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Posted to dev@spamassassin.apache.org by Iavor Stoev <ia...@icdsoft.com> on 2008/10/08 13:14:40 UTC
spamc failover behavior
Hello,
First my system information is:
OS - Debian Etch
SA version - 3.2.3
I am trying to use SpamAssassin in the following setup to accomplish
load balancing:
I have 3 testing servers with spamd installed and configured to accept
network connections from a whole /24 network.
On an another testing machine I invoke spamc with the following options:
cat test-email.txt | spamc -c -t 120 -p 783 -H -d
server1.com,server2.com,server3.com
In that scenario everything is ok and works as expected.
The spamc client connects to a random server from the round robin pool
and receives an answer with the spam score for the email from every server.
Ok then I tried to make some trouble.
On server1.com I stopped the Spamd so there was no service listening on
port 783.
On server2.com I added a firewall rule using iptables to DROP requests
to port 783.
On server3.com I left the Spamd working without any intervention.
I executed again the spamc command written above several times and
everything was perfect.
Depending on which server is accessed first from the spamc, sooner or
later I always received an answer from server3.com (the only server that
is operational).
I reverted all the servers back to fully operational mode and decided to
check what will happen if one of the servers is heavily loaded and don't
respond to the spamc request in the timeout limit.
On server3.com I executed:
killall -STOP spamd
and the effect was that the server was with port 783 open and you can
establish a successful TCP connection but the server doesn't return
anything to the spamc client.
So when I invoked the spamc again and it accessed server3.com the spamc
waited for response from the server and when it didn't received one for
120 seconds it returned spam score 0/0, instead of connecting to another
server from the pool.
Could you tell me is that behavior indented and if not what can I do to
make the spamc to connect to another server in this scenario?
Thank You
Iavor Stoev
Re: [LIST:spamassassin-dev] spamc failover behavior
Posted by Iavor Stoev <ia...@icdsoft.com>.
Hello Ty! Boyack,
It works like charm with the patch that you provided.
I just want to report that you have to invoke spamc with
--filter-retries with some value (greater than 1 in my setup case) to
achieve the desired failover behavior, even that in the spamc help is
described that it has default value 3.
I don't know if that is a code or documentation bug.
--filter-retries retries
Retry filtering this many times if the spamd
process fails (usually times out) [default: 3]
Thank You again !
Iavor Stoev
Ty! Boyack wrote:
> I submitted a patch to address this behavior -- you can see the
> discussion at
> https://issues.apache.org/SpamAssassin/show_bug.cgi?id=5871. I think
> the goal is to include this in 3.3, but you can grab the patch from
> here if it helps:
> https://issues.apache.org/SpamAssassin/attachment.cgi?id=4303&action=view
>
> What I found was that the behavior your describe below is correct.
> The patch adds an option of --filter-retries to specify how many times
> it should retry the filtering process (moving to the next spamd host
> for each retry) before giving up.
>
> Hope this helps.
>
> -Ty!
>
>
>
> Iavor Stoev wrote:
>> Hello,
>> First my system information is:
>> OS - Debian Etch
>> SA version - 3.2.3
>>
>> I am trying to use SpamAssassin in the following setup to accomplish
>> load balancing:
>>
>> I have 3 testing servers with spamd installed and configured to
>> accept network connections from a whole /24 network.
>> On an another testing machine I invoke spamc with the following options:
>>
>> cat test-email.txt | spamc -c -t 120 -p 783 -H -d
>> server1.com,server2.com,server3.com
>>
>> In that scenario everything is ok and works as expected.
>> The spamc client connects to a random server from the round robin
>> pool and receives an answer with the spam score for the email from
>> every server.
>>
>> Ok then I tried to make some trouble.
>>
>> On server1.com I stopped the Spamd so there was no service listening
>> on port 783.
>> On server2.com I added a firewall rule using iptables to DROP
>> requests to port 783.
>> On server3.com I left the Spamd working without any intervention.
>>
>> I executed again the spamc command written above several times and
>> everything was perfect.
>> Depending on which server is accessed first from the spamc, sooner or
>> later I always received an answer from server3.com (the only server
>> that is operational).
>>
>>
>> I reverted all the servers back to fully operational mode and decided
>> to check what will happen if one of the servers is heavily loaded and
>> don't respond to the spamc request in the timeout limit.
