On-Demand App Generation (ODAG): App Reload Load Balancing

Zareh_T — Wed, 14 Jul 2021 09:37:59 GMT

Qlik Sense On-Demand App Generation (ODAG) app reloads are primarily distributed over worker scheduler nodes. The ODAG app reloads may also fall back on other nodes, including Central Node, in case no worker scheduler is available due to custom load balancing rules or scheduler node failure.

Environment:

ODAG is a three-step process in a nutshell;

Generate and validate the template app script based on current selections
Duplicate the template app
Reload the newly copied app

Below is a high-level sequence of how ODAG service identifies where to allocate the app duplication and reload;

Get valid nodes list from Qlik Repository Service
- List of load balancing candidates
- See QMC Audit for reference of valid nodes based on current load balancing rules
Select node for app duplication
- Select among nodes with Node Purpose development or both in the valid nodes list
- Note, if no valid node has development purpose, then app duplication fails and the execution stops
- Duplicate app through Qlik Sense Repository (QRS) service on the selected node
Select worker scheduler Engine for app reload
- Select among worker scheduler nodes in the valid nodes list
- Exclude worker schedulers where Engine is not available
- Select next available Engine among the remaining worker scheduler node
Fall back to the valid manager scheduler node
- If not valid worker scheduler can be found, the reload falls back to Engine on the same node as ODAG service
- If not engine on the same node as ODAG, the reload falls back to Central Node
On-Demande App generation
- Template app is copied on the node selected in step 2
- App copy is reloaded on the node selected in steps 3 and 4
- App is published for user consumption the user in a stream or My Work space

IMPORTANT: The app copy action requires Qlik Sense node purpose to be Development or Both.
NOTE: App duplication and reload can fall on the same or different nodes, depending on the Qlik Sense load balancing rules and the Node Purpose congifuration.

Troubleshooting:

Problem: ODAG app generation fails at duplication of the template app
Cause: Commonly that app reload is allocated to a node with node purpose Production
Solution: Change ODAG reload node's purpose to Both
Problem: ODAG app reload is not executed on node defined by load balancing rule
Cause: The intended ODAG reload nodes are not defined as worker schedulers
Solution: Confirm that scheduler service is running as type Worker or Both on the expected ODAG reload nodes

References:

Re: On-Demand App Generation (ODAG): App Reload Load Balancing

BuTbka — Fri, 09 Sep 2022 10:14:04 GMT

Is there any way to prevent the use of the central node for ODAG applications?

Re: On-Demand App Generation (ODAG): App Reload Load Balancing

Sonja_Bauernfeind — Wed, 21 Sep 2022 08:22:11 GMT

Hello @BuTbka

You can configure load balancing rules to narrow down what nodes you wish to be used. See ODAG: Controlling reloads in a multi-node environment. If you require further assistance, I would recommend posting your query directly in our Qlik Sense Deployment and Management forum to make use of the wider reach into our community and our active support engineers.

All the best,
Sonja

article On-Demand App Generation (ODAG): App Reload Load Balancing in Official Support Articles

On-Demand App Generation (ODAG): App Reload Load Balancing

Environment:

Re: On-Demand App Generation (ODAG): App Reload Load Balancing

Re: On-Demand App Generation (ODAG): App Reload Load Balancing