Best Practices of Qlik Sense Multi-Node Setup, Load Balancing & Maintenance(Let's Discuss Here)

[rohitk1609]

Hello Everyone,

First of all, thanks for reading! I found it is amazing to connect myself to people around the world and communicate with my writings.

This page is indented to discuss best practices for  Multi-Node Setup & Load Balancing primarily, You may drop your use case or problem in comment, we will provide you best possible solution instantly.

Below content guide you to set up Multi-Node Qlik Setup & Load Balancing. It will help you to know Qlik technical terms, ask question more precious way which will help usor anyoe to provide solution more accurately.

Business intelligence is an agile process, gradually BI solution changes and updates. Enterprise grows so are data and end users.

When data grows and business logic gets complex, we need more resources to calculate the result and serve to users. Afterwards, Single Node (small) site performance decreases with time which could lay down the credibility and quality of BI solution.

Multi node site is  Qlik site(could have multiple Qlik servers ) where load is getting managed between more than one system and could have more than one  Fai-lover Candidate which takes charge in absence of central node automatically.

Note: we can have multiple fail-over candidates in one site, we call it passive central.

There are certain parameter which help you to take decision whether we should move to multi node site or remain on single node.

Qlik Sense Enterprise on Windows on-premises Deployment Scenarios

So below content is for such users who have made mind to upgrade their Qlik site to multi node.

Few naming conventions we will follow in below content:

1. Consumer node: which must has proxy service enable
2. Scheduler node: which has scheduler and engine services are enabled
3. Central: which is controlling whole Qlik site.
4. Failover Candidate(Passive central)
5. Resources: RAM and Cores(virtual cores)

Since June 2017 , installation setup has shared persistence way only where Apps and RepoDB data stay at persistence layer and both are shared with other nodes (rim or child).

Now why do we need to share Apps and Repository data with child or rim nodes?

Answer: to manage load in simple

Next Question: what exactly we share to balance the load practically?

Answer: Resources in Qlik site.

Next Question: what will be achieved if we share the resources?

Answer: Reduce the resource consumption while end users are accessing apps from one node i.e. central to consumer node (proxy service is must) and reduce the resource consumption and distribute it to scheduler node (scheduler and engine service is must) while any app reloads.

There could be many scenario how you would design your multi node site:

1. You want one central and one consumer and one scheduler node.
2. Two scheduler and two consumer and central
3. Central and scheduler node.

Ideally: Two scheduler and two consumer and central node comes in best practice for extra large enterprise.

You can read about single node, small, medium , large and extra large Qlik shared site in detail:

Qlik Sense Enterprise on Windows on-premises Deployment Scenarios

Multi node site would increase your Qlik Sense site availability, how?

We have a concept fail-over candidate, which is one of the scheduler node or such node which has all services and take charge automatically while Central node is down. We can manipulate the sensing time of failover candidate to central node in latest version.

Solutions which will guide you to deply multi node side

1. How to Install multi node site:

Installation of Multi Node site

Installing Qlik Sense in a multi node site - Qlik Sense

1. How to configure multi-node site:

Installing Qlik Sense in a multi-node site

       2.  Load balancing:

Adding load balancing

Configuring load balancing to isolate development nodes

          3. Fail-over candidate

Fail- candidate or we can call it passive central node which is ping in a set time(you can customize it below 10 minutes) to central or master node and when it doesn't get response it will take charge and become active central or master node.

Note: Where you install your postgresDB during installation that server has one extra service Qlik Repository Database which is running the postgresDB. So in case you don't have a dedicated persistence layer and installed Repo DB on central node(any server which has Qlik Sense too) then if your central node get down due to power failure or blue screen then fail-over node won't take charge. 

Primary condition of fail over concept needs QlikSenseRepositoryDatabase to be run all time. if QlikSenseRepositoryDatabase is down then whole site is down. 

One important application is attached to article which helps you to review your Qlik site. If you  have any concern over Qlik repository size, QLogs DB size or any component which is accessing excess size than expected, then download the app, import to your Qlik Sense, open it on HUB, there will be three connection which come along with application i.e. PostgreSQL_postgres, PostgreSQL_QLogs and PostgreSQL_QSR. Update password with your super user password of postgresDB which you entered during installation and save it. 

If your user name added as postfix after updatation of connections , go to QMC and make it as they were earlier.

Please do above activities by RDP not from end user side. Reload the app and share it with me so I can review it.

After utilizing above solutions, please post your queries in comment section what is your use case i.e. how many servers are available, how your user comes to site, network load balancer is available or not, reloads are executing on scheduler nodes etc.

In general, multi node or load balancing concept is vast and vary with client to client, so I do believe you may ask question much better when you understand the right terms of Qlik, went through above articles and requirements are clear.

Consider this resource as a open form where we all can post our queries on load balancing and multi node site.

There are few other documents which would help you in Qlik administration

1.Dynamic Sheet Exception With Stream and App Level Security

2.Sheet or App Object Level Security Qlik Sense

Reach to me if there is need of any clarification or need assistance with kumar.rohit1609@gmail.com

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When applicable please mark the appropriate replies as ACCEPT AS SOLUTION and LIKE it. This will help community members and Qlik Employees know which discussions have already been addressed and have a possible known solution. Please mark threads as LIKE if the provided solution is helpful to the problem, but does not necessarily solve the indicated problem. You can mark multiple threads as LIKE if you feel additional info is useful to others.

