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We have a number of sites in a number of environments. Many of the environments are load balanced with two web servers (and in some cases two app servers). Twice in the past two months we've run into a situation in which a server was inadvertently taken out of the load balancer. This bit us a few days later when the second server was taken out and the site went down completely. In both cases the problem was discovered and corrected quickly, but it leads me to believe that we need an alert when a server is out of the load balancer. Our normal alerts don't work here because in both cases the website on the server was up and responding, it just wasn't in the LB.

It might be possible to set up alerts on the load balancer itself, but they are managed by our hosting provider and dealing with them can be a pain.

My thought is to have an app that scans the server logs every 15 minutes and sends an email when the number of unique visitors per hour drops below a certain threshold. Doesn't sound terribly difficult to write, but seems like there may already be a standard 3rd party tool that already does something along these lines.

We use Windows, ASP.NET, IIS, if that matters.

Recommendation for a tool that alerts when a website is not getting hits?

  • Can your load balancer forward certain urls to a specific server? Rather than always balancing. If so just have two urls, one that points to each upstream server and then use your current normal alerts – Drifter104 Dec 29 '16 at 14:14
  • What kind of load balancer are you using? – Anthony Fornito Dec 29 '16 at 15:01
  • @AnthonyFornito I believe they are all Brocade ADX – mhenry1384 Dec 29 '16 at 15:43
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Check out this link

http://rtomaszewski.blogspot.com/2013/07/default-adx-brocade-health-settings.html

I am more familiar with F5 terminology, what you are looking for is to create an irule, im not sure what Brocade calls them.

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We ended up using Splunk. We have an alert that scans the IIS logs and checks the number of requests on each server separately. If the number of requests drops below a certain threshold, it emails an alert.

Another possibility is to set up a rule on the Brocade that if an HTTP request has a particular header, e.g., ForceServer = PROD1, then always send that request to a particular server. That works if your web monitor supports sending custom HTTP headers. AlertSite, which we use, does if you use their API monitor.

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