Two separate HSRP groups on a single SVI with different subnets?

[Xabi]

I have a question regarding HSRP configuration. I want to know if it’s possible to configure two separate HSRP groups on a single SVI, where each HSRP group uses a different subnet.

The goal is to provide gateway redundancy for two different subnets using the same VLAN interface.Is this configuration supported by Cisco, and if so, are there any best practices or limitations I should be aware of?

interface Vlan999
ip address 192.168.1.2 255.255.255.0
standby 1 ip 192.168.1.1

ip address 192.168.2.2 255.255.255.0 secondary
standby 2 ip 192.168.2.1

[Ben Weber]

Hey Xabi

This is definitely possible and is a common way to enable FHRP in your scenario (multiple subnets going through a single SVI).

Check these out for further guidance: Solved: HSRP and multiple Subnets in VLAN - Cisco Community

HSRP two groups for one interface

FHRP - HSRP Multiple Group Optimization

[Joseph W. Doherty]

As already noted by @Ben Weber, yes it's possible.

There's also an "secondary" keyword option for the standby # IP statement, but unclear when it's needed and/or required.

As to practices or limitations, using secondary IPs, can bump into a few considerations.  For example, hosts using DHCP, by default (recall [???] there's some option to support DHCP on secondary IP subnets), will only pull IPs from the primary IP's subnet.  Router protocols (all/some?) will only use the primary IP's subnet to communicate with neighbors/peers, although secondaries can be routable.

Usually (best practice?) might be to avoid using secondaries.  Most common usage for them, appears to be transitioning a set of hosts, on a L2 domain from one subnet to another.  I.e. secondary usage removed after all hosts reconfigured to be on replacement subnet.