Sticky sessions in vShield Edge Gateway Load Balancer

One of the features of edge gateways in VMware vCloud Director is the capability of implementing load balancer for HTTP, HTTPS and TCP-based applications in a virtual data center. For web applications (in specific HTTP), session management is an important matter. If web developers don’t implement session management in application level (using database, … to store sessions) and rely on Cookies, load balancer could be an issue. In these cases, network administrators are asked to configure load balancer with sticky session. Simply it means that if a client is forwarded to a web server for the first time (especially login page), it should stick to that specific server in later web requests. If it doesn’t happen, user may be forced to login again that would be frustrating!

By the way, when it comes to configuring vShield Edge Gateway to do load balancing, there is no obvious option to choose Sticky Session but it’s possible to do this by specifying proper value for Cookie name in the Virtual Server. As it’s shown in the picture, the procedure is as follows. I assume that you already know how to implement Load Balancer by creating Pool Servers and Virtual Server. See this link fore more information on how to create Load Balancer.

 

lb_vcns

  1. Right Click on the Edge Gateway and choose ‘Configure Services’
  2. Select ‘Load Balancer’ tab
  3. Go to ‘Virtual Servers’ section
  4. Edit selected Virtual Server
  5. Choose ‘Cookie’ as Persistence Method instead of default ‘None’
  6. Type proper value as Cookie Name; i.e, ‘ASP.NET_SessionId’ for .NET application, ‘PHPSESSID’ for PHP, … (ask your developer)

Software Defined Networking

Last week I attended a seminar about SDN (Software Defined Networking) and SDDC (Software Defined Data Center) and I met some high profile people from high profile companies. It seems this topic will be hot in coming years and many manufacturers and providers are coming in to this road. The good news is that there are some standards like OpenFlow managed and maintained by Open Networking Foundation (ONF) and OpenStack that will help in orchestration and inter-operatability to the benefit of customers.
Although, there are some different ideas about the approaches to SDN; for example VMware likes to implement SDN in an all-software solution (NSX) , while Cisco (and other device manufacturers) apparently prefers hardware implemented devices which support SDN. For this latter one, imagine that you have a SDN-enabled switch with some API’s that you can program it to perform in your desired way. That’s cool! Maybe, somethings like load balancing or geofencing can be implemented on the fly by using these APIs in a networking appliance!
For someone with hardware background like myself, this hardware approach seems more attractive and I’m thrilled how it goes. As a matter of fact, a while ago I was thinking: if we can have a tiny device doing a lot of things that can be programmed by developers (I meant Smartphone), why we don’t do the same with more advanced equipments like networking devices?  And now it’s coming to the reality! Smart switch or router! combining them with Virtualization and Cloud and on-demand services, customers can implement interesting functionalities which are more cost effective and agile. HP networking was talking about HP SDN App Store! You see! I’m not an advocate of HP but as a result of this, maybe we see a revolution in networking area!

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