HTTPS on Gitlab Pages using Let's Encrypt / Certbot

[DEPRECIATED] These instructions are for Mac OS, uses Let's Encrypt's certbot, and does not require a challenge file, which makes things much easier.

December 17, 2018

UPDATE 09/17/19: Turns out Gitlab recently added native HTTPS support for Pages! This means that my guide below is now entirely useless, but I’ll keep this as an archive.

I decided to move a personal project’s webpage over from Github to Gitlab recently, mainly because Gitlab offers private repositories for free. However, unlike Github, HTTPS encryption for custom domain names on Gitlab requires manual setup. I couldn’t find any comprehensive guides, so here’s the easiest method I’ve found so far that utilizes DNS verification with a TXT entry. These instructions are for Mac OS, uses Let’s Encrypt’s certbot, and does not require a challenge file, which makes things much easier.

Prerequisites

  1. Homebrew installed
  2. Access to domain DNS settings

Again, these instructions are for Mac OS. Refer to Certbot’s installation guides for all other environments.

Installation Process

1. Install Certbot

brew install certbot

2. Create verification keys

certbot -d yourdomain.com --manual --preferred-challenges dns certonly

Make sure to replace yourdomain.com with you actual domain. Do not add http:// or https:// to the beginning of your domain. Once the verification key is created, copy the key and move on to the next step without hitting “Enter” in the terminal window.

3. Add TXT entry to DNS settings

Log into your domain’s admin page and go into the DNS settings. In Google Domains, scroll all the way to the bottom of the “Configure DNS” tab to find “Custom resource recods”.

Put _acme-challenge.yourdomain.com into the name field, change the Type to TXT, and place the resulting key into the Text field.

4. Flush Google DNS cache

Flush Google DNS’s cache for your domain’s TXT entry using Google’s Public DNS tool. This makes your changes effective immediately so that certbot can verify you own the domain.

5. Continue on Certbot

Go back into the terminal window and hit “Enter”. You should get the following congrats message if everything was implemented correctly. Your certificate and SSL key will be created and placed in a folder.

IMPORTANT NOTES:
 - Congratulations! Your certificate and chain have been saved at
   /etc/letsencrypt/live/YOURDOMAIN.org/fullchain.pem. Your cert will
   expire on 2016-07-04. To obtain a new version of the certificate in
   the future, simply run Let's Encrypt again.
 - If you like Let's Encrypt, please consider supporting our work by:

   Donating to ISRG / Let's Encrypt:   https://letsencrypt.org/donate
   Donating to EFF:                    https://eff.org/donate-le

If you got an error message instead, try create another key and repeat the above steps, but wait a few minutes after flushing the cache but before continuing on and hitting “Enter” in the terminal window.

6. Copy the keys into Gitlab’s repo settings

Navigate to the resulting folder using root access.

sudo su
cd /etc/letsencrypt/live/yourdomain.com/

Back on Gitlab, go to the Pages setting page and copy the contents of fullchain.pem using nano fullchain.pem into the “Certificate (PEM)” field on Gitlab. Similarly, use nano privkey.pem and copy the contents into the “Key (PEM)” field. Or use any editor of your choice, obviously.

7. Enable SSL on Gitlab

Once saved, make sure to check the “Force domains with SSL certificates to use HTTPS” checkbox on the Pages settings page.

Finished!

If everything was done correctly, HTTPS should now be working on your website. Changes may take an hour or two to appear, so give it some time.