Creating SSL Certificates

This tutorial briefly covers creating new SSL certificates for your panel and kuber.

Method 1: Certbot

To begin, we will install certbot, a simple script that automatically renews our certificates and allows much easier creation of them. The command below is for Ubuntu distributions, but you can always check Certbot's official site (opens new window)for installation instructions. We have also included a command below to install certbot's Nginx/Apache plugin so you won't have to stop your webserver.

sudo apt update
sudo apt install -y certbot
# Run this if you use Nginx
sudo apt install -y python3-certbot-nginx
# Run this if you use Apache
sudo apt install -y python3-certbot-apache

Creating a Certificate

After installing the certbot, we need to generate a certificate. There are a couple of ways to do that, but the easiest is to use the web server-specific certbot plugin you just installed. For Kuber-only machines that don't need a web server, use the standalone or DNS method of the certbot as you don't need a web server for it.

Then, in the command below, you should replace example.com with the domain you would like to generate a certificate for. When you have multiple domains you would like certificates for, simply add more -d anotherdomain.com flags to the command. You can also look into generating a wildcard certificate but that is not covered in this tutorial.

When you are using certbot's Nginx/Apache plugin, you won't need to restart your webserver to have the certificate applied assuming that you've already configured the webservers to use SSL as instructed in the web server configuration step (opens new window).

HTTP challenge

HTTP challenge requires you to expose port 80 for the challenge verification.

# Nginx
certbot certonly --nginx -d example.com
# Apache
certbot certonly --apache -d example.com
# Standalone - Use this if neither works. Make sure to stop your webserver first when using this method.
certbot certonly --standalone -d example.com

DNS challenge

DNS challenge requires you to create a new TXT DNS record to verify domain ownership, instead of having to expose port 80. The instructions are displayed when you run the certbot command below.

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

Auto Renewal

You'll also probably want to configure the automatic renewal of certificates to prevent unexpected certificate expirations. You can open crontab with sudo crontab -e and add the line from below to the bottom of it for attempting renewal every day at 23 (11 PM).

Deploy hook would restart the Nginx service to apply a new certificate when it's renewed successfully. Change nginx in the restart command to suit your own needs, such as to apache or kuber.

For advanced users, we suggest installing and using acme.sh (opens new window)which provides more options, and is much more powerful than certbot.

0 23 * * * certbot renew --quiet --deploy-hook "systemctl restart nginx"

Troubleshooting

If you get an Insecure Connection or SSL/TLS related error when trying to access your panel or kuber, the certificate has likely expired. This can be easily fixed by renewing the SSL certificate, although using the command certbot renew might not do the job if port 80 is in use, as it'll return errors like: Error: Attempting to renew cert (domain) from /etc/letsencrypt/renew/domain.conf produced an unexpected error.

This will happen especially if you're running Nginx instead of Apache. The solution for this is to use Nginx or Apache plugins with --nginx and --apache. Alternatively, you can stop Nginx, then renew the certificate, finally restart Nginx. Replace nginx with your own web server or with kuber should you be renewing the certificate for Kuber.

Stop Nginx:

systemctl stop nginx

Renew the certificate:

certbot renew

Once the process has complete, you can restart the Nginx service:

systemctl start nginx

You may also need to restart Kuber as not every service is able to automatically apply an updated certificate:

systemctl restart kuber

Method 2: acme.sh (using Cloudflare API)

This is for advanced users, whose server systems do not have access to port 80. The command below is for Ubuntu distributions and CloudFlare API (you may google for other APIs for other DNS providers), but you can always check acme.sh's official site (opens new window)for installation instructions.

curl https://get.acme.sh | sh

Obtaining CloudFlare API Key

After installing acme.sh, we need to fetch a CloudFlare API key. Please make sure that a DNS record (A or CNAME record) is pointing to your target node, and set the cloud to grey (bypassing CloudFlare proxy). Then go to My Profile > API keys and on Global API Key subtab, click on "view", enter your CloudFlare password, and copy the API key to clipboard.

Creating a Certificate

Since the configuration file is based on Certbot, we need to create the folder manually.

sudo mkdir /etc/letsencrypt/live/example.com

After installing acme.sh and obtaining CloudFlare API key, we need to then generate a certificate. First input the CloudFlare API credentials.

export CF_Key="Your_CloudFlare_API_Key"
export CF_Email="[email protected]"

Then create the certificate.

acme.sh --issue --dns dns_cf -d "example.com" --server letsencrypt \
--key-file /etc/letsencrypt/live/example.com/privkey.pem \
--fullchain-file /etc/letsencrypt/live/example.com/fullchain.pem

Auto Renewal

After running the script for the first time, it will be added to the crontab automatically. You may edit the auto renewal interval by editing the crontab.

sudo crontab -e