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Introduction

Either during the installation of Denodo or in a subsequent stage, users might come across licensing errors. These can arise for various reasons, such as attempting to use more cores than the available amount or operating on an expired license.

In this document, we will be guiding you through the most common issues Denodo users come across when they face licensing issues, in hopes you can easily troubleshoot and learn about these for future reference.

Before starting, it is important to quickly understand how licenses work in Denodo. You can find more information on the subject under our Solution Manager Administration Guide on How Licenses Work.

In most scenarios, licensing is managed through the Denodo License Manager Server. Each component requests a license from the License Manager every time it boots, and checks it periodically to ensure the license is valid at all times.

When a Denodo Server component starts, it requests its license as explained before and revalidates it. If the validation is successful, the server runs normally. If there is any problem during this process, the server will shut down, which can be due to:

  • The license is expired. Note that after a license expires there is a Grace Period. The grace period is a period of time in which the server can still work normally, despite not having a valid license. This period is composed of 5 days. However, this grace period only applies to Denodo components that are already started, a new Denodo component cannot be started if the license is already expired.
  • The License Manager received a request to free the license assigned to that server. See Free License Usage for more information.
  • The license is invalid.
  • The license has changed. In this case, a new row is added with the new license.
  • The maximum number of cores/processors defined by the license was exceeded.
  • The maximum number of servers defined by the license has been exceeded.

Normally Denodo licenses limit the number of cores and servers that are allowed to run. To be able to determine the number of cores and servers allocated to a particular environment, Denodo uses License Scenarios.

For instance, if using the example of a typical multi-server license with a limitation of 8 cores, the administrator will be able to configure unlimited servers for non-production environments (License Scenarios), provided each server uses a maximum of 8 cores. However, for the production environment, a maximum of 8 cores in total can be used, for instance, 1 production server with 8 cores or 2 production servers of 4 cores each.

By allocating a License Scenario to each server, License Manager will be able to tell which server belongs where and distribute the cores accordingly. Hence, if an environment attempts to use more cores than the allocated amount, it will result in the License Manager triggering an error message.

An appropriate solution to this would be to turn off one of the servers, which will then release the cores necessary for other instances to run.

Common Errors Messages and How to Troubleshoot Them

Now with a fundamental understanding of how licenses work in Denodo, we can address the most common issues users face. The following section outlines their causes alongside potential solutions.

Remote license not found. The maximum number of processors defined in the license for the environment “<ENVIRONMENT_NAME>” was reached. There are 0 processors available but 8 have been requested (MaxTotalProcessors: 8)

As seen before, this is one of the most common scenarios, where the maximum number of cores allocated to an environment has been reached, hence the License Manager does not allow any extra server to run as it will require the need to use more cores than the allowed threshold.

Note that sometimes the servers might not be running but users still face this error message. This happens if the servers have been stopped unexpectedly. In this specific scenario, administrators need to notify the License Manager that the license for this certain Denodo server is no longer in use, as it most likely has not been released.

To debug this issue:

  1. Open your Denodo Solution Manager Administration Tool and navigate to License Usage.
  2. Verify if the license is blocked in grace period. If this is true, there might be two reasons:
  • The license might have expired.
  • There is a connection issue between the License Manager and the Virtual DataPort server.

To solve this issue, you need to free up the license usage of all servers that are in grace period. To do this, follow the steps highlighted in the Solution Manager Administration Guide on Free License Usage.

Once done, go back to the Solution Manager’s License Usage table to ensure the license has been freed up. You can then attempt to start the server after verifying this.

Alternatively, to force the release of the license when cores are not being used or have not been correctly released, you can reinstall the license, by navigating to Licenses > Install License under your Solution Manager Administration Tool.

Error obtaining license (1/3). Retrying in 5000 ms. Connection refused

This error can be triggered by a number of different reasons, which are often connected to some network failure, either the actual network infrastructure or between the Denodo Server component and the License Manager.

Be aware that this scenario is common after reboots, this is, when rebooting Solution Manager and the Denodo Server, if these are rebooted at the same time, there might be a chance the Denodo Server boots first and tries to retrieve the license when the License Manager is still being started.

Hence, we advise that when doing planned reboots, to ensure that there is a delay between the start time of the Denodo server and the Solution Manager server. If you are using startup scripts to start your Denodo services automatically, you can specify a delay to be triggered automatically once the operating system starts.

If the problem still persists we recommend to use network tools to verify the connectivity between the Denodo server and the License Manager server. More specifically to verify that the License Manager host and port (by default 10091) are reachable from the Denodo server host.

Remote license not found. The server is not registered in Solution Manager

This error is thrown when the Solution Manager is not able to resolve the license request as the server’s host and port do not match with any of the servers created in the Solution Manager.

Therefore, in order to solve this error, you should ensure that you have created the server in your Solution Manager server.

Note that each server, meaning Virtual DataPort, Scheduler, Data Catalog - need to be created inside their designated cluster in your Solution Manager server. You can find more information in regards to this in our Solution Manager Administration Guide on Creating Servers.

References

How Licenses Work

Free License Usage

Creating Servers

Disclaimer
The information provided in the Denodo Knowledge Base is intended to assist our users in advanced uses of Denodo. Please note that the results from the application of processes and configurations detailed in these documents may vary depending on your specific environment. Use them at your own discretion.
For an official guide of supported features, please refer to the User Manuals. For questions on critical systems or complex environments we recommend you to contact your Denodo Customer Success Manager.

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