This post is contributed by Mike Coleman | Developer Advocate for Lightsail | Twitter: @mikegcoleman

This is the final post in a series about getting a highly available WordPress site up and running on Amazon Lightsail. For reference, the other blog posts are:

  1. Implementing a highly available Lightsail database with WordPress
  2. Using Amazon S3 with WordPress to securely deliver media files
  3. Increasing security and performance using Amazon CloudFront

In this post, you’ll learn how to stand up a Lightsail load balancer, create a snapshot of your WordPress server, deploy new instances from those snapshots, and place the instances behind your load balancer.

A load balancer accepts incoming web traffic and routes it to one or (usually) more servers. Having multiple servers allows you to scale the number of incoming requests your site can handle, as well as allowing your site to remain responsive if a web server fails. The following diagram shows the solution architecture, which features multiple front-end WordPress servers behind a Lightsail load balancer, a highly available Lightsail database, and uses S3 alongside CloudFront to deliver your media content securely.

Graphic showing the final HA architecture including 3 servers behind a load balancer, S3 alongside cloudfront, and a highly-available database

Prerequisites

This post assumes you built your WordPress site by following the previous posts in this series.

Configuring SSL requires a registered domain name and sufficient permissions to create DNS records for that domain.

You don’t need AWS or Lightsail to manage your domain, but this post uses Lightsail’s DNS management. For more information, see Creating a DNS zone to manage your domain’s DNS records in Amazon Lightsail.

Deploying the load balancer and configuring SSL

To deploy a Lightsail load balancer and configure it to support SSL, complete the following steps:

  1. Open the Lightsail console.
  2. From the menu, choose Networking.
  3. Choose Create Load Balancer.
  4. For Identify your load balancer, enter a name for your load balancer.

This post names the load balancer wp-lb.

  1. Choose Create Load Balancer.

The details page for your new load balancer opens. From here, add your initial WordPress server to the load balancer and configure SSL.

  1. For Target instances, choose your WordPress server.

The following screenshot indicates that this post chooses the server WordPress-1.

screenshot showing an instance being selected from the drop down

 

  1. Choose Attach.

It can take a few seconds for your instance to attach to the load balancer and the Health Check to report as Passed. See the following screenshot of the Health Check status.

 Picture of healh check status

  1. From the menu, choose Inbound traffic.
  2. Under Certificates, choose Create certificate.
  3. For PRIMARY DOMAIN, enter the domain name that you want to use to reach your WordPress site.

You can either accept the default certificate name Lightsail creates or change it to something you prefer. This post uses www.mikegcoleman.com.

  1. Choose Create.

The following screenshot shows the Create a certificate section.

Picture of the Create a Certificate section

Creating a CNAME record

As you did with CloudFront, you need to create a CNAME record as a way of validating that you have ownership of the domain for which you are creating a certificate.

  1. Copy the random characters and the subdomain from the name field.

The following screenshot shows the example record information.

screenshot showing the portion of the name value that needs to be copied

  1. Open a second copy of the Lightsail console in another tab or window.
  2. Choose Networking.
  3. Choose your domain name.
  4. Choose Add record.
  5. From the drop-down menu, choose CNAME record.

The following screenshot shows the drop-down menu options.

Screenshot showing CNAME record selected in the dropdown box

  1. For Subdomain, enter the random characters and subdomain you copied from the load balancer page.
  2. Return to the load balancer page.
  3. Copy the entire Value
  4. Return to the DNS page.
  5. For Maps to, enter the value string.
  6. Choose the green check box.

The following screenshot shows the CNAME record details.

Screenshot showing the completed cname record and green checkbox highlighted

  1. Return to the load balancer page and wait a few minutes before refreshing the page.

You should see a notification that the certificate is verified and ready to use. This process can take several minutes; continue refreshing the page every few minutes until the status updates. The following screenshot shows the notification message.

Screenshot showing the verification complete message for the load balancer ssl certificate

  1. In the HTTPS box, select your certificate from the drop-down menu.

The following screenshot shows the HTTPS box.

screenshot showing the newly validated certificate in the drop down box

  1. Copy the DNS name for your load balancer.

The following screenshot shows the example DNS name.

Screenshot showing the DNS name of the load balancer

  1. Return to the Lightsail DNS console and follow steps 13 through 23 as a guide in creating a CNAME record that maps your website address to the load balancer’s DNS name.

Use the subdomain you chose for your WordPress server (in this post, that’s www) and the DNS name you copied for the Maps to field.

The following screenshot shows the CNAME record details.

screenshot showing the completed cname record for the load balancer

Updating the wp-config file

The last step to configure SSL is updating the wp-config file to configure WordPress to deliver content over SSL.