>>
>> On server3.com I executed:
>>
>> killall -STOP spamd
>>
>> and the effect was that the server was with port 783 open and you can
>> establish a successful TCP connection but the server doesn't return
>> anything to the spamc client.
>>
>>
>> So when I invoked the spamc again and it accessed server3.com the
>> spamc waited for response from the server and when it didn't received
>> one for 120 seconds it returned spam score 0/0, instead of connecting
>> to another server from the pool.
>>
>> Could you tell me is that behavior indented and if not what can I do
>> to make the spamc to connect to another server in this scenario?
>>
>>
>> Thank You
>>
>> Iavor Stoev
>>
>
>
Re: [LIST:spamassassin-dev] spamc failover behavior
Posted by Ty! Boyack <ty...@nrel.colostate.edu>.
I submitted a patch to address this behavior -- you can see the
discussion at
https://issues.apache.org/SpamAssassin/show_bug.cgi?id=5871. I think
the goal is to include this in 3.3, but you can grab the patch from here
if it helps:
https://issues.apache.org/SpamAssassin/attachment.cgi?id=4303&action=view
What I found was that the behavior your describe below is correct. The
patch adds an option of --filter-retries to specify how many times it
should retry the filtering process (moving to the next spamd host for
each retry) before giving up.
Hope this helps.
-Ty!
Iavor Stoev wrote:
> Hello,
> First my system information is:
> OS - Debian Etch
> SA version - 3.2.3
>
> I am trying to use SpamAssassin in the following setup to accomplish
> load balancing:
>
> I have 3 testing servers with spamd installed and configured to accept
> network connections from a whole /24 network.
> On an another testing machine I invoke spamc with the following options:
>
> cat test-email.txt | spamc -c -t 120 -p 783 -H -d
> server1.com,server2.com,server3.com
>
> In that scenario everything is ok and works as expected.
> The spamc client connects to a random server from the round robin pool
> and receives an answer with the spam score for the email from every
> server.
>
> Ok then I tried to make some trouble.
>
> On server1.com I stopped the Spamd so there was no service listening
> on port 783.
> On server2.com I added a firewall rule using iptables to DROP requests
> to port 783.
> On server3.com I left the Spamd working without any intervention.
>
> I executed again the spamc command written above several times and
> everything was perfect.
> Depending on which server is accessed first from the spamc, sooner or
> later I always received an answer from server3.com (the only server
> that is operational).
>
>
> I reverted all the servers back to fully operational mode and decided
> to check what will happen if one of the servers is heavily loaded and
> don't respond to the spamc request in the timeout limit.
>
> On server3.com I executed:
>
> killall -STOP spamd
>
> and the effect was that the server was with port 783 open and you can
> establish a successful TCP connection but the server doesn't return
> anything to the spamc client.
>
>
> So when I invoked the spamc again and it accessed server3.com the
> spamc waited for response from the server and when it didn't received
> one for 120 seconds it returned spam score 0/0, instead of connecting
> to another server from the pool.
>
> Could you tell me is that behavior indented and if not what can I do
> to make the spamc to connect to another server in this scenario?
>
>
> Thank You
>
> Iavor Stoev
>
--
-===========================-
Ty! Boyack
NREL Unix Network Manager
ty@nrel.colostate.edu
(970) 491-1186
-===========================-
Re: spamc failover behavior
Posted by Karsten Bräckelmann <gu...@rudersport.de>.
On Wed, 2008-10-08 at 14:14 +0300, Iavor Stoev wrote:
> and the effect was that the server was with port 783 open and you can
> establish a successful TCP connection but the server doesn't return
> anything to the spamc client.
>
> So when I invoked the spamc again and it accessed server3.com the spamc
> waited for response from the server and when it didn't received one for
> 120 seconds it returned spam score 0/0, instead of connecting to another
> server from the pool.
Bug 5975 [1] and possibly some other related bugs. Too lazy to look for
dupes.
guenther
[1] https://issues.apache.org/SpamAssassin/show_bug.cgi?id=5975
--
char *t="\10pse\0r\0dtu\0.@ghno\x4e\xc8\x79\xf4\xab\x51\x8a\x10\xf4\xf4\xc4";
main(){ char h,m=h=*t++,*x=t+2*h,c,i,l=*x,s=0; for (i=0;i<l;i++){ i%8? c<<=1:
(c=*++x); c&128 && (s+=h); if (!(h>>=1)||!t[s+h]){ putchar(t[s]);h=m;s=0; }}}