Re: AW: [users@httpd] Apache drops connection but ifdown/up resolves the issue!

["Neil A. Hillard" <hi...@whl.co.uk>]

Hi,

Oliver.Schaudt@unilog.de wrote:
> Are you running out of file descriptors with your Apache Process ? [ulimit -a]

I don't believe so, results of ulimit -a:

core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
file size               (blocks, -f) unlimited
pending signals                 (-i) 32767
max locked memory       (kbytes, -l) 32
max memory size         (kbytes, -m) unlimited
open files                      (-n) 1024
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
stack size              (kbytes, -s) 10240
cpu time               (seconds, -t) unlimited
max user processes              (-u) 32767
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited


Once this problem happens I can restart Apache, start it with 'httpd 
-X', start it with strace and the exact same thing happens.

As soon as I do a ifconfig bond0.2 down it starts working.  If I then 
bring that interface up it carries on working for a while and then stops!

This box is not in production yet so has virtually no loading and no 
clients (apart from me).  I have the same config running on identical 
hardware that doesn't have a bonded connection to the network or VLAN 
tagging that has been in production for over 6 months and no problems at 
all.

The odd thing is that Apache sees the connection request and then just 
drops it!

Is there any further debugging I can perform to try to locate this?

Many thanks in advance,


				Neil.

> -----Ursprüngliche Nachricht-----
> Von: Neil A. Hillard [mailto:hillardn@whl.co.uk]
> Gesendet: Mi 25.01.2006 10:53
> An: users@httpd.apache.org
> Betreff: [users@httpd] Apache drops connection but ifdown/up resolves the issue!
>  
> Hi,
> 
> 	I've got Apache 2.0.55 built from source and am seeing an odd problem 
> related to multiple IP addresses on VLANs.
> 
> The server has a trunked connection back to our switch and has the IP 
> addresses 172.24.12.9, 172.24.11.3 and 172.16.14.104.  These are 
> configured as bond0, bond0:2 and bond0.2 respectively.  There are other 
> aliases IP addresses on bond0 but they're probably irrelevant for this 
> problem.
> 
> Apache is listening on all interfaces, port 80 and 443.
> 
> I have a client at 172.16.40.32 attempting to connect to port 80 on 
> 172.24.11.3.  The following occurs:
> 
> # telnet 172.24.11.3 80
> Trying 172.24.11.3...
> Connected to 172.24.11.3 (172.24.11.3).
> Escape character is '^]'.
> Connection closed by foreign host.
> 
> 
> An strace against httpd shows:
> 
> [pid 31138] accept(3, {sa_family=AF_INET, sin_port=htons(44894), 
> sin_addr=inet_addr("172.16.40.32")}, [16]) = 16
> [pid 31138] semop(6914069, 0xb79f0c, 1) = 0
> [pid 31138] futex(0x837c474, FUTEX_WAKE, 1 <unfinished ...>
> [pid 31130] <... futex resumed> )       = 0
> [pid 31138] <... futex resumed> )       = 1
> [pid 31138] semop(6914069, 0xb79f12, 1) = 0
> [pid 31138] poll( <unfinished ...>
> [pid 31130] futex(0x837c43c, FUTEX_WAKE, 1) = 0
> [pid 31130] getsockname(16, {sa_family=AF_INET, sin_port=htons(80), 
> sin_addr=inet_addr("172.24.11.3")}, [16]) = 0
> [pid 31130] fcntl64(16, F_GETFL)        = 0x2 (flags O_RDWR)
> [pid 31130] fcntl64(16, F_SETFL, O_RDWR|O_NONBLOCK) = 0
> [pid 31130] read(16, 0x83eccf8, 8000)   = -1 EAGAIN (Resource 
> temporarily unavailable)
> [pid 31130] poll([{fd=16, events=POLLIN, 
> revents=POLLIN|POLLERR|POLLHUP}], 1, 300000) = 1
> [pid 31130] read(16, 0x83eccf8, 8000)   = -1 ECONNRESET (Connection 
> reset by peer)
> [pid 31130] gettimeofday({1138182161, 971221}, NULL) = 0
> [pid 31130] shutdown(16, 1 /* send */)  = -1 ENOTCONN (Transport 
> endpoint is not connected)
> [pid 31130] close(16)                   = 0
> 
> 
> If I then perform 'ifconfig bond0.2 down', 'ifconfig bond0.2 up' and 
> repeat the test everything works as expected!  It carries on working for 
> a while and then gives up the ghost again!
> 
> Apache is receiving the connection and I can see from a packet capture 
> that the three-way handshake is completing but for some reason it's 
> dropping the connection - almost like tcpwrappers does!
> 
> Whilst Apache is refusing the connections, I can still ssh to the same 
> IP address.
> 
> This one has me puzzled - if anyone can shed some light on it, it would 
> be much appreciated!
> 
> Many thanks in advance,
> 
> 
> 				Neil.

-- 
Neil Hillard                    hillardn@whl.co.uk
Westland Helicopters Ltd.       http://www.whl.co.uk/

Disclaimer: This message does not necessarily reflect the
             views of Westland Helicopters Ltd.

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