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sanchayan
Creator
Creator

Multiple Management Services detected error

Hi Everyone,

We have a standalone server say X where all the QV services are installed without any clustering. All the 5 services run fine and QMC opens up as well.

We have another server say A where QVS, DSC, QDS and QMS are installed and all running fine.

--> Here QVS is clustered with QVS of server X.

Resulting in Error : Multiple Management Services detected and QVS of server X is down as a result. This error I understand may be as we cannot use QVS of server X with more than one QMC heads.

We have another server say B (used for publishing purpose only) where QDS and QMS are installed.

--> Here in QMC when I configure DSC of server A, then NO ERROR comes up, though DSC of server A is already being used by QMS of server A.

--> Here in QMC when I further cluster DSC of server A with DSC of server X. Above ERROR shows up and DSC of server X goes down as well.

NOTE : We are using QV administrator group for authentication among services.

So my question is that :

1. Why is this error only showing up when any service of server X is being utilized in any other environments service clusters?

2. Or is it that when DSC of server A is configured in QMC  of server B then also this error should be thrown? But it isnt though.

mbaeyens

Please help. Thanks.

Sanchayan Bhowmik

13 Replies
Miguel_Angel_Baeyens

If I find time, I will draw a diagram so we can discuss over the same, if you already have one, discussing over it would be much less time consuming and clearer.

To remain with Qlik's naming conventions and avoid misunderstandings, you have only 1 cluster, to which you add multiple QVS (or other services) for load balancing. That is OK.


Therefore, you have one single environment, not three.

In this single environment, named CLUSTER, you want to have three different computers with different services each, so the expected output I understand from your experiments is

Cluster name: CLUSTER (name your own if you want to be more specific)

SERVER X (initial server, installation happens here, QMS is also running, it is the server first licensed): QVS Node 1

SERVER A: QVS Node 2 (QMS must be disabled here)

SERVER B: QVS Node 3 (QMS must be disabled here)

You mention that when you want to add the SERVER A to the CLUSTER started in SERVER X, since both have the QMS service running with the same license, services go down, which is expected. Then you disable QMS and services go back to normal, which is expected.

But then you add SERVER B (which supposedly has all services running) to the CLUSTER using the QMC and you see no errors:

Is QMS running in SERVER B?

  • If yes
    • Does it already have a different license to SERVER X?
      • If yes: what for? Then you don't have a cluster, but two clusters (one cluster per serial number). If you want this server to be a member of CLUSTER, remove the server from the cluster, remove the license (leave it with no license at all), unisntall all services you don't want in this computer, and add it back to the cluster using the QMS running in SERVER X
      • If not: it uses the same license as SERVER X, but there are two different QMS.exe running in the same cluster --> This is not expected: contact Qlik Support (and engage with Qlik Consulting)
  • If not, it is expected not to throw any error

When installing a QlikView cluster, you start first with the computer which will host the QMS service, regardless other services which may be also hosted here. When you complete the installation of at least one of the QVS services of the cluster, in the same computer than the QMS or a different one, and in order to have it up and running and test, you add the license for the licenseable component: QlikView Server (QVS). Similarly, once you have installed the first QlikView Distribution Service a.k.a. QlikView Publisher, you license it using the QMC in the original and only QMS running in your cluster. DSC, QVWS and QMS do not need a license to run.

Only after you did that you can add more QVS nodes or QDS engines to the cluster. When doing so, you only install those components you need, for example, only the QlikView Server service, specifying it in the installer. Once every node is installed, you add them to the cluster in the QMC to apply the corresponding license.

You do not install all components in each server that will be part of the cluster, nor you license each separate server which will be part of such cluster, you do it only from the QMC that you installed in the first round.

If you do the other way around, and install separately each computer individually with all components, licensing it and then trying to cluster, then, that message will appear. Why? Because there are at least two QMS services running in different computers with the same license number, and since the QMS cannot be clustered (it's a technical requirement, not a license issue), it understands there is a violation of the license, shutting itself down.


That's why you don't install nor license all servers independently, but only one, and then use the QMC to add more nodes (or remove) to the already existing, licensed cluster.

For this same reason, if you are using virtual machines or instances in Amazon, you just don't clone them after installing and licensing the software, as they will have the same internal SSIDs and will conflict between them. You first have to sysprep them before installing any software, then you license Windows, and only then you should install other software. This could also be a reason why the conflict happens.

Still, if you have more than one QMS service running, working or not, it is an unsupported scenario and it can work, but it can break, which, based on your description, is what is actually happening. Each QMS generates its own set of PGO files which may not be synced and create conflicts or even lockdowns on the files, and disconnections to users, who can be sent to different nodes for the same application during the same session.

This is key to understand how a QlikView cluster works (and very similar to how a Qlik Sense multinode deployment works so far), and to take into account when you scale out, adding more computers to your cluster to balance the load or simply to have more computing power for larger applications.

EDIT: For reference, see the official help for the latest version at https://help.qlik.com/en-US/qlikview/November2017/Subsystems/Server/Content/QlikView-Server/QVSRM_Cl...

View solution in original post

sanchayan
Creator
Creator
Author

Hi Miguel,

First of all, thanks a lot for describing this in so much detail.

Also, you understood the issue correctly. The issue as you wrote lies in this part :

Quoted :

" But then you add SERVER B (which supposedly has all services running) to the CLUSTER using the QMC and you see no errors:

Is QMS running in SERVER B?

Yes, QMS is running in server B.

If yes

Does it already have a different license to SERVER X? No it does not have a separate license.


If yes: what for? Then you don't have a cluster, but two clusters(one cluster per serial number). If you want this server to be a member of CLUSTER, remove the server from the cluster, remove the license (leave it with no license at all), unisntall all services you don't want in this computer, and add it back to the cluster using the QMS running in SERVER X.

If not: it uses the same license as SERVER X, but there are two different QMS.exe running in the same cluster --> This is not expected: contact Qlik Support (and engage with Qlik Consulting) "

So this was the issue, as this is unexpected to happen. But is happening though.

Again, thanks a lot for your support.

Regards,

Sanchayan

Miguel_Angel_Baeyens

Glad to help!

But don't forget to shut that service down and disable it (or better, uninstall it) to avoid further conflicts when you need to reboot your computers.

sanchayan
Creator
Creator
Author

Hi Miguel,

Actually we need that QVS os server X node in the CLUSTER for load balancing purpose on all the weekdays when user traffic is high. So during weekdays we are switching off the QMS of server X.

On weekends we need QMS of server X node to trigger some QV tasks, so we are switching it ON again and after task reloads are done we are switching it OFF again.

This is normal and multiple QMC heads must not be there for any service. But, still the abnormal behavior is noticed for Server B's QVS when added to the CLUSTER. Thanks a lot for your help and will raise the same issue with QLIK Support.

Would be very kind of you if you can please look into this below issue as well.

Multiple QVBs spawned on QDS nodes with only a single reload resulting in Task failures

Regards,

Sanchayan