FRR - Support for SNMP missing in 1.4?

[matthewr]

Currently, my network makes use of SNMP to monitor OSPF and BGP adjacencies against routers running 1.3 and 1.2.

I am limbering up to do upgrades respectively to 1.4 & 1.3 and seem to be having problems with SNMP when migrating to 1.4. Before posting any bug report, I wanted to check if this is known.

For example, pointing at a 1.3 router, its OSPF adjancies are shown in SNMP:-

[matthew@m40 ~]$ snmpwalk -v 2c -c testsnmp 193.201.42.173 1.3.6.1.2.1.14.10.1.6
SNMPv2-SMI::mib-2.14.10.1.6.193.201.42.161.0 = INTEGER: 4
SNMPv2-SMI::mib-2.14.10.1.6.193.201.42.163.0 = INTEGER: 4
SNMPv2-SMI::mib-2.14.10.1.6.193.201.42.168.0 = INTEGER: 8
SNMPv2-SMI::mib-2.14.10.1.6.193.201.42.169.0 = INTEGER: 4
SNMPv2-SMI::mib-2.14.10.1.6.193.201.42.171.0 = INTEGER: 4
SNMPv2-SMI::mib-2.14.10.1.6.193.201.42.172.0 = INTEGER: 8

with the router showing:-

vyos@lab-vyos-r1:~$ sh ip ospf ne
Neighbor ID Pri State Dead Time Address Interface RXmtL RqstL DBsmL
192.168.160.250 110 2-Way/DROther 3.675s 193.201.42.161 eth0.20:193.201.42.173 0 0 0
193.201.42.165 1 2-Way/DROther 3.675s 193.201.42.163 eth0.20:193.201.42.173 0 0 0
193.201.42.250 120 Full/Backup 3.675s 193.201.42.168 eth0.20:193.201.42.173 1 0 0
193.201.42.215 120 2-Way/DROther 3.690s 193.201.42.169 eth0.20:193.201.42.173 0 0 0
193.201.42.210 110 2-Way/DROther 3.675s 193.201.42.171 eth0.20:193.201.42.173 0 0 0
193.201.42.209 120 Full/DR 3.674s 193.201.42.172 eth0.20:193.201.42.173 1 0 0

Having taken that router and upgraded it to 1.4.0-epa1, the SNMP is no longer returned:-

[matthew@m40 ~]$ snmpwalk -v 2c -c testsnmp 193.201.42.173 1.3.6.1.2.1.14.10.1.6
SNMPv2-SMI::mib-2.14.10.1.6 = No Such Object available on this agent at this OID

Having done some (not very comprehensive) research, it seems that FRR can be compiled with or without SNMP support and I wonder if this may be the issue.

On 1.3, “vtysh -c 'show modules” includes:-

Module information for ospfd:
Module Name Version Description
libfrr 7.5.1-20230529-02-gba1778129 libfrr core module
ospfd 7.5.1-20230529-02-gba1778129 ospfd daemon
ospfd_snmp 7.5.1-20230529-02-gba1778129 ospfd AgentX SNMP module
from: /usr/lib/x86_64-linux-gnu/frr/modules/ospfd_snmp.so

whereas on 1.4.0-epa1, one gets:-

Module information for ospfd:
Module Name Version Description
libfrr 9.1 libfrr core module
ospfd 9.1 ospfd daemon

One can therefore see that the “AgentX SNMP module” is absent. The same applies to BGP.

Is there still meant to be SNMP support for FRR in 1.4?

If this is not intentional (and I hope not), I am happy to file a bug report.

[Viacheslav]

You have to enable SNMP as it was disabled by default due to many bugs with SNMP/FRR

vyos@r1-right# set system frr snmp 
Possible completions:
   bgpd                 BGP
   isisd                IS-IS
   ldpd                 LDP
   ospf6d               OSPFv3
   ospfd                OSPFv2
   ripd                 RIP
   zebra                Zebra (IP routing manager)

[matthewr]

Thanks for your splendidly prompt response!

A quick test on my lab router shows the expected results for OSPFD.

Did I miss this in any release notes?

Out of interest, are you expecting LESS stability in 1.4 compared with earlier. I have had not much trouble with SNMP in 1.3 & 1.2.

[zsdc]

You were just lucky enough. SNMP/AgentX never was really stable enough and random lockups were only a question of the time with some monitoring systems.

P.S. This is not a VyOS-specific thing, the problem exists in all (or almost all) snmpd-based implementations.