F5 force connection reset on pool member

There is no built-in function to delete active connections to a pool member; disabling a pool member keeps new connections from being load-balanced to a pool member, setting a pool member to forced offline will stop persistence from being honored, but to end an active connection, the general advice is to go to the connection table and delete the connection there.

You could create the functionality you are looking for (where connections to the secondary instance are reset as soon as the primary node is available) by doing the following:

• Change the 'action on service down' setting on your virtual server to 'reject'
• Create a monitor that checks the primary node status, but use the 'reverse' option, which means that the monitor is successful when the primary node is -down- and set the alias address to the IP address of the primary node
• Apply the monitor you just created directly to the secondary node.

When your primary node goes down, the secondary node comes up, new connections get load-balanced to the secondary node. When the primary node comes back up, the reverse logic of the monitor will force the secondary node offline, and the action on service down reject behavior should reset the client connection, forcing the client to make a new connection, which will be load-balanced to the primary node.