MYSQL Redundancy by using Master-Master Replication

Video Link: https://www.youtube.com/watch?v=2AnCVMnr7FQ

In this Guide, I will show you howto create replica of your radius server so that in case of any server failure , you can instantly switch to backup server with the latest data available. In this model we will use MYSQL master-master concept in which whatever changes / records you make on any server, it will replicate to other as well. Also in mikrotik we can use primary and secondary radius server entries OR we can make a script to detect both radius status and act accordingly, all depend on your network requirements & infrastructure.

Scenario:

In this example we have FREERADIUS base billing system which uses freeradius and MYSQL DB as its backend engine,  installed (with basic level of installation) on two servers. Now we want to create redundancy by replicating radius DB to each other so that in case of one server failure, second server should come to rescue.

Requirements:

• I assume that you have working mysql installed on both PC and tested its working by creating users in it.

Components Used:

• SERVER1 NAME = MASTER-RADIUS
  OS = Ubuntu
  IP = 101.11.11.241
• SERVER2 NAME = REPLICA-RADIUS
  OS = Ubuntu
  IP = 101.11.11.245

 

Let’s Start

Step – 1

Server1 = ‘master-radius’ Configuration

Open mysql config file

for Ubuntu 12.4 use following location

nano /etc/mysql/my.cnf

for Ubuntu 16.4 use following location

nano /etc/mysql/mysql.conf.d/mysqld.cnf

and add following under [mysqld] section

log-bin=mysql-bin
#(uncomment below line if you want only this DB replication)
#binlog-do-db=radius
server-id=1
log_bin = /var/log/mysql/mysql-bin.log
bind-address = 0.0.0.0  # Search this and change it manualy , donot copypaste 

SAVE and EXIT.

Now restart mysql service so changes can take effect.

service mysql restart

Now we need to create a user that will be used by mysql for replicating data between our two radius (or mysql) servers. As an example I am using id “zaib”. Replace “password” with the password you wish to use for replication.

create user 'zaib'@'%' identified by 'password';
grant replication slave on *.* to 'zaib'@'%'; 

Now we need to get some information about the current MySQL instance which we will later provide to server2 (replica).

The following command will output a few pieces of important information, which we will need to make note of:

show master status;

The output will look similar to the following, and will have two pieces of critical information: [file and position note it down)

+------------------+----------+--------------+------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000001 |      336 | radius       |                  |
+------------------+----------+--------------+------------------+

1 row in set (0.00 sec)

We need to make a note of the above file name and position which will be used in the later step.

Now Lock tables to so that we can dump our db/tables

We can do that by typing the following:

FLUSH TABLES WITH READ LOCK;

Now dumpt the DB/Tables

mysqldump -u root -p --all-databases --master-data > dbdump.sql

Now UNLOCK the tables by

UNLOCK TABLES;

Upload this DBDUMP.SQL to secondary replica server, you can use scp command as well.

 

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Step – 2

Server2 = ‘replica-radius’ Configuration

Open mysql config file

for Ubuntu 12.4 use following location

nano /etc/mysql/my.cnf

for Ubuntu 16.4 use following location

nano /etc/mysql/mysql.conf.d/mysqld.cnf

and add following under [mysqld] section

log-bin=mysql-bin
#(uncomment this if you want only this DB replication)
#binlog-do-db=radius
server-id=2
log_bin = /var/log/mysql/mysql-bin.log
bind-address = 0.0.0.0  # Search this and change it manualy , donot copypaste 

Make sure server-id is different then primary server

SAVE and EXIT.

