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      How To Use Certbot Standalone Mode to Retrieve Let’s Encrypt SSL Certificates on CentOS 7


      Introduction

      Let’s Encrypt is a service offering free SSL certificates through an automated API. The most popular Let’s Encrypt client is EFF’s Certbot.

      Certbot offers a variety of ways to validate your domain, fetch certificates, and automatically configure Apache and Nginx. In this tutorial, we’ll discuss Certbot’s standalone mode and how to use it to secure other types of services, such as a mail server or a message broker like RabbitMQ.

      We won’t discuss the details of SSL configuration, but when you are done you will have a valid certificate that is automatically renewed. Additionally, you will be able to automate reloading your service to pick up the renewed certificate.

      Prerequisites

      Before starting this tutorial, you will need:

      • An CentOS 7 server with a non-root, sudo-enabled user, as detailed in this CentOS 7 initial server setup tutorial.
      • A domain name pointed at your server, which you can accomplish by following “How to Set Up a Host Name with DigitalOcean.” This tutorial will use example.com throughout.
      • Port 80 or 443 must be unused on your server. If the service you’re trying to secure is on a machine with a web server that occupies both of those ports, you’ll need to use a different mode such as Certbot’s webroot mode.

      Step 1 — Installing Certbot

      Certbot is packaged in an extra repository called Extra Packages for Enterprise Linux (EPEL). To enable this repository on CentOS 7, run the following yum command:

      • sudo yum --enablerepo=extras install epel-release

      Afterwards, the certbot package can be installed with yum:

      You may confirm your install was successful by calling the certbot command:

      Output

      certbot 0.31.0

      Now that we have Certbot installed, let's run it to get our certificate.

      Step 2 — Running Certbot

      Certbot needs to answer a cryptographic challenge issued by the Let's Encrypt API in order to prove we control our domain. It uses ports 80 (HTTP) or 443 (HTTPS) to accomplish this. If you're using a firewall, open up the appropriate port now. For firewalld this would be something like the following:

      • sudo firewall-cmd --add-service=http
      • sudo firewall-cmd --runtime-to-permanent

      Substitute https for http above if you're using port 443.

      We can now run Certbot to get our certificate. We'll use the --standalone option to tell Certbot to handle the challenge using its own built-in web server. The --preferred-challenges option instructs Certbot to use port 80 or port 443. If you're using port 80, you want --preferred-challenges http. For port 443 it would be --preferred-challenges tls-sni. Finally, the -d flag is used to specify the domain you're requesting a certificate for. You can add multiple -d options to cover multiple domains in one certificate.

      • sudo certbot certonly --standalone --preferred-challenges http -d example.com

      When running the command, you will be prompted to enter an email address and agree to the terms of service. After doing so, you should see a message telling you the process was successful and where your certificates are stored:

      Output

      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 2018-10-09. 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" - 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. - 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

      We've got our certificates. Let's take a look at what we downloaded and how to use the files with our software.

      Step 3 — Configuring Your Application

      Configuring your application for SSL is beyond the scope of this article, as each application has different requirements and configuration options, but let's take a look at what Certbot has downloaded for us. Use ls to list out the directory that holds our keys and certificates:

      • sudo ls /etc/letsencrypt/live/example.com

      Output

      cert.pem chain.pem fullchain.pem privkey.pem README

      The README file in this directory has more information about each of these files. Most often you'll only need two of these files:

      • privkey.pem: This is the private key for the certificate. This needs to be kept safe and secret, which is why most of the /etc/letsencrypt directory has very restrictive permissions and is accessible by only the root user. Most software configuration will refer to this as something similar to ssl-certificate-key or ssl-certificate-key-file.
      • fullchain.pem: This is our certificate, bundled with all intermediate certificates. Most software will use this file for the actual certificate, and will refer to it in their configuration with a name like 'ssl-certificate'.

      For more information on the other files present, refer to the "Where are my certificates" section of the Certbot docs.

      Some software will need its certificates in other formats, in other locations, or with other user permissions. It is best to leave everything in the letsencrypt directory, and not change any permissions in there (permissions will just be overwritten upon renewal anyway), but sometimes that's just not an option. In that case, you'll need to write a script to move files and change permissions as needed. This script will need to be run whenever Certbot renews the certificates, which we'll talk about next.

      Step 4 — Enabling Automatic Certificate Renewal

      Let's Encrypt's certificates are only valid for ninety days. This is to encourage users to automate their certificate renewal process. The certbot package we installed includes a systemd timer to check for renewals twice a day, but it is disabled by default. Enable the timer by running the following command:

      • sudo systemctl enable --now certbot-renew.timer

      Output

      Created symlink from /etc/systemd/system/timers.target.wants/certbot-renew.timer to /usr/lib/systemd/system/certbot-renew.timer.

      You may verify the status of the timer using systemctl:

      • sudo systemctl status certbot-renew.timer

      Output

      ● certbot-renew.timer - This is the timer to set the schedule for automated renewals Loaded: loaded (/usr/lib/systemd/system/certbot-renew.timer; enabled; vendor preset: disabled) Active: active (waiting) since Fri 2019-05-31 15:10:10 UTC; 48s ago

      The timer should be active. Certbot will now automatically renew any certificates on this server whenever necessary.

