yahoo-eng-team team mailing list archive

[norman shen <1893015@xxxxxxxxxxxxxxxxxx>]

Public bug reported:

We are using neutron rocky, with security driver set to iptables_hybrid,
the cluster is deployed on top of a kubernetes cluster. And all the
networks are set to mtu 1500

The problem I am facing right now is that ping across compute nodes
fails with a packet size larger than mtu.

ping -s 2000 172.20.93.171

Surprisingly, if I ping an IP address from the same node, it works
without any issue.

I have done a simple tcpdump on qvb like (both on remote and local
compute node)

tcpdump -i qbvxxxx host 172.20.93.171 and icmp

And I saw the traffic, but if I am listening on tap or qbr, no traffic
is captured.

I try to add a log iptable rule to debug, by

iptables -t raw -I PREROUTING 1 -m physdev --physdev-in qvb373214e3-8d
-p icmp -s 172.20.93.173/12 -j LOG --log-prefix='[netfilter] '

Weird enough, there are no packets counted when packet size set to 2000.

** Affects: neutron
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1893015

Title:
  ping with large package size fails

Status in neutron:
  New

Bug description:
  We are using neutron rocky, with security driver set to
  iptables_hybrid, the cluster is deployed on top of a kubernetes
  cluster. And all the networks are set to mtu 1500

  The problem I am facing right now is that ping across compute nodes
  fails with a packet size larger than mtu.

  ping -s 2000 172.20.93.171

  Surprisingly, if I ping an IP address from the same node, it works
  without any issue.

  I have done a simple tcpdump on qvb like (both on remote and local
  compute node)

  tcpdump -i qbvxxxx host 172.20.93.171 and icmp

  And I saw the traffic, but if I am listening on tap or qbr, no traffic
  is captured.

  I try to add a log iptable rule to debug, by

  iptables -t raw -I PREROUTING 1 -m physdev --physdev-in qvb373214e3-8d
  -p icmp -s 172.20.93.173/12 -j LOG --log-prefix='[netfilter] '

  Weird enough, there are no packets counted when packet size set to
  2000.

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