Citrix Netscaler NS7000 : how to create a content switched load balanced farm/service (Part II)

In the previous part of this article, how to create a load balance virtual server (or 'lb vserver' using CLI) was described. Now we'll describe how to create content switching. Currently, as of Netscaler 7.0 beta, Citrix Netscaler supports only HTTP protocol for content switching.

Again, the logical, conceptual flow is clear and intuitive. However, the work flow is less so, the same as any object-oriented model applied to a more procedural mind-set or work flow.

In Citrix Netscaler's terminology, you need to create

• a Content Switching (CS) policy. The policy basics states a matching rule set that the HTTP request object must comply. Three basic

• domain, aka, URI
• URL
• any other request attributes/headers using regular expression or absolute matching.
  

• create a CS virtual server to direct traffic regulated by this policy to go to either individual service or a load balancing virtual server.
• a default mapping is allowed. The policy field would be 'blank'. It'd make more sense to actually call it 'Default' and displays it as such. This basically directs all traffic that fails to satisfy all the policy-vserser mapping to a default LB virtual server.
  

• Regular Expression can be created on the fly under the 'policy' node, or pre-created with a name from under 'System' node.
  

Redhat/Intel breakfast : Linux para-virtualization on Intel dual core processor

This past Tuesday, I attended the breakfast seminar series of Linux Virtualization and Dual Core processors at Westin near I-285 and peachtree-dunwoody interaction. Once the Westin waitress followed me into the breakfast area and lifted several party tray covers, I instantly understood why the invitation email said 'hot breakfast'. The breakfast consists of hot scrambled eggs, steamed sausages, fried bacon, oven-warm bread, pancakes, and ice-chilled fresh orange juice. "Nice", many said.

Ken from WorldSpan sat next to me. He's a programmer turned systems administrator. He told me that the WorldSpan building at I-75 and I-285 I drive by everyday is the headquarters. Its data center is down at the airport and it used to be part of Delta. They have mostly mainframes with code written in the '60s, a few Solaris servers, and a few Linux servers.

The Intel speaker is OK. A few points I take home are:

* AMD has a very very small footprint in terms of market share. Based on the noise it generates in the media, I thought it is making strides.

* Intel's dual Core processors will come hard and heavy to the market in the coming
years.

* Intel led AMD in 20 of the 22 industry benchmark results.

Andy from Redhat presents the Xen in Fedora Core 5 (and the coming
RHEL 5, beta1 at the end of August). A charming Brit. Xen basically
allows Para-Virtualization, with which the guest OS is aware of the
fact that it is a guest and its kernel is also modified to expedite
its access to raw hardware, esp. CPU/memory. One thing it doesn't do
is the bandwidth allocation for guests.
Two cool features I like about Zen (or enhanced feature available via
RHN, Redhat Network, subscriptions) are:
* snapshot of a guest. such a snapshot can then be used to restore or replicate
* a guest can be migrated, alive, to another physical host, with
minimal downtime appreciable to the end users.

I got a FC5 DVD (good thing I didn't start my download a few days ago)
from a pile Andy put out. Ken and I recalled the fact that we used the
3.5" floppy diskettes to install Debian 0.92 in '96 onto a 486dx.