For people who need mysqldump (ie, for Wordpress on ec2), install mariadb from the native amzn2-core repo.
yum install mariadb.x86_64
Info about the package:
# yum info mariadb.x86_64
Loaded plugins: extras_suggestions, langpacks, priorities, update-motd
Name : mariadb
Arch : x86_64
Epoch : 1
Version : 5.5.68
Release : 1.amzn2
Size : 49 M
Repo : installed
From repo : amzn2-core
Summary : A community developed branch of MySQL
URL : http://mariadb.org
License : GPLv2 with exceptions and LGPLv2 and BSD
Description : MariaDB is a community developed branch of MySQL.
: MariaDB is a multi-user, multi-threaded SQL database server.
: It is a client/server implementation consisting of a server daemon (mysqld)
: and many different client programs and libraries. The base package
: contains the standard MariaDB/MySQL client programs and generic MySQL files.