Now restart mysql service so changes can take effect.

service mysql restart

Here we are going to create the user which will be responsible for the replication. Replace “password” with the password you wish to use.

create user 'zaib'@'%' identified by 'password';
grant replication slave on *.* to 'zaib'@'%'; 

IMPORT THE DB

mysql -u root -p < dbdump.sql

The next step involves taking the information that we took a note of earlier and applying it to our mysql instance. This will allow replication to begin. The following should be typed at the mysql shell:

stop slave;
CHANGE MASTER TO MASTER_HOST = '101.11.11.241', MASTER_USER = 'zaib', MASTER_PASSWORD = 'password', MASTER_LOG_FILE = 'mysql-bin.000001', MASTER_LOG_POS = 336;
start slave; 

Your values for MASTER_LOG_FILE and MASTER_LOG_POS may differ than those above. You should copy the values that “SHOW MASTER STATUS” returns on Server-1.

The last thing we have to do before we complete the mysql master-master replication is to lock tables and make note of the master log file and position to use to replicate in the other direction (from Server 2 to Server 1).

We can do that by typing the following:

SHOW MASTER STATUS; 

The output will look similar to the following:

+------------------+----------+--------------+------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000002 |      125 | radius       |                  |
+------------------+----------+--------------+------------------+
1 row in set (0.00 sec)

Take note of the file and position, as we will have to enter this entry on server 1, to complete the two-way replication.

Step – 3

Completing Replication on Server1 [Master-radius]

Back on Server 1, we need to finish configuring replication on the command line.

Running this command will replicate all data from Server 2.

stop slave;
CHANGE MASTER TO MASTER_HOST = '101.11.11.245', MASTER_USER = 'zaib', MASTER_PASSWORD = 'password', MASTER_LOG_FILE = 'mysql-bin.000002', MASTER_LOG_POS = 125;
start slave; 

Keep in mind that your values may differ from those above. Please also replace the value of MASTER_PASSWORD with the password you created when setting up the replication user.

The output will look similar to the following:

Query OK, 0 rows affected (0.01 sec)

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Now test the status by issuing command to mysql cli

show slave status\G

and you should see something similar to this. [don’t get confused with different numbers of log file file and position number, as this snap was taken in another lab]

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TEST

The last thing to do is to test that replication is working on both servers.

Open server1 radius panel, and try to create new user, after creation, it will be automatically replicated to server2 : )

As shown in the images below …

At a moment no users have been created.

 

Now create test user

 

After creation, Goto Server2 (Replica) and check Users List, and you will find the user replicated.

and when you will create any user , it will replicate back to server1.

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Adding both Radius Server entries in Mikrotik

Add both radius server

and at radius manager, add the NAS (mikrotik)

Don’t forget to rebuild clients.conf (from the menu) at secondary radius as well.

Now test by connecting any client , once successful, disconnect the primary radius, and try to connect the client again, once mikrotik will be unable to find primary entry, it will auto contact secondary server. as showed in the images below …

I will add few more details later….

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Tips for Radius Manager

Tip: Make sure you have same credentials for both servers, that includes, root, mysql users, and in config files as well.

Example:

Change MYSQL Root ID password (old password to new)

mysql -u root -pROOTPASSWORD
use mysql;
update user set password=PASSWORD('MYNEWPASSWORD') where User='root';
flush privileges;

CHANGE RADIUS USER PASSWORD in mysql;

use mysql;
SET PASSWORD FOR 'radius'@'localhost' = PASSWORD('MYNEWPASSWORD');

=====================================

Then change password in following files for user ‘radius’

/etc/radiusmanager.cfg
/var/www/radiusmanager/config/system_cfg.php
/usr/local/etc/raddb/sql.conf

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TIP: Remove MYSQL Replication

# Stop Mysql Service
service mysql stop
# Remove mysql replication entries
cd /var/lib/mysql
rm -f master.info relay-*`
# Start Mysql Service
service mysql start

To check MYSQL table Health and Auto Repair

show warnings;
SHOW TABLE STATUS;
mysqlcheck -uroot -pSQLROOTPASS --all-databases --auto-repair

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DMA Note:

Please note that you may need to rebuild clients.conf from DMA web panel in order to initialize NAS list.