Generating and Renewing SSL Certificates with Certbot

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1. Generate SSL Certificate with Certbot

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Install Certbot and Nginx (Required only for Method 1 and 2)

sudo apt update
sudo apt install certbot python3-certbot-nginx nginx  

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Pause the frontend container

sudo docker pause id_container_frontend

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Start Nginx

sudo systemctl start nginx

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Method 1 – Certbot with Nginx (No DNS Validation), this is the recommended method for simplicity and automation.

sudo certbot --nginx -d <your-domain>

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Method 2 – Certbot Manual with DNS Validation, use this if DNS challenge is required.

sudo certbot certonly --manual \
  --preferred-challenges=dns \
  --email info@<your-domain> \
  --server https://acme-v02.api.letsencrypt.org/directory \
  --agree-tos \
  -d <your-domain>

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Create the DNS TXT Record, Access your DNS management console and add a TXT record:

• Type: TXT
• Name: _acme-challenge. your-domain
• Value: (provided by Certbot)

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Method 3 – Using Certificates from a Trusted Certificate Authority (CA)

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Replace existing certificates

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1. Copy the provided certificate and private key files:

sudo cp your_certificate.crt /utmstack/cert/utm.crt  
sudo cp your_private_key.key /utmstack/cert/utm.key  

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Stop the frontend container, use docker ps to identify the container ID:

sudo docker stop id_container_frontend

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Stop and Disable Nginx (Only if used for Method 1 or 2)

sudo systemctl disable nginx  
sudo systemctl stop nginx  

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2. Renew SSL Certificate (For Certbot methods only), recommended every 60–90 days.

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Pause the frontend container

sudo docker pause id_container_frontend  

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Start Nginx

sudo systemctl start nginx  

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Renew Certbot Certificates

sudo certbot renew  

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Stop and Disable Nginx

sudo systemctl disable nginx  
sudo systemctl stop nginx  

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Update Certificates in UTMStack

sudo cp /etc/letsencrypt/live/<your-domain>/fullchain.pem /utmstack/cert/utm.crt  
sudo cp /etc/letsencrypt/live/<your-domain>/privkey.pem /utmstack/cert/utm.key  

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Stop the frontend container

sudo docker stop id_container_frontend  

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Final Notes

• Certbot stores your certificates at: /etc/letsencrypt/live/your-domain/
• Check expiration with:

sudo certbot certificates