What Is VMware vCenter Agent and How to Restart It

What is VMware vCenter Agent

The vCenter Server Agent, also referred to as vpxa or the vmware-vpxa service, which is the activated on an ESXi host when the ESXi host joins vCenter Server. VMware vCenter agent acts as the intermediate service for communication between vCenter and hostd.

If you use vSphere Client and vCenter to manage an ESXi host, vCenter passes commands to the ESXi host through the vpxa process running on the ESXi host.

How to Restart VMware vCenter Agent [2 Ways]

When an ESXi host is added to the vCenter Server, a VMware vCenter Agent service is installed and started on the ESXi host. If you get some of the following symptoms while using it, the VMware vpxa service is not available.

• Unable to connect with the VMware Infrastructure /vSphereClient to the ESX host from VirtualCenter/vCenter Server.
• Unable to directly connect with the vSphere Client to the ESX host.

vCenter Server displays the error:

Virtual machine creation may fail because agent is unable to retrieve VM creation options from the host.

Please refer to this article which will provide you with a specific solution to restart the vCenter Server Agent.

Way 1. Using VMware Host Client

Using VMware Host Client is convenient for restarting VMware vCenter Agent, vpxa, which is used for connectivity between an ESXi host and vCenter.

1. Log in to your ESXi host as root.

2. In the Navigation pane, access to Host >> Manage, and select the Services tab.

3. Right-click the vpxa service and, in the context menu, select Restart.

If you cannot open VMware Host Client, you can use remote SSH to restart VMware vCenter Agent.

Way 2. Restarting VMware vCenter Agent using ESXi Shell

The ESXi Command Line Interface (CLI) is a powerful tool for managing and troubleshooting ESXi hosts. Use an SSH client to connect to an ESXi host remotely and use the command line interface. You can use PuTTY on a Windows machine as an SSH client. Define the IP address or host name of the ESXi server, select the port (22 by default), and enter the administrative credentials in the SSH client. You should then see the console (terminal) session via SSH.

If you want to use ESXi shell directly (without remote access), you must enable ESXi shell, and use a keyboard and monitor physically attached to the ESXi server.

1. List all services available on the ESXi host (optional) with the command:

2. Find the hostd and vpxa services in the console output and check their status.

3. Restart the ESXi host daemon and vCenter Agent services using these commands:

✍ Alternatively:

• Use this command to restart all management agents on the ESXi host.

The progress of the VMware agents restart is displayed in the console output.

• Reset the management network on a VMkernel interface, by default vmk0, run the command:

This complex command consists of two basic commands separated by a ; (semicolon). The first part of the command disables the vmk0 management network interface. When this part is successfully executed and vmk0 is disabled, then the second part of the command is executed to enable the vmk0 interface. The result is that the ESXi management network interface is restarted.

In general, virtual machines are not affected by restarting agents, but more attention is needed if vSAN, NSX, or shared graphics for VDI are used in the vSphere virtual environment. Back up your VMware VMs in vSphere regularly to protect data and have the ability to quickly recover data and restore workloads.

Agentless Backup Solution for VMware vSphere

AOMEI Cyber Backup is the all-in-one data protection solution that supports the backup of VMs in VMware vSphere. The product can be installed on Windows and Linux devices, and as a VMware virtual appliance.

It simplifies the VMware backup process and present the steps with intuitive GUI interface. In addition, it offers you the following benefits.

✦ Agentless Backup: create complete and independent image-level backup for VMware ESXi and Hyper-V VMs.
✦ Flexible vSphere Backup: batch backup large numbers of VMs managed by vCenter Server, or multiple VMs on a standalone ESXi host.
✦ Multiple Storage Destinations: backup to local drive, or network destinations like Windows share or NAS.
✦ Automated Execution: create backup schedules to automate backups daily, weekly, monthly.
✦ Role Assignment: allows one administrator to create sub-accounts with limited privileges.
✦ Email notification: Send email notification when the task is completed or abnormal.

Download AOMEI Cyber Backup Trial Edition and run VMware VM backup in your infrastructure.

*You can choose to install this VM backup software on either Windows or Linux system.

Backup vSphere Virtual Machines from Central Console

1. Bind Devices: Access to AOMEI Cyber Backup web client, navigate to Source Device > VMware > + Add VMware Device to Add vCenter or Standalone ESXi host. And then click … > Bind Device.

2. Create Backup Task: Navigate to Backup Task > + Create New Task, and select VMware ESXi Backup as the Backup Type.

3. Set the Task Name, Device, Target, Schedule and Cleanup as needed.

• Task Name: you can change the task name or use the default name with an ordinal.
• Device: batch backup multiple VMs on vCenter or standalone host within one backup task.

• Target: select to back up to a local path, or to a network path like NAS.
• Schedule (optional): perform full, differential, or incremental backup, and automate execution according to the frequency you specified.

• Cleanup (optional): automatically delete the old backup copies that exceed the retention period you specified.

4. Run Backup: Now you can click Start Backup and select Add the schedule and start backup now, or Add the schedule only.

Created backup tasks will be listed and monitored separately for restoring, progress checking and schedule changing.

▶ Restore VM from Backup: Choose to Restore to original location or Restore to new location. And click Start Restore to recover the virtual machine in place.

• Restore to new location: Create a new VM in the same or another datastore/host directly from the backup to perform out-of-spacre recovery, saves the trouble of re-configuring the new VM.

Summary

Restarting VMware vCenter agents can help you resolve issues related to the disconnected status of an ESXi host in vCenter, errors that occur when connecting to an ESXi host directly, etc. This article has covered 2 methods to restart ESXi management agents by using VMware Host Client and ESXi command line.