From: Gebhardt Thomas (gebhardt_at_hrz.uni-marburg.de)
Date: Tue 03 Feb 2004 - 16:16:14 GMT
On Monday 02 February 2004 11:48, you wrote:
> > suddenly all vservers on that host seem to be offline, they do not
> > reply a ping request and all tcp connections get disconnected. The
> > master is fine, however. I can ssh to the master, enter one vserver
> hmm, that sounds like some router, which gets
> confused by many ip addresses for one MAC ...
>
> older cisco routers showed that behaviour, flushing
> their arp caches after some overflow ...
I was thinking of something like that, therefore I had a look
at the router arp cache.
> PS: I'm not saying that it might not be vserver
> related, but that was my first thought ...
After I tried to ping the lost vserver, the router should send
an arp request and rebuild its tables. Nethertheless I found
no arp table entry for the lost vserver in the routers arp cache.
So there are several possibilities:
1. The router did not send an arp request.
2. The host did not receive the request for some reason
3. The host did not answer the request
4. The router did not cache the answer
Don't know what exactly happened, but I tend to believe
that 3. is the most probable case.
Clueless, I set up a cron job on the master that
sends an unsolicited arp reply for each vserver
every five minutes.
Cheers, Thomas
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