High Availability MySQL Cookbook phần 2 pps

Chapter 1

17

Creating an initial cluster configuration

file—config.ini

In this recipe, we will discuss the initial configuration required to start a MySQL Cluster.

A MySQL Cluster has a global configuration file—config.ini, which resides on all

management nodes. This file defines the nodes (processes) that make up the cluster

and the parameters that the nodes will use.

Each management node, when it starts, reads the config.ini file to get information on the

structure of the cluster and when other nodes (storage and SQL / API) start, they contact the

already-running management node to obtain the details of the cluster architecture.

The creation of this global configuration file—config.ini, is the first step in building the

cluster and this recipe looks at the initial configuration for this file. Later recipes will cover

more advanced parameters which you can define (typically to tune a cluster for specific

goals, such as performance).

How to do it…

The first step in building a cluster is to create a global cluster configuration file. This file,

called config.ini, by convention, is stored on each management node and is used by the

management node process to show the cluster makeup and define variables for each node.

In our example, we will store this in the file /usr/local/mysql-cluster/config.ini,

but it can be stored anywhere else.

The file consists of multiple sections. Each section contains parameters that apply to a

particular node, for example, the node's IP address or the amount of memory to reserve for

data. Each type of node (management, SQL, and data node) has an optional default section

to save duplicating the same parameter in each node. Each individual node that will make up

the cluster has its own sections, which inherits the defaults defined for its type and specifies

the additional parameters, or overrides the defaults.

This global configuration file is not complex, but is best analyzed with an example, and in

this recipe, we will create a simple cluster configuration file for this node. The first line to

add in the config.ini file is a block for this new management node:

[ndb_mgmd]

Now, we specify an ID for the node. This is absolutely not required, but can be

useful—particularly if you have multiple management nodes.

Id=1