Skip to content

WordPress

WordPress is a web content-management system.

Resources

Overview

You need to perform two steps before WordPress can be launched:

  1. Install the service definition.
  2. Configure the environment.

Note:

  • Do not "up" your stack until you have completed step 2.

Install the service definition

Be in the correct directory:

$ cd ~/IOTstack

option 1 - the IOTstack menu

  1. Launch the menu

    $ ./iotstack-menu.sh

  2. Select "Services".

  3. Place the cursor on "wordpress" and press enter to select it.
  4. Select "Install".
  5. Select "Return".
  6. Select "Build".
  7. Select "Exit", twice.

option 2 - from the command line

$ ./iotstack-menu.sh install wordpress
$ ./iotstack-menu.sh build

Configure the environment

check dependency

The password-generation steps in the next section assume uuidgen is available on your system. The following command installs uuidgen if it is not present already:

$ [ -z "$(which uuidgen)" ] && sudo apt update && sudo apt install -y uuid-runtime

generate passwords

WordPress relies on MariaDB, and MariaDB requires both a user password and a root password. You can generate the passwords like this:

$ echo "WORDPRESS_DB_PASSWORD=$(uuidgen)" >>~/IOTstack/.env
$ echo "WORDPRESS_ROOT_PASSWORD=$(uuidgen)" >>~/IOTstack/.env

Key points:

  1. You will not need to know either of these passwords in order to use WordPress.

    These passwords govern access to the WordPress database (the wordpress_db container). WordPress (the wordpress container) has a separate system of credentials. You set up an administrator account the first time you login to WordPress.

  2. You will not need to know either password in order to use the mysql command line interface to inspect the WordPress database. See accessing the MariaDB command line interface.

  3. The WordPress database container does not expose any ports to the outside world. That means you can't use general-purpose MariaDB/MySQL GUI-based front-ends to reach the WordPress database.
  4. Both passwords are applied when the MariaDB container is first initialised. Changing either password value in .env will break your installation.

set hostname

WordPress (running inside the container) needs to know the domain name of the host on which the container is running. You can satisfy the requirement like this:

$ echo "WORDPRESS_HOSTNAME=$HOSTNAME.local" >>~/IOTstack/.env

The above assumes the host is advertising a multicast domain name. This is a safe assumption for Raspberry Pis but may not necessarily be applicable in other situations. If your host is associated with a fully-qualified domain name (A record or CNAME), you can use that instead. For example:

$ echo "WORDPRESS_HOSTNAME=iot-hub.my.domain.com" >>~/IOTstack/.env

checking your WordPress environment values

You can confirm that the passwords and hostname have been added to .env like this:

$ grep "^WORDPRESS" ~/IOTstack/.env
WORDPRESS_DB_PASSWORD=41dcbe76-9c39-4c7f-bd65-2f0421bccbeb
WORDPRESS_ROOT_PASSWORD=ee749d72-f1a5-4bc0-b182-21e8284f9fd2
WORDPRESS_HOSTNAME=raspberrypi.local

Starting WordPress

$ cd ~/IOTstack
$ docker compose up -d wordpress

This starts both WordPress and its database.

Accessing the WordPress GUI

Use a URL in the following form, where «host» should be the value you chose at set hostname.

http://«host»:8084

Examples:

  • http://raspberrypi.local:8084
  • http://iot-hub.my.domain.com:8084

You will be prompted to:

  1. Set your language; and
  2. Create your administrator account.

After that, you should refer to the WordPress documentation.

About MariaDB

The MariaDB instance associated with WordPress is private to WordPress. It is included along with the WordPress service definition. You do not have to select MariaDB in the IOTstack menu.

multiple MariaDB instances
  • There is nothing stopping you from also selecting MariaDB in the IOTstack menu. Multiple instances of MariaDB will coexist quite happily but they are separate and distinct Relational Database Manager Systems (RDBMS).

Accessing the MariaDB command line interface

If you need inspect or manipulate the WordPress database, begin by opening a shell into the WordPress MariaDB container:

$ docker exec -it wordpress_db bash

While you are in the shell, you can use the MYSQL_ROOT_PASSWORD environment variable to reference the root password. For example:

# mysql -p$MYSQL_ROOT_PASSWORD
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 169
Server version: 10.11.6-MariaDB-log Alpine Linux

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]>

Note:

  • There is no space between the -p and $MYSQL_ROOT_PASSWORD. If you insert a space, mysql will prompt you to enter the password interactively.

Once you have opened a session using mysql, you can execute MySQL commands. For example:

MariaDB [(none)]> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
| wordpress          |
+--------------------+
5 rows in set (0.010 sec)

To exit mysql, either press control+d or use the exit command:

MariaDB [(none)]> exit
Bye

#

Similarly, control+d or exit will terminate the container's bash shell and return you to the host's command line.

Getting a clean slate

If you start the WordPress container and then decide that you need to change its environment variables, you must first erase the container's persistent store:

$ cd ~/IOTstack
$ docker compose down wordpress wordpress_db
$ sudo rm -rf ./volumes/wordpress

Notes:

  • Both the wordpress and wordpress_db containers need to be taken down before the persistent store can be removed safely.
  • Be very careful with the sudo rm command. Double-check before pressing the return key!

Once the persistent store has been erased, you can change the environment variables.

When you are ready, start WordPress again:

$ cd ~/IOTstack
$ docker compose up -d wordpress

Note:

  • The wordpress_db container does not need to be brought up explicitly. It is started automatically as a by-product of starting wordpress.