Mariadb

juju deploy mariadb

14.04 LTS

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Overview

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 either MariaDB, using packages provided by the MariaDB Foundation, including packages for IBM's POWER8 platform; or MariaDB Enterprise, using packages in a repository provided by MariaDB Corporation, Inc.

Note: Packages for IBM's POWER8 platform are only available from the MariaDB Foundation repository.

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

Usage

General Usage

Deploying MariaDB

To deploy MariaDB from the MariaDB Foundation, simply deploy like so:

juju deploy mariadb

MariaDB will be deployed.

Deploying MariaDB Enterprise

To deploy a MariaDB Enterprise service, first login to the MariaDB Portal. On that page you will find your MariaDB Enterprise download token. It is of the form xxxx-xxxx.

Next create a file called enterprise.yaml with the following contents, replacing the placeholder token with your actual token:

mariadb:
  enterprise-eula: true
  token: "xxxx-xxxx"

Lastly, deploy MariaDB Enterprise like so:

juju deploy --config ./enterprise.yaml mariadb

MariaDB Enterprise will be deployed. You must agree to all terms contained in ENTERPRISE-LICENSE.md in the charm directory to use MariaDB Enterprise.

Installing a different series of MariaDB

Different series of MariaDB can be installed using the charm. The default series is MariaDB 10.1, but the older MariaDB 5.5 and 10.0 are also available. To install one of these older series, create a mariadb.yaml file with the following contents (example is for MariaDB 5.5):

mariadb:
  series: "5.5"

You could also add the series line to your enterprise.yaml file, if you are using MariaDB Enterprise. Then when deploying MariaDB, reference the file like so:

juju deploy --config ./mariadb.yaml mariadb

Warning: Using the set command to downgrade MariaDB after initial deployment, for example, like so:

juju set mariadb series="5.5"

...does not work. Using the set command to upgrade MariaDB; from 5.5 to 10.0, or from 10.0 to 10.1; does work.

After deploying

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 the root MariaDB user at the MariaDB console you can, for example, issue the following:

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

Scale Out Usage

Replication

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 performance.

To deploy a slave:

# deploy second service
juju deploy --config ./enterprise.yaml 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

Monitoring

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

Configuration

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