IOS-XR commit confirm command and how to 'resume' vty session

[Benjamin Bartsch]

I've run into this problem a few times and can't seem to find how to resolve it.  The scenario is this - I connect to an ASR9k via SSH and make a change then use 'commit confirm' to test.  The change causes me to lose my SSH connection.  I can connect via SSH again after the change, but now I'm in a different session with the same username.  I'd like to be able to resume my original SSH session and commit my changes.  Today, I have to wait for the commit confirm to rollback, then make my changes again using commit instead of commit confirm.

For example - we want to move our management interface to an out-of-band VRF:

RP/0/RSP0/CPU0:ASR9K-2(config)#interface MgmtEth0/RSP0/CPU0/0
RP/0/RSP0/CPU0:ASR9K-2(config-if)#no ipv4 address 172.17.80.177 255.255.255.0
RP/0/RSP0/CPU0:ASR9K-2(config-if)#vrf MGMT
RP/0/RSP0/CPU0:ASR9K-2(config-if)#ipv4 address 172.17.80.177 255.255.255.0
RP/0/RSP0/CPU0:ASR9K-2(config-if)#commit confirm

I then lose my SSH connection, but I can re-establish a new one:

RP/0/RSP0/CPU0:ASR9K-2#sh users
Mon Mar  9 04:09:45.072 EDT
   Line            User                 Service  Conns   Idle        Location
   vty0            admin                ssh          0  00:03:33     172.20.200.210
*  vty1            admin                ssh          0  00:00:00     172.20.200.210

I can't seem to resume any sessions or use key combos like ctrl-shift-6 x

RP/0/RSP0/CPU0:ASR9K-2#resume 
% No open connections

All I can do is wait for the commit confirm to rollback, make may changes again, then do a commit.  It's not too bad doing it this way, but I would like to be able to commit my changes right away if they are correct instead of waiting.

[Benjamin Bartsch]

Crickets and tumbleweeds in here...

Anybody got anything for me?

[DIEGO ZORRILLA · Accepted solution]

Hi Benjamin,

What Version are you running? Does this happen also with Telnet insted of SSH?

[xthuijs · Accepted solution]

yeah that is the nature of commit confirm, so that if you get disconnected the config will rollback,allowing the confirm from a different session may beat that purpose.

so today there is no option to send a signal to the dangling vty session and you would need to wait for the rollback to happen.

cheers

xander

[Benjamin Bartsch]

Thanks, Xander.  We can live with this.  The upside is that commit confirm does what it's supposed to do and we can get back in if we make a mistake and have to rollback automatically.

[xthuijs]

ok cool thanks for the confirmation Ben!

the config action you have there will indeed destroy the tty because the mgmt interface has its ip removed, hence all sockets are closed. so this change is best not done with a commit confirmed if you are connecting through that interface.

cheers!

xander