Let's Encrypt for GitLab Pages

If you have a GitLab Pages website served under your own domain, you might want to secure it with a SSL/TSL certificate.

Let's Encrypt is a free, automated, and open source Certificate Authority.

Requirements

To follow along with this tutorial, we assume you already have:

Created a project in GitLab which contains your website's source code.
Acquired a domain (example.com) and added a DNS entry pointing it to your Pages website.
Added your domain to your Pages project and verified your ownership.
Cloned your project into your computer.
Your website up and running, served under HTTP protocol at http://example.com.

Obtaining a Let's Encrypt certificate

Once you have the requirements addressed, follow the instructions below to learn how to obtain the certificate.

NOTE: Note: The instructions below were tested on macOS Mojave. For other operating systems the steps might be slightly different. Follow the CertBot instructions according to your OS.

On your computer, open a terminal and navigate to your repository's root directory:
```
cd path/to/dir
```
Install CertBot (the tool Let's Encrypt uses to issue certificates):
```
brew install certbot
```
Request a certificate for your domain (example.com) and provide an email account (your@email.com) to receive notifications:
```
sudo certbot certonly -a manual -d example.com --email your@email.com
```
Alternatively, you can register without adding an e-mail account, but you won't be notified about the certificate expiration's date:
```
sudo certbot certonly -a manual -d example.com --register-unsafely-without-email
```
TIP: Tip: Read through CertBot's documentation on their command line options.

You'll be prompted with a message to agree with their terms. Press A to agree and Y to let they log your IP.

CertBot will then prompt you with the following message:

Create a file containing just this data:

Rxnv6WKo95hsuLVX3osmT6LgmzsJKSaK9htlPToohOP.HUGNKk82jlsmOOfphlt8Jy69iuglsn095nxOMH9j3Yb

And make it available on your web server at this URL:

http://example.com/.well-known/acme-challenge/Rxnv6WKo95hsuLVX3osmT6LgmzsJKSaK9htlPToohOP

Press Enter to Continue

Do not press Enter yet. Let's Encrypt will need to verify your domain ownership before issuing the certificate. To do so, create 3 consecutive directories under your website's root: /.well-known/acme-challenge/Rxnv6WKo95hsuLVX3osmT6LgmzsJKSaK9htlPToohOP/ and add to the last folder an index.html file containing the content referred on the previous prompt message:
```
Rxnv6WKo95hsuLVX3osmT6LgmzsJKSaK9htlPToohOP.HUGNKk82jlsmOOfphlt8Jy69iuglsn095nxOMH9j3Yb
```
Note that this file needs to be accessed under http://example.com/.well-known/acme-challenge/Rxnv6WKo95hsuLVX3osmT6LgmzsJKSaK9htlPToohOP to allow Let's Encrypt to verify the ownership of your domain, therefore, it needs to be part of the website content under the repo's public folder.

Add, commit, and push the file into your repo in GitLab. Once the pipeline passes, press Enter on your terminal to continue issuing your certificate. CertBot will then prompt you with the following message:

Waiting for verification...
Cleaning up challenges

IMPORTANT NOTES:
 - Congratulations! Your certificate and chain have been saved at:
   /etc/letsencrypt/live/example.com/fullchain.pem
   Your key file has been saved at:
   /etc/letsencrypt/live/example.com/privkey.pem
   Your cert will expire on 2019-03-12. To obtain a new or tweaked
   version of this certificate in the future, simply run certbot
   again. To non-interactively renew *all* of your certificates, run
   "certbot 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

Add your certificate to GitLab Pages

Now that your certificate has been issued, let's add it to your Pages site:

Back at GitLab, navigate to your project's Settings > Pages, find your domain and click Details and Edit to add your certificate.
From your terminal, copy and paste the certificate into the first field Certificate (PEM):
```
sudo cat /etc/letsencrypt/live/example.com/fullchain.pem | pbcopy
```

Copy and paste the public key into the second field Key (PEM):

sudo cat /etc/letsencrypt/live/example.com/privkey.pem | pbcopy

Click Save changes to apply them to your website.
Wait a few minutes for DNS propagation.
Visit your website at https://example.com.

To force https connections on your site, navigate to your project's Settings > Pages and check Force domains with SSL certificates to use HTTPS.

Renewal

Let's Encrypt certificates expire every 90 days and you'll have to renew them periodically. To renew all your certificates at once, run:

sudo certbot renew