OpenWorld 2014 - Schema Management: versioning and automation with Puppet and MySQL Utilities

Schema Management: Versioning and
Automation with Puppet and MySQL Utilities
Oracle Open World 2014 : MySQL Central Frédéric Descamps

Who am I ?
●
Frédéric Descamps «lefred»
●
@lefred
●
http://about.me/lefred
●
within Percona since 2011
●
managing MySQL since 3.23 (as far as I remember)
●
devops believer

We live in a devops world o/
Oracle Open World 2014 : MySQL Central
-3-

devops ?
we can say that devops is
bringing together people and
practices from development
and operations

devops ?
we can say that devops is
bringing together people and
practices from development
and operations
I am a happy dev !I am a happy op !

CAMS
●
devops is about CAMS
– Culture
– Automation
– Measurement
– Sharing
@botchagalupe @damonedwards
http://www.opscode.com/blog/2010/07/16/what-devops-means-to-me/

This talk is about automation
●
What techniques can I use ?
– Infrastructure as Code
– Continuous Improvement

WE are already between
devs and ops

WE are already between
devs and ops
I am a happy DBA !

so... AUTOMATION
●
Can we automate DBAs job ?
●
Should we ??
●
Even if we have only one database ?

●
Everything needs to be reproducible

What do we «usually» automate ?
●
binaries installation (which version of MySQL)
●
configuration (my.cnf ?)
●
cron jobs
●
monitoring
●
databases (schemas)
●
grants
●
replication ?

Infrastructure as code
●
So to automate all these tasks a multiplicity of projects
appeared on the web:
– puppet
– chef
– cfengine
– ansible
– saltstack
– ...

let's focus on Puppet
●
we will install MySQL on a new node
or or

●
we will install MySQL on a new node
5.5 or 5.6 or 10.0 or 5.7 ?

●
Puppet recipes will take care of the OS
or

●
Puppet recipes will take care of the OS
or
case $::osfamily {
     'RedHat': {
           $require = Yumrepo['mysqlrepo']
      }
      'Debian': {
           $require = Apt::Source['mysqlrepo']
      }
}

Example in hiera

classes:
mysql
mysql::server
mysql::mysql_root_password: «fred»
mysql::mysql_distro: «community»
mysql::mysql_version: «5.6»
mysql::mysql_serverid: «2»
mysql::mysql_bind_interface: «eth1»
mysql::ensure: «running»

puppet (continue)
●
And we can automate many things like schema creation,
grants:
mysql::db { $graphite_db_name:
      user     => $graphite_db_user,
      password => $graphite_db_password,
      host     => $graphite_db_host,
      grant    => ['SELECT', 'UPDATE'],
   }

puppet: MySQL modules
●
You can find many MySQL modules for puppet:
– https://github.com/olindata/puppetlabs-mysql
– https://github.com/lefred/puppet-lefred-mysql

and now ?
●
can we go further ?
●
what could we automate ?
●
schemas !
– using mysqldump ?
– using frameworks ?

but... automation !
●
we want this automated
●
easy to test multiple times in development, staging, ...
●
to use in production
●
and if possible to rollback easily if needed !
v1 v2

Database Schema Migration Tools
●
There are some existing tools:
– Liquibase
– Flyway
– c5-db-migration
– dbdeploy
– MyBatis
– Autopatch
– Sqitch

Most of them are...
Integrated with a framework or an ORM

Most of them are...
for JAVA applications

Most of them use...
XML definitions

XML Definitions
●
What is easier to read and maintain for us, DBAs ?
<?xml version="1.0" encoding="UTF8"?>

<databaseChangeLog
xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
xmlns:xsi="http://www.w3.org/2001/XMLSchemainstance"
xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog2.0.xsd">

<changeSet id="1" author="lefred">
<createTable tableName="department">
<column name="id" type="int">
<constraints primaryKey="true" nullable="false"/>
</column>
<column name="name" type="varchar(50)">
<constraints nullable="false"/>
</column>
<column name="active" type="boolean" defaultValueBoolean="true"/>
</createTable>
</changeSet>

</databaseChangeLog>

XML Definitions
●
or this ?
CREATE TABLE department (
id INT NOT NULL PRIMARY KEY,
name VARCHAR(50) NOT NULL
);

most of them are...
blocking schema changes

and finally...
not designed to be used via a
configuration management system

so are we blocked ? NO !
●
Oracle's MySQL-Utilities
●
Percona Toolkit
●
a standalone Python script
●
a new Puppet type and provider

Oracle's MySQL-Utilities
●
toolkit that was generally distributed via MySQL Workbench
●
Dec 7th 2010 : v 1.0.0
●
Aug 20th 2014: v.1.5.1 RC
●
it contains a package of tools used for maintenance and
administration of MySQL servers
●
they are written in Python
●
the utilities are command line commands and a Python
library

Oracle's MySQL-Utilities (2)
●
Utilities can help for
– database operations: provision a slave, copy a db, diff tables, synchronize tables
– general operations: find disk space used, table structure, duplicate users, work on
indexes, find database objects matching patterns
– HA operations: add a slave, setup failover, find slaves, check replication
– server operations: make a temp copy of the server, use secure connection
– «specialized operations»: record login events, copy/move audit log, show failed
queries, show connections