      Step 5 — Running Tasks When Certificates are Renewed

      Now that our certificates are renewing automatically, we need a way to run certain tasks after a renewal. We need to at least restart or reload our server to pick up the new certificates, and as mentioned in Step 3 we may need to manipulate the certificate files in some way to make them work with the software we're using. This is the purpose of Certbot's renew_hook option.

      To add a renew_hook, we update Certbot's renewal config file. Certbot remembers all the details of how you first fetched the certificate, and will run with the same options upon renewal. We just need to add in our hook. Open the config file with you favorite editor:

      • sudo vi /etc/letsencrypt/renewal/example.com.conf

      A text file will open with some configuration options. Add your hook on the last line:

      /etc/letsencrypt/renewal/example.com.conf

      renew_hook = systemctl reload rabbitmq
      

      Update the command above to whatever you need to run to reload your server or run your custom file munging script. Usually, on CentOS, you’ll mostly be using systemctl to reload a service. Save and close the file, then run a Certbot dry run to make sure the syntax is ok:

      • sudo certbot renew --dry-run

      If you see no errors, you're all set. Certbot is set to renew when necessary and run any commands needed to get your service using the new files.

      Conclusion

      In this tutorial, we've installed the Certbot Let's Encrypt client, downloaded an SSL certificate using standalone mode, and enabled automatic renewals with renew hooks. This should give you a good start on using Let's Encrypt certificates with services other than your typical web server.

      For more information, please refer to Certbot's documentation.



      Source link

      How To Use Certbot Standalone Mode to Retrieve Let’s Encrypt SSL Certificates on Debian 9


      Introduction

      Let’s Encrypt is a service offering free SSL certificates through an automated API. The most popular Let’s Encrypt client is EFF’s Certbot.

      Certbot offers a variety of ways to validate your domain, fetch certificates, and automatically configure Apache and Nginx. In this tutorial, we’ll discuss Certbot’s standalone mode and how to use it to secure other types of services, such as a mail server or a message broker like RabbitMQ.

      We won’t discuss the details of SSL configuration, but when you are done you will have a valid certificate that is automatically renewed. Additionally, you will be able to automate reloading your service to pick up the renewed certificate.

      Prerequisites

      Before starting this tutorial, you will need:

      • A Debian 9 server with a non-root, sudo-enabled user and basic firewall set up, as detailed in this Debian 9 server setup tutorial.
      • A domain name pointed at your server, which you can accomplish by following “How to Set Up a Host Name with DigitalOcean.” This tutorial will use example.com throughout.
      • Port 80 or 443 must be unused on your server. If the service you’re trying to secure is on a machine with a web server that occupies both of those ports, you’ll need to use a different mode such as Certbot’s webroot mode or DNS-based challenge mode.

      Step 1 — Installing Certbot

      Debian 9 includes the Certbot client in their default repository, and it should be up-to-date enough for basic use. If you need to do DNS-based challenges or use other newer Certbot features, you should instead install from the stretch-backports repo as instructed by the official Certbot documentation.

      Use apt to install the certbot package:

      You may test your install by asking certbot to output its version number:

      Output

      certbot 0.28.0

      Now that we have Certbot installed, let's run it to get our certificate.

      Step 2 — Running Certbot

      Certbot needs to answer a cryptographic challenge issued by the Let's Encrypt API in order to prove we control our domain. It uses ports 80 (HTTP) or 443 (HTTPS) to accomplish this. Open up the appropriate port in your firewall:

      Substitute 443 above if that's the port you're using. ufw will output confirmation that your rule was added:

      Output

      Rule added Rule added (v6)

      We can now run Certbot to get our certificate. We'll use the --standalone option to tell Certbot to handle the challenge using its own built-in web server. The --preferred-challenges option instructs Certbot to use port 80 or port 443. If you're using port 80, you want --preferred-challenges http. For port 443 it would be --preferred-challenges tls-sni. Finally, the -d flag is used to specify the domain you're requesting a certificate for. You can add multiple -d options to cover multiple domains in one certificate.

      • sudo certbot certonly --standalone --preferred-challenges http -d example.com

      When running the command, you will be prompted to enter an email address and agree to the terms of service. After doing so, you should see a message telling you the process was successful and where your certificates are stored:

      Output

      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 2019-08-28. 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" - 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. - 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

      We've got our certificates. Let's take a look at what we downloaded and how to use the files with our software.

      Step 3 — Configuring Your Application

      Configuring your application for SSL is beyond the scope of this article, as each application has different requirements and configuration options, but let's take a look at what Certbot has downloaded for us. Use ls to list out the directory that holds our keys and certificates:

      • sudo ls /etc/letsencrypt/live/example.com

      Output

      cert.pem chain.pem fullchain.pem privkey.pem README

      The README file in this directory has more information about each of these files. Most often you'll only need two of these files:

      • privkey.pem: This is the private key for the certificate. This needs to be kept safe and secret, which is why most of the /etc/letsencrypt directory has very restrictive permissions and is accessible by only the root user. Most software configuration will refer to this as something similar to ssl-certificate-key or ssl-certificate-key-file.
      • fullchain.pem: This is our certificate, bundled with all intermediate certificates. Most software will use this file for the actual certificate, and will refer to it in their configuration with a name like 'ssl-certificate'.

