Using MySQL Fabric from any programming language

MySQL Fabric is a framework for MySQL Replication high availability, automatic failover and sharding. Technically, a MySQL Fabric daemon monitors a set of MySQL servers and takes appropriate actions upon failure. Clients use Fabric aware drivers to learn about failed servers and shards to distribute queries accordingly. Simple to understand, simple to sell, simple to raise false expectations and simple to fail [, dear Sales]. With the usual blog posts telling only the story of the first three sentences, major parts of the story are covered in silence.

Development preview = announcement of a vision != ready

You first challenge will be to find the documentation for the MySQL Fabric development preview. From the documentation overview page it takes three clicks down to the server side documentation for Fabric:

1. MySQL Workbench


2. MySQL Utilities 1.4+ (not the older one!)


3. MySQL Fabric

You better do not start your search in the MySQL Reference Manual under High Availability and Scalability. Fabric, a command line utility, is well hidden inside the documentation of a GUI tool. Eventually, you may find a download and attempt to install Fabric using an install prefix.

~/mysql-utilities-1.4.1/install/bin # ./mysqlfabric manage start
~/mysql-utilities-1.4.1/install/bin # Traceback (most recent call last):
  File "./mysqlfabric", line 23, in <module>
    from mysql.fabric.services import (
ImportError: No module named mysql.fabric.services
~/mysql-utilities-1.4.1/install/bin # export PYTHONPATH=/home/nixnutz/ftp/mysql-utilities-1.4.1/install/lib/python2.7/site-packages/

80% of the development community is out, true?

Pretty much all blogs and tutorials claim that Fabric aware drivers must be used. According to the manual, such drivers exist for Python and Java only. This covers an estimated 20% of the software development communities. Let’s cry for help:

~#47;mysql-utilities-1.4.1/install/bin # ./mysqlfabric help
Usage: %fabric <group> <cmd> [<option> ...] arg ...

mysqlfabric: error: Error (dispatch() takes exactly 3 arguments (1 given)).
Wrong number of parameters were provided for command (manage help).

~#47;mysql-utilities-1.4.1/install/bin # ./mysqlfabric help help help
Command (help, help) was not found.

Being among the 20% of priviledged Python or Java users you may not bother until you browse the etc/ directory for configuration files. Here you will find something seemingly related to PHP’s Doctrine…

~/mysql-utilities-1.4.1/install/bin # ls -la ../etc/mysql/
insgesamt 32
drwxr-xr-x 2 nixnutz users  4096 11. Feb 16:34 .
drwxr-xr-x 3 nixnutz users  4096 11. Feb 16:33 ..
-rw-r----- 1 nixnutz users   119 11. Feb 16:34 default_plugins.cnf
-rw-r--r-- 1 nixnutz users   527 11. Feb 16:34 fabric.cfg
-rw-r--r-- 1 nixnutz users 13132 11. Feb 16:34 mysql-fabric-doctrine-1.4.0.zip

There is something for the PHP driver but it is not documented. Why there is something for a PHP application before the driver part is ‘done done’ may make some scratch their heads.

Putting expectations straight and low

Any project should state what is included and what is not. Fabrics’ vision should be clear and bright. Please, see the slides.

MySQL 5.7 Fabric: Introduction to High Availability and Sharding from Ulf Wendel

But, Fabric is available as a development preview release only. Core functionality exists. The examples from the manual work for me. But, no other scenarios do. For example, mysqlfabric group import_topology lacks documentation and mysqlfabric group promote blog_repl fails for me.

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