### Human: Can you tell about NCC Health Check: cfs_fatal_check. ### Assistant: NCC health check cfs_fatal_check  is a check to determine if the CFS process is in a stable state.. The NCC health check cfs_fatal_check  is a check to determine if the CFS (Collector Framework Service) process is stable. The CFS process resides under the cluster_health service and sends Pulse data to Insights. The check will trigger if the CFS process has restarted at least 4 times in the past 2 hours. Until the CFS process has stabilized, sending remote support/pulse Insights data and proactive support may be delayed.Before running this check, upgrade NCC to the latest version. This check was introduced in NCC 4.6.1.Running the NCC CheckYou can run this check as part of the complete NCC Health Checks.
nutanix@cvm$ ncc health_checks run_all
Or you can run this check separately.

nutanix@cvm$ ncc health_checks run_all
You can also run the checks from the Prism web console Health page: select Actions > Run Checks. Select All checks and click Run.

This check is scheduled to run every 7200 seconds.This check will generate the CFS process that is not in a stable state alert.

Sample Outputs

For Status: PASS

nutanix@cvm$ ncc health_checks run_all

For Status: Warning

nutanix@cvm$ ncc health_checks run_all

Output messaging

Check ID140005DescriptionThis is a check to determine if the CFS process is stable. The CFS process resides under the cluster_health service and sends Pulse data to Insights. The check will trigger if the CFS process has restarted at least 4 times in the past 2 hours.Causes of failureThe CFS process could repeatedly restart if it hits an unrecoverable error, or the CFS process fails to perform a task dependent on the filesystem or zookeeper process, or if it is killed by Out Of Memory (OOM) killer.ResolutionsThe CFS process sits under the cluster_health service on the Controller VM. Verify that the cluster_health service on the affected node is running. Check the cfs.out and cluster_health service logs for more details about the cause of the crash.ImpactInsights data and proactive support can be delayed until the CFS process has stabilized.. NOTE: cfs_fatal_check may show WARN when Pulse was disabled, this is a false positive and has been fixed with NCC-4.6.3. Upgrade to the latest NCC version for a permanent fix of this issue. The CFS process could repeatedly restart if it hits an unrecoverable error, or CFS process fails to perform a task dependent on the filesystem or zookeeper process, or if it is killed by out of memory (OOM) killer.
Verify that the CFS service is running on the cluster:

nutanix@CVM:~$ ps aux | grep /home/nutanix/ncc/bin/nusights/cfs | grep -v grep | awk '$11 == "/home/nutanix/ncc/bin/nusights/cfs" { print $0 }'

Check if the CFS service has recently crashed. In the below command, the CFS process has been running for 2 days, 6 hours, 2 minutes and 33 seconds.

nutanix@CVM:~$ ps aux | grep /home/nutanix/ncc/bin/nusights/cfs | grep -v grep | awk '$11 == "/home/nutanix/ncc/bin/nusights/cfs" { print $0 }'

Verify the cluster_health service is running and check for recent fatals in the health_server.log. Note that a large number of PIDS next to the cluster_health service can indicate that the CFS process has been restarting:

nutanix@CVM:~$ ps aux | grep /home/nutanix/ncc/bin/nusights/cfs | grep -v grep | awk '$11 == "/home/nutanix/ncc/bin/nusights/cfs" { print $0 }'

Restart the cluster_health service to attempt to stabilize the CFS process:

nutanix@CVM:~$ ps aux | grep /home/nutanix/ncc/bin/nusights/cfs | grep -v grep | awk '$11 == "/home/nutanix/ncc/bin/nusights/cfs" { print $0 }'

Monitor the stability of the CFS process by re-running this NCC check or via steps 1 and 2.  
If the above steps do not resolve the issue, consider engaging Nutanix Support. Additionally, gather the following command output and attach it to the support case:  

nutanix@CVM:~$ ps aux | grep /home/nutanix/ncc/bin/nusights/cfs | grep -v grep | awk '$11 == "/home/nutanix/ncc/bin/nusights/cfs" { print $0 }'. ### Human: Now explain this as a Nutanix support agent summarizing the answer step by step. In case, you don't know the answer say - I don't know.