Revision as of 17:34, 24 February 2020

Simple Cluster configuration

Will consist of 5 components:

Management Node

holds the configuration for MySQL Cluster in a file called config.ini. It also writes a cluster log, and takes part in arbitration to prevent split-brain or network partitioning.

(2) Data Nodes

stores the data and the tables. The data nodes takes cares of managing the transactions, recovery, etc

(2) SQL Nodes

the most common way to read/write data to the Data Nodes is by using the MySQL Server (aka SQL Node)

Management Node Configuration

yum installation

While most of the guides I found perform installation directly using the RPM packages, I prefer to install packages from a repository whenever available. MySQL provides a YUM repository.

~$ wget https://dev.mysql.com/get/mysql80-community-release-el7-3.noarch.rpm
~$ sudo yum localinstall mysql80-community-release-el7-3.noarch.rpm

Verify you can see the new cluster packages and search them.

~$ yum repolist all | grep mysql
~$ yum --enablerepo=mysql-cluster-8.0-community search mysql

Enable the cluster repo by setting enabled=1

~$ sudo vim /etc/yum.repos.d/mysql-community.repo
...
[mysql-cluster-8.0-community]
name=MySQL Cluster 8.0 Community
baseurl=http://repo.mysql.com/yum/mysql-cluster-8.0-community/el/7/$basearch/
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-mysql

package installation

There are a couple of dependencies we need to install.

~$ sudo yum install -y epel-release && sudo yum install -y perl-Class-MethodMaker

Install the packages

 ~$ sudo yum install -y mysql-cluster-community-management-server mysql-cluster-community-client mysql-cluster-community-libs

Configure cluster

Now we can setup a basic configuration file for the cluster.

~$ sudo mkdir -p /var/lib/mysql-cluster
~$ sudo vim /var/lib/mysql-cluster/config.ini
...
[ndb_mgmd default]
# Directory for MGM node log files
DataDir=/var/lib/mysql-cluster

[ndb_mgmd]
#Management Node db1
HostName=rncv-sqlmgmt01.virtual.local

[ndbd default]
NoOfReplicas=2      # Number of replicas
DataMemory=256M     # Memory allocate for data storage
IndexMemory=128M    # Memory allocate for index storage
#Directory for Data Node
DataDir=/var/lib/mysql-cluster

[ndbd]
#Data Node db2
HostName=rncv-sqldata01.virtual.local

[ndbd]
#Data Node db3
HostName=rncv-sqldata02.virtual.local

[mysqld]
#SQL Node db4
HostName=rncv-sql01.virtual.local

[mysqld]
#SQL Node db5
HostName=rncv-sql02.virtual.local

Now we can implement the config

~$ sudo ndb_mgmd --config-file=/var/lib/mysql-cluster/config.ini
MySQL Cluster Management Server mysql-8.0.19 ndb-8.0.19
2020-02-24 16:17:03 [MgmtSrvr] WARNING  -- at line 12: [DB] IndexMemory is deprecated, will use Number bytes on each ndbd(DB) node allocated for storing indexes instead

And finally we can view the implementation:

~$ ndb_mgm
-- NDB Cluster -- Management Client --
ndb_mgm> show
Connected to Management Server at: localhost:1186
Cluster Configuration
---------------------
[ndbd(NDB)]	2 node(s)
id=2 (not connected, accepting connect from rncv-sqldata01.virtual.local)
id=3 (not connected, accepting connect from rncv-sqldata02.virtual.local)

[ndb_mgmd(MGM)]	1 node(s)
id=1	@10.10.0.40  (mysql-8.0.19 ndb-8.0.19)

[mysqld(API)]	2 node(s)
id=4 (not connected, accepting connect from rncv-sql01.virtual.local)
id=5 (not connected, accepting connect from rncv-sql02.virtual.local)

ndb_mgm> quit