diff --git a/provisioning/vars/Debian.yml b/provisioning/vars/Debian.yml
index c9db91e02..22383cfcd 100644
--- a/provisioning/vars/Debian.yml
+++ b/provisioning/vars/Debian.yml
@@ -32,3 +32,4 @@ php_packages:
   - "php{{ php_version }}-opcache"
   - "php{{ php_version }}-sqlite3"
   - "php{{ php_version }}-xml"
+  - "php{{ php_version }}-yaml"
diff --git a/provisioning/vars/RedHat.yml b/provisioning/vars/RedHat.yml
index ed97d539c..ab3c1a715 100644
--- a/provisioning/vars/RedHat.yml
+++ b/provisioning/vars/RedHat.yml
@@ -1 +1,19 @@
 ---
+# Defaults set by `ansible-role-php` with the addition of `php-pecl-yaml`.
+php_packages:
+  - php
+  - php-cli
+  - php-common
+  - php-devel
+  - php-fpm
+  - php-gd
+  - php-imap
+  - php-ldap
+  - php-mbstring
+  - php-opcache
+  - php-pdo
+  - php-pear
+  - php-pecl-apcu
+  - php-xml
+  - php-xmlrpc
+  - php-pecl-yaml