      For more information on the other files present, refer to the "Where are my certificates" section of the Certbot docs.

      Some software will need its certificates in other formats, in other locations, or with other user permissions. It is best to leave everything in the letsencrypt directory, and not change any permissions in there (permissions will just be overwritten upon renewal anyway), but sometimes that's just not an option. In that case, you'll need to write a script to move files and change permissions as needed. This script will need to be run whenever Certbot renews the certificates, which we'll talk about next.

      Step 4 — Handling Certbot Automatic Renewals

      Let's Encrypt's certificates are only valid for ninety days. This is to encourage users to automate their certificate renewal process. The certbot package we installed takes care of this for us by adding a renew script to /etc/cron.d. This script runs twice a day and will renew any certificate that's within thirty days of expiration.

      With our certificates renewing automatically, we still need a way to run other tasks after a renewal. We need to at least restart or reload our server to pick up the new certificates, and as mentioned in Step 3 we may need to manipulate the certificate files in some way to make them work with the software we're using. This is the purpose of Certbot's renew_hook option.

      To add a renew_hook, we update Certbot's renewal config file. Certbot remembers all the details of how you first fetched the certificate, and will run with the same options upon renewal. We just need to add in our hook. Open the config file with you favorite editor:

      • sudo nano /etc/letsencrypt/renewal/example.com.conf

      A text file will open with some configuration options. Add your hook on the last line:

      /etc/letsencrypt/renewal/example.com.conf

      renew_hook = systemctl reload rabbitmq
      

      Update the command above to whatever you need to run to reload your server or run your custom file munging script. Usually, on Debian, you’ll mostly be using systemctl to reload a service. Save and close the file, then run a Certbot dry run to make sure the syntax is ok:

      • sudo certbot renew --dry-run

      If you see no errors, you're all set. Certbot is set to renew when necessary and run any commands needed to get your service using the new files.

      Conclusion

      In this tutorial, we've installed the Certbot Let's Encrypt client, downloaded an SSL certificate using standalone mode, and enabled automatic renewals with renew hooks. This should give you a good start on using Let's Encrypt certificates with services other than your typical web server.

      For more information, please refer to Certbot's documentation.



      Source link

      How To Secure a Containerized Node.js Application with Nginx, Let’s Encrypt, and Docker Compose


      Introduction

      There are multiple ways to enhance the flexibility and security of your Node.js application. Using a reverse proxy like Nginx offers you the ability to load balance requests, cache static content, and implement Transport Layer Security (TLS). Enabling encrypted HTTPS on your server ensures that communication to and from your application remains secure.

      Implementing a reverse proxy with TLS/SSL on containers involves a different set of procedures from working directly on a host operating system. For example, if you were obtaining certificates from Let’s Encrypt for an application running on a server, you would install the required software directly on your host. Containers allow you to take a different approach. Using Docker Compose, you can create containers for your application, your web server, and the Certbot client that will enable you to obtain your certificates. By following these steps, you can take advantage of the modularity and portability of a containerized workflow.

      In this tutorial, you will deploy a Node.js application with an Nginx reverse proxy using Docker Compose. You will obtain TLS/SSL certificates for the domain associated with your application and ensure that it receives a high security rating from SSL Labs. Finally, you will set up a cron job to renew your certificates so that your domain remains secure.

      Prerequisites

      To follow this tutorial, you will need:

      • An Ubuntu 18.04 server, a non-root user with sudo privileges, and an active firewall. For guidance on how to set these up, please see this Initial Server Setup guide.
      • Docker and Docker Compose installed on your server. For guidance on installing Docker, follow Steps 1 and 2 of How To Install and Use Docker on Ubuntu 18.04. For guidance on installing Compose, follow Step 1 of How To Install Docker Compose on Ubuntu 18.04.
      • A registered domain name. This tutorial will use example.com throughout. You can get one for free at Freenom, or use the domain registrar of your choice.
      • Both of the following DNS records set up for your server. You can follow this introduction to DigitalOcean DNS for details on how to add them to a DigitalOcean account, if that’s what you’re using:

        • An A record with example.com pointing to your server’s public IP address.
        • An A record with www.example.com pointing to your server’s public IP address.

      Step 1 — Cloning and Testing the Node Application

      As a first step, we will clone the repository with the Node application code, which includes the Dockerfile that we will use to build our application image with Compose. We can first test the application by building and running it with the docker run command, without a reverse proxy or SSL.

      In your non-root user’s home directory, clone the nodejs-image-demo repository from the DigitalOcean Community GitHub account. This repository includes the code from the setup described in How To Build a Node.js Application with Docker.

