By default with VRRP in Junos, a device with higher priority takes “preemption” and becomes master. When preemption is not preferred, an option “no-preempt” could be added into the configuration. This article describes the VRRP state change when this option is added and committed.
After adding the “no-preempt” option and committing, the device`s VRRP state becomes Backup.
Is this expected?
# Before adding “no-premept”
root@SRX210-A# show | display set | grep vrrp
set interfaces ge-0/0/0 unit 0 family inet address 10.0.1.2/24 vrrp-group 0 virtual-address 10.0.1.1
set interfaces ge-0/0/0 unit 0 family inet address 10.0.1.2/24 vrrp-group 0 priority 110
set interfaces ge-0/0/0 unit 0 family inet address 10.0.1.2/24 vrrp-group 0 accept-data
set interfaces ge-0/0/0 unit 0 family inet address 10.0.1.2/24 vrrp-group 0 track interface ge-0/0/0.0 priority-cost 50
root@SRX210-B# show | display set | grep vrrp
set interfaces ge-0/0/0 unit 0 family inet address 10.0.1.3/24 vrrp-group 0 virtual-address 10.0.1.1
set interfaces ge-0/0/0 unit 0 family inet address 10.0.1.3/24 vrrp-group 0 priority 100
set interfaces ge-0/0/0 unit 0 family inet address 10.0.1.3/24 vrrp-group 0 accept-data
set interfaces ge-0/0/0 unit 0 family inet address 10.0.1.3/24 vrrp-group 0 track interface ge-0/0/0.0 priority-cost 50
root@SRX210-A# run show vrrp
Interface State Group VR state VR Mode Timer Type Address
ge-0/0/0.0 up 0 master Active A 0.442 lcl 10.0.1.2
vip 10.0.1.1
# Adding “no-preempt” on SRX210-A
root@SRX210-A# set interfaces ge-0/0/0 unit 0 family inet address 10.0.1.2/24 vrrp-group 0 no-preempt root@SRX210-A# commit commit complete
# After commit
root@SRX210-A# show | display set | grep vrrp
set interfaces ge-0/0/0 unit 0 family inet address 10.0.1.2/24 vrrp-group 0 virtual-address 10.0.1.1
set interfaces ge-0/0/0 unit 0 family inet address 10.0.1.2/24 vrrp-group 0 priority 110
set interfaces ge-0/0/0 unit 0 family inet address 10.0.1.2/24 vrrp-group 0 no-preempt <<<<<< "no-preempt" is added
set interfaces ge-0/0/0 unit 0 family inet address 10.0.1.2/24 vrrp-group 0 accept-data
set interfaces ge-0/0/0 unit 0 family inet address 10.0.1.2/24 vrrp-group 0 track interface ge-0/0/0.0 priority-cost 50
root@SRX210-B# show | display set | grep vrrp
set interfaces ge-0/0/0 unit 0 family inet address 10.0.1.3/24 vrrp-group 0 virtual-address 10.0.1.1
set interfaces ge-0/0/0 unit 0 family inet address 10.0.1.3/24 vrrp-group 0 priority 100
set interfaces ge-0/0/0 unit 0 family inet address 10.0.1.3/24 vrrp-group 0 accept-data
set interfaces ge-0/0/0 unit 0 family inet address 10.0.1.3/24 vrrp-group 0 track interface ge-0/0/0.0 priority-cost 50
root@SRX210-A# run show vrrp
Interface State Group VR state VR Mode Timer Type Address
ge-0/0/0.0 up 0 backup Active D 2.833 lcl 10.0.1.2
vip 10.0.1.1
mas 10.0.1.3 <<<<<< The SRX210-B becomes master
This is expected behavior per current design.
Currently, there is no plan to change this behavior.
However, after configured, the no-preempt option does work as-expected:
http://www.juniper.net/techpubs/en_US/junos/topics/reference/configuration-statement/preempt-edit-interfaces-vrrp.html
When no-preempt is configured, the backup router cannot preempt the master router even if the backup router has a higher priority.