phpMyAdmin
You can access phpMyAdmin after creating ssh tunnel. Please refer to Amazon Linux 2 LAMP with phpMyAdmin AMI
Find database password
You can find the database server password by accessing the System Log in the EC2 management console:
1. Go to the Amazon EC2 console at https://console.aws.amazon.com/ec2/.
2. Chose your Instance and Click on Actions → Monitor and troubleshoot → Get System Log.

3. Get System log as shown below.
You can also SSH into your instance and find the login credential using the following command.
$ cat /home/ec2-user/credentials
////////////////////credentials info////////////////////
--- WordPress
----- Setting : Success
--- phpMyAdmin
----- Setting : Success
--- MariaDB
----- User : root
----- Password : ****************
----- User : wordpress
----- Password : ****************
////////////////////////////////////////////////////////
Changing URL
You can change the WordPress URL by using wp-cli. You can change it by executing the following command after logging into the instance over SSH.
$ curl -s localhost | grep wp-content
$ wp search-replace 'old_site_url' 'new_site_url' --path=/var/www/html/wordpress --skip-columns=guid
For example, when your instance IP was changed from xxx.xxx.xxx.xxx to yyy.yyy.yyy.yyy you can check URL as shown below:
$ curl -s localhost | grep wp-content
<link rel=’stylesheet’ id=’twentynineteen-style-css’ href=’http://xxx.xxx.xxx.xxx/wp-content/themes/twentynineteen/style.css?ver=1.4' type=’text/css’ media=’all’ />
<link rel=’stylesheet’ id=’twentynineteen-print-style-css’ href=’http://xxx.xxx.xxx.xxx/wp-content/themes/twentynineteen/print.css?ver=1.4' type=’text/css’ media=’print’ />
To update the URL, execute the following command:
$ wp search-replace xxx.xxx.xxx.xxx yyy.yyy.yyy.yyy --path=/var/www/html/wordpress --skip-columns=guid
+------------------+-----------------------+--------------+------+
| Table | Column | Replacements | Type |
+------------------+-----------------------+--------------+------+
| wp_commentmeta | meta_key | 0 | SQL |
| wp_commentmeta | meta_value | 0 | SQL |
<...>
| wp_options | option_value | 2 | PHP |
| wp_options | autoload | 0 | SQL |
| wp_postmeta | meta_key | 0 | SQL |
| wp_postmeta | meta_value | 0 | SQL |
| wp_posts | post_content | 2 | SQL |
<...>
| wp_users | user_url | 1 | SQL |
| wp_users | user_activation_key | 0 | SQL |
| wp_users | display_name | 0 | SQL |
+------------------+-----------------------+--------------+------+
Success: Made 5 replacements.