Tag: ADC

Citrix ADC, Developer monitor

Again, by a customer I was asked to deliver a solution to there Citrix ADC. The customer has a web server farm which is controlled and maintained by their web developers. There needed their web developers to control witch servers where active in the farm and witch there where in maintains mode.

The easy way is to create a login for the web developers for the Citrix ADC, but there where other system load balanced through the Citrix ADC, and the web developers may not change the configuration for the other systems. We could have created a partition on the Citrix ADC, but I came up with a custom monitor solution. The web developers agreed to put a file on the web servers, and I created a monitor the checked for the content of that file.

GUI:

CLI:

add lb monitor lb_mon_www HTTP-ECV -send "GET https://www.domain.dk/nodestatus.txt" -recv online -LRTM DISABLED -secure YES

If the “nodstatus.txt” return online, the monitor detects the web server as “up” and the load balancing will send traffic to the web server. If anything, else than online is received the monitor will set the web server as “down” and no traffic will be sent to it.

The web developers control the content of the nodestatus.txt file, and in that way, they can control which web servers receive request and which is not, and the developers have no login/access to the Citrix ADC.

Citrix ADC 12.1 (NetScaler ADC), New licensing

Expiration:

 

With the new version 12.1 Build 48.13, Citrix added information about license expiration date. This is nice when running a Trial or Demo license:

With that they added another change, if care reading their documentation:

From https://docs.citrix.com/en-us/netscaler/12-1/licensing/netscaler-licensing-overview.html:

“Upon license expiration, the Citrix ADC appliance automatically restarts to revoke the license. If Citrix ADC appliance uses Citrix service provider (CSP) licenses, the appliance does not restart automatically to revoke the license. However, if the user restarts the appliance, it restarts as unlicensed.”

And trust me it will restart the NetScaler. As a consultant I offend use Trial versions for PoC. There where no problems in running beyond the expiration date if you did not restart the NetScaler. This is over now.

 

Express vs. Freemium:

 

Some time a go the Express version was replaced with the Freemium license. The Express license need to be updated every year because of the 1-year expiration. The Freemium have no expiration date, but it has not the Access Gateway feature.

This is a problem as the Express version was for very small customers with a replace for their old Citrix Secure Gateway (Yes, I am that old and have done a lot of installations of the Citrix Secure Gateway). So, what to customers running the Express version then do?

If we look at https://support.citrix.com/article/CTX121291 we find the answer:

Just update the NetScaler, and you will end up with an Express version with no expiration:

This must be done before the expiration of the old Express license, because if you restart the NetScaler with an expired license all features are disabled.

 

Conclusion:

 

Changes are made, so read the documentation. Get out there and upgrade the Express installations to version 12.1.

 

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