/letsencrypt-domain.pem
You can now configure nginx to use it:
server {
listen 443;
ssl on;
ssl_certificate /etc/ssl/private/letsencrypt-domain.pem;
ssl_certificate_key /etc/ssl/private/letsencrypt-domain.key;
ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
...
To renew it simply rerun the command! You can put it in cron, but don't forget about letsencrypt rate limits.
More complicated scenario: you have both account, domain keys and custom virtual host
sudo acme-nginx \
-k /path/to/account.key \
--domain-private-key /path/to/domain.key \
--virtual-host /etc/nginx/sites-enabled/customvhost \
-o /path/to/signed_certificate.pem \
-d example.com -d www.example.com
To debug please use --debug flag. With debug enabled all intermediate files
will not be removed, so you can check /etc/nginx/sites-enabled for temporary
virtual host configuration, by default it's /etc/nginx/sites-enabled/0-letsencrypt.
Execute acme-nginx --help to see all available flags and their default values.
Personally i use following cronjob to renew certificates of my blog:
cat /etc/cron.d/renew-cert
MAILTO=insider@prolinux.org
12 11 10 * * root /usr/local/bin/acme-nginx -d prolinux.org -d www.prolinux.org >> /var/log/letsencrypt.log