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Cannot add tunnel interface to isis within vrf
Closed, ResolvedPublicBUG



it is not possible to add an tunnel interface wo isis within vrf:

set interfaces tunnel tun0 address 'xxx'
set interfaces tunnel tun0 description 'xxx
set interfaces tunnel tun0 encapsulation 'ip6gretap'
set interfaces tunnel tun0 multicast 'enable'
set interfaces tunnel tun0 parameters ip ttl '255'
set interfaces tunnel tun0 parameters ipv6 hoplimit '255'
set interfaces tunnel tun0 remote 'xxx'
set interfaces tunnel tun0 source-address 'xxx'
set interfaces tunnel tun0 vrf 'core'
set vrf name core protocols isis interface dum0
set vrf name core protocols isis net '49.0001.1900.0700.0003.00'
set vrf name core protocols isis interface tun0
vyos@vyos# commit
[ vrf name core protocols isis ]
VyOS had an issue completing a command.

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Report Time:      2021-05-05 15:15:21
Image Version:    VyOS 1.4-rolling-202105050912
Release Train:    sagitta

Built by:
Built on:         Wed 05 May 2021 08:12 UTC
Build UUID:       78b8bd29-d828-4d2f-9903-d602aaaddcc0
Build Commit ID:  d3e2f3801f3db1

Architecture:     x86_64
Boot via:         installed image
System type:      KVM guest

Hardware vendor:  QEMU
Hardware model:   Standard PC (i440FX + PIIX, 1996)
Hardware S/N:     
Hardware UUID:    d9b6a227-a7cf-4897-9dc5-07aaa9c9b988

Traceback (most recent call last):
  File "/usr/libexec/vyos/conf_mode/", line 227, in <module>
  File "/usr/libexec/vyos/conf_mode/", line 209, in apply
  File "/usr/lib/python3/dist-packages/vyos/", line 458, in commit_configuration
    reload_configuration('\n'.join(self.config), daemon=daemon)
  File "/usr/lib/python3/dist-packages/vyos/", line 206, in reload_configuration
    raise CommitError('FRR configuration failed while running commit. Please ' \
vyos.frr.CommitError: FRR configuration failed while running commit. Please enable debugging to examine logs.

To enable debugging run: "touch /tmp/vyos.frr.debug" and "sudo systemctl stop vyos-configd"

[[vrf name core protocols isis]] failed
Commit failed


Difficulty level
Easy (less than an hour)
VyOS 1.4-rolling-202105050912
Why the issue appeared?
Will be filled on close
Is it a breaking change?
Unspecified (possibly destroys the router)

Event Timeline

Maybe I found the issue:

Script is not checking lsp-mtu against interface mtu. FRR only allows if lsp-mtu => interface mtu but this is not check during commit.

Problem is because of LSP MTU missmatch

frr-reload output: 116 Error description: Interface tun0 has MTU 1473, minimum MTU for the area is 1497

c-po changed the task status from Open to In progress.May 5 2021, 7:52 PM
c-po triaged this task as Normal priority.
c-po changed Difficulty level from Normal (likely a few hours) to Easy (less than an hour).