Troubleshooting problems arising in vCenter/ESX Discovery

During vCenter discovery, there are two major issues that users might encounter. Below are those issues and the steps to systematically troubleshoot them:

1. Failed to connect to the VMware WebService (Device may not be reachable/Credentials may be wrong)


  1. Check whether the given IP Address/DNS Name/VMware credentials are valid.
  2. If vCenter discovery fails with DNS name, then try with IP Address.
  3. Check whether the same credential that is being used for MOB connection/vSphere client has been provided in OpManager. You can check if it is valid by accessing the vCenter URL (https://<vCenter_IP>) and trying to login with the same credentials.
  4. Check if there are any firewall restrictions that are preventing OpManager from reaching the vCenter server.
  5. Check if the provided credentials have access to all the hosts/VMs in the vCenter.
  6. Check whether the vCenter Server is being discovered via the vCenter discovery mode. If it is an ESX/ESXi host that is to be discovered, then ESX discovery mode should be selected in the discovery page.
  7. Check if a proxy server has been configured in OpManager (from Settings → General Settings → Proxy Server Settings). If it has been enabled, then OpManager will not be able to connect with the vCenter/ESX host to be discovered, and the vCenter IP/DNS needs to be added in the "No Proxy for" field to resolve this issue.
  8. From vCenter version 6 onwards, two new settings are available under the ESXi Host Advanced System Settings page:
    1. Security.AccountLockFailures: Maximum allowed failed login attempts before locking out a user's account.
    2. Security.AccountUnlockTime: Time window (in seconds) to lock out a user's account after exceeding the maximum allowed failed login attempts.
  9. Sometimes, you might encounter an error even if you provide valid credentials, with "Invalid Login exception" errror message being displayed. This can be resolved by increasing the timeout value for the connection.
  10. You might also encounter this error if you are trying to discover vCenter version 7 or higher in OpManager builds 125181 or below, since vCenter v7 is not compatible with those versions. You will need to upgrade your OpManager installation to monitor that server.

2. Device already exists in OpManager.

This means that the device you are trying to discover has already been added in OpManager, as an "Unknown" device or a physical server. If it has been discovered with a different device type and you wish to discover it as a vCenter/Host, you can:

  1. Rediscover the device using vCenter credentials by clicking the hamburger menu in the Snapshot page and selecting "Rediscover device". You can then choose the appropriate credential profile and add it as a vCenter device.
  2. Delete the device and discover it again using the Virtualization discovery wizard.
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