Icinga2: Haproxy- master/slave setup

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In This tutorial I will be setting up Icinga2 to use a database proxy (dbproxy) to connect to it's master database and fail-over to the slave database if master database is not available for some reasons.

Note: We will not cover the Icinga2, Icingaweb2 and master/slave setup in this tutorial

Prerequisites

1 icinga2 server: icinga1001

1 master database master server: db1001

1 dbproxy server: dbproxy1001

2 slaves database severs: db1002 and db1005

Setup

Existing configuration

In my existing configuration, I have Icinga2 connecting directly to the database master (db1001). See image below

Icinga2.png

New configuration

In the new configuration we will need to put a dbproxy between Icinga2 and the database master server. See image below

Icinga21.png

Haproxy setup and configuration

On the dbpoxy1001, install haproxy:

sudo apt-get install haproxy

Open the configuration file and copy and paste the configuration below.

cd /etc/haproxy
sudo vi haproxy.cfg
# HAProxy's stats
listen stats
  bind 10.192.32.8:80
  stats enable
  stats hide-version
  stats uri     /
  stats realm   HAProxy Statistics
  stats auth    user_name:user_password
listen mysql-cluster
  bind 0.0.0.0:3306
  mode tcp
  option tcplog
  balance roundrobin
  option log-health-checks
  log /dev/log local0 crit
  option tcpka
  option mysql-check user haproxy_user
  server db1001 10.192.16.9:3306 check inter 3s fall 3 rise 6
  server db1002 10.192.32.2:3306 check backup
  server db1005 10.192.32.2:3306 check backup

Note: change the Bind address in the "listen start" with your dbproxy IP address and the server name and IP addresses in the "listen mysql-cluster" with your master and slaves names and IP addresses. If you are running UFW make sure port 3306 is open on the dbproxy node

As we can see in the haproxy.cfg file, we have a user called " haproxy_user" this user will check the status on all 3 database servers so we need to create this user.The user don't need and privileges on the database but we have to create the user on all 2 database servers.

Database configuration

Create the haproxy_user

The user don't have to be called "haproxy_use" you can call the user anything you want. login on all 3 database servers and issue the command

create user 'haproxy_user'@'dbproxy1001.dfw.labnet';

Create the application user

We are going to create the user that the application will use to access the database from the dbproxy node.

Overview

In my previous setup, I had 2 users(icinga2@icinga1001.dfw.labnet and icingaweb@icinga1001.dfw.labnet) for the icinga_ido and icingweb_ido settings. I had also 2 databases (icinga and icingaweb).

Why 2 databases and 2 users?

Icinga 2 uses 2 backend databases needed by Icinga 2 monitoring web application and Icinga Web 2 frontend to store users, contacts and other collected data. in this setting I will use only one user haproxy_root@dbproxy1001.dfw.labnet with the same databases.

Create the user command line

create user 'haproxy_root'@'dbhaproxy1001.dfw.labnet';
grant SELECT, UPDATE, INSERT, DELETE privileges on *.* to 'haproxy_root'@'dbproxy1001.dfw.labnet' identified by 'your_password' with grant option;

Create the user with yaml file

In my environment, I am using the puppetlabs/mysql module to install, setup and configure all my nodes. I have a yaml file for each database node and the setting to create the haproxy_root user using the yaml file looks like the one below.

 ##application user to  access mysql cluster from haproxy
mysql::server::users:
  haproxy_root@dbproxy1001.dfw.labnet:
    ensure: present
    password_hash: '*EAA615A0970C05B84915C0772FD1C23831586837'
mysql::server::grants:
  haproxy_root@dbproxy1001.dfw.labnet/*.*:
    ensure: present
    privileges: INSERT, UPDATE, DELETE, SELECT
    table: '*.*'
    user: haproxy_root@dbproxy1001.dfw.labnet

Verification

Go to your dbproxy stats page by typing your_server_ip_address in the browser

Icinga22.png

WE see that all 3 database nodes are up and only db1001 is in active mode.

Icinga2 configuration

Using the WEB GUI=

- Login to Icinga with a user with Admin rights

- click on Configuration

- click on Application

- click on Resources

- click on icingaweb_ido

- change the Host to your dbproxy host name

- change username to your user allow to access the database from the dbproxy node

- change the pasword to the the password of the user allow to access the database from the dbproxy node

- click on validation configuration

- click on save changes

Do the same for the icinga_ido section

icingaweb_ido

Icinga23.png

icinga_ido

Icinga24.png

Changing the ido-mysql.conf file

cd /etc/icinga2/features-enabled
sudo vi ido_mysql.conf
library "db_ido_mysql"
object IdoMysqlConnection "ido-mysql" {
  host = "dbproxy1001.dfw.labnet"
  port = 3306
  user = "haproxy_root"
  password = "password_here"
  database = "icinga"
  enable_ssl = false
}
sudo systemctl restart icinga2.service

changing the resources.ini file

cd /etc/icingaweb2
sudo vi resources.ini
[icingaweb_db]
type = "db"
db = "mysql"
host = "dbproxy1001.dfw.labnet"
port = ""
dbname = "icingaweb2"
username = "haproxy_root"
password = "password_here"
charset = ""
persistent = "0"
use_ssl = "1"
[icinga_ido]
type = "db"
db = "mysql"
host = "dbproxy1001.dfw.labnet"
port = ""
dbname = "icinga"
username = "haproxy_root"
password = "password_here"
charset = ""
persistent = "0"
use_ssl = "1"

Testing

We will stop MySQL on db1001 which is the master and see if we can still access the application

ppaul@db1001:~$ sudo systemctl stop mysql

The haproxy stats show that db1001 is offline

Icinga25.png

But we can login to the application. We notice that the back-end is not working because the application is connected to db1002 which is a slave server set to ready only mode

Icinga26.png