Log number of times web page contains specific content?

1) How can we log the number of times this happens?

 

 

 

You can query the HTTP::payload in your HTTP_RESPONSE event and search for this string of characters. Then, simply by using the log command you can log a message to the system log. This won't keep a count for you, but it will give you a timestamp for each occurrence and from that you could build a rate calculation by pulling out all the entries.

 

 

If you just want a raw count (and you are above v9.2), you can use the Statistics Profile to store values from within iRules. See this tech tip on how to do it

 

 

http://devcentral.f5.com/Default.aspx?tabid=63&articleType=ArticleView&articleId=66

 

Click here

 

 

 

2) How can we select another node when this happens (other than utilizing a monitor)? My thinking is that if we examine the content and find this string (which is the sole content of a page when the restart occurs) we should be able to select another node instantaneously.

 

 

 

For this you'll have to search the HTTP::payload from the HTTP_RESPONSE event and if you find this condition, you can use LB::reselect along with the HTTP::retry command to retry the request to another backend resource. Here's a post that goes over the LB::reselect command:

 

 

http://devcentral.f5.com/default.aspx?tabid=53&view=topic&forumid=5&postid=5201

 

Click here

 

 

 

Hope this helps...

 

 

-Joe

Since LB::reselect cannot be used in an HTTP:RESPONSE event, can you provide guidance on how to invoke it?

The example shows the LB::reselect called in a when LB_SELECTED event in the same iRule. You will enter the LB_SELECTED event when you hit the HTTP::retry.