After cBR reload SmartPHY started multiple SSH sessions and locked me out of the box:

[yuanliu2]

Hi, Expers

   We met a issue that NSO started multiple SSH sessions and locked me out of the box after cBR reload:

1. SVS.RPCC01#show users

    Line       User       Host(s)              Idle       Location

*  0 con 0     cisco      idle                 00:00:00

   2 vty 0     sereno     idle                 00:01:48 9.13.100.89

   3 vty 1     sereno     idle                 00:01:42 9.13.100.89

   4 vty 2     epnm       idle                 00:00:31 9.13.100.231

   5 vty 3     sereno     idle                 00:01:33 9.13.100.89

   6 vty 4     sereno     idle                 00:01:53 9.13.100.89

   7 vty 5     sereno     idle                 00:01:47 9.13.100.89

   8 vty 6     sereno     idle                 00:01:35 9.13.100.89

   9 vty 7     sereno     idle                 00:01:30 9.13.100.89

  10 vty 8     sereno     idle                 00:01:24 9.13.100.89

  11 vty 9     sereno     idle                 00:01:18 9.13.100.89

  12 vty 10    sereno     idle                 00:01:12 9.13.100.89

  13 vty 11    sereno     idle                 00:01:06 9.13.100.89

  14 vty 12    sereno     idle                 00:00:59 9.13.100.89

  15 vty 13    sereno     idle                 00:00:53 9.13.100.89

  17 vty 15    epnm       idle                 00:00:09 9.13.100.231

These were the commands it was executing:

[ CmdAV=show configuration id  ]

[ CmdAV=show configuration id  ]

[ CmdAV=show version  ]

[ CmdAV=terminal width 0  ]

[ CmdAV=terminal length 0  ]

Most of the sessions were terminated soon after; but this shouldn’t happen. 

[haofan]

I  also hit this issue, whether have experts know why ?

[vleijon]

There are some settings under devices device X session-pool that might be of interest, they allow you to limit the maximum number of sessions NSO will open towards a device.

[haofan]

Hi Viktor,

Thanks for info. Two questions.

1. why NSO will connect device by multi sessions. Based on my idea, only need one ssh session connect to device.
2. what is default value of max-sessions and idle time ?

admin@ncs# show running-config devices device e8ba21ae-a0c8-344e-af08-32ec1dc79be8 session-pool max-sessions

% No entries found.

admin@ncs# show running-config devices device e8ba21ae-a0c8-344e-af08-32ec1dc79be8 session-pool idle-time

% No entries found.

[vleijon]

Hi Hao Fan.

You can read more about session pooling in the user guide (Chapter: "Device Session Pooling").

1. There are several potential reasons, one reason is because you might be reading operational data, or you might be executing commands towards the device. NSO tries to run things in parallel towards the device where possible.

2. The default is unlimited (but the total pool is limited to 200 spread over all devices). You can control it either per device or globally under devices global-settings session-pool

[haofan]

Thanks viktor, I will read more about "Device Session Pooling".

[yuanliu2]

Thanks viktor very much