I’ll introduce how to set up SSL with Let’s Encrypt on a server with CentOS + Nginx configuration.
Installing certbot
While there’s a method to install with yum, Python dependencies seemed troublesome, so I decided to download and use it as a zip from GitHub.
cd /usr/local/
wget https://github.com/certbot/certbot/archive/master.zip
unzip master.zip
mv certbot-master certbot
cd certbot/
Checking the certbot-auto Command
Verify that the certbot-auto command can be executed.
$ ./certbot-auto --help
Usage: certbot-auto [OPTIONS]
A self-updating wrapper script for the Certbot ACME client. When run, updates
to both this script and certbot will be downloaded and installed. After
ensuring you have the latest versions installed, certbot will be invoked with
all arguments you have provided.
Help for certbot itself cannot be provided until it is installed.
--debug attempt experimental installation
-h, --help print this help
-n, --non-interactive, --noninteractive run without asking for user input
--no-bootstrap do not install OS dependencies
--no-self-upgrade do not download updates
--os-packages-only install OS dependencies and exit
--install-only install certbot, upgrade if needed, and exit
-v, --verbose provide more output
-q, --quiet provide only update/error output;
implies --non-interactive
All arguments are accepted and forwarded to the Certbot client when run.
Obtaining SSL Certificate
Execute the certbot-auto command as follows:
./certbot-auto certonly --standalone \\
-d example.com \\
-m [email protected] \\
--agree-tos \\
--non-interactive
Failure Example
By the way, executing ./certbot-auto certonly --standalone while Nginx is running will fail.
Problem binding to port 80: Could not bind to IPv4 or IPv6.
IMPORTANT NOTES:
- Your account credentials have been saved in your Certbot
configuration directory at /etc/letsencrypt. You should make a
secure backup of this folder now. This configuration directory will
also contain certificates and private keys obtained by Certbot so
making regular backups of this folder is ideal.
Stop Nginx:
service nginx stop
Execute ./certbot-auto certonly --standalone again, and this time it succeeded.
IMPORTANT NOTES:
- Congratulations! Your certificate and chain have been saved at:
/etc/letsencrypt/live/codenote.net/fullchain.pem
Your key file has been saved at:
/etc/letsencrypt/live/codenote.net/privkey.pem
Your cert will expire on 2018-09-09. To obtain a new or tweaked
version of this certificate in the future, simply run certbot-auto
again. To non-interactively renew *all* of your certificates, run
"certbot-auto renew"
- If you like Certbot, please consider supporting our work by:
Donating to ISRG / Let's Encrypt: https://letsencrypt.org/donate
Donating to EFF: https://eff.org/donate-le
Checking Let's Encrypt Retrieved Files
Finally, let’s verify the files retrieved by the ./certbot-auto certonly command.
/etc/letsencrypt/
|-- accounts # Account information
|-- archive # Retrieved certificate files are saved in directories for each domain
| `-- example.com
| |-- cert1.pem
| |-- chain1.pem
| |-- fullchain1.pem
| `-- privkey1.pem
|-- csr
|-- keys
|-- live # Symbolic links to the latest certificates are created
| `-- example.com
| |-- README
| |-- cert.pem -> ../../archive/example.com/cert1.pem
| |-- chain.pem -> ../../archive/example.com/chain1.pem
| |-- fullchain.pem -> ../../archive/example.com/fullchain1.pem
| `-- privkey.pem -> ../../archive/example.com/privkey1.pem
|-- renewal
| `-- example.com.conf
`-- renewal-hooks
Once you’ve obtained the SSL certificate, you need to add SSL configuration to Nginx, but I’ll explain that method in a separate article.
That’s all from the Gemba where I obtained an SSL certificate with Let’s Encrypt.