> igb0.2: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST>
metric 0 mtu 1500
> status: active
> vlan: 2 vlanpcp: 0 parent interface: igb0
> carp: BACKUP vhid 3 advbase 1 advskew 50
> groups: vlan
>
> That's two internal vlans and one external network. Each interface has
its
> own vhid since that's the advice I had in the past.
>
> Now, what command can I type that I could run remotely (SSH over the em0
> link) to force all the CARP addresses simultaneously to decrease the
advskew
> and become MASTER. Alternatively I could run something on the MASTER to
make
> it BACKUP. Everything I've done so far is one command per interface
which has
> got me in trouble before as I manage to accidentally remove my own access
to
> the box before I'm done.
You have to provide the correct subset of the parameters to change the behaviour
without changing the other properties.
# ifconfig igb0.2 vhid 3 advbase 1 advskew 250 pass 'xxxx'
This will change the parameters for the vhid 3 on the interface igb0.2 only.
But the change will cover *all* vhid parameters, so if you left some off, they
will vanish.
Of course, you are free to use multiple IPs per interface using the
"alias" option.
It does work even for carp instances.
VHIDs needs to be unique per layer2 segment, because they are used as selectors
for the kernel code to validate the CARP packet.
Please note, that VRRP/HSRP/GLBP may use the same packet format as CARP, so
their VHIDs should be different from yours.