How to Properly disable Pool Members

[Cowboy Denny]

Differences between Force Offline vs Disabled

Force Offline

Forced Offline: Specifies that the node can handle only active connection.

That's means that F5 continues to manage connections already established only.

When set to Forced Offline, a node or pool member allows existing connections to time out, but no new connections are allowed.

tmsh modify /ltm node <node name> state user-down session user-disabled

 

Disabled

Disabled: Specifies that the node/pool member can handle only persistent or active connections.

That's means that F5 continues to manage connections already established and everything in the persistence table (or connection with right cookie persistence)

When set to Disabled, a node or pool member continues to process persistent and active connections. It can accept new connections only if the connections belong to an existing persistence session.

tmsh modify /ltm node <node name> session user-disabled

In both case F5 will remove the connections, but Force Offline is faster.  If the node is set to Disabled or Forced Offline, any pool member in the BIG-IP configuration that uses that same IP address is also set to Disabled or Forced Offline.

When you remove a pool member from a pool, the system immediately discontinues the pool member monitoring and removes existing persistence entries. This action does not disrupt existing established connections. They remain open until the client disconnects or the connection times out.

 

Delete existing connections to the Disabled or Forced Offline node (Optional)

If after disabling or forcing the node offline, you want to delete all connections to that node, perform the following procedure.

Impact of procedure: This command deletes all connections to the node's specific IP and every possible service port.

Note: Connections to nodes are on the server side (ss-server) of the BIG-IP connection. Connections to virtual servers are on the client side (cs-server) of the BIG-IP connection.

To delete all connections to the node, use the following command syntax:

tmsh delete /sys connection ss-server-addr <node IP address>