Archive for the ‘Load Balancing’ Category

Load balancing Windows Terminal Server – HAProxy and RDP Cookies

Tuesday, October 27th, 2009

When you have users depending on Windows Terminal Services for their main desktop, it’s a good idea to have more than one Terminal Server. RDP, however, is not an easy protocol to load balance; sessions are long-lived and need to be persistent to a particular server, and users may connect from different source addresses during one session.

The current development version of HAProxy has made an important step forward in making this possible. Thanks to work by Exceliance, it now supports RDP Cookies, offering a solution to the persistence problem.

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Loadbalancing FAQ (Frequently Asked Questions)

Saturday, October 3rd, 2009

This load balancing post is a little bit cheeky.. as its a bit of an experiment with catching Google’s eye on the net, the Loadbalancer.org site does pretty well for the search term “Load Balancer”… but sucks big time for the second most popular term “Load Balancing”… Now I noticed that Loadbalancing.net gets a first search page result with no virtually zero relevant content so the domain name must help a lot! (more…)

Transparent proxy of SSL traffic using Pound to HAProxy backend patch and howto

Monday, July 20th, 2009

OK so I’ve previously blogged about how to get TPROXY and HAProxy working nicely together. But what if you want to terminate SSL traffic on the load balancer in order to use HaProxy to insert cookies in the standard HTTP stream to the backend servers?

Many thanks to Krisztián Ivancsó  for working on the TPROXY patch for Pound for us, we can finally do this!

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Loadbalancer.org - Now in the Cloud

Friday, July 10th, 2009

Over the last few months we’d experienced two fairly lengthly outages on our web server. It was a dedicated server with a UK host and we’re not exactly sure of the reason for the downtime - could have been network failure, could have been the server crashing. It had become pretty annoying for us, and we realised that for a company touting the use of load balancers for High Availability, it is important that our own website should be up! Also, as Loadbalancer.org recieves traffic from every corner of the globe, we wanted to see what we could do to reduce latency to the farther-flung continents. (more…)

How to recover your load balancers to v6.6 via USB stick

Wednesday, May 13th, 2009

The following instructions detail how to recover any Loadbalancer.org appliance to v6.6 via any USB stick 1 Gb or greater.

NB. This will only work on 64Bit hardware. All version 6 appliances are 64Bit. If you are running an older version this may still be possible depending on the hardware you are running on. (more…)

How to upgrade VMware tools on ClusterLoad ESX or Loadbalancer.org VA

Wednesday, May 13th, 2009

VMware tools are based on  proprietary modules for the Linux Kernel and therefore need compiling from source to install.

NB. Unless you have a specific reason to upgrade the supplied tools don’t worry about it. Our appliances make heavy use of the 64Bit e1000 network driver which is part of the default kernel, the appliance doesn’t strictly need any of the extra VMware tool functionality.

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Loadbalancer.org guarantee 99.999% (5 nines) uptime to all of our customers.

Thursday, March 12th, 2009

Yeah right :-). Maybe after we sort out problems in our own back yard….

Our web server crashed again the other day (It last happened about 2 years ago). I was on holiday at the time and got an automated message saying “www.loadbalancer.org is toast!”.  I thought OK thats annoying but not the end of the world, but it was a Sunday afternoon and about an hour later I got a message from one of our support guys saying that they could not get through to the 24*7 support engineers to look into the server failure. Thats when I remembered that last time this happened I thought about setting up a mirror dedicated server to save downtime in the event of a re-build being required… oops didn’t do  that did I?

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Configure HAProxy with TPROXY kernel for full transparent proxy

Wednesday, February 11th, 2009

Standard Kernel builds don’t support TPROXY ( 2.6.28 does now!).
For example if you use HaProxy as the load balancer then all of the backend servers see the traffic coming from the IP address of the load balancer. TPROXY allows you to make sure the backend servers see the true client IP address in the logs.

Ps. An easier alternative is inserting the clients ip in the x-forwarded-for header (option forwardfor).

For TPROXY to work you need three things:

1) TPROXY compiled into the linux kernel
2) TPROXY / Socket compiled into netfilter / iptables (due in v1.4.3?)
3) HaProxy compiled with the USE_LINUX_TPROXY option

The TPROXY patch for Linux Kernel 2.6.25.11 is here:
http://www.balabit.com/downloads/files/tproxy/tproxy-kernel-2.6.25-20080519-165031-1211208631.tar.bz2

The following is a guide how to install on Centos 5.1:
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Don’t blame the load balancer if your bank fails!

Friday, October 10th, 2008

I know the world is falling apart with the credit crunch and all that, but please don’t call the load balancer vendor when your internet bank falls over. We’ve had a couple of messages similar to the following:

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Customers results…

Tuesday, September 16th, 2008

Recently I was asked by a customer for an R16 evaluation unit. After dispatching the unit it appeared the R16 would be in good company, namely; Citrix, F5, Jetnexus and CIA. The customer was evaluating a unit from all the above manufactures. Win or lose I felt this would be an interesting independent test of the R16 against some well know names………

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