Starting the ESS Mode

After the ESS mode is started, you can view the startup result on the ResourceManager WebUI and submit a Spark SQL task to verify it.

Prerequisites

You have completed the operations described in Preparations.

Procedure

Configure a partition for the CapacityScheduler.
Remove the RSS configuration items from the capacity-scheduler.xml file and distribute the updated file to all nodes.
Leave the ESS compute node label blank, that is, use the default partition. See Figure 1.
```
yarn rmadmin -replaceLabelsOnNode "agent02="
```
Figure 1 ESS compute node
Complete the necessary configurations before starting the ESS.
1. Modify the /home/ockadmin/opt/ock/conf/ock.conf file to change the OCK mode to the ESS mode.
```
ock.ucache.rss.mode = false
```
2. In the Yarn startup script /home/ockadmin/opt/ock/ucache/24.0.0/linux-aarch64/sbin/ock-launch-cluster.sh, set ock_memory to a value greater than ock.mf.mem_size in the mf.conf file, and leave the partition label blank.
  An example of ock-launch-cluster.sh:
```
# If you want to set the Yarn partition label of the launch server to ESS, leave this parameter blank.
ock_master_partition_label=""
...
# Memory space occupied by OCK, in MB.
ock_memory="61440"
```
  An example of mf.conf:
```
# Memory space occupied by MF, in bits.
ock.mf.mem_size = 53687091200
```
3. Write the host names of all nodes to /home/ockadmin/opt/ock/conf/ock_node_list. For example:
```
agent01
agent02
agent03
```
  After the modification is complete, distribute the new file to all nodes.
Run the startup script.
```
sh /home/ockadmin/opt/ock/ucache/24.0.0/linux-aarch64/sbin/ock-launch-cluster.sh
```
As shown in Figure 2, the ESS mode is started.

Figure 2 Startup result

The log indicates that the OCK compute node is started successfully.

Figure 3 Log information
Submit a Spark SQL task.
If the task is executed successfully, the following information is displayed:

Figure 4 Command output

Parent topic: Starting in Yarn Mode