Diagnosing an ESXi/ESX host that is disconnected or not responding in VMware vCenter Server

Symptoms

For more information, see  Location of VMware vCenter Server 6.0 log files (2110014)

Purpose

This article guides you through the process of troubleshooting an ESXi/ESX host that is in a disconnected or a not responding state in vCenter Server. It provides steps to help you eliminate common causes for your problem by verifying that the configuration of your networking and management server agents is correct, as well as confirming the availability of resources on your ESXi/ESX host.

Resolution

Validate that each troubleshooting step below is true for your environment. Each step provides instructions or a link to a document to eliminate possible causes and take corrective action as necessary. The steps are ordered in the most appropriate sequence to isolate the issue and identify the proper resolution. After each step, try to connect to vCenter Server. Do not skip a step.

VMware ESX/ESXi host that is in a Not Responding state

ESXi

1. Verify that the ESXi host is in a powered ON state. For more information, see Determining why an ESXi/ESX host was powered off or restarted (1019238).
2. Verify that the ESXi host can be reconnected, or if reconnecting the ESXi host resolves the issue. For more information, see Changing an ESXi or ESX host's connection status in vCenter Server (1003480).
3. Verify that the ESXi host is able to respond back to vCenter Server at the correct IP address. If vCenter Server does not receive heartbeats from the ESXi host, it goes into a not responding state. To verify if the correct Managed IP Address is set, see Verifying the vCenter Server Managed IP Address (1008030) and ESXi 5.0 hosts are marked as Not Responding 60 seconds after being added to vCenter Server (2020100). See also, ESXi/ESX host disconnects from vCenter Server after adding or connecting it to the inventory (2040630) and ESX/ESXi host keeps disconnecting and reconnecting when heartbeats are not received by vCenter Server (1005757).
4. Verify that network connectivity exists from vCenter Server to the ESXi host with the IP and FQDN. For more information, see Testing network connectivity with the ping command (1003486).
5. Verify that you can connect from vCenter Server to the ESXi host on TCP/UDP port 902. If the host was upgraded from version 2.x and you cannot connect on port 902, then verify that you can connect on port 905. For more information, see Testing port connectivity with Telnet (1003487).
6. Verify if restarting the ESXi Management Agents resolves the issue. For more information, see Restarting the Management agents on an ESXi or ESX host (1003490).
7. Verify if the hostd process has stopped responding on the affected ESXi host. For more information, see Troubleshooting vmware-hostd service if it fails or stops responding on an ESX/ESXi host (1002849)
8. The vpxa agent has stopped responding on the affected ESXi host. For more information, see Troubleshooting the vCenter Server Agent when it does not start (1006128)
9. Verify if the ESXi host has experienced a Purple Diagnostic Screen. For more information, see Interpreting an ESX/ESXi host purple diagnostic screen (1004250)
10. ESXi hosts can disconnect from vCenter Server due to underlying storage issues. For more information, see Identifying Fibre Channel, iSCSI, and NFS storage issues on ESXi/ESX hosts (1003659).

ESX

1. Verify that the ESX host is in a powered on state.
2. Verify that the ESX host can be reconnected, or if reconnecting the ESX host resolves the issue. For more information, see Changing an ESXi or ESX host's connection status in vCenter Server (1003480).
3. Verify that the ESX host is able to respond back to vCenter Server at the correct IP address. If vCenter Server does not receive heartbeats from the ESX host, it goes into a not responding state. To verify if the correct Managed IP Address is set, see Verifying the vCenter Server Managed IP Address (1008030). See also, ESXi/ESX host disconnects from vCenter Server after adding or connecting it to the inventory (2040630)
4. Verify that network connectivity exists from vCenter Server to the ESX host with the IP and FQDN. For more information, see Testing network connectivity with the ping command (1003486).
5. Verify that you can connect from vCenter Server to the ESX host on TCP/UDP port 902. If the ESX host was upgraded from version 2.x and you cannot connect on port 902, then verify that you can connect on port 905. For more information, see Testing port connectivity with Telnet (1003487).
6. Verify that the ESX management service vmware-hostd is running. For more information, see Verifying that the Management Service is running on an ESX host (1003494) and Troubleshooting vmware-hostd service if it fails or stops responding on an ESXi/ESX host (1002849).
7. Verify that the VirtualCenter agent service vmware-vpxa is running. For more information, see Verifying that the vCenter Server Agent Service is running on an ESX host (1003495).
8. Verify that the xinetd service is running. If xinetd is not running, authentication may fail. For more information, see Determining if the xinetd service is running on an ESX host (1007323).
9. Verify if restarting the ESX Management Agents resolves the issue. For more information, see Restarting the Management agents on an ESXi or ESX host (1003490).
10. Verify that no processes are over-utilizing the resources on the Service Console. For more information, see Checking for resource starvation of the ESX Service Console (1003496).
11. ESX hosts can disconnect from vCenter Server due to underlying storage issues. To investigate further, see Identifying Fibre Channel, iSCSI, and NFS storage issues on ESXi/ESX hosts (1003659).

VMware ESXi host that is in a Disconnected state

1. The affected ESXi host has been explicitly disconnected by a user from the vCenter Server. For more information, see the Disconnecting and Reconnecting a Host section of VMware vSphere 5.1 Documentation.
2. The ESXi host license has expired. For more information, see the Licensing for ESXi Hosts section of the VMware vSphere 6.0 Documentation.
3. Firewall issues that is preventing traffic to pass through Port 902. For more information, see TCP and UDP Ports required to access VMware vCenter Server, VMware ESXi and ESX hosts, and other network components (1012382)

Note: If your problem still exists after trying the steps in this article:

• Gather VMware Support Script Data. For more information, see Collecting diagnostic information in a VMware Virtual Infrastructure Environment (1003689).
• File a support request with VMware Support and note this Knowledge Base article ID (1003409) in the problem description. For more information, see How to Submit a Support Request.