Flapping interface

Issues related to configuring your network
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mattps
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Joined: 2020/08/28 09:08:47

Flapping interface

Post by mattps » 2020/08/28 09:13:56

Hi,

6 Centos servers are used to run CAE simulations in a cluster and we have noticed recently that CAE jobs have been failing. Looking at dmesg logs of one server and I can see the networking interface flapping down, then up a a few seconds later. This happens randomly every 12 - 24 hours or so.

Aug 25 08:42:30 misspiggy kernel: bnx2x 0000:01:00.1: em2: NIC Link is Down
Aug 25 08:42:30 misspiggy NetworkManager[2834]: <info> (em2): carrier now OFF (device state 3)
Aug 25 08:42:30 misspiggy NetworkManager[2834]: <info> (em2): device state change: disconnected -> unavailable (reason 'carrier-chagned') [3 2 40]
Aug 25 08:42:30 misspiggy NetworkManager[2834]: <info> (em2): deactivating device (reason 'carrier-chagned') [40]
Aug 25 08:42:30 misspiggy NetworkManager[2834]: <info> Policy set 'System em3' (em3) as default for IPv4 routing and DNS.
Aug 25 08:42:30 misspiggy NetworkManager[2834]: <info> Policy set 'System em3' (em3) as default for IPv4 routing and DNS.
Aug 25 08:42:34 misspiggy kernel: bnx2x 0000:01:00.1: em2: NIC Link is Up, 10000 Mbps full duplex, Flow control: none


The 6 servers are connected to their own 10GbE switch.

I am a Windows admin and don't really have much experience with Linux which is why the configuration with these boxes haven't changed.

Can anyone suggest anything?

Thanks,

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TrevorH
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Re: Flapping interface

Post by TrevorH » 2020/08/28 15:44:34

It says the interface went down. You should check the switch logs and see if there is a problem that side. Also try a different switch port and a different cable. All the info here looks like a hardware problem.

Also, that NetworkManager output doesn't really look like you are running CentOS 6. Are you sure it is? If it is then it will be using a 2.6.32-xxx series of kernels so that will show up in uname -a. If it's not 6 then we can move this topic elsewhere.
CentOS 6 will die in November 2020 - migrate sooner rather than later!
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
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mattps
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Joined: 2020/08/28 09:08:47

Re: Flapping interface

Post by mattps » 2020/08/28 15:50:56

Thanks TrevorH,

I sure it's 6.8 (that's what was specified by our team to the installer). uname output is:

[root@bunsen ~]# uname -a
Linux bunsen 2.6.32-642.el6.x86_64 #1 SMP Tue May 10 17:27:01 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

It's strange as I have continuous pings running between the hosts on this switch and they all show zero packet loss. Cables have been replaced and the switch has stock configuration on it.

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TrevorH
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Re: Flapping interface

Post by TrevorH » 2020/08/28 16:48:00

That's already 4 years out of date.

At a minimum you should be on 6.10 plus all the latest fixes and CentOS 6 itself goes EOL in November so you need to get off it quick.
CentOS 6 will die in November 2020 - migrate sooner rather than later!
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 is dead, do not use it.
Full time Geek, part time moderator. Use the FAQ Luke

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