      Clone the repository into a directory called node_project:

      • git clone https://github.com/do-community/nodejs-image-demo.git node_project

      Change to the node_project directory:

      In this directory, there is a Dockerfile that contains instructions for building a Node application using the Docker node:10 image and the contents of your current project directory. You can look at the contents of the Dockerfile by typing:

      Output

      FROM node:10 RUN mkdir -p /home/node/app/node_modules && chown -R node:node /home/node/app WORKDIR /home/node/app COPY package*.json ./ RUN npm install COPY . . COPY --chown=node:node . . USER node EXPOSE 8080 CMD [ "node", "app.js" ]

      These instructions build a Node image by copying the project code from the current directory to the container and installing dependencies with npm install. They also take advantage of Docker's caching and image layering by separating the copy of package.json and package-lock.json, containing the project's listed dependencies, from the copy of the rest of the application code. Finally, the instructions specify that the container will be run as the non-root node user with the appropriate permissions set on the application code and node_modules directories.

      For more information about this Dockerfile and Node image best practices, please see the complete discussion in Step 3 of How To Build a Node.js Application with Docker.

      To test the application without SSL, you can build and tag the image using docker build and the -t flag. We will call the image node-demo, but you are free to name it something else:

      • docker build -t node-demo .

      Once the build process is complete, you can list your images with docker images:

      You will see the following output, confirming the application image build:

      Output

      REPOSITORY TAG IMAGE ID CREATED SIZE node-demo latest 23961524051d 7 seconds ago 896MB node 10 8a752d5af4ce 10 days ago 894MB

      Next, create the container with docker run. We will include three flags with this command:

      • -p: This publishes the port on the container and maps it to a port on our host. We will use port 80 on the host, but you should feel free to modify this as necessary if you have another process running on that port. For more information about how this works, see this discussion in the Docker docs on port binding.
      • -d: This runs the container in the background.
      • --name: This allows us to give the container a memorable name.

      Run the following command to build the container:

      • docker run --name node-demo -p 80:8080 -d node-demo

      Inspect your running containers with docker ps:

      You will see output confirming that your application container is running:

      Output

      CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 4133b72391da node-demo "node app.js" 17 seconds ago Up 16 seconds 0.0.0.0:80->8080/tcp node-demo

      You can now visit your domain to test your setup: http://example.com. Remember to replace example.com with your own domain name. Your application will display the following landing page:

      Application Landing Page

      Now that you have tested the application, you can stop the container and remove the images. Use docker ps again to get your CONTAINER ID:

      Output

      CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 4133b72391da node-demo "node app.js" 17 seconds ago Up 16 seconds 0.0.0.0:80->8080/tcp node-demo

      Stop the container with docker stop. Be sure to replace the CONTAINER ID listed here with your own application CONTAINER ID:

      You can now remove the stopped container and all of the images, including unused and dangling images, with docker system prune and the -a flag:

      Type y when prompted in the output to confirm that you would like to remove the stopped container and images. Be advised that this will also remove your build cache.

      With your application image tested, you can move on to building the rest of your setup with Docker Compose.

      Step 2 — Defining the Web Server Configuration

      With our application Dockerfile in place, we can create a configuration file to run our Nginx container. We will start with a minimal configuration that will include our domain name, document root, proxy information, and a location block to direct Certbot's requests to the .well-known directory, where it will place a temporary file to validate that the DNS for our domain resolves to our server.

      First, create a directory in the current project directory for the configuration file:

      Open the file with nano or your favorite editor:

      • nano nginx-conf/nginx.conf

      Add the following server block to proxy user requests to your Node application container and to direct Certbot's requests to the .well-known directory. Be sure to replace example.com with your own domain name:

      ~/node_project/nginx-conf/nginx.conf

      server {
              listen 80;
              listen [::]:80;
      
              root /var/www/html;
              index index.html index.htm index.nginx-debian.html;
      
              server_name example.com www.example.com;
      
              location / {
                      proxy_pass http://nodejs:8080;
              }
      
              location ~ /.well-known/acme-challenge {
                      allow all;
                      root /var/www/html;
              }
      }
      

      This server block will allow us to start the Nginx container as a reverse proxy, which will pass requests to our Node application container. It will also allow us to use Certbot's webroot plugin to obtain certificates for our domain. This plugin depends on the HTTP-01 validation method, which uses an HTTP request to prove that Certbot can access resources from a server that responds to a given domain name.

      Once you have finished editing, save and close the file. To learn more about Nginx server and location block algorithms, please refer to this article on Understanding Nginx Server and Location Block Selection Algorithms.

      With the web server configuration details in place, we can move on to creating our docker-compose.yml file, which will allow us to create our application services and the Certbot container we will use to obtain our certificates.

      Step 3 — Creating the Docker Compose File

      The docker-compose.yml file will define our services, including the Node application and web server. It will specify details like named volumes, which will be critical to sharing SSL credentials between containers, as well as network and port information. It will also allow us to specify specific commands to run when our containers are created. This file is the central resource that will define how our services will work together.

