iRule to check if pool member is unavailable.

As far as I can tell, that article only applies when you have manually disabled pool members that would otherwise be online. (Pool member status shows a black circle and mouseover text "Available (Disabled) - Pool member is available, user disabled")

This then also results in the virtual server status with a gray circle "Available (Disabled Parent) - The children pool member(s) might be disabled"

In any scenario where a health check automatically marks all pool members down, the pool members go into status offline, the vserver status also switches to offline and the above iRule works perfectly fine. At least for me, with version 14.

Which by the way also opens up a simple, if not very elegant, workaround: Instead of manually disabling the entire pool, just attach a monitor with an impossible condition to mark all members offline.

If there are any scenarios where what I wrote is not correct, I'd really like to know, because that could certainly come to bite me in my backside.