acme-nginx
Simple way to get SSL certificates for free.
Table of Contents
Features
- Works with both ACMEv1 (deprecated) and ACMEv2 protocols
- Can issue wildcard certificates!
- Easy to use and extend
Description
This is ACME client implementation in
Python originally based on https://github.com/diafygi/acme-tiny code.
Now completely different.
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 700 lines of code.
Script should be run as root on host with running nginx server if you use http verification or if you use DNS verification as a regular user. Domain for which you request certificate should point to that host's IP and port 80 should be available from outside if you use HTTP challenge. Script can generate all keys for you if you don't set them with command line arguments. 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 >= 3.6
ACME v2
ACME v2 requires more logic so it's not as small as ACME v1 script.
ACME v2 is supported partially: only http-01 and dns-01 challenges.
Check https://tools.ietf.org/html/draft-ietf-acme-acme-07#section-9.7.6
New protocol is used by default.
http-01 challenge is passed exactly as in v1 protocol realization.
dns-01 currently supports following providers:
- DigitalOcean
- AWS Route53
- Cloudflare
Technically nginx is not needed for this type of challenge but script still calls nginx reload by default
because it assumes that you store certificates on the same server where you issue
them. To disable that behavior please specify --no-reload-nginx parameter.
AWS Route53 uses default profile in session, specifying profile works with environment variables only.
Please check https://boto3.amazonaws.com/v1/documentation/api/latest/guide/configuration.html#environment-variable-configuration
In case you want to add support of different DNS providers your contribution is highly appreciated.
Wildcard certificates can not be issued with non-wildcard for the same domain.
I.e. it's not possible to issue certificates for *.example.com and
www.example.com at the same time.
ACME v1
Still supported with flag --acme-v1.
Only HTTP challenge is supported at the moment.
Installation
Preferred way
Using poetry.
-
First install poetry:
curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/get-poetry.py | python3 - source ~/.poetry/env
-
Clone acme-nginx:
git clone https://github.com/kshcherban/acme-nginx
-
Install it:
cd acme-nginx poetry install
Python pip way
Automatically
pip3 install acme-nginx
or manually
git clone https://github.com/kshcherban/acme-nginx
cd acme-nginx
python setup.py install
Docker way
You can build docker image with acme-nginx inside:
docker build -t acme-nginx .
docker run --rm -v /etc/nginx:/etc/nginx --pid=host \
-d example.com -d www.example.com
There is also single binary in docker image compiled by pyinstaller , you can copy it like this:
docker run --name acme acme-nginx
docker cp acme:/usr/bin/acme-runner acme-nginx
docker rm acme
Debian/Ubuntu way
sudo apt-get install -y python-openssl python-crypto python-setuptools
sudo python setup.py install
CentOS/RedHat/Fedora way
sudo yum install -y pyOpenSSL python-crypto python-setuptools
sudo yum groupinstall -y "Development tools"
sudo python setup.py install
Usage
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;
...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
Wildcard certificates
For wildcard certificate you need to have your domain managed by DNS provider with API. Currently only DigitalOcean DNS, Cloudflare and AWS Route53 are supported.
Example how to get wildcard certificate without nginx
sudo acme-nginx --no-reload-nginx --dns-provider route53 -d "*.example.com"
DigitalOcean
Please create and export your DO API token as API_TOKEN env variable.
Now you can generate wildcard certificate
sudo su -
export API_TOKEN=yourDigitalOceanApiToken
acme-nginx --dns-provider digitalocean -d '*.example.com'Cloudflare
Create API token first. Then export it as API_TOKEN environment variable and use like this:
sudo su -
export API_TOKEN=yourCloudflareApiToken
acme-nginx --dns-provider cloudflare -d '*.example.com'Debug
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.conf.
Execute acme-nginx --help to see all available flags and their default values.
Renewal
Personally i use following cronjob to renew certificates of my blog. Here's contents
of /etc/cron.d/renew-cert
[email protected]
12 11 10 * * root timeout -k 600 -s 9 3600 /usr/local/bin/acme-nginx -d prolinux.org -d www.prolinux.org >> /var/log/letsencrypt.log 2>&1 || echo "Failed to renew certificate"