MariaDB is an open source database server. It can be used as the backing
database for web, business, and other applications and application servers.
It is an evolution of the popular MySQL database, the M in the popular LAMP
(Linux, Apache, MySQL, PHP) web-based application server software stack.
MariaDB offers enhanced performance, more features, and greater scalability
while maintaining full transparent compatibility with the many existing
applications built to work with MySQL. This charm downloads and deploys
MariaDB on an Ubuntu system.


MariaDB strives to be the logical choice for database
professionals looking for a robust, scalable, and reliable SQL server. To
accomplish this, the MariaDB Foundation works closely and cooperatively with
the larger community of users and developers in the true spirit of Free and
open source software, and release software in a manner that balances
predictability with reliability.

MariaDB Enterprise from MariaDB Corporation, Inc. takes
MariaDB and enhances it with an optimized configuration, additional testing,
and available 24/7 professional support and consulting.

This charm deploys MariaDB using packages in a repository provided by the
MariaDB Foundation or, optionally, MariaDB Enterprise packages in a repository
provided by MariaDB Corporation, Inc.

Packages for IBM's Power8 platform are only available from the MariaDB
Enterprise repository.

As much as possible this charm uses the same charm structure as the MySQL charm
for the sake of compatability.


General Usage

To deploy a MariaDB service:

juju deploy mariadb

Once deployed, you can retrive the MariaDB root user password by logging in to
the machine via juju ssh and reading the /var/lib/mysql/mysql.passwd file.
To log in as root MariaDB User at the MariaDB console you can issue the

juju ssh mariadb/0
mysql -u root -p$(sudo cat /var/lib/mysql/mysql.passwd)

To deploy MariaDB Enterprise instead of MariaDB

First obtain a username/password from the MariaDB Portal
and you will then have access to the MariaDB Enterprise repository.

Next create a file called enterprise.yaml with the following contents,
replacing username:password with your actual username and password:

  enterprise-eula: true
  key: 0xd324876ebe6a595f
  source: "deb trusty main"

Lastly, deploy MariaDB as normal but with the addition of:

juju deploy --config ./enterprise.yaml mariadb

MariaDB Enterprise will be deployed instead of MariaDB. You must agree to all
terms contained in in the charm directory to use
MariaDB Enterprise.

To switch from MariaDB to MariaDB Enterprise

If you deployed MariaDB and would like to switch to MariaDB Enterprise, first
obtain a username/password from the MariaDB Portal and
you will then have access to the MariaDB Enterprise repository. You can then
enable the repository in the charm with the following configuration:

juju set mariadb enterprise-eula=true key="0xd324876ebe6a595f" source="deb trusty main"

This will perform an in-place binary upgrade on all the MariaDB nodes from
MariaDB to MariaDB Enterprise. You must agree to all terms contained in in the charm directory to use MariaDB Enterprise.

Scale Out Usage


MariaDB supports the ability to replicate databases to slave instances. This
allows you, for example, to load balance read queries across multiple slaves or
use a slave to perform backups, all whilst not impeding the master's

To deploy a slave:

# deploy second service
juju deploy mariadb mariadb-slave

# add master to slave relation
juju add-relation mariadb:master mariadb-slave:slave

Any changes to the master are reflected on the slave.

Any queries that modify the database(s) should be applied to the master only.
The slave should be treated strictly as read only.

You can add further slaves with:

juju add-unit mariadb-slave


This charm provides relations that support monitoring via either
Nagios or
Munin. Refer to the appropriate charm
for usage.


You can tweak various options to optimize your MariaDB deployment:

  • max-connections - Maximum connections allowed to server or '-1' for default.

  • preferred-storage-engine - A comma separated list of storage engines to
    optimize for. First in the list is marked as default storage engine. 'InnoDB'
    or 'MyISAM' are acceptable values.

  • tuning-level - Specify 'safest', 'fast' or 'unsafe' to choose required
    transaction safety. This option determines the flush value for innodb commit
    and binary logs. Specify 'safest' for full ACID compliance. 'fast' relaxes the
    compliance for performance and 'unsafe' will remove most restrictions.

  • dataset-size - Memory allocation for all caches (InnoDB buffer pool, MyISAM
    key, query). Suffix value with 'K', 'M', 'G' or 'T' to indicate unit of
    kilobyte, megabyte, gigabyte or terabyte respectively. Suffix value with '%'
    to use percentage of machine's total memory.

  • query-cache-type - Specify 'ON', 'DEMAND' or 'OFF' to turn query cache on,
    selectively (dependent on queries) or off.

  • query-cache-size - Size of query cache (no. of bytes) or '-1' to use 20%
    of memory allocation.

Each of these can be applied by running:

juju set <service> <option>=<value>

For example:

juju set mariadb preferred-storage-engine=InnoDB
juju set mariadb dataset-size=50%
juju set mariadb query-cache-type=ON
juju set mariadb query-cache-size=-1

MariaDB Contact Information


                            Network Interface where to place the Virtual IP
                            This value dictates the number of replicas ceph must make of any
object it stores within the mysql rbd pool. Of course, this only
applies if using Ceph as a backend store. Note that once the mysql
rbd pool has been created, changing this value will not have any
effect (although it can be changed in ceph by manually configuring
your ceph cluster).

                            Default block storage size to create when setting up MySQL block
storage. This value should be specified in GB (e.g. 100 not 100GB).

                            Valid values are 'safest', 'fast', and 'unsafe'. If set to safest,
all settings are tuned to have maximum safety at the cost of
performance. Fast will turn off most controls, but may lose data on
crashes. unsafe will turn off all protections.

                            The name that will be used to create the Ceph's RBD image with. If
the image name exists in Ceph, it will be re-used and the data will
be overwritten.

                            Override the computed version from dataset-size. Still works if
query-cache-type is "OFF" since sessions can override the cache type
setting on their own.

                            Repository Mirror string to install MariaDB from

deb trusty main
                            Query cache is usually a good idea, but can hurt concurrency. Valid
values are "OFF", "ON", or "DEMAND".

                            Virtual IP to use to front mariadb in ha configuration
                            If binlogging is enabled, this is the format that will be used.
Ignored when tuning-level == fast.

                            How much data do you want to keep in memory in the database. This
will be used to tune settings in the database server appropriately.
Any more specific settings will override these defaults though. This
currently sets innodb_buffer_pool_size or key_cache_size depending on
the setting in preferred-storage-engine. If query-cache-type is set
to 'ON' or 'DEMAND' 20% of this is given to query-cache-size. Suffix
this value with 'K','M','G', or 'T' to get the relevant
kilo/mega/etc. bytes. If suffixed with %, one will get that
percentage of RAM devoted to dataset and (if enabled) query cache.

                            GPG Key used to verify apt packages.

                            Default multicast port number that will be used to communicate
between HA Cluster nodes.

                            Maximum connections to allow. -1 means use the server's compiled in

                            Tune the server for usage of this storage engine. Other possible
value is MyISAM. Comma separated will cause settings to split
resources evenly among given engines.

                            Netmask that will be used for the Virtual IP
                            I have read and agree to the ENTERPRISE TRIAL agreement, located
in located in the charm, or on the web here:

                            Default network interface on which HA cluster will bind to
communication with the other members of the HA Cluster.