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Why would you want to do that. If one of the directors die round robin (dns?)
will still send requests to the dead server, so half of your incoming mail
connections would die. Why would you create a single point of failover in a ha
environment?
I am doing smtp load balancing with active passive directors.
-----Original Message-----
From: lvs-users-bounces@xxxxxxxxxxxxxxxxxxxxxx
[mailto:lvs-users-bounces@xxxxxxxxxxxxxxxxxxxxxx] On Behalf Of Anthony Roberts
Sent: Sunday, February 22, 2009 7:31 AM
To: lvs-users@xxxxxxxxxxxxxxxxxxxxxx
Subject: [lvs-users] Round Robin and SMTP server.
Hi everyone.
I'd like to use ldirectord to load balance TCP services, including SMTP.
I've set up two SLES10 VMs to test. sles10vm3 (192.168.40.134) is
running ldirectord and is also a real server. sles10vm4 (192.168.40.135)
is a real server. All services will be available from the virtual IP
address of 192.168.40.222. I've been able to create an active/passive
setup using heartbeat but I'd like to use round robin to have an
active/active configuration.
Once I'm happy ldirectord is working I'd like to use heartbeat to do
failover of ldirectord.
sles10vm3 has /etc/ha.d/ldirectord.conf ...
sles10vm3:/etc # cat /etc/ha.d/ldirectord.cf
checktimeout=3
checkinterval=5
autoreload=yes
logfile="/var/log/ldirectord.log"
quiescent=no
virtual=192.168.40.222:25
emailalert="root"
fallback=127.0.0.1:25
real=192.168.40.134:25 gate
real=192.168.40.135:25 gate
service=smtp
scheduler=rr
protocol=tcp
When I start up ldirectord I see ..
sles10vm3:/etc # clear;ldirectord -d /etc/ha.d/ldirectord.cf start
DEBUG2: Running exec(/usr/sbin/ldirectord -d /etc/ha.d/ldirectord.cf
start)
Running exec(/usr/sbin/ldirectord -d /etc/ha.d/ldirectord.cf start)
DEBUG2: Invoking ldirectord invoked as: /usr/sbin/ldirectord
/etc/ha.d/ldirectord.cf start
Invoking ldirectord invoked as: /usr/sbin/ldirectord
/etc/ha.d/ldirectord.cf start
DEBUG2: Starting Linux Director v1.143 with pid: 12602
Starting Linux Director v1.143 with pid: 12602
DEBUG2: Running system(/sbin/ipvsadm -A -t 192.168.40.222:25 -s rr )
Running system(/sbin/ipvsadm -A -t 192.168.40.222:25 -s rr )
DEBUG2: Added virtual server: 192.168.40.222:25
Added virtual server: 192.168.40.222:25
DEBUG2: Running system(/sbin/ipvsadm -a -t 192.168.40.222:25 -r
127.0.0.1:25 -g -w 1)
Running system(/sbin/ipvsadm -a -t 192.168.40.222:25 -r 127.0.0.1:25 -g
-w 1)
DEBUG2: Added fallback server: 127.0.0.1:25 ( x 192.168.40.222:25)
(Weight set to 1)
Added fallback server: 127.0.0.1:25 ( x 192.168.40.222:25) (Weight set
to 1)
DEBUG2: Disabled server=192.168.40.135
DEBUG2: Disabled server=192.168.40.134
DEBUG2: Checking negotiate: real
server=negotiate:smtp:tcp:192.168.40.134:25::::\/:
(virtual=tcp:192.168.40.222:25)
DEBUG2: Checking http: server=192.168.40.134 port=25
DEBUG2: Running system(/sbin/ipvsadm -a -t 192.168.40.222:25 -r
192.168.40.134:25 -g -w 1)
Running system(/sbin/ipvsadm -a -t 192.168.40.222:25 -r
192.168.40.134:25 -g -w 1)
DEBUG2: Added real server: 192.168.40.134:25 ( x 192.168.40.222:25)
(Weight set to 1)
Added real server: 192.168.40.134:25 ( x 192.168.40.222:25) (Weight set
to 1)
DEBUG2: Running system(/sbin/ipvsadm -d -t 192.168.40.222:25 -r
