[Linuxha-users] Caught in a loop
Michael Mansour
mic at npgx.com.au
Mon Jan 31 04:50:46 GMT 2005
Hi Simon,
After thinking about this alot and running through some of my own setups for
it, I couldn't get it to work. What I tried was to have a separate /etc/httpd/
conf.d.cluster directory together with the normal /etc/httpd/conf directory.
So I decided to test your suggestion below, but found this didn't work either,
with the problem being that the report shown in /var/log/cluster/apache.start.
log is:
/apache/admin/scripts/apachectl start: httpd (pid 9605) already running
so it seemed no attempt at running another port 80 listener was made.
I'll explain this test setup for you. I set this up as:
1. /etc/httpd_local be the ServerRoot for the local httpd (local:80)
2. /etc/httpd be the ServerRoot for the cluster (clusternode1:80)
For 1, it starts up fine using the normal OS start scripts "service httpd
start":
9605 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
9608 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
9609 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
9610 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
9611 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
9612 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
9613 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
9614 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
and:
tcp 0 0 local:80 0.0.0.0:* LISTEN
But when I then execute 2, the apache app starts up fine with "clstartapp":
[root at node1 conf]# clstartapp -A apache -V
INFO 31/01/2005 04:10:43 Validated checksum for cluster configuration
INFO 31/01/2005 04:10:43 Checked that node names resolve to IP addresses
INFO 31/01/2005 04:10:43 Validated Build run has completed against this
configuration.
INFO 31/01/2005 04:10:43 drbd kernel module loaded already on xxx.xxx.xxx.xxx
INFO 31/01/2005 04:10:43 Checking heartbeats for any sign of life...
WARN 31/01/2005 04:10:43 Attemping ICMP ping of xxx.xxx.xxx.xxx...
INFO 31/01/2005 04:10:44 drbd kernel module loaded already on xxxxxxxxx
INFO 31/01/2005 04:10:44 Local DRBD devices started successfully.
INFO 31/01/2005 04:10:44 DRBD: Skipping ENBD decisioning and relying on meta
data...
INFO 31/01/2005 04:10:44 Attempting to start DRBD services on xxxxxxxxx
INFO 31/01/2005 04:10:45 DRBD devices started successfully on xxxxxxxxx
INFO 31/01/2005 04:10:45 Validated consistency of available data for DRBD.
INFO 31/01/2005 04:10:45 Both data copies believed good.
WARN 31/01/2005 04:10:45 Locking services not available.
INFO 31/01/2005 04:10:45 Attempting to register application apache as
starting...
INFO 31/01/2005 04:10:46 Application registered successfully as starting.
INFO 31/01/2005 04:10:46 Checking IP address for application is not in use...
INFO 31/01/2005 04:10:48 Required application IP address is not pingable -
continuing.
INFO 31/01/2005 04:10:48 Attempting to make local DRBD devices primary...
INFO 31/01/2005 04:10:48 All local DRBD now primary.
INFO 31/01/2005 04:10:48 Running "/sbin/fsck -t ext3 -a /dev/drbd0"...
INFO 31/01/2005 04:10:48 Running "PATH=$PATH:/sbin:/bin:/usr/sbin; mount -t
ext3 -o rw /dev/drbd0 /apache"...
INFO 31/01/2005 04:10:48 File systems mounted on DRBD devices.
INFO 31/01/2005 04:10:48 choose_interface: Link beat ok on interface eth0
INFO 31/01/2005 04:10:48 choose_interface: Assigning IP address xxx.xxx.xxx.
xxx to interface eth0...
INFO 31/01/2005 04:10:48 cmd=/sbin/ifconfig eth0:1 inet xxx.xxx.xxx.xxx
netmask 255.255.255.0 2>&1
INFO 31/01/2005 04:10:48 Running /sbin/cluster/tools/send_arp xxx.xxx.xxx.xxx
xx:xx:xx:xx:xx:xx xxx.xxx.xxx.xxx FF:FF:FF:FF:FF:FF eth0 to send gratuitous
arp request
INFO 31/01/2005 04:10:48 choose_interface: Successfully assigned IP address
xxx.xxx.xxx.xxx to eth0:1
INFO 31/01/2005 04:10:48 choose_interface: Running IP level testing for
interface eth0:1
INFO 31/01/2005 04:10:48 choose_interface: Test for IP xxx.xxx.xxx.xxx(tcp)
was OK.
INFO 31/01/2005 04:10:48 choose_interface: IP level testing for interface
eth0:1 succeeded
INFO 31/01/2005 04:10:48 Applications start completed successfully
but the output of the apache.start.log being:
/apache/admin/scripts/apachectl start: httpd (pid 12088) already running
so there's no listen on port 80 of the cluster IP (clusternode1:80).
So you know also, if I start 2 by itself (without first starting 1), the
listen on clusternode1:80 works.
