Cisco Embedded Event Manager Applets

Embedded event manager is a feature incorporated into most new cisco equipment. You can find more information on the Cisco site and some excellent examples at the IOSHINTS blog.

This applet is used to add/delete static arp entries on 6509 core switches in a HSRP pairing, since you can’t have a static arp configured more than once on the HSRP cluster.  The mac address is a multicast mac address of a windows network load balanced server.

Listing 1

event manager applet deletearpvlan234
event syslog occurs 1 pattern "%HSRP-5-STATECHANGE: Vlan234 Grp 1 state Speak -> Standby"
action 0.0 cli command "enable"
action 1.0 cli command "configure terminal"
action 2.0 cli command "no arp vrf SERVERS 192.168.1.100 0100.5e7f.00ac ARPA"
action 4.0 syslog msg "EEM deleted arp entry for 192.168.1.100"

event manager applet addarpvlan234
event syslog occurs 1 pattern "%HSRP-5-STATECHANGE: Vlan234 Grp 1 state Standby -> Active"
action 0.0 cli command "enable"
action 1.0 cli command "configure terminal"
action 2.0 cli command "arp vrf SERVERS 192.168.1.100 0100.5e7f.00ac ARPA"
action 4.0 syslog msg "EEM added arp entry for 192.168.1.100"