IP addresses to set up fault tolerance?

Why do I need so many IP addresses to set up fault tolerance?

There are three 'classes' of IP addresses that we use:

1) 'Front-end' IP addresses - think of these as what are the current IP addresses of each of the Load Balancer machines. Each machine must have a unique IP address to identify itself, so you can contact it directly.

'2) Traffic' IP addresses - these are the addresses of your load balancers that the outside world will see and know about. You need at least two of these (so the balancers can have an address each). Unlike the 'front-end' IP addresses, traffic IP addresses are not tied to one machine - they get shared around and moved. For instance, if one of the balancer machines dies, then the other balancer will take its traffic IP address. This way, visitors will always be able to reach your site.

'3) Back-end' IP addresses - the balancer machines use these IP addresses to contact the back-end servers. The balancer machines will normally have two network cards for performance. The front-end and traffic IP addresses should be on one of the network cards, and the back-end IP address will be on the other card.

The Load Balancer will control the traffic IP addresses itself. The other IP addresses should be configured properly in the operating system.



Janu

Comments

Post a Comment

Popular posts from this blog

Is a Google Talk Contact Invisible?

Image
Is a Google Talk Contact Invisible? Sometimes error messages can reveal more than they were supposed to. Rahul Bansal writes about a simple trick that helps you find out if one of your Google Talk contacts is offline or uses the invisible mode. The trick takes advantage of Google's off the record feature which lets you chat with your contacts without saving the conversations in Gmail. "Chats that have been taken off the record aren't stored in your Gmail chat history, or in the Gmail chat history of your contact. You and the person you're talking to can both see when a chat is taken off the record, and you'll be notified if off the record mode is disabled. Your off the record settings will apply whenever you chat with this person, until one of you makes a change." Let's say you want to know if your co-worker Michael is really offline. If you start a chat when he is online and select "go off the record", none of your messages will be saved in Mi
Read more

How Web Works

Inside This Article 1. Introduction to How Web Servers Work 2.The Basic Process 3.Behind the Scenes 4.The Internet 5.Clients and Servers 6.IP Addresses 7.Domain Names 8.Name Servers 9.Ports 10.Protocols 11.Putting It All Together 12.Extras: Security 13.Extras: Dynamic Pages 14.Lots More Information 15.See all Internet articles Basic Process Your browser formed a connection to a Web server, requested a page and received it. Behind the Scenes If you want to get into a bit more detail on the process of getting a Web page onto your computer screen, here are the basic steps that occurred behind the scenes: • The browser broke the URL into three parts: 1. The protocol ("http") 2. The server name ("www.howstuffworks.com") 3. The file name ("web-server.htm") • The browser communicated with a name server to translate the server name "www.howstuffworks.com" into an IP Address, which it uses to connect to the server machine. • The browser then formed a conn
Read more