Forum Discussion
Albert_Coll
Cirrus
CirrusIrule to modify the VIP route advertisement setting upon pool down
Hi,
I have an Big-IP LTM in which I need to create a procedure to set a VIP "route advertisement" setting to "disabled" whenever a pool goes down. I think that this can be achieved by an iRule.
Does anyone have any example close to this? I think I got the first part of the irule identifying the pool going down:
when LB_FAILED { pool <pool name>
But I have trouble to properly finishing it by properly referencing the VIP and the "route advertisement" setting to modify it to "disabled"
Thank you in advance.
Albert.
What you could do is create a gateway monitor and give it an Alias Address of the gwy. Assign that to the pool as a second monitor that is the default pool of the virtual server the vip address is assigned to. That way, when the gwy fails, it marks the pool members down which in turn will retact the advertisment of the route.
How are your Route Advertisement settings configured? Depending on the how the Availability Calculation and Route Advertisement is set, when the pool has no available members the routes are retracted.
Albert_CollHi Jim,
Thank you for your post.The Big-IP LTM VM is integrated into the network through two Firewalls:
* There is a static default route pointing to a FW in a DMZ, which is the incoming interface of all user's traffic.
* There is another firewall on another interface, through which a BGP session is established to a PE located beyond it.
I redistribute the VIP to BGP to this PE through a redistribute kernel & a route map.Now, the network manager requests me to cease advertising the VIP through BGP as soon as the default route fails: I created a pool to properly monitor the default gateway, so that this pool gets down when the gwy stops replying icmps.
What I would need is to define some function (irule, iapp maybe) to disable the "route advertisement" flag when the pool gets down, or triggering some BGP reconfiguration to remove the VIP advertisement.
Regards.
Is the pool that monitors the GWY the default pool of the virtual server that is using the VIP that is being advertised? Also, is there a single or multiple pool members?
James9780Nimbostratus
The network manager requests me to cease advertising the VIP through BGP as soon as the default route fails: I created a pool to properly monitor the default gateway, so that this pool gets down when the gwy stops replying icmps. MyMileStoneCard
- Albert_Coll
Hi James,
Thank you for your post.From your answer I understand that using pools for purposes not related to Virtual Servers, like signaling the availability of external IP addresses to cooperate with routing protocols, is not the right way to use them.
In that case, I guess BFD should be the right tool to use.Regards.
Another way, you could write a custom script to monitor the LTM logs looking for the gwy pool to have no member available then run the TMSH commond to set the advertisment to disabled. Remember to also write a command to re-enable the advertisment when members become available.