What are the interresting tools for us
●
mysqldbcompare — compares two databases and
identify differences (objects, row counts, data concistency)
●
mysqldiff — identifies differences among database
objects
●
And all those options can be integrated into a Python script
using the library

Percona-Toolkit
●
collection of advanced command-line tools
●
Aug 6th 2014: v2.2.10
●
They can do a lot of useful tasks like table checksum and
synchronization, delay slave on version where it wasn't
implemented yet, digest the queries
●
But for us, the most important:
ptonlineschemachange

pt-online-schema-change
●
this tool allows to alter a table's structure without blocking
reads or writes
●
the tool works on a copy of the table you wish to alter
●
switches them at the end of the process
●
and delete the original one

online-migration.py
●
standalone Python script
●
command line only no GUI sorry ;-)
●
uses Oracle's MySQL-Utilities library
●
uses pt-online-schema-change
●
uses normal SQL statements that all DBAs understand
●
can be integrated in Puppet

what can it do ?
●
The script is able to
– return the schema version of a database
– list all versions and their status
– migrate up
– migrate down (rollback a migration)
– checksum the schema
– return the difference between expected schema and installed schema

and in Puppet ?
node percona1 {
include mysql
include mysql::server
include mysql::utilities
include mysql::percona_toolkit
include onlinemigration
        Class['percona::repository'] > Class['percona::server']
        mysql_schema { "world":
                     ensure  => present,
         require => [ Package["onlinemigration"],
   Service['mysql'] ],
                     version => 2,
                      cwd     => "/root/om",
        }
        ...
}

and in Puppet ?
node percona1 {
include mysql
include mysql::server
include mysql::utilities
include mysql::percona_toolkit
include onlinemigration
        Class['percona::repository'] > Class['percona::server']
        mysql_schema { "world":
                     ensure  => present,
         require => [ Package["onlinemigration"],
   Service['mysql'] ],
                     version => 2,
                      cwd     => "/root/om",
        }
        ...
}
...
info: Mysql_schema[world](provider=mysql_schema): performing the check, last_version is 1
info: Mysql_schema[world](provider=mysql_schema): we need to migrate to another version (2)
info: Mysql_schema[world](provider=mysql_schema): performing the migration
...

online-migration.py internals
●
uses a dedicated table :
online_migration.migration_sys
– it contains some meta data like db, version, apply date, status
– created by: onlinemigration.py init_sysdb
– first entry is version 0 and is created by the «init» command
●
uses a folder with meta-data:
– XXXXup.meta: meta data required to upgrade to version XXXX, like version,
checksum and comment
– XXXXup.mig: contains the required changes/statements
– XXXXdown.mig: contains the automated reverse statements

online-migration.py: features (2)
●
migration up
$ onlinemigration.py up world to 3
INFO : You want to migrate up to version 0003
INFO : Ok this version is pending
INFO : Preparing migration to version 0001
INFO : Applied changes match the requested schema
+++++
+++++
|    0000 | 20140922 09:17:16 |               ok |           Initial file |
|    0001 | 20140922 09:17:46 |               ok |                   none |
|    0002 | 20140922 09:18:24 |               ok |                   none |
|    0003 | 20140922 09:18:36 |               ok | add nice column to cit |
+++++

●
checksum
+++++
+++++
|    0000 | 20140922 09:17:16 |               ok |           Initial file |
|    0001 | 20140922 09:17:46 | checksum problem |                   none |
+++++
$ onlinemigration.py checksum world
world's current schema checksum = 3239e7245d98d27681020e36d0085676

●
migration down (rollback)
$ onlinemigration.py down world 2
INFO : You want to migrate down 2 version(s)
INFO : rollback from 0003 to 0002
INFO : rollback from 0002 to 0001
+++++
+++++
|    0000 | 20140922 09:17:16 |               ok |           Initial file |
|    0001 | 20140922 09:17:46 |               ok |                   none |
|    0002 | 20140922 09:18:24 |         rollback |                   none |
|    0003 | 20140922 09:18:36 |         rollback | add nice column to cit |
|    0003 |                none |          pending | add nice column to cit |
+++++

●
schema diff
$ onlinemigration.py diff world
WARNING : Schema of world doesn't have expected checksum
(4478d85870969436400bac023f2b2b7c)
TABLE `City`
`CountryCode` varchar(10) DEFAULT NULL,
+ `CountryCode` char(3) NOT NULL DEFAULT '',

todo
●
Make the code more robust (handling errors)
●
Write support for store procedures, functions,...
●
Support online DDL (ALGORITHM=INPLACE)
●
Add configuration file

Resources
●
Oracle MySQL — http://dev.mysql.com/downloads/mysql/
●
MySQL-Utilities — http://dev.mysql.com/downloads/utilities/
●
Percona-Toolkit - http://www.percona.com/doc/percona-
toolkit/2.2/index.html
●
pt-online-schema-change — http://www.percona.com/doc/percona-
toolkit/2.2/pt-online-schema-change.html
●
puppet — http://puppetlabs.com
●
online-migration.py — https://github.com/lefred/online-migration

Thank you
Questions ?

OpenWorld 2014 - Schema Management: versioning and automation with Puppet and MySQL Utilities

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OpenWorld 2014 - Schema Management: versioning and automation with Puppet and MySQL Utilities