127.0.0.1:25)
Running system(/sbin/ipvsadm -d -t 192.168.40.222:25 -r 127.0.0.1:25)
DEBUG2: Deleted fallback server: 127.0.0.1:25 ( x 192.168.40.222:25)
Deleted fallback server: 127.0.0.1:25 ( x 192.168.40.222:25)
DEBUG2: Enabled server=192.168.40.134
DEBUG2: Checking negotiate: real
server=negotiate:smtp:tcp:192.168.40.135:25::::\/:
(virtual=tcp:192.168.40.222:25)
DEBUG2: Checking http: server=192.168.40.135 port=25
DEBUG2: Running system(/sbin/ipvsadm -a -t 192.168.40.222:25 -r
192.168.40.135:25 -g -w 1)
Running system(/sbin/ipvsadm -a -t 192.168.40.222:25 -r
192.168.40.135:25 -g -w 1)
DEBUG2: Added real server: 192.168.40.135:25 ( x 192.168.40.222:25)
(Weight set to 1)
Added real server: 192.168.40.135:25 ( x 192.168.40.222:25) (Weight set
to 1)
DEBUG2: Enabled server=192.168.40.135
DEBUG2: Checking negotiate: real
server=negotiate:smtp:tcp:192.168.40.134:25::::\/:
(virtual=tcp:192.168.40.222:25)
DEBUG2: Checking http: server=192.168.40.134 port=25
DEBUG2: Enabled server=192.168.40.134
DEBUG2: Checking negotiate: real
server=negotiate:smtp:tcp:192.168.40.135:25::::\/:
(virtual=tcp:192.168.40.222:25)
DEBUG2: Checking http: server=192.168.40.135 port=25
DEBUG2: Enabled server=192.168.40.135
DEBUG2: Checking negotiate: real
server=negotiate:smtp:tcp:192.168.40.134:25::::\/:
(virtual=tcp:192.168.40.222:25)
DEBUG2: Checking http: server=192.168.40.134 port=25
DEBUG2: Enabled server=192.168.40.134
DEBUG2: Checking negotiate: real
server=negotiate:smtp:tcp:192.168.40.135:25::::\/:
(virtual=tcp:192.168.40.222:25)
DEBUG2: Checking http: server=192.168.40.135 port=25
DEBUG2: Enabled server=192.168.40.135
DEBUG2: Checking negotiate: real
server=negotiate:smtp:tcp:192.168.40.134:25::::\/:
(virtual=tcp:192.168.40.222:25)
DEBUG2: Checking http: server=192.168.40.134 port=25
DEBUG2: Enabled server=192.168.40.134
DEBUG2: Checking negotiate: real
server=negotiate:smtp:tcp:192.168.40.135:25::::\/:
(virtual=tcp:192.168.40.222:25)
DEBUG2: Checking http: server=192.168.40.135 port=25
DEBUG2: Enabled server=192.168.40.135
DEBUG2: Checking negotiate: real
server=negotiate:smtp:tcp:192.168.40.134:25::::\/:
(virtual=tcp:192.168.40.222:25)
DEBUG2: Checking http: server=192.168.40.134 port=25
DEBUG2: Enabled server=192.168.40.134
ipvsadm shows ...
sles10vm3:~ # ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.40.222:25 rr
-> 192.168.40.135:25 Route 1 0 0
-> 192.168.40.134:25 Local 1 0 0
At this point I can telnet to port 25 of the virtual IP address and get
connected ...
sles10vm3:~ # telnet 192.168.40.222 25
Trying 192.168.40.222...
Connected to 192.168.40.222.
Escape character is '^]'.
220 sles10vm3.anix.com ESMTP Postfix
helo sles10vm3
250 sles10vm3.anix.com
quit
221 Bye
Connection closed by foreign host.
So ldirectord has redirected me to sles10vm3. As I've configured round
robin I'd expect ldirectord to re-direct me to sles10vm4 for the next
test ...
sles10vm3:~ # telnet 192.168.40.222 25
Trying 192.168.40.222...
Connected to 192.168.40.222.
Escape character is '^]'.
220 sles10vm3.anix.com ESMTP Postfix
helo sles10vm3
250 sles10vm3.anix.com
quit
221 Bye
Connection closed by foreign host.
... which it doesn't. I know that the SMTP server is working ...
sles10vm3:~ # telnet sles10vm4 25
Trying 192.168.40.135...