      Open the file in your current directory:

      First, define the application service:

      ~/node_project/docker-compose.yml

      version: '3'
      
      services:
        nodejs:
          build:
            context: .
            dockerfile: Dockerfile
          image: nodejs
          container_name: nodejs
          restart: unless-stopped
      

      The nodejs service definition includes the following:

      • build: This defines the configuration options, including the context and dockerfile, that will be applied when Compose builds the application image. If you wanted to use an existing image from a registry like Docker Hub, you could use the image instruction instead, with information about your username, repository, and image tag.
      • context: This defines the build context for the application image build. In this case, it's the current project directory.
      • dockerfile: This specifies the Dockerfile that Compose will use for the build — the Dockerfile you looked at in Step 1.
      • image, container_name: These apply names to the image and container.
      • restart: This defines the restart policy. The default is no, but we have set the container to restart unless it is stopped.

      Note that we are not including bind mounts with this service, since our setup is focused on deployment rather than development. For more information, please see the Docker documentation on bind mounts and volumes.

      To enable communication between the application and web server containers, we will also add a bridge network called app-network below the restart definition:

      ~/node_project/docker-compose.yml

      services:
        nodejs:
      ...
          networks:
            - app-network
      

      A user-defined bridge network like this enables communication between containers on the same Docker daemon host. This streamlines traffic and communication within your application, since it opens all ports between containers on the same bridge network, while exposing no ports to the outside world. Thus, you can be selective about opening only the ports you need to expose your frontend services.

      Next, define the webserver service:

      ~/node_project/docker-compose.yml

      ...
       webserver:
          image: nginx:latest
          container_name: webserver
          restart: unless-stopped
          ports:
            - "80:80"
          volumes:
            - web-root:/var/www/html
            - ./nginx-conf:/etc/nginx/conf.d
            - certbot-etc:/etc/letsencrypt
            - certbot-var:/var/lib/letsencrypt
          depends_on:
            - nodejs
          networks:
            - app-network
      

      Some of the settings we defined for the nodejs service remain the same, but we've also made the following changes:

      • image: This tells Compose to pull the latest Nginx image from Docker Hub.
      • ports: This exposes port 80 to enable the configuration options we've defined in our Nginx configuration.

      We have also specified the following named volumes and bind mounts:

      • web-root:/var/www/html: This will add our site's static assets, copied to a volume called web-root, to the the /var/www/html directory on the container.
      • ./nginx-conf:/etc/nginx/conf.d: This will bind mount the Nginx configuration directory on the host to the relevant directory on the container, ensuring that any changes we make to files on the host will be reflected in the container.
      • certbot-etc:/etc/letsencrypt: This will mount the relevant Let's Encrypt certificates and keys for our domain to the appropriate directory on the container.
      • certbot-var:/var/lib/letsencrypt: This mounts Let's Encrypt's default working directory to the appropriate directory on the container.

      Next, add the configuration options for the certbot container. Be sure to replace the domain and email information with your own domain name and contact email:

      ~/node_project/docker-compose.yml

      ...
        certbot:
          image: certbot/certbot
          container_name: certbot
          volumes:
            - certbot-etc:/etc/letsencrypt
            - certbot-var:/var/lib/letsencrypt
            - web-root:/var/www/html
          depends_on:
            - webserver
          command: certonly --webroot --webroot-path=/var/www/html --email sammy@example.com --agree-tos --no-eff-email --staging -d example.com  -d www.example.com 
      

      This definition tells Compose to pull the certbot/certbot image from Docker Hub. It also uses named volumes to share resources with the Nginx container, including the domain certificates and key in certbot-etc, the Let's Encrypt working directory in certbot-var, and the application code in web-root.

      Again, we've used depends_on to specify that the certbot container should be started once the webserver service is running.

      We've also included a command option that specifies the command to run when the container is started. It includes the certonly subcommand with the following options:

      • --webroot: This tells Certbot to use the webroot plugin to place files in the webroot folder for authentication.
      • --webroot-path: This specifies the path of the webroot directory.
      • --email: Your preferred email for registration and recovery.
      • --agree-tos: This specifies that you agree to ACME's Subscriber Agreement.
      • --no-eff-email: This tells Certbot that you do not wish to share your email with the Electronic Frontier Foundation (EFF). Feel free to omit this if you would prefer.
      • --staging: This tells Certbot that you would like to use Let's Encrypt's staging environment to obtain test certificates. Using this option allows you to test your configuration options and avoid possible domain request limits. For more information about these limits, please see Let's Encrypt's rate limits documentation.
      • -d: This allows you to specify domain names you would like to apply to your request. In this case, we've included example.com and www.example.com. Be sure to replace these with your own domain preferences.

      As a final step, add the volume and network definitions. Be sure to replace the username here with your own non-root user:

      ~/node_project/docker-compose.yml

      ...
      volumes:
        certbot-etc:
        certbot-var:
        web-root:
          driver: local
          driver_opts:
            type: none
            device: /home/sammy/node_project/views/
            o: bind
      
      networks:
        app-network:
          driver: bridge
      

      Our named volumes include our Certbot certificate and working directory volumes, and the volume for our site's static assets, web-root. In most cases, the default driver for Docker volumes is the local driver, which on Linux accepts options similar to the mount command. Thanks to this, we are able to specify a list of driver options with driver_opts that mount the views directory on the host, which contains our application's static assets, to the volume at runtime. The directory contents can then be shared between containers. For more information about the contents of the views directory, please see Step 2 of How To Build a Node.js Application with Docker.

