'wait-for-lock' by config or ncs.conf

[Koji Yokoe]

Hi. I want an advice from someone who are familiar with 'wait-for-lock' which has been implemented since NSO 4.4.2 as follows.

- ncs: 'sync-from'/'sync-to'/'check-sync'/'partial-sync-from' actions now
have a 'wait-for-lock' parameter that can be used to specify a timeout
that the action waits until the device lock is released and any commit
queue items that contain the device are done. If the 'wait-for-lock'
parameter is not specified, the action will fail immediately for the
device if the lock is taken for the device or if the device is placed
in the commit queue.

A commit now use the /devices/global-settings/commit-retries to wait
for any device lock to be released.

(Issue tracker: #27591)

When compare-config and sync-to are executed almost at the same time (compare-config first, sync-to second), sync-to fails as follows because device is locked in a compare-config-operation.

# devices device R1 sync-to
result false
info R1: Device is locked in a compare-config operation by session 328060

This can be solved by adding 'wait-for-lock' option as follows.

# devices device R1 sync-to wait-for-lock { timeout 60 }
# (Success after waiting for device unlocked)

I was expecting this is also achieved by /devices/global-settings/commit-retries setting because above statement says so.

(config)# devices global-settings commit-retries timeout 60
(config)# commit
Commit complete.

But it doesn't work as follows.

# devices device R1 sync-to
result false
info R1: Device is locked in a compare-config operation by session 328630

Is it any way to achieve it by config or ncs.conf setting?

[gmuloche · Accepted solution]

According to the YANG model in my NSO 5.2.0.3 install for devices you can configure it at the global-settings level:

  revision 2019-04-09 {
    description
      "Released as part of NCS-5.1.
       ...
       Added 'wait-for-lock' choice under
       'device-profile-parameters'
       grouping.

And the mentioned grouping:

    grouping device-profile-parameters {
      description
        "A set of parameters to use when communicating with a device.

         These parameters can be set on:

           o  global-settings
           o  device-profile
           o  device

         If a parameter is set on the device, its value is used.
         Otherwise, if the paramater is set in the device's
         device-profile, its value is used.  Otherwise, the global
         setting is used, if set.  Otherwise, the value used depends on
         the NED type.";

      uses timeouts;

      uses wait-for-lock{
          refine wait-for-lock-choice{
            description
              "When an action accepting the wait-for-lock parameter is
               called without providing the wait-for-lock parameter, the
               wait-for-lock-choice device setting is going to be used.";
          }
      }

I checked NSO 4.7.4.2 YANG model and this is not present so it seems you can achieve what you want starting with NSO 5.1

[Koji Yokoe]

Hi Guillaume.

Thank you for your kind advice.

Yes. You are right. In NSO 5.2.0.3, I could configure 'wait-for-lock' and it worked as expected.

Here is a log from my test.

admin@ncs# show ncs-state version
ncs-state version 5.2.0.3

First, I executed 'compare-config'

admin@ncs# devices device vCPE001 compare-config

Right after this, I executed 'check-sync'. It failed as I expected due to the lock by 'compare-config'

admin@ncs# devices device vCPE001 check-sync
result error
info vCPE001: Device is locked in a compare-config operation by session 39

Then I added 'wait-for-lock' option to the command.

Of course it works (same as NSO 4.7)

admin@ncs# devices device vCPE001 check-sync wait-for-lock { timeout 60 }
result in-sync

Then I configured 'wait-for-lock' which is newly implemented at NSO 5.x

admin@ncs# config
Entering configuration mode terminal

admin@ncs(config)# devices global-settings wait-for-lock timeout 60
admin@ncs(config)# commit
Commit complete.
admin@ncs(config)# exit

Then I executed check-sync without 'wait-for-lock' option right after compare-config.

It worked as I expected.

admin@ncs# devices device vCPE001 check-sync
result in-sync

I would be glad if it was implemented at NSO 4.x

Thank you again Guillaume