Connected to sles10vm4.
Escape character is '^]'.
220 sles10vm4.anix.com ESMTP Postfix
helo sles10vm4
250 sles10vm4.anix.com
quit
221 Bye
Connection closed by foreign host.
My next test was to stop postfix on sles10vm3 to see if ldirectord would
pick this up and begin re-directing to sles10vm4.
sles10vm3:~ # /etc/init.d/postfix stop
Shutting down mail service (Postfix)
done
It looks like ldirectord picked up that change ...
\/: (virtual=tcp:192.168.40.222:25)
DEBUG2: Checking http: server=192.168.40.135 port=25
DEBUG2: Enabled server=192.168.40.135
DEBUG2: Checking negotiate: real
server=negotiate:smtp:tcp:192.168.40.134:25::::\/:
(virtual=tcp:192.168.40.222:25)
DEBUG2: Checking http: server=192.168.40.134 port=25
DEBUG2: Running system(/sbin/ipvsadm -d -t 192.168.40.222:25 -r
192.168.40.134:25)
Running system(/sbin/ipvsadm -d -t 192.168.40.222:25 -r
192.168.40.134:25)
DEBUG2: Deleted real server: 192.168.40.134:25 ( x 192.168.40.222:25)
Deleted real server: 192.168.40.134:25 ( x 192.168.40.222:25)
DEBUG2: Disabled server=192.168.40.134
DEBUG2: Checking negotiate: real
server=negotiate:smtp:tcp:192.168.40.135:25::::\/:
(virtual=tcp:192.168.40.222:25)
DEBUG2: Checking http: server=192.168.40.135 port=25
DEBUG2: Enabled server=192.168.40.135
DEBUG2: Checking negotiate: real
server=negotiate:smtp:tcp:192.168.40.134:25::::\/:
(virtual=tcp:192.168.40.222:25)
DEBUG2: Checking http: server=192.168.40.134 port=25
DEBUG2: Disabled server=192.168.40.134
sles10vm3:~ # ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.40.222:25 rr
-> 192.168.40.135:25 Route 1 0 0
sles10vm2:~ # telnet 192.168.40.222 25
Trying 192.168.40.222...
telnet: connect to address 192.168.40.222: Connection refused
I've checked the mail logs on the remaining active SMTP server and can't
see any connection being from another VM I've running to the virtual IP.
(This VM works when I telnet to the real address) If I restart postfix
it works ...
sles10vm3:~ # /etc/init.d/postfix status
Checking for service Postfix:
running
sles10vm2:~ # telnet 192.168.40.222 25
Trying 192.168.40.222...
Connected to 192.168.40.222.
Escape character is '^]'.
220 sles10vm3.anix.com ESMTP Postfix
quit
221 Bye
Connection closed by foreign host.
sles10vm3:/etc/ha.d # ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.40.222:25 rr
-> 192.168.40.134:25 Local 1 0 0
-> 192.168.40.135:25 Route 1 0 0
I've the following RPM installed ..
sles10vm3:~ # rpm -qa | grep ldir
heartbeat-ldirectord-2.0.7-1.3
So my questions ...
1) Why didn't round robin work?
2) Why did ldirectord not redirect when I shut down the SMTP
server?
I've already searched the mail archives but having only just started
using ldirectord I'm a still a little unsure of some of the
configuration options so thought it best to ask early on.
Many thanks.
Anthony.
Anix Group Ltd (Registered in England and Wales; company no. 2367983; VAT no.
674406133). Registered Office: 100 Fetter Lane, London, EC4A 1BN
This email has been scanned for viruses and message content by Anix Group Ltd.
_______________________________________________
Please read the documentation before posting - it's available at:
http://www.linuxvirtualserver.org/
LinuxVirtualServer.org mailing list - lvs-users@xxxxxxxxxxxxxxxxxxxxxx
Send requests to lvs-users-request@xxxxxxxxxxxxxxxxxxxxxx
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_______________________________________________
Please read the documentation before posting - it's available at:
http://www.linuxvirtualserver.org/
LinuxVirtualServer.org mailing list - lvs-users@xxxxxxxxxxxxxxxxxxxxxx
Send requests to lvs-users-request@xxxxxxxxxxxxxxxxxxxxxx
or go to http://lists.graemef.net/mailman/listinfo/lvs-users
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