topic Re: Can a failover node work as scheduling node in Integration, Extension & APIs

Can a failover node work as scheduling node

rohitk1609 — Tue, 26 Sep 2017 11:10:54 GMT

Hi,

I have configured a failover node and now I need to configure one node which will handle reloading tasks, My Questions is , Can I use the same Failover node as reloading node , If yes , how ? As reloading node need to set SLAVE and if I set it to SLAVE on central and on the time when my central node stop working , will it automatically set to MASTER and SLAVE which manage and reload the tasks ?

Re: Can a failover node work as scheduling node

Vincenzo_Esposito — Tue, 26 Sep 2017 12:47:46 GMT

From the September 2017 release you can set up a RIM node as candidate master. If the master node fails the RIM node replaces it, so also the scheduler will change from slave to Master/Slave.

In previous release you need to guarantee the Master HA for Slaves Scheduler to work

Re: Can a failover node work as scheduling node

rohitk1609 — Tue, 26 Sep 2017 12:53:29 GMT

It means, when I add a new node and select the Failover Candidate and then I can use the same node for reloading purpose, by going to schedulers , and change its Type to Master and when it central node get failed, my Rim node type will change to MASTER and SLAVE automatically and it will works as central node which can do the reloads ?

Re: Can a failover node work as scheduling node

rohitk1609 — Tue, 26 Sep 2017 12:57:16 GMT

See what I am trying to do, I have a central node and one RIM node which is working as a failover node. Now I need to add one more node for reloading purpose, here I am trying to use failover node as reloading node too so I donot need to add one more node for only reloading purpose.

I ca say I am, trying to use utilize failover node in more ways.

Re: Can a failover node work as scheduling node

rohitk1609 — Wed, 27 Sep 2017 05:16:23 GMT

Hi Viencezo,

Can you please explain in detail

scheduler will change from slave to Master/Slave

I have one Central node, one Failover node and one Scheduler node. I have settled , Central Node as MASTER only, Failover node as SLAVE only and Scheduler node to SLAVE only.

As you have said, when my Central node will get down, My failover node type will change automatically to MASTER only and Scheduler node will communicate to Failover node and reload will continue , Please correct me if I am wrong

Re: Can a failover node work as scheduling node

Vincenzo_Esposito — Wed, 27 Sep 2017 06:51:40 GMT

Hi Rohit,

What I said is from the September 2017 release you can select an "Alternative Master Node". An alternative master node need to have all services (as the real master node). It work on a polling base system (by default each 10 min) check whether the master is on-line and in case of fails it replaces the master node. As result also the Scheduler on this node acts as Master.

Hope is more clear, if not don't hesitate to ask more details

Re: Can a failover node work as scheduling node

rohitk1609 — Wed, 27 Sep 2017 07:35:17 GMT

As I have configured one RIM node and on the time of adding to central node, I have selected Failover candidate which made it select all the services automatically.

But when I went to scheduler option and open my this new node, the type was there SLAVE, so as per your suggestion , I am making it MASTER, for now, There are two master type nodes in my qlik site, Central Node and Failover node

Please correct me if I am wrong somewhere

Re: Can a failover node work as scheduling node

Vincenzo_Esposito — Wed, 27 Sep 2017 13:56:32 GMT

As long as your Master node is on-line, the RIM node (master candidate) act as RIM, so the Scheduler is only Slave. The promotion to Master happen only in case of failure. Did you test this case? Wait also the setted time-out

Re: Can a failover node work as scheduling node

rohitk1609 — Wed, 27 Sep 2017 14:18:22 GMT

See, The node which i settled failover candidate and running all the services has Type SLAVE in schedulers , I can't make it master until my central node is active, Now you are saying when failover node will become MASTER TYPE after central node down, How to check it , do you have any way to check now my failover scheduler node is MASTER now ?

Re: Can a failover node work as scheduling node

Vincenzo_Esposito — Wed, 27 Sep 2017 14:37:44 GMT

If I were you I'll check the Scheduler node role (the one you're interested in). I expect to have rule Master/Slave

Re: Can a failover node work as scheduling node

rohitk1609 — Wed, 27 Sep 2017 15:26:56 GMT

How would I check when I central node down, Can I open the QMC on Failover node after getting down of Central node ?

