Robots Do Not Show Up After Primary Hub Restart

[Marius Nitu]

Hi guys,

New environment with UIM version 23.4 CU2 installed during December. About 20 robots (both Linux and Windows servers) attached to the primary hub and a secondary hub with snmpcollector. One month later I restart the controller on the primary hub. Surprise: no robots show up anymore, except the secondary hub.

Telnet works both ways. Controller.log on the robots show:

Controller: failed to send alive (async) to hub PRI_HUB(x.x.x.x) - not found

Found an article that says that it could be because of too much memory usage on the primary hub. The actual usage is 20%.

Restarting the robots solves the issue. I am currently restarting the robots. Can't imagine what it would be like having this issue with thousands of robots.

Did this happen to you?

Marius

[Jason Allen]

Normally this should not occur, but I have seen this type of behavior occasionally. I am not sure why it occurs, but there seems to be an issue sometimes when the hub is reachable but the robots are not properly connecting to it on their own.

In such cases, instead of individually restarting each robot, the following often helps:

• stop the robot on the hub where these robots report to
• wait a full 5 minutes - not one second less (I usually wait 6 minutes just to be safe)
• start the robot again

When the hub is fully down and not responding whatsoever on the hub port for 5 minutes the robots will go into a sort of more aggressive reconnection mode and this will often help them to show up again once the hub comes back, without needing to restart each one.

[Marius Nitu]

Thanks, Jason!

I will try it the next time it happens.

Marius

[Sam Green]

Hey Jason,

I had this issue recently.  All probes had crashed over the weekend and filled the drives up with mdmp files.

After a clear down and restart only a small number of robots checked back in.  I found this post, shut down the primary for 6 minutes and fired it back up again.  All robots checked in again.

Very helpful post, thank you.

Cheers,

Sam

[Stephen Danseglio]

Hi Marius, Sam,

Agreed Sam, very helpful post by Jason!

As a result, I asked him to create a KB Article, so here it is: 

Robots do not show up after a hub restart

Best Regards,
Steve

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Steve Danseglio
Senior Principal Support Engineer (Technical Support Engineer 5)
Broadcom Software-IMS Division
UIM Certified Expert
KCSv6 Practices Certified
Certified Customer Success Manager (CCSM) Level 1
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