So what I decided to do was a test, for the following bit:
# check for pidfile
if [ -f $PIDFILE ] ; then
PID=`cat $PIDFILE`
if [ "x$PID" != "x" ] && kill -0 $PID 2>/dev/null ; then
STATUS="httpd (pid $PID) running"
RUNNING=1
in the /apache/admin/scripts/apachectl file, I modified it to RUNNING=0 to see
what would happen, basically forcing the startup of apache on clusternode1. I
then halted the app and stopped the local httpd.
I then restarted the local httpd (which establishes a local:80) and then
clstartapp of the apache app, which successfully loaded the clusternode1:80 as
we can see:
tcp 0 0 clusternode1:80 0.0.0.0:* LISTEN
tcp 0 0 local:80 0.0.0.0:* LISTEN
and:
16683 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
16686 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
16687 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
16688 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
16689 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
16690 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
16691 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
16692 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
16693 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
16839 ? S 0:00 /usr/sbin/httpd -f /apache/admin/conf/httpd.conf
16840 ? S 0:00 /usr/sbin/httpd -f /apache/admin/conf/httpd.conf
16841 ? S 0:00 /usr/sbin/httpd -f /apache/admin/conf/httpd.conf
16842 ? S 0:00 /usr/sbin/httpd -f /apache/admin/conf/httpd.conf
16843 ? S 0:00 /usr/sbin/httpd -f /apache/admin/conf/httpd.conf
16844 ? S 0:00 /usr/sbin/httpd -f /apache/admin/conf/httpd.conf
16845 ? S 0:00 /usr/sbin/httpd -f /apache/admin/conf/httpd.conf
16846 ? S 0:00 /usr/sbin/httpd -f /apache/admin/conf/httpd.conf
16848 ? S 0:00 /usr/sbin/httpd -f /apache/admin/conf/httpd.conf
as we can see modification produced the result I wanted.
I tested the websites and they all worked fine.
Halting the apache app also stopped just clusternode1:80 listen, again what I
wanted.
I'm not sure what impact the modification above will make to the overall usage
of linuxha.net, but it's the only way I was able to get this to work.
One other thing of note, when I ran:
# service httpd stop
while both local:80 and clusternode1:80 were up, the clusternode1:80 httpd
processes were killed instead of local:80, not something I wanted. Also, while
this was the case clstat showed the apache application was still running on
clusternode1:
Application Node State Started Monitor Stale Fail-over?
apache local STARTED 0:00:00 Running 0 Yes
even though this isn't the case since we see:
16683 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
16686 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
16687 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
16688 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
16689 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
16690 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
16691 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
16692 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
16693 ? S 0:00 /usr/sbin/httpd -d /etc/httpd_local
which is the local:80 instance of httpd and not clusternode1:80 - I suspect
the lems monitor is only assessing whether httpd daemons are running, and not
specifically whether the httpd running is local:80 or clusternode1:80.
I'd really like to get this working properly, so if you have any suggestions
as to how I can achieve this I'd really appreciate it.
Michael.
> Hello Michael,
> Having two Server roots (i.e. /etc/httpd and /etc/httpd_local) is
> the way to go I would guess. Initially copy all the files form one
> to the other and then customise each by changing the Listen entry in
> each to the local and clustered IP addresses as appropriate.
>
> The -d option on httpd startup can then be using to specify the
> required server root (/etc/httpd or /etc/httpd_local) as required.
>
> Regards,
> Simon.
>
> On Fri, 2005-01-28 at 14:10 +1000, Michael Mansour wrote:
> > Hi Simon,
> >
> > Just so you know, I have only one apache instance which runs as the
"apache"
> > application starts up. I didn't realise I could have had two.
> >
> > The way I have it setup is to not have any apache server started on system
> > boot. I then form the cluster and start the apache app, which reads the
other
> > conf files from /etc/httpd/conf.d/*conf and starts up the virtual servers.
> >
> > I'm going to think about how I can now have two apache instances running,
the
> > local one and the clustered one. Do I need to have two sets of /etc/httpd/
> > conf.d directories in this case? one for the local and one for the
clustered?
> >
> > Thanks.
> >
> > Michael.
> >
> > > Hello Michael,
> > > From what you're saying when the use clhaltapp on node1 both Apache
> > > daemons stop? If that is the case you will need to modify the script
> > > that is in place for the" stopscript" command for the application in
> > > the /etc/cluster/apache/appconf.xml. First thing to do is to test it-
> > > with the apache application running on node1 as well as your local
> > > Apache, run whatever the "stopscript" is. It should only stop the
> > > clustered Apache instance. If no httpd processes are running you now
> > > know that this script needs to be modified in some way.
> > >
> > > Possibly both use the same pid file (/var/run/httpd.pid)?
> > >
> > > Regards,
> > > Simon
> >
> >
> >
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