Re: Can a failover node work as scheduling node

Vincenzo_Esposito — Thu, 28 Sep 2017 18:13:35 GMT

Yes of course you can. Since you have all service (including proxy) you can access to it

Re: Can a failover node work as scheduling node

rohitk1609 — Thu, 28 Sep 2017 18:34:14 GMT

Yes I saw we can open QMC on Rim node too.

One quick question:

I have added one RIM to CENTRAL node and created an application, added =computername() to see application is consuming which server resource, central or rim and published to a stream.

then I went to virtual proxy => Central => added my RIM in load balancing nodes

then I went to virtual proxy of RIM node and added CENTRAL in load balancing.

So now both virtual proxy has both CENTRAL and RIM

When I open my application on central node it is showing computer name CENTRAL and when I open my application on RIM it is showing RIM in computer name.

Then I disabled ResourcesOnNonCentralNodes and created a new rule and check load balancing option and filter my application id in resource filter tab and select the node as RIM

Now when I preview it is showing RIM node "B" Application

I don't know what B signifies exactly

now when I opening the application on central node it is still showing CENTRAL in computer name and it suppose to show RIM because i have written a rule for it.

Can you please help me how to run a application on CENTRAL node but consume RIM node, what I am missing ?

Re: Can a failover node work as scheduling node

Vincenzo_Esposito — Fri, 29 Sep 2017 07:59:24 GMT

The rule "ResourcesOnNonCentralNodes" make (as the description) "All resources need to be accessible on the non-central nodes, except the monitoring apps". This means resources will be shared across all other nodes. If you disable it you expect to use only the central node. Actually, you can't deny having resource on the central node due to the first rule "ResourceOnTheCentralNode" which is ReadOnly therefore unmodifiable.

try to create a new Balancing rule as:

((node.name="<RIM>" and resource.id="<APP_ID>"))

Re: Can a failover node work as scheduling node

rohitk1609 — Fri, 29 Sep 2017 09:08:12 GMT

I have disabled ResourcesOnNonCentralNodes and created the rule as you have stated but even if I open the application on master it show master and if I open the application on RIM it show RIM,

Do I need to do some configuration on virtual proxies for both central and rim node?

secondly,

Can you please tell me what if the benefit of create repository database and app storage out of the central node in shared persistence ?

Re: Can a failover node work as scheduling node

vlad_komarov — Fri, 29 Sep 2017 12:29:05 GMT

Vincenzo,

To add a little bit more complexity to the question rohitk1609 was asking: we need to have a system that works behind our own Network’s Load Balancer (F5).

And I need to setup 2 (at least) Proxy nodes that will handle the users’ traffic in this configuration. I do not want to separate users for “App 1” go to “Proxy 1” and “App 2” go to “Proxy 2”… The F5 has no control over Qlik and just redirects users to “next available” node in my case, so all Proxy Nodes are better be capable to handle all apps from all users…

I was not able to do it in the previous configuration (with QS 3.2) and I was hoping the Sept 2017 release is more flexible to handle that. Appreciate your help and suggestions…

Regards,

Vlad

Re: Can a failover node work as scheduling node

Vincenzo_Esposito — Fri, 29 Sep 2017 17:45:41 GMT

To achieve your goal should be enough to set a balanancing rule as earlier defined. Check if it works looking the resources on the server or using the operation monitor. You don't need to link users to proxys.

Re: Can a failover node work as scheduling node

Vincenzo_Esposito — Fri, 29 Sep 2017 17:48:46 GMT

You want to move db and share persistence out ou the central node to avoid any single point of failure. Of course you need to manage an HA for both (e.g. NAS/HA DB or HA VMs). In that case all the QlikSense site can still work even if the central node fails

Re: Can a failover node work as scheduling node

rohitk1609 — Fri, 29 Sep 2017 19:11:53 GMT

We are asking, what is the benefit of mode db and share location out of the central node. We already created one failover candidate. So can you please help me to know how taking DB and apps out of the central node?

what will happen if my DB or apps storage server will get down ??

Re: Can a failover node work as scheduling node

Vincenzo_Esposito — Fri, 29 Sep 2017 20:36:08 GMT

Rohit, seems this thread is getting a bit confusing and out of the original post's subject. For the benefit of all, I suggest you to close this post if the original question has been answered and open one more specific on HA configuration if this is your real need.

Just to conclude on the topic, if the node running the DB or Share folder will fail, Qlik Sense is no longer available.