      The docker-compose.yml file will look like this when finished:

      ~/node_project/docker-compose.yml

      version: '3'
      
      services:
        nodejs:
          build:
            context: .
            dockerfile: Dockerfile
          image: nodejs
          container_name: nodejs
          restart: unless-stopped
          networks:
            - app-network
      
        webserver:
          image: nginx:latest
          container_name: webserver
          restart: unless-stopped
          ports:
            - "80:80"
          volumes:
            - web-root:/var/www/html
            - ./nginx-conf:/etc/nginx/conf.d
            - certbot-etc:/etc/letsencrypt
            - certbot-var:/var/lib/letsencrypt
          depends_on:
            - nodejs
          networks:
            - app-network
      
        certbot:
          image: certbot/certbot
          container_name: certbot
          volumes:
            - certbot-etc:/etc/letsencrypt
            - certbot-var:/var/lib/letsencrypt
            - web-root:/var/www/html
          depends_on:
            - webserver
          command: certonly --webroot --webroot-path=/var/www/html --email sammy@example.com --agree-tos --no-eff-email --staging -d example.com  -d www.example.com 
      
      volumes:
        certbot-etc:
        certbot-var:
        web-root:
          driver: local
          driver_opts:
            type: none
            device: /home/sammy/node_project/views/
            o: bind
      
      networks:
        app-network:
          driver: bridge  
      

      With the service definitions in place, you are ready to start the containers and test your certificate requests.

      Step 4 — Obtaining SSL Certificates and Credentials

      We can start our containers with docker-compose up, which will create and run our containers and services in the order we have specified. If our domain requests are successful, we will see the correct exit status in our output and the right certificates mounted in the /etc/letsencrypt/live folder on the webserver container.

      Create the services with docker-compose up and the -d flag, which will run the nodejs and webserver containers in the background:

      You will see output confirming that your services have been created:

      Output

      Creating nodejs ... done Creating webserver ... done Creating certbot ... done

      Using docker-compose ps, check the status of your services:

      If everything was successful, your nodejs and webserver services should be Up and the certbot container will have exited with a 0 status message:

      Output

      Name Command State Ports ------------------------------------------------------------------------ certbot certbot certonly --webroot ... Exit 0 nodejs node app.js Up 8080/tcp webserver nginx -g daemon off; Up 0.0.0.0:80->80/tcp

      If you see anything other than Up in the State column for the nodejs and webserver services, or an exit status other than 0 for the certbot container, be sure to check the service logs with the docker-compose logs command:

      • docker-compose logs service_name

      You can now check that your credentials have been mounted to the webserver container with docker-compose exec:

      • docker-compose exec webserver ls -la /etc/letsencrypt/live

      If your request was successful, you will see output like this:

      Output

      total 16 drwx------ 3 root root 4096 Dec 23 16:48 . drwxr-xr-x 9 root root 4096 Dec 23 16:48 .. -rw-r--r-- 1 root root 740 Dec 23 16:48 README drwxr-xr-x 2 root root 4096 Dec 23 16:48 example.com

      Now that you know your request will be successful, you can edit the certbot service definition to remove the --staging flag.

      Open docker-compose.yml:

      Find the section of the file with the certbot service definition, and replace the --staging flag in the command option with the --force-renewal flag, which will tell Certbot that you want to request a new certificate with the same domains as an existing certificate. The certbot service definition should now look like this:

      ~/node_project/docker-compose.yml

      ...
        certbot:
          image: certbot/certbot
          container_name: certbot
          volumes:
            - certbot-etc:/etc/letsencrypt
            - certbot-var:/var/lib/letsencrypt
            - web-root:/var/www/html
          depends_on:
            - webserver
          command: certonly --webroot --webroot-path=/var/www/html --email sammy@example.com --agree-tos --no-eff-email --force-renewal -d example.com -d www.example.com
      ...
      

      You can now run docker-compose up to recreate the certbot container and its relevant volumes. We will also include the --no-deps option to tell Compose that it can skip starting the webserver service, since it is already running:

      • docker-compose up --force-recreate --no-deps certbot

      You will see output indicating that your certificate request was successful:

      Output

      certbot | IMPORTANT NOTES: certbot | - Congratulations! Your certificate and chain have been saved at: certbot | /etc/letsencrypt/live/example.com/fullchain.pem certbot | Your key file has been saved at: certbot | /etc/letsencrypt/live/example.com/privkey.pem certbot | Your cert will expire on 2019-03-26. To obtain a new or tweaked certbot | version of this certificate in the future, simply run certbot certbot | again. To non-interactively renew *all* of your certificates, run certbot | "certbot renew" certbot | - Your account credentials have been saved in your Certbot certbot | configuration directory at /etc/letsencrypt. You should make a certbot | secure backup of this folder now. This configuration directory will certbot | also contain certificates and private keys obtained by Certbot so certbot | making regular backups of this folder is ideal. certbot | - If you like Certbot, please consider supporting our work by: certbot | certbot | Donating to ISRG / Let's Encrypt: https://letsencrypt.org/donate certbot | Donating to EFF: https://eff.org/donate-le certbot | certbot exited with code 0

      With your certificates in place, you can move on to modifying your Nginx configuration to include SSL.

