Thanks again for replying quickly... i did not know that you can use 2
ip addresses for heartbeat.... so with a config like that your saying i
can independently have either web or mail moved over... i see not bad..
:) perhaps i can work on this later on....
However for now my boss wants some sort of failover to be working very
soon, with the configs i showed as is if Joe goes down stewie should
take over, correct?
Also if i understand you i should be using both serial and eth0 as my
heartbeat?
Thats the thing with the docs, if you can find what your looking for ,
its handy, but the problem is finding it first... :)
I have a maintenance window tonight at 11pm est and i would like to try
a failover test, do you think from my configs it should be ok? i know
DRBD is working fine, i have no problems there......
also another question the server names joe and stewie should i be using
them fully qualified in the conf file IE: joe.domain.com rather than
just joe? and that FQDN should be point to the public IP not the private
right....?
sorry for being a pain....
Thanks so much for all your help!
Rob Morin
Dido Internet Inc.
Montreal,Canada
http://www.dido.ca
514-990-4444
Dejan Muhamedagic wrote:
Hi,
On Mon, Apr 14, 2008 at 01:21:56PM -0400, Rob Morin wrote:
Thanks for the reply Dejan....
Our company has a policy to use Debian apt-get packages only, to my
knowledge what i am running is the latest available for AMD64 in apt-get i
know its not the latest.
|The point of having a service in a cluster is to make
|it more available, right? So, if your service is unstable, it
|should first be fixed.
Yes i agree with the above, but is it not better to have pop, imap, mysql
and mail deleviery working while apache is down? clients accessing some
services will be happier than having everything down...??
Agreed. However, in the setup you have, it is impossible. If you
have a single IP address as a dependency for all other resources,
then any resource failure will result in a failover of all
resources. The v1/haresources resource manager is not that
versatile and it is simply not possible to express what you want,
i.e. one dependency for all (the IP address) but that some of the
other resources are independent of each other. For that you'd
have to use v2/crm.
Implementing heart & drbd ended up being more complicated on a production
system then i expected... i had to integrate into a live systems my test in
a dev system... its not as easy as 1 2 3 i found the HA website a bit
confusing as there seems to be a mix in documentation between versions.....
Yes, it is generally agreed that the documentation is not
very good. So far nobody managed to fix it (and many tried).
Personally, I find it not too bad, just not well organized. Once
you get a grip on concepts, terminology, and clusters in general,
it boils down to searching the site (or wiki.linux-ha.org).
Unfortunately, that's not an option if one's in a hurry and there
are quite a few.
so this is why i am asking questions here... I wanted the heartbeat
implementation as simple as possible.... we use one IP for web, pop, mysql
and imap...
You would be better off with more than one IP address. In that
case, you could also have an active-active configuration. And,
more important, less artificial dependencies. I would go with at
least two: one for the mail and one for the web services.
Otherwise, a failure of one resource could bring down healthy
services. For example, according to your haresources, a failed
mail filesystem would stop not only mail services but also web
services.
I did realize an error i had in my haresources file however i had the
server name in there as primary, i should have had Joe rather than stewie,
i changed that just before i sent my email.... i prefer to use the
haresource file for config as i found the xml config a bit confusing as i
tried to use it....
Admittedly it has a rather steep learning curve and it takes some
time to get used to it. You could still create an initial XML
configuration using the conversion tool (see
http://www.linux-ha.org/ClusterInformationBase/Conversion).
I do not understand when you say i need 2 com links... you mean for
replication of of data, or for the heartbeat itself...?
For heartbeat. Otherwise you risk a split-brain which is a very
bad thing for clusters.
Thanks,
Dejan
I very much appreciate your input, thanks again...
Rob Morin
Dido Internet Inc.
