Use the fs2cs conversion utility

You can use the fs2cs conversion utility to automatically convert certain Fair Scheduler configuration to Capacity Scheduler configuration as part of the Upgrade Cluster Wizard in Cloudera Manager.

From the CDP Private Cloud Base 7.1 release, Cloudera provides a conversion tool, called fs2cs conversion utility. This utility is a CLI application that is part of the yarn CLI command. It generates capacity-scheduler.xml and yarn-site.xml as output files.

Be aware of the Fair Scheduler properties that are auto-converted, those that require manual configuration, and those that do not have an equivalent feature in Capacity Scheduler.
You must have downloaded and distributed parcels for the target version of CDP.
In VPC, to use your current Compute Cluster queue configurations in your new installation after the upgrade, you must have manually saved them before starting the update process and then added the configurations to your new installation. Else, your Compute Cluster queue configurations will be lost because the Upgrade Wizard transitions only the queues from your Base Cluster.
1. In Cloudera Manager, navigate to Host > All Hosts.
2. Find the host with the ResourceManager role and click the YARN ResourceManager role.
3. Click the Processes tab.
4. Find and save the fair-scheduler.xml and yarn-site.xml configuration files for future reference.
Ensure that the configuration is not stale, there is no unsaved changes. Ensure that there is no unsaved changes on the Dynamic Resource Pools view, meaning that the Refresh Dynamic Resource Pools button is inactive.
Reach the Copy Scheduler Settings part of the upgrade process using the Upgrade Cluster Wizard in Cloudera Manager. That is the first step when you add YARN Queue Manager service:

Download the Fair Scheduler configuration files from the Cloudera Manager data store:
1. In the Copy Scheduler Settings window during the upgrade process, click Download fair-scheduler.xml and Download yarn-site.xml to download the fair-scheduler.xml and yarn-site.xml files.
2. Copy the downloaded configuration files to any host in your cluster.
Use the fs2cs conversion utility:
1. Log in to the host machine where you downloaded the fair-scheduler.xml and yarn-site.xml files using ssh.
2. Create a new directory to save the capacity-scheduler.xml file that is generated by the fs2cs conversion utility:
```
$ mkdir -p output
```
3. Use the fs2cs conversion utility to auto-convert the structure of resource pools. Options listed between braces [] are optional:
```
$ yarn fs2cs [--cluster-resource ***VCORES/MEMORY***][--no-terminal-rule-check] --yarnsiteconfig ***FULL PATH TO yarn-site.xml***> [--fsconfig ***FULL PATH TO fair-scheduler.xml***] --output-directory ***OUTPUT PATH*** [--print] [--skip-verification]  
```
important
You have to provide absolute path for the yarn-site.xml and the fair-scheduler.xml configuration file. If only the file names are provided the command fails.
For example:
```
yarn fs2cs --yarnsiteconfig /home/hadoop/yarn-site.xml --fsconfig /home/hadoop/fair-scheduler.xml --output-directory /tmp
```
Upload the generated Capacity Scheduler configuration files to save the configuration in Cloudera Manager:
Click Choose File and select the generated capacity-scheduler.xml file to save the configuration.

note
The configurations in the generated yarn-site.xml output file have to be manually configured using Cloudera Manager Advanced configuration snippet (Safety Valves) once the upgrade is completed.

If the fs2cs conversion utility command fails, check if you provided the correct full path for the yarn-site.xml and the fair-scheduler.xml configuration file.

Proceed with the CDP upgrade.

After the upgrade is completed, manually add the yarn-site.xml configurations using Cloudera Manager Advanced configuration snippet (Safety Valves), and tune the configuration generated by the fs2cs conversion utility using Queue Manager UI and Cloudera Manager Advanced configuration snippet (Safety Valves).