[rabbitmq-discuss] questions about log messages and problems with connections

[Rosa, Andrea]

Hi Simon,

> -----Original Message-----
> 
> On 09/09/11 09:53, Andrea Rosa wrote:
> > in the rabbitmq file I found this error:
> > =ERROR REPORT==== 8-Sep-2011::14:13:39 ===
> > exception on TCP connection<0.27709.5838>  from ipaddr:port
> > {inet_error,etimedout}
> >
> > When this error occurs?
> > Unfortunately this problem affects 70% of our nodes!
> 
> We've only seen this error before when there's a TCP load balancer or
> firewall in between Rabbit and its clients that is somehow futzing with
> TCP connections - could this be happening to you?

Unfortunately this is not our case. We don't have a TCP load balancer installed yet.
How rabbitmq count consumers registered on a queue? It counts


> > Analysing the rabbitmq log file I found other strange messages:
> > =WARNING REPORT==== 8-Sep-2011::14:49:08 ===
> > exception on TCP connection<0.11485.6171>  from ipaddr:port
> > connection_closed_abruptly
> >
> > This message is repeated a lot of times in the log file, but It seems
> > that didn't affect the behaviour of our application.
> > It's normal to have so much WARNING messages?
> 
> That just means that a connection was closed at the TCP level without
> going through the AMQP close handshaking. If you're seeing this all the
> time and it's not associated with clients getting disconnected when you
> don't expect it, it could be a badly-written client? Which client are
> you using?
 
We are using python carrot library. We verified that the connection is refused just for one of our nodes.
We needed to restart rabbitmq server in order to fix that problem.

> > And finally these messages:
> > =INFO REPORT==== 8-Sep-2011::13:13:13 ===
> >      alarm_handler: {clear,file_descriptor_limit}
> >
> > =INFO REPORT==== 8-Sep-2011::13:13:13 ===
> >      alarm_handler: {set,{file_descriptor_limit,[]}}
> >
> > These are related with socket problems?
> 
> Ah, that's interesting. On Unix every TCP connection requires a file
> descriptor and often operating systems are configured with a fairly low
> limit (1024 is fairly typical). And Rabbit needs to keep some file
> descriptors back for... files. If you want Rabbit to support large
> numbers of connections, look into raising the limit with limits.conf.
> 

Ok thank you, we are going to raise this limit.

> However, even if you're running into the limit then this shouldn't kill
> existing connections, just make Rabbit unable to accept new ones, so I
> think you still have multiple issues to fix I'm afraid.
> 
> Cheers, Simon
> 
> --
> Simon MacMullen
> RabbitMQ, VMware
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