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Installing A High Availability Web Server Cluster On Ubuntu 12.10 Using HAProxy, HeartBeat And Lampp

14/02/2019 Aucun commentaire

What is the main objective of this entire topology?

high availability web server clusterRedundancy and Load Sharing! Imagine a scenario where your single web server is receiving millions and millions of HTTP requests per second, the CPU load is going insane, as well as the memory usage, when suddenly “crash!”, the server dies without saying good-bye (probably because of some weird hardware out-stage that you certainly won’t have time to debug). Well, this simple scheme might lead you into a brand new world of possibilities

What is this going to solve?

Hardware Failures! We are going to have redundant hardware all over the place, if one goes down, another one will be immediately ready for taking its place. Also, by using load sharing schemes, this is going to solve our High Usage! issue. Balancing the load among every server on our “farm” will reduce the amount of HTTP request per server (but you already figured that out, right?).
Let’s set it up! Firstly, we’re not going to use a domain scheme (let’s keep it simple), make sure your /etc/hosts file looks exactly like the picture below on every machine:
#vi /etc/hosts
192.168.0.241   haproxy
192.168.0.39 Node1
192.168.0.30 Node2
192.168.223.147 Node1
192.168.223.148 Node2
192.168.0.58 Web1
192.168.0.139 Web2
192.168.0.132 Mysql

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Categories: Système Tags: ,

Installing a high availability web server cluster on Ubuntu 12.04 LTS using HAProxy, HeartBeat and Nginx

14/02/2019 Comments off

How to set-up a high-availability cluster

Here are a few notes about how to set-up a high-availability web server farm using Ubuntu 12.04 LTS using a whole load of awesome software (HAProxy, HeartBeat, Watchdog and Nginx)

The setup

In my setup I have five virtual machines, these are named and used for the following:-

haproxy1 – Our first proxy (master)/load-balancer (running HAProxy, HeartBeat and Watchdog) [IP address: 172.25.87.190]
haproxy2 – Our second proxy (failover)/load-balancer (running HAProxy, HeartBeat and Watchdog) [IP address: 172.25.87.191]
web1 – Our first web server node (running nginx) [IP address: 172.25.87.192]
web2 – Our second web server node (running nginx) [IP address: 172.25.87.193]
web3 – Our third web server node (running nginx) [IP address: 172.25.87.194]

The servers are connected in the following way:-

thesetup

In my next post I will also explain how to configure the web servers to point to a backend shared storage cluster (using NFS) and a MySQL cluster server to have a truly highly available web hosting platform.

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Categories: Système Tags: , , ,

How To Create a High Availability Setup with Heartbeat and Floating IPs on Ubuntu 14.04

30/01/2019 Comments off

Source: Digital Ocean – Mitchell Anicas

Introduction

Heartbeat is an open source program that provides cluster infrastructure capabilities—cluster membership and messaging—to client servers, which is a critical component in a high availability (HA) server infrastructure. Heartbeat is typically used in conjunction with a cluster resource manager (CRM), such as Pacemaker, to achieve a complete HA setup. However, in this tutorial, we will demonstrate how to create a 2-node HA server setup by simply using Heartbeat and a DigitalOcean Floating IP.

If you are looking to create a more robust HA setup, look into using Corosync and Pacemaker or Keepalived.

Goal

When completed, the HA setup will consist of two Ubuntu 14.04 servers in an active/passive configuration. This will be accomplished by pointing a Floating IP, which is how your users will access your services or website, to point to the primary, or active, server unless a failure is detected. In the event that the Heartbeat service detects that the primary server is unavailable, the secondary server will automatically run a script to reassign the Floating IP to itself via the DigitalOcean API. Thus, subsequent network traffic to the Floating IP will be directed to your secondary server, which will act as the active server until the primary server becomes available again (at which point, the primary server will reassign the Floating IP to itself).

ha-diagram-animated

Note: This tutorial only covers setting up active/passive high availability at the gateway level. That is, it includes the Floating IP, and the load balancer servers—Primary and Secondary. Furthermore, for demonstration purposes, instead of configuring reverse-proxy load balancers on each server, we will simply configure them to respond with their respective hostname and public IP address.

To achieve this goal, we will follow these steps:

  • Create 2 Droplets that will receive traffic
  • Create Floating IP and assign it to one of the Droplets
  • Create DNS A record that points to Floating IP (optional)
  • Install Heartbeat on Droplets
  • Configure Heartbeat to Run Floating IP Reassignment Service
  • Create Floating IP Reassignment Service
  • Test failover

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MySQL Cluster Replication: Multi-Master and Circular Replication

28/01/2019 Comments off

mysql-multi-master-replication-14-638Beginning with MySQL 5.1.18, it is possible to use MySQL Cluster in multi-master replication, including circular replication between a number of MySQL Clusters.

Prior to MySQL 5.1.18, multi-master replication including circular replication was not supported with MySQL Cluster replication. This was because log events created in a particular MySQL Cluster were wrongly tagged with the server ID of the master rather than the server ID of the originating server.

Circular replication example. In the next few paragraphs we consider the example of a replication setup involving three MySQL Clusters numbered 1, 2, and 3, in which Cluster 1 acts as the replication master for Cluster 2, Cluster 2 acts as the master for Cluster 3, and Cluster 3 acts as the master for Cluster 1. Each cluster has two SQL nodes, with SQL nodes A and B belonging to Cluster 1, SQL nodes C and D belonging to Cluster 2, and SQL nodes E and F belonging to Cluster 3.

Circular replication using these clusters is supported as long as the following conditions are met:

  • The SQL nodes on all masters and slaves are the same
  • All SQL nodes acting as replication masters and slaves are started using the --log-slave-updates option

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Simple failover cluster using UCARP on Ubuntu

09/01/2019 Comments off

In this tutorial, I’ll show you the steps to create a simple failover cluster on Ubuntu using CARP. To make the things meaningful,we’ll create the cluster for Apache service but you can use it for any other service, which relay on IP.

Scenario:

Here is my Setup:

PrimarySrv: This is the main server, where I configured the apache and which act as Master (IP: 192.168.1.202)
SecondarySrv: 2nd Apache Server where I configured the apache exactly like on PrimarySrv (IP : 192.168.1.203)
192.168.1.250 : Virtual IP address,created using Ucarp.

Ucarp is really simple, it works like this,when the PrimarySrv is up,it will assign the virtual IP 192.168.1.250 to it, in case that PrimarySrv is down then it will assign virtual IP to the SeconadrySrv and when the PrimarySrv will come online, it will assign the virtual IP once again to it.

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