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Community Member

CSS - source based stickyness

hello everyone

Has anyonef faced this before in the below situation

webserver 1  and webserver 2 are front end webservers. A CSS is connected behind these 2 servers.

Then there are 2 backend webservers , say websrv 3 and 4 loadbalanced by the css

the requirment is webserver 1 and 2 looks for a url with say /abc, that requests hit LB vip and then LB load balances between websrv3  and 4

everything works as expected. but when webserv3 is brought down, css confirms the service is down but then webserver 1 and 2 cant access the /abc

they get error connection refused.

within the content rule src based stickyness is configured.

we brought the websrv 3 and everythign works. we then restarted the all 4 websevers, then websrv 4 was brought down. same issue again

question is

css confirms that a server has gone down , but both webserver1 and 2 cant access the url /abc

is there any problem with src based stickyness

it can be the way application is design, some problem within thier code but we want to verify if css is causing it

didnt get chance to sniff and check , but can you suggest if there are any known or potential issue with stickyness in this case

Cisco Employee

Re: CSS - source based stickyness

Do you configure 'no persistent' on content rule and 'persistent reset remap' on global mode?

If new http request uses existing connection, it will be forwarded to same server even if it goes down

since CSS enables persistent command.

If new connection is established and CSS receives new request, it will load balance and never send

to failed server.

At first, please check existing connection is used or new connection is established.

Since sticky entry is purged when service goes down, I guess sticky configuration is not affected.

Regarding sticky issue, following commands are useful.

# show sticky-stats

# show sticky-table l3-sticky

I'm not sure about your application design. If your application wants to receive RST from CSS to purge

connection when server goes down, 'flow-reset-reject' command may useful.



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