  1. Start an SSH session with your WordPress server.
  2. Copy and paste the following code into the terminal window to create a temporary file that holds the configuration string that will be added to the WordPress configuration file.
cat <<EOT >> ssl_config.txt
if (\$_SERVER['HTTP_X_FORWARDED_PROTO'] == 'https') \$_SERVER['HTTPS']='on';
EOT
  1. Copy and paste the following sed command into your terminal window to add the SSL line to the configuration file.
sed -i "/define( 'WP_DEBUG', false );/r ssl_config.txt" \
/home/bitnami/apps/wordpress/htdocs/wp-config.php
  1. The sed command changes the permissions on the configuration file, so you’ll need to reset them. See the following code:
sudo chown bitnami:daemon /home/bitnami/apps/wordpress/htdocs/wp-config.php

You also need to update two variables that WordPress uses to identify which address is used to access your site.

  1. Update the WP_SITEURL variable (be sure to specify https) by running the following command in the terminal window:
wp config set WP_SITEURL https://<your wordpress site domain name>

For example, this post uses the following code:

wp config set WP_SITEURL https://www.mikegcoleman.com

You should get a response that the variable updated.

  1. Update the WP_HOME variable (be sure to specify https) by issuing the following command in the terminal window:
wp config set WP_HOME https://<your wordpress site domain name>

For example, this post uses the following code:

wp config set WP_HOME https://www.mikegcoleman.com

You should get a response that the variable updated.

  1. Restart the WordPress server to read the new configuration with the following code:
sudo /opt/bitnami/ctlscript.sh restart

After the server has restarted, visit the DNS name for your WordPress site. The site should load and your browser should report the connection is secure.

You can now finish any customization of your WordPress site, such as adding additional plugins, setting the blog name, or changing the theme.

Scaling your WordPress servers

With your WordPress server fully configured, the last step is to create additional instances and place them behind the load balancer so that if one of your WordPress servers fails, your site is still reachable. An added benefit is that your site is more scalable because there are additional servers to handle incoming requests.

Complete the following steps:

  1. On the Lightsail console, choose the name of your WordPress server.
  2. Choose Snapshots.
  3. For Create instance snapshot, enter the name of your snapshot.

This post uses the name WordPress-version-1. See the following screenshot of your snapshot details.

Screenshot of the snapshot creation dialog

  1. Choose Create snapshot.

It can take a few minutes for the snapshot creation process to finish.

  1. Click the three-dot menu icon to the right of your snapshot name and choose Create new instance.

The following screenshot shows the Recent snapshots section.

Screenshot showing the location of the three dot menu

To provide the highest level of redundancy, deploy each of your WordPress servers into a different Availability Zone within the same region. By default, the first server was placed in zone A; place the subsequent servers in two different zones (B and C would be good choices). For more information, see Regions and Availability Zones.

  1. For Instance location, choose Change AWS Region and Availability Zone.
  2. Choose Change your Availability Zone.
  3. Choose an Availability Zone you have not used previously.

The following screenshot shows the Availability Zones to choose from.

screenshot showing availability zone b selected

  1. Give your instance a new name.

This post names the instance WordPress-2.

  1. Choose Create Instance.

You should have at least two WordPress server instances to provide a minimum degree of redundancy. To add more, create additional instances by following steps 1–10.

Return to the Lightsail console home page, and wait for your instances to report back Running.

Adding your instances to the load balancer

Now that you have your additional WordPress instances created, add them to the load balancer. This is the same process you followed previously to add the first instance:

  1. On the Lightsail console, choose Networking.
  2. Choose the load balancer you previously created.
  3. Choose Attach another.
  4. From the drop-down menu, select the name of your instance.

The following screenshot shows the available instances on the drop-down menu.

screenshot showing the WordPress instances in the load balancer drop down

  1. Choose Attach.
  2. Repeat steps 3–5 for any additional instances.

When the instances report back Passed, your site is fully up and running.

Conclusion

You have configured your site to provide a good degree of redundancy and performance, while delivering your content over secure connections. S3 and CloudFront allow your site to deliver static content over a secured connection, while the Lightsail load balancer and database make sure your site can keep serving your customers in the event of a failure.

If you haven’t got one already, head on over and create a free AWS account, and start building your own WordPress site – or whatever else might think of!

from AWS Compute Blog: https://aws.amazon.com/blogs/compute/deploying-a-highly-available-wordpress-site-on-amazon-lightsail-part-4-increasing-performance-and-scalability-with-a-lightsail-load-balancer/