50 lines
2.1 KiB
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50 lines
2.1 KiB
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=========
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Databases
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=========
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Almost all OpenStack components have an underlying database to store
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persistent information. Usually this database is MySQL. Normal MySQL
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administration is applicable to these databases. OpenStack does not
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configure the databases out of the ordinary. Basic administration
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includes performance tweaking, high availability, backup, recovery, and
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repairing. For more information, see a standard MySQL administration guide.
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You can perform a couple of tricks with the database to either more
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quickly retrieve information or fix a data inconsistency error—for
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example, an instance was terminated, but the status was not updated in
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the database. These tricks are discussed throughout this book.
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Database Connectivity
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~~~~~~~~~~~~~~~~~~~~~
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Review the component's configuration file to see how each OpenStack
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component accesses its corresponding database. Look for either
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``sql_connection`` or simply ``connection``. The following command uses
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``grep`` to display the SQL connection string for nova, glance, cinder,
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and keystone:
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.. code-block:: console
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# grep -hE "connection ?=" /etc/nova/nova.conf /etc/glance/glance-*.conf \
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/etc/cinder/cinder.conf /etc/keystone/keystone.conf
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sql_connection = mysql+pymysql://nova:nova@cloud.alberta.sandbox.cybera.ca/nova
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sql_connection = mysql+pymysql://glance:password@cloud.example.com/glance
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sql_connection = mysql+pymysql://glance:password@cloud.example.com/glance
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sql_connection = mysql+pymysql://cinder:password@cloud.example.com/cinder
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connection = mysql+pymysql://keystone_admin:password@cloud.example.com/keystone
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The connection strings take this format:
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.. code-block:: console
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mysql+pymysql:// <username> : <password> @ <hostname> / <database name>
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Performance and Optimizing
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~~~~~~~~~~~~~~~~~~~~~~~~~~
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As your cloud grows, MySQL is utilized more and more. If you suspect
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that MySQL might be becoming a bottleneck, you should start researching
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MySQL optimization. The MySQL manual has an entire section dedicated to
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this topic: `Optimization Overview
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<http://dev.mysql.com/doc/refman/5.5/en/optimize-overview.html>`_.
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