CARP is not enabled by default

• Temporarily load the CARP kernel module

kldload carp

• Then restart network services

service netif restart
service routing restart

• Verify CARP election

router-003 should be the master for Public network and router-002 the backup (it is the case)

• Analyze of the CARP advertisements with tcpdump

add here : https://agora.nasqueron.org/Protocol_CARP

• And if everything works, we can add on the file /boot/loader.conf : carp_load="YES"

like this if we turn off the routers and restart the machines, CARP will be enabled

• Verify CARP election

Analysis : router-003 is the master for Public network and router-002 is the backup

• Test the failure of the Master and the recovery of the role Master

Analysis: router-003 does not regain the master role...

• So we need to enable CARP preemption

Analysis: router-003 does now regain the master role...

• Automate CARP activation and parameter preemption (D4006)

• Deploy with Salt and check the CARP system's operation

commands :

1. salt 'node' state.apply roles/router test=True
2. salt 'node' state.apply roles/router
3. salt 'node' state.apply roles/core/sysctl test=True
4. salt 'node' state.apply roles/core/sysctl

Final analysis :

1. CARP is automatically activated.
2. Router-003 is the Master and router-002 the Backup, even when router-002 is started beforehand, thanks to preemption.
3. If router-003 becomes unavailable, it becomes the Backup, but if it returns to the network, it resumes its role as Master because preemption is automatically activated.