Using a Different Scheduler

Myriad uses MyriadFairScheduler by default. However, MyriadCapacityScheduler and MyriadFifoScheduler can also be used to run jobs.

The Myriad Scheduler property is set in the yarn-site.xml file:
<property>
  <name>yarn.resourcemanager.scheduler.class</name>
  <value>org.apache.myriad.scheduler.yarn.MyriadFairScheduler</value>
  <description>You can configure other schedulers from following list: 
     org.apache.myriad.scheduler.yarn.MyriadCapacityScheduler, 
     org.apache.myriad.scheduler.yarn.MyriadFifoScheduler</description>
</property>
Important: Fine-grained scaling only works with a MyriadFairScheduler configuration.

To use either MyriadCapacityScheduler or MyriadFifoScheduler:

  1. Edit the /opt/mapr/hadoop/hadoop-2.7.0/etc/hadoop/yarn-site.xml file.
  2. For the yarn.resourcemanager.scheduler.class property, specify either org.apache.myriad.scheduler.yarn.MyriadCapacityScheduler or org.apache.myriad.scheduler.yarn.MyriadFifoScheduler
  3. Modify the YARN scheduler minimum allocation properties.
    The configure.sh sets these properties to zero (0) by default. When using a different scheduler, the properties must be set (as a minimum) to the following values:
    
    yarn.scheduler.minimum-allocation-mb = 1024
    yarn.scheduler.minimum-allocation-vcores = 1
    yarn.scheduler.minimum-allocation-disks = 0
                    
  4. Copy or update the yarn-site.xml file on every node in the cluster.
  5. Restart the initial Resource Manager from Marathon.