      Step 5 — Modifying the Web Server Configuration and Service Definition

      Enabling SSL in our Nginx configuration will involve adding an HTTP redirect to HTTPS and specifying our SSL certificate and key locations. It will also involve specifying our Diffie-Hellman group, which we will use for Perfect Forward Secrecy.

      Since you are going to recreate the webserver service to include these additions, you can stop it now:

      • docker-compose stop webserver

      Next, create a directory in your current project directory for your Diffie-Hellman key:

      Generate your key with the openssl command:

      • sudo openssl dhparam -out /home/sammy/node_project/dhparam/dhparam-2048.pem 2048

      It will take a few moments to generate the key.

      To add the relevant Diffie-Hellman and SSL information to your Nginx configuration, first remove the Nginx configuration file you created earlier:

      Open another version of the file:

      • nano nginx-conf/nginx.conf

      Add the following code to the file to redirect HTTP to HTTPS and to add SSL credentials, protocols, and security headers. Remember to replace example.com with your own domain:

      ~/node_project/nginx-conf/nginx.conf

      
      server {
              listen 80;
              listen [::]:80;
              server_name example.com www.example.com;
      
              location ~ /.well-known/acme-challenge {
                allow all;
                root /var/www/html;
              }
      
              location / {
                      rewrite ^ https://$host$request_uri? permanent;
              }
      }
      
      server {
              listen 443 ssl http2;
              listen [::]:443 ssl http2;
              server_name example.com www.example.com;
      
              server_tokens off;
      
              ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
              ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;
      
              ssl_buffer_size 8k;
      
              ssl_dhparam /etc/ssl/certs/dhparam-2048.pem;
      
              ssl_protocols TLSv1.2 TLSv1.1 TLSv1;
              ssl_prefer_server_ciphers on;
      
              ssl_ciphers ECDH+AESGCM:ECDH+AES256:ECDH+AES128:DH+3DES:!ADH:!AECDH:!MD5;
      
              ssl_ecdh_curve secp384r1;
              ssl_session_tickets off;
      
              ssl_stapling on;
              ssl_stapling_verify on;
              resolver 8.8.8.8;
      
              location / {
                      try_files $uri @nodejs;
              }
      
              location @nodejs {
                      proxy_pass http://nodejs:8080;
                      add_header X-Frame-Options "SAMEORIGIN" always;
                      add_header X-XSS-Protection "1; mode=block" always;
                      add_header X-Content-Type-Options "nosniff" always;
                      add_header Referrer-Policy "no-referrer-when-downgrade" always;
                      add_header Content-Security-Policy "default-src * data: 'unsafe-eval' 'unsafe-inline'" always;
                      # add_header Strict-Transport-Security "max-age=31536000; includeSubDomains; preload" always;
                      # enable strict transport security only if you understand the implications
              }
      
              root /var/www/html;
              index index.html index.htm index.nginx-debian.html;
      }
      

      The HTTP server block specifies the webroot for Certbot renewal requests to the .well-known/acme-challenge directory. It also includes a rewrite directive that directs HTTP requests to the root directory to HTTPS.

      The HTTPS server block enables ssl and http2. To read more about how HTTP/2 iterates on HTTP protocols and the benefits it can have for website performance, please see the introduction to How To Set Up Nginx with HTTP/2 Support on Ubuntu 18.04. This block also includes a series of options to ensure that you are using the most up-to-date SSL protocols and ciphers and that OSCP stapling is turned on. OSCP stapling allows you to offer a time-stamped response from your certificate authority during the initial TLS handshake, which can speed up the authentication process.

      The block also specifies your SSL and Diffie-Hellman credentials and key locations.

      Finally, we've moved the proxy pass information to this block, including a location block with a try_files directive, pointing requests to our aliased Node.js application container, and a location block for that alias, which includes security headers that will enable us to get A ratings on things like the SSL Labs and Security Headers server test sites. These headers include X-Frame-Options, X-Content-Type-Options, Referrer Policy, Content-Security-Policy, and X-XSS-Protection. The HTTP Strict Transport Security (HSTS) header is commented out — enable this only if you understand the implications and have assessed its "preload" functionality.

      Once you have finished editing, save and close the file.

      Before recreating the webserver service, you will need to add a few things to the service definition in your docker-compose.yml file, including relevant port information for HTTPS and a Diffie-Hellman volume definition.

      Open the file:

      In the webserver service definition, add the following port mapping and the dhparam named volume:

      ~/node_project/docker-compose.yml

      ...
       webserver:
          image: nginx:latest
          container_name: webserver
          restart: unless-stopped
          ports:
            - "80:80"
            - "443:443"
          volumes:
            - web-root:/var/www/html
            - ./nginx-conf:/etc/nginx/conf.d
            - certbot-etc:/etc/letsencrypt
            - certbot-var:/var/lib/letsencrypt
            - dhparam:/etc/ssl/certs
          depends_on:
            - nodejs
          networks:
            - app-network
      

      Next, add the dhparam volume to your volumes definitions:

      ~/node_project/docker-compose.yml

      ...
      volumes:
        ...
        dhparam:
          driver: local
          driver_opts:
            type: none
            device: /home/sammy/node_project/dhparam/
            o: bind
      

      Similarly to the web-root volume, the dhparam volume will mount the Diffie-Hellman key stored on the host to the webserver container.