Montreal,Canada
http://www.dido.ca
514-990-4444
Dejan Muhamedagic wrote:
Hi,
On Mon, Apr 14, 2008 at 09:22:08AM -0400, Rob Morin wrote:
Hello all my first post here so be gentle.... :)
I have setup already DRBD and Heartbeat-2 on 2 Debian Etch servers.
Primary named Joe secondary named Stewie
DRBD version 8 via apt-get and heartbeat-2 via apt-get version 2.0.7-2
2.0.7-2 is rather old. You would want to upgrade, in particular
if you run v2/crm style configurations.
I am using 2 NICS, eth0 which is private for DRBD replication and
heartbeat and eth1 used for my real public IP address where outsiders
connect to for the services.
See below.
I am not using heartbeat yet, but i am using drbd, as i am having a
trouble getting heartbeat to take over on the secondary server(Stewie).
The problem is Apache is dying for some reason... however i would like
the other resources to start, such as pop and mail and a couple others..
i figure its better to have only one server dead such as web , rather
than all services dead...
My question is, is it possible to have heartbeat ignore a problem when a
problem or error occurs starting up a service?
In v1 probably not, but other services/groups shouldn't be
affected. The point of having a service in a cluster is to make
it more available, right? So, if your service is unstable, it
should first be fixed.
As its is hard to troubleshoot a problem when it occurs as heartbeat
gives up if it encounters one error....
Why should it be hard to troubleshoot? There are logs I guess.
Also i noticed in the in the ha.cf file ther is a comment that says "#
Node name must be same as uname -r."
SO i have "Joe" and "Stewie" as my hostnames but if i do a uname -r on
either host i get this in return
2.6.18-6-amd64
That must be a typo. It should read 'uname -n'.
Could this be an issue... here are my conf files....
ha.cf file
-------------------------------------
logfacility daemon # This is deprecated
keepalive 2 # Interval between heartbeat (HB) packets.
deadtime 60 # How quickly HB determines a dead node.
warntime 5 # Time HB will issue a late HB.
initdead 120 # Time delay needed by HB to report a dead
node.
udpport 694 # UDP port HB uses to communicate between
nodes.
#ping 192.168.5.1 # Ping VMware Server host to simulate
network resource.
bcast eth0
You need at least two comm links for production servers. Another
link could be your public network interface.
#baud 115200
#serial /dev/ttyS0 # Which interface to use for HB packets.
coredumps true
auto_failback off # Auto promotion of primary node upon
return to cluster.
node joe # Node name must be same as uname -r.
node stewie # Node name must be same as uname -r.
###
respawn hacluster /usr/lib/heartbeat/ipfail
# Specifies which programs to run at startup
------------------------------------------------------------
haresources file
------------------------------------------------------
joe IPaddr::xxx.xxx.xxx.150 \
drbddisk::mail Filesystem::/dev/drbd0::/var/mail/virtual::ext3::defaults
apache2 mysql ispcp_daemon \
drbddisk::web Filesystem::/dev/drbd1::/var/www::ext3::defaults postfix
courier-authdaemon courier-pop courier-imap
Looks like you put everything in a single group. You should try
to split them into several, if possible. For example, I'd assume
that drbddisk::mail and drbddisk::web don't depend on each other
and that various services depend on either the former or the
latter. Then create at least two groups. If all depend on the
IP address, then all have to be in a single group if you're
running a v1/haresources based configuration. In that case, you
would want to consider a v2/crm configuration. At any rate, you
may consider introducing an extra IP address for the second group
of services.
See http://linux-ha.org/LearningAboutHeartbeat,
http://linux-ha.org/HeartbeatTutorials, and
http://linux-ha.org/GettingStartedV2 for more information.
HTH,
Dejan
----------------------------------------------------------------------------------------------------------------------
Thanks to all for your help and have a great day!
--
Rob Morin
Dido Internet Inc.
Montreal,Canada
http://www.dido.ca
514-990-4444
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See also: http://linux-ha.org/ReportingProblems
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See also: http://linux-ha.org/ReportingProblems
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