Clustering Issues

[#1]

Hi,

We recently got a cluster license and after trying to cluster the 2 server we are experiencing inconsistency.

The setup:

- 2 Servers (for the sake of server names lets call server 1 as server A and server 2 as server B)

- Each server running all the default QV services

- We have put a VIP (Vitual IP with Stickeness) on top of the 2 server in round robin mode so that the load on the web app is distributed equally

- The QVD files are located on server A and are shared with a UNC path (\\ servername\C$\path....). Both servers are pointing to a shared drive

- 64bit server on windows 2008

Issues we are facing:

- Server A where we have put in the cluster license first sees both servers and it appears that the cluster is setup correectly

- Server B does not see server A. It appears that its pointing to local host even though the cluster license has been put in and all the clustering steps are followed

- Server A shows the cluster name and Server B shows local host under cluster section as well as access point server connections

- I have tried to use the QvsStatus tool from server A and see clustering for both server up and running however when going fro B server, I only see localhost

[garystrader · Accepted solution]

First problem - you shouldn't install all the default QV services on each server.  In particular, you should only have one QMS installed.  There is supposed to be one master QMS within an environment that coordinates everything between the multiple servers.  If you have multiple the can conflict with each other, and it's possible this is your problem.

Rather than trying to fix it, I would get the official clustering setup document from QlikTech Support and start from scratch.  Otherwise you may spend days troubleshooting a corrupted environment.

[Bill_Britt]

I would agree with Gary here. This isn't something you can easly fix. I am going to mark Gary's answer as the correct answer also.

[#4]

Gary,

Thanks for your inputs. Interestingly enough, I did follow Qlikview white paper documentation on clustering, however it still does not seem to work as expected. It does not say anywhere in the document that all the services should not be installed on the same servers. I think the issue is that the 2nd server does not recognize the 1st server as a cluster and I think there are some settings which need to be configured on the second server to get it recognized.

Have you setup clustering before and if so, did you have to copy or replicate the xml files from master server to the other servers in the cluster?

Thanks.

[garystrader]

I have set up clustering many times.  I've never done anything with XML files.  When properly set up, the cluster servers coordinate with the others via the shared PGO files.

Can you attach the documentation you're using, and if I have time I will see if it's the same documentation I've used before.

[Bill_Britt]

Gray, I am writing him an email offline right now. I am going to try to explain the differences in setup so he will understand that he doesn't need everything on the second server.

[markmccoid]

Hi,

I'm going through the same thing with Clustering.  I'm going to try and attach the document I followed, but would be very appreciative if you have more detailed information.

This document (From QV Support) seems focused just on the clustering the server without mention of the other services.

Thanks,

Mark

[garystrader]

That's the correct document, although there might be a new version out.  The steps in the document aren't very detailed, but the basic idea is that you should only have one QlikView Management Service installed in your environment.  In the minimal possible configuration, you would have three servers.  On the first server you would do a full service install - all five services will be installed - QVS, QVWS, QDS, DSC, and QMS.  On server 2 and 3, you only install QVS.  These two servers are "headless", they don't have a local QMS to manage them.  You would license server 1, and add server 2 and 3 QVS instances to the server 1 cluster configuration in QEMC system/setup.  You do NOT add server 2 and 3 to the "QlikView Servers" list shown in the tree menu in system/setup.  Again, they're headless and you're not supposed to be able to configure them independently of the cluster.

As of version 10 you can cluster QDS and DSC, but this isn't something that you would do by default.  The clustering of each service serves a different purpose and it's only worth purchasing and setting it up if you need it.

[markmccoid]

Thanks for the clarification Gary.

Another question...we had originally thought about doing an active/passive failover, but then decided to go with the cluster, however when looking at the recommended configuration, it looks like if the server with the Managment server and web server on it failed, we would be dead in the water.

Do you have any recomendations on making a cluster more resilant?

I'm no expert with clusters and the like, so I may have missed something obvious.

Thanks,

Mark

[garystrader]

In a QlikView Server cluster, the single point of failure are the PGO files which are located on a network share.  Since QlikTech does not currently support storing PGO files on a SAN or NAS, you are stuck with local drive shares.  If the drive fails (hopefully you have RAID), or the server dies or crashes, your cluster is dead.  I am not aware of a workaround or alternative.

A single web server would also be a single point of failure.  For this reason they are commonly put in a "cluster" of two or more web server machines, with a hardware load balancer directing sticky sessions to them.  You can do this without any special licensing, but it does require a hardware load balancer.

With any QlikView service, you can always set up a cold failover.  Have servers on standby and when one of the active servers dies, apply the license to the failover machine, repoint DNS, etc.