Forum Discussion
pj_109705
Nimbostratus
NimbostratusN:N loadbalancing and failure recovery
We have 3 devices and 3 servers where each Device maintains 1 TCP conn with a Server.
We need to setup Irule to maintain following failback:
- each Device needs to be connected to separate server if all 3 servers are healthy
- if 1 server fails, particular device will be reconnected to another server so that server will handle 2 TCP connections
- after failed server comes back, we need to resume 1:1 situation
This would require to track the healh status of each server and kill the recently relocated connection so the device reinitiates new connection and 1:1 state is reestablished.
thank you
8 Replies
pj_109705Can you please help to see which functions could be used to achieve the above?
thank you- nitass
Employee
- each Device needs to be connected to separate server if all 3 servers are healthy
- if 1 server fails, particular device will be reconnected to another server so that server will handle 2 TCP connectionsi am thinking to use table and node command i.e. recording client and server mapping in table and using node command to direct traffic to specific server.
table
https://devcentral.f5.com/wiki/irules.table.ashx
node
https://devcentral.f5.com/wiki/iRules.node.ashx
- after failed server comes back, we need to resume 1:1 situationmay we delete existing connection when server comes back?
Acton on Log - using the alertd deamon
https://devcentral.f5.com/wiki/advdesignconfig.Acton-on-Log-using-the-alertd-deamon.ashx 
What_Lies_Bene1Cirrostratus
pj, is this authorisation traffic?
Nitass, could we not use the CLIENT_DATA event and your table and node suggestion to select each time data is received. If this is (card/payment) authorisation traffic I expect everything for a transaction to be contained in one packet.- pj_109705H Steve, thi is BCAAA trafic between bluecoat proxy and bcaaa server forwarding NTLM auth requests to DC.
- pj_109705Hi Nittas,
yes we need to delete existing conn after server comes back.
thanks - What_Lies_Bene1OK, so single, long lived connections between one proxy and one server (x3)? No persistence configured?
- pj_109705indeed, no persistence needed since it is only 1 pernament conn per proxy
- What_Lies_Bene1OK, thanks for the info. I was considering something funky with timeouts and/or priority group activation but after some thought an iRule is probably the best way to go. I'm hoping Nitass will post an example shortly.
