Creating an alarm in VMware vSphere for a specific service like NTP (ntpd) when it stops is not directly available through the standard alarm definitions in the vSphere Client. However, you can achieve monitoring and alerting for the NTP service status through a combination of custom scripting and vSphere's ability to trigger alarms based on certain conditions or events.
Here's a general approach to setting up an NTP service alarm:
Step 1: Script to Check NTP Service Status
First, you need a script that runs on each host to check the status of the NTP service. This can be a simple shell script for ESXi hosts. For example:
#!/bin/sh
# Check NTP service status
ntpStatus=$(esxcli network firewall ruleset list | grep ntpClient | awk '{print $2}')
if [ "$ntpStatus" != "true" ]; then
# NTP service is not running, perform an action
echo "NTP service is stopped."
# Potentially log this event or trigger an alert directly from here
else
echo "NTP service is running."
fi
This script checks the status of the NTP client ruleset as a proxy for the NTP service running status (since direct `ntpd` service status checks might vary based on ESXi version and setup). You might need to adjust the script based on your specific requirements or the exact method you use to determine the NTP service status.
Step 2: Schedule Script Execution
Use the `cron` tab on ESXi hosts to schedule regular execution of the script. Editing the `crontab` on ESXi requires enabling SSH and directly editing the file `/var/spool/cron/crontabs/root`, then reloading the cron service. This process is not officially supported by VMware and can be overwritten by updates or patches, so proceed with caution and consider the implications.
Step 3: Integrate with vCenter Alarms
For the script to integrate with vCenter alarms, you need a mechanism to report the status back to vCenter. One approach is to use the VMware PowerCLI or vSphere API to create a custom event or use an existing event type within vCenter when the script detects the NTP service is stopped.
An example PowerCLI command to create a custom event might look like this:
Connect-VIServer -Server <vCenterServer> -User <username> -Password <password>
$vmHost = Get-VMHost -Name <HostName>
$event = New-Object VMware.Vim.HostEvent
$event.createdTime = Get-Date
$event.userName = "Automated NTP Check"
$event.fullFormattedMessage = "NTP service is stopped on host: <HostName>"
$vmHost.ExtensionData.CreateUserEvent($event)
Disconnect-VIServer -Server <vCenterServer> -Confirm:$false
Step 4: Create a vCenter Alarm
- In the vSphere Client, navigate to the alarms definition section (under the Configure tab of the vCenter or ESXi host object).
- Create a new alarm and select the trigger as a specific event or condition that matches what your script reports. Since this involves a custom event, you'll need to look for that event or a generic catch-all event type if your script uses an existing event type for notification.
Considerations
- This approach requires custom scripting and scheduling, which may not be supported by VMware.
- Directly modifying ESXi `crontab` or other configurations can be overwritten by updates or not recommended in a production environment without thorough testing.
- Consider the security implications of enabling SSH and running custom scripts on your hosts.
For a more supported and integrated solution, consider using existing monitoring tools that can check service statuses and integrate with vCenter or your organization's alerting mechanisms. VMware vRealize Operations Manager, for example, offers extensive monitoring capabilities and might be able to achieve similar outcomes with less manual scripting and configuration.
