Solved

Problems with two node redhat cluster with quorum disk.

Posted on 2010-09-02
7
2,727 Views
Last Modified: 2012-08-14
Hello,

I'm building a RHEL 5.5 cluster with 2 nodes and a quorum disk. When I reboot both the nodes in the cluster at the same time, clustat shows both the nodes online and the quorum disk. When I disable one node, it fences the node and reboots. The problem is, this node is not able to quorate to the cluster and never joins back to the cluster. Hence the cluster is left with one node and the quorum disk and the node which was rebooted thinks it is online (split-brain).

Following is how my cluster.conf looks like. Any comments/suggestions will be helpful :)


<?xml version="1.0"?>
<cluster alias="clu" config_version="25" name="clu">
        <fence_daemon clean_start="0" post_fail_delay="0" post_join_delay="30"/>
        <clusternodes>
                <clusternode name="node1" nodeid="1" votes="1">
                        <fence>
                                <method name="1">
                        --                                  
                                </method>
                        </fence>
                </clusternode>
                <clusternode name="node2" nodeid="2" votes="1">
                        <fence>
                                <method name="1">
                                  --
                                </method>
                        </fence>
                </clusternode>
        </clusternodes>
        <cman expected_votes="3"/>
        <fencedevices>
          --
        </fencedevices>
        <rm>
                <failoverdomains>
                        <failoverdomain name="nofailback" nofailback="1" ordered="1" restricted="1">
                                <failoverdomainnode name="node1" priority="1"/>
                                <failoverdomainnode name="node2" priority="2"/>
                        </failoverdomain>
                </failoverdomains>
                <resources/>
        </rm>
        <totem consensus="4800" join="60" token="136000" token_retransmits_before_loss_const="20"/>
        <quorumd interval="3" label="quorumdisk" min_score="1" tko="15" votes="1"/>
</cluster>

0
Comment
Question by:smary
  • 5
  • 2
7 Comments
 
LVL 76

Expert Comment

by:arnold
ID: 33597128
Is the quorum disk on separate system?

I'm not seeing fencedevices nor fence method.
0
 
LVL 1

Author Comment

by:smary
ID: 33598267
Quorum is a shared SAN space between these two nodes and I do have fencedevices and fence method, but I've not included it here. It shouldnt make any difference in deciding this, but I can include it if required.
0
 
LVL 76

Assisted Solution

by:arnold
arnold earned 500 total points
ID: 33598457
Are you using iscsi to access the storage or do you have FC connection to the drives?
When both nodes are up, can both nodes access the data on the shared drive?
Which fencingmethod and fencing device are you using?
A complete cluster.conf would be helpful.

See if the info in http://sourceware.org/cluster/doc/usage.txt helps.
The example has FC connected storage (brocade fencing)
0
Find Ransomware Secrets With All-Source Analysis

Ransomware has become a major concern for organizations; its prevalence has grown due to past successes achieved by threat actors. While each ransomware variant is different, we’ve seen some common tactics and trends used among the authors of the malware.

 
LVL 76

Expert Comment

by:arnold
ID: 33598525
One other thing, make sure that both nodes have an identical copy of the cluster.conf file.
Each node may have itself listed as active and you have post_fail_delay="0"  which I think may lead to both trying to comeup as active nodes.

Any error message in /var/log/messages on either node.  You should also not reboot both at the same time. power off one, then reboot the other which should configure itself as the active one.  Then power up the second node which should then run and attempt to rejoin the cluster.  Double check that the IP resource is configured.
0
 
LVL 76

Expert Comment

by:arnold
ID: 33598598
Not sure which version this deals with centos is based on the redhat foundation http://www.centos.org/docs/5/

If you have access to rhn.redhat.com a similar set of documents should be available there.
0
 
LVL 1

Author Comment

by:smary
ID: 33613217
"Are you using iscsi to access the storage or do you have FC connection to the drives?"
-> FC Connection

"When both nodes are up, can both nodes access the data on the shared drive?"
-> Should be. Both the nodes can see the quorum drive online at the same time.

Which fencingmethod and fencing device are you using?"
-> IBM blade center.

I've verified the both the nodes have identical cluster.conf. The problem is, eventually when one of the two nodes goes down and is rebooted, that node can not form a quorum with the cluster and shows as offline. The node is not able to rejoin the cluster. So the logs in /var/log/messages says that 'Cluster is not quorate. Refusing connections'

I was not able to find much useful info about two node cluster with quorum disk, hence seeking help here.

Any idea why is the node not able to form quorum and join the cluster.
0
 
LVL 76

Accepted Solution

by:
arnold earned 500 total points
ID: 33613987
Other than the storage fencing, don't you also have an IP based fencing?
Can you post the cluster config?
You need to fence based on all the shared resources.
IP,
http://sources.redhat.com/cluster/wiki/FAQ/Fencing

http://www.redhat.com/docs/manuals/csgfs/browse/rh-cs-en/s1-config-fence-devices.html

What is the error if any on the active node.  I think the issue is that when a rebooted node comes up, it can not
0

Featured Post

Highfive + Dolby Voice = No More Audio Complaints!

Poor audio quality is one of the top reasons people don’t use video conferencing. Get the crispest, clearest audio powered by Dolby Voice in every meeting. Highfive and Dolby Voice deliver the best video conferencing and audio experience for every meeting and every room.

Join & Write a Comment

Suggested Solutions

In this article, I provide some information on storage disks which go into calculations that will help you figure out how much Input/output Operations Per Second (IOPS) your disk subsystem can deliver. To effectively size & tune up applications l…
It’s 2016. Password authentication should be dead — or at least close to dying. But, unfortunately, it has not traversed Quagga stage yet. Using password authentication is like laundering hotel guest linens with a washboard — it’s Passé.
Learn how to navigate the file tree with the shell. Use pwd to print the current working directory: Use ls to list a directory's contents: Use cd to change to a new directory: Use wildcards instead of typing out long directory names: Use ../ to move…
This video teaches viewers how to encrypt an external drive that requires a password to read and edit the drive. All tasks are done in Disk Utility. Plug in the external drive you wish to encrypt: Make sure all previous data on the drive has been …

746 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

13 Experts available now in Live!

Get 1:1 Help Now