Track group of objects

Let’s say we want to configure a group of objects to track and if some or all objects are down then we will trigger a failover.

IP SLA and track object are both used frequently for FHRP monitoring; with IP SLA we can measure responsiveness of nodes in the network and if we can’t access them then we can trigger HSRP/VRRP failover to second member. 

So first let’s configure the IP SLA objects:

! ip sla 101  icmp-echo 208.67.222.222 source-interface gigabitEthernet 0/0  owner OPENDNS_SERVER  frequency 5  threshold 2000  timeout 4000  history buckets-kept 15 exit ! ip sla 102  icmp-echo 8.8.8.8 source-interface gigabitEthernet 0/0  owner GOOGLE_DNS_SERVER  frequency 5  threshold 2000  timeout 4000  history buckets-kept 15 exit ! ip sla 103  icmp-echo 8.8.4.4 source-interface gigabitEthernet 0/0  owner GOOGLE_DNS_SERVER  frequency 5  threshold 2000  timeout 4000  history buckets-kept 15 exit ! ip sla 104  icmp-echo 4.2.2.1 source-interface gigabitEthernet 0/0  owner LEVEL3_ANYCAST  frequency 5  threshold 2000  timeout 4000  history buckets-kept 15 exit ! ip sla schedule 101 start-time now life forever ip sla schedule 102 start-time now life forever ip sla schedule 103 start-time now life forever ip sla schedule 104 start-time now life forever !

Here I used OpenDNS and Google DNS servers and Level3 anycast IP’s.

Then configure track objects:

track 101 ip sla 101 track 102 ip sla 102 track 103 ip sla 103 track 104 ip sla 104 !

Each track object is linked to IP SLA object.

Then configure track group:

track 10 list boolean and  object 101  object 102  object 103  object 104 exit !

Here I used Boolean syntax with AND operator but we can also use OR operator or even change it to weighted threshold where each object has certain weight on the trigger decision.

And last link the track group to the FHRP monitoring:

interface Gi0/1 standby 1 ip 192.168.10.1 standby 1 preempt standby 1 priority 150 standby 1 track 10 decrement 100 !

In order to view the tracking group type:

show track

Here is a list of best tracking IP’s:

#Google DNS servers 8.8.8.8 8.8.4.4 #OpenDNS servers 208.67.222.222 208.67.220.220 #Level3 anycast 4.2.2.1 4.2.2.2 4.2.2.3