      Save and close the file when you are finished editing.

      Recreate the webserver service:

      • docker-compose up -d --force-recreate --no-deps webserver

      Check your services with docker-compose ps:

      You should see output indicating that your nodejs and webserver services are running:

      Output

      Name Command State Ports ---------------------------------------------------------------------------------------------- certbot certbot certonly --webroot ... Exit 0 nodejs node app.js Up 8080/tcp webserver nginx -g daemon off; Up 0.0.0.0:443->443/tcp, 0.0.0.0:80->80/tcp

      Finally, you can visit your domain to ensure that everything is working as expected. Navigate your browser to https://example.com, making sure to substitute example.com with your own domain name. You will see the following landing page:

      Application Landing Page

      You should also see the lock icon in your browser's security indicator. If you would like, you can navigate to the SSL Labs Server Test landing page or the Security Headers server test landing page. The configuration options we've included should earn your site an A rating on both.

      Step 6 — Renewing Certificates

      Let's Encrypt certificates are valid for 90 days, so you will want to set up an automated renewal process to ensure that they do not lapse. One way to do this is to create a job with the cron scheduling utility. In this case, we will schedule a cron job using a script that will renew our certificates and reload our Nginx configuration.

      Open a script called ssl_renew.sh in your project directory:

      Add the following code to the script to renew your certificates and reload your web server configuration:

      ~/node_project/ssl_renew.sh

      #!/bin/bash
      
      /usr/local/bin/docker-compose -f /home/sammy/node_project/docker-compose.yml run certbot renew --dry-run 
      && /usr/local/bin/docker-compose -f /home/sammy/node_project/docker-compose.yml kill -s SIGHUP webserver
      

      In addition to specifying the location of our docker-compose binary, we also specify the location of our docker-compose.yml file in order to run docker-compose commands. In this case, we are using docker-compose run to start a certbot container and to override the command provided in our service definition with another: the renew subcommand, which will renew certificates that are close to expiring. We've included the --dry-run option here to test our script.

      The script then uses docker-compose kill to send a SIGHUP signal to the webserver container to reload the Nginx configuration. For more information on using this process to reload your Nginx configuration, please see this Docker blog post on deploying the official Nginx image with Docker.

      Close the file when you are finished editing. Make it executable:

      Next, open your root crontab file to run the renewal script at a specified interval:

      If this is your first time editing this file, you will be asked to choose an editor:

      crontab

      no crontab for root - using an empty one
      Select an editor.  To change later, run 'select-editor'.
        1. /bin/ed
        2. /bin/nano        <---- easiest
        3. /usr/bin/vim.basic
        4. /usr/bin/vim.tiny
      Choose 1-4 [2]: 
      ...
      

      At the bottom of the file, add the following line:

      crontab

      ...
      */5 * * * * /home/sammy/node_project/ssl_renew.sh >> /var/log/cron.log 2>&1
      

      This will set the job interval to every five minutes, so you can test whether or not your renewal request has worked as intended. We have also created a log file, cron.log, to record relevant output from the job.

      After five minutes, check cron.log to see whether or not the renewal request has succeeded:

      • tail -f /var/log/cron.log

      You should see output confirming a successful renewal:

      Output

      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ** DRY RUN: simulating 'certbot renew' close to cert expiry ** (The test certificates below have not been saved.) Congratulations, all renewals succeeded. The following certs have been renewed: /etc/letsencrypt/live/example.com/fullchain.pem (success) ** DRY RUN: simulating 'certbot renew' close to cert expiry ** (The test certificates above have not been saved.) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Killing webserver ... done

      You can now modify the crontab file to set a daily interval. To run the script every day at noon, for example, you would modify the last line of the file to look like this:

      crontab

      ...
      0 12 * * * /home/sammy/node_project/ssl_renew.sh >> /var/log/cron.log 2>&1
      

      You will also want to remove the --dry-run option from your ssl_renew.sh script:

      ~/node_project/ssl_renew.sh

      #!/bin/bash
      
      /usr/local/bin/docker-compose -f /home/sammy/node_project/docker-compose.yml run certbot renew 
      && /usr/local/bin/docker-compose -f /home/sammy/node_project/docker-compose.yml kill -s SIGHUP webserver
      

      Your cron job will ensure that your Let's Encrypt certificates don't lapse by renewing them when they are eligible.

      Conclusion

      You have used containers to set up and run a Node application with an Nginx reverse proxy. You have also secured SSL certificates for your application's domain and set up a cron job to renew these certificates when necessary.

      If you are interested in learning more about Let's Encrypt plugins, please see our articles on using the Nginx plugin or the standalone plugin.

      You can also learn more about Docker Compose by looking at the following resources:

      The Compose documentation is also a great resource for learning more about multi-container applications.



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