A very very newbie question about CSS

[haopang75]

Hi, All,

I'm software engineer and has no idea about CSS.

In one of our project, the hardware guys use CSS 115xxx to load balancing some of our servers for HTTP request(not web request). The servers will shut down one by one each hour to do some maint jobs. The LBer can detect it and forward request to active servers. Because the LBer's min refresh interval is 2 seconds, we still got a lot of bad request because of this 2 seconds problem, LBer still forward a lot of request to the server already shut down.

My question is, first, is their any way to send a command/script outside the LBer and deactive one service, after the server restarted, send another command/script to LBer to active the service again. We have a control server to start/stop each server one by one and we can build a program to do complex communication requests from control server to LBer.

If this is impossible, can LBer detect the server before forwarding the request and send to others if failed?

Much much thanks and our hardware guys said it's impossible to avoid the 2 seconds thing.

haohao

[jphilope]

It should be possible within the CSS itself to initiate a script to suspend a service at a given time. You could suspend the corresponding service a minute or so before your maintenance script runs on given server. This would take that server out of the pool fo servers for load balancing.

If both the server and the CSS were utilizing NTP for date/time setting from the same source, the clock would (should) remain syncronized and timing would (should) not drift too far apart.

Creat a CSS script to suspend the service and the "cmd-sched' command in the CSS to tell it when to run.

Don't forget another script/cmd-sched to activate the service when the maintenance window is over.

Make sure your hardware guys understand these are the services on the CSS you are talking about, not a server service.

[haopang75]

So no way to send something to disable one service outside the CSS? The down time for each server is 15 seconds and it's changed every time. We know it will happened in, for example, 10 minutes period, but don't know what exactly the time for each server.

You reply still give us a good idea, maybe we can split to 2 server farms, group A and group B. We update these two groups one by one and use a script in CSS to switch the services between these two groups. That cost more hardware but only required a little script job on CSS.

[Gilles Dufour]

the css can be configured by XML.

So, you could send an XML request with a command to disable a particular service and re-enable it once the operation is done.

Here is a link to some examples

http://www.cisco.com/en/US/products/hw/contnetw/ps792/products_tech_note09186a0080094009.shtml

Regards,

Gilles.

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