Thanks,
Rohit Kumar

[prasanthanr]

Dear Mr. Rohit ,

Answer to your query: 1) We couldn't access QMC via the public domain or IP via the virtually proxy of the proxy node. However, we could access the QMC locally in the central node server via the virtual proxy of the central node using the hostname. What might be the reason for this? We have removed and reinstalled the certificates also

Answer(Question asked by you): When you say you couldn't access QMC from virtual proxy, Here, can you access hub? if not , did you check your public DNS, did you add virtual proxy IP address or DNS host name to white list host ids in virtual proxy section of Proxy server.

Answer to your query

We can access only the hub when we are going through the virtual proxy of the Proxy Node. We also have checked the DNS and done whitelisting the Public IP address and the public domain on the Virtual Proxy of the Proxy Node.

when accessing the QMC it is showing an error that "Request to the Server was aborted"

Testing 2 - HA Solution  

Load balancing says, when you current master or central node is down , failover server takes change but shut down proxy server is not the right way of testing. You should stop central node services and test faillover candidate takes charge or not? This is how to check load balancing.

Question

Once the services are started again on the Central Node… Do we need to shut the services of the failover node to transfer the work back to  Central Node? Or is this an automatic process

[rohitk1609]

@prasanthanr 

Answer to 1st query: You need to investigate why this error is coming "Request to the Server was aborted". Seems like configuration issue.

2. You can desgin a API request script and run it by Powershell and run it whenever your central node is up. I have seen people run the script and it makes central node back to Master node and to do this you don't need to stop and start services. Stopping Failover server's services and wait for some time is bad idea. This is again down your Qlik site for several minutes which would loose credibility of Qlik site.

Thanks,
Rohit

[akhil_jain]

 Need your guidance to resolve the Network Load Balancer issue at one of our clients.

Requirement is to have a high availability environment . Load balancer should distribute the loads equally on both the servers.

1) We have installed a Multi Node Architecture at one of our clients:

• Central Server 
• Rim Server (FailOver Candidate)
• PostGres Database 
• SAN Drive btw Central  and RIM Server

 2) On top of it we have Load Balancer to redirect our users' requests to QlikSense. (as shown in the attached Snapshot)

With this architecture we have tested 3 Scenarios:  

1st Scenario:

  - IT team has only passed the Central Server IP request from Load Balancer , after this when we run a request with URL https://xyz outside the server  it is redirected completely fine on QlikSense Central Server ( https://xyz/hub).  

2nd Scenario:

- IT team has only passed the Rim Server request from Load Balancer , after this when we run a request with URL https://xyz outside the server  it is redirected completely fine on QlikSense RIM Server ( https://xyz/hub).  

3rd Scenario

-  IT team has passed both the  (Central) and  (RIM) Server request from Load Balancer , after this when we run a request with URL https://xyz outside the server it is giving a "Page not found error" .

We need your guidance to verify if it is an issue at Load Balancer end or we are missing some configuration level at Qlik Level. The IT team had tried their hands on solving this issue from Load Balancer but they could not find any problem. 

[rohitk1609]

If Qlik is accessible from host name or IP address of server and not accessible via NLB link it seems like it is issue from NLB.

What error it throws back? any specific message?

Thanks,

Rohit

[zlamrani10]

Hello Mr Rohit,

I have a question if you can help me. I'd be grateful.

I've added a new rim node to an existing cluster (a central and a one rim node), to optimize the applications because we have large data volume (later I'll add a consumer node and a schedular) but for the moment I'm testing.

I have a problem with the new node, it appears offline on the Central QMC. The services on the new rim node start except the qlik sense repository service, it suddenly stops.

Could the reason be that the new node is not on the same subnet as the Central ?

Thank you.

ZL.

[rohitk1609]

@zlamrani10  Please go to Programdata=>Qlik=>Sense=>Logs=>Repository=>Trace and tell me what is the error message you can see?

[zlamrani10]

thank you for your answer.

I see this one :

Unhandled exception: Access to the path 'Qlik.Sense.Common_CertificatesInstalled' is denied.↓

and in qmc :

[rohitk1609]

Please confirm me few points:

1.Did you install the certificates while adding new node in QMC?

2. All required ports are open between central and rim node?

3. Service user on both node is same and access to folders from one server to another?

At last try this one

https://community.qlik.com/t5/Qlik-Support-Knowledge-Base/Rim-node-not-communicating-with-central-no...

If a post helps to resolve your issue, please mark the appropriate replies as "Accept as Solution" or Like it.
Best,
Rohit

[zlamrani10]

Hello Mr Rohit,

Thank you for your answer.

1. Yes 

2. Yes rim node( 4444, 4242, 443), i don't know if i have to open new ports in the central  for the new rim node.

3.Yes

You think both node should be in the same subnet ? i find this :

https://support.qlik.com/articles/000038891

I will try restoring certificates and let you know if it can resolve my issue.

Thanks a lot.

ZL.

[zlamrani10]

Hello Mr Rohit,

Thanks a lot, this link helped me :

https://community.qlik.com/t5/Qlik-Support-Knowledge-Base/Rim-node-not-communicating-with-central-no...

Thank you.

ZL.