You can disconnect and reconnect a host that a vCenter Server system manages. Disconnecting a managed host does not remove it from vCenter Server, but temporarily suspends all monitoring activities that vCenter Server performs.

The managed host and its associated virtual machines remain in the vCenter Server inventory. By contrast, removing a managed host from vCenter Server deletes the managed host and all its associated virtual machines from the vCenter Server inventory.

If an ESXi host becomes disconnected due to a loss of network connectivity to vCenter Server, the ESXi host reconnects automatically to vCenter Server after network connectivity is restored. If you manually disconnect an ESXi host, see How to Reconnect Your Managed ESXi Host for more information.

Reconnecting an ESXi host automatically or manually does not impact the running virtual machines, unless the host is part of a cluster and there are resource pool privileges configured. For more information about creating and managing resource pools, see the vSphere Resource Management documentation.

Tip: You can use the vSphere Automation API to automate the management of managed ESXi hosts. For more information about the available options, see the vCenter Host APIs reference documentation.

How to Disconnect Your Managed ESXi Host

Use the vSphere Client to disconnect a managed host from vCenter Server.

Procedure

  1. Navigate to Home > Hosts and Clusters and select a host.
  2. Right-click the host and select Connection > Disconnect from the pop-up menu.
  3. In the confirmation dialog box that appears, click Ok.
    If the managed host is disconnected, the word “disconnected” is appended to the object name in parentheses, and the object is dimmed. All associated virtual machines are similarly dimmed and labeled.

How to Reconnect Your Managed ESXi Host

Use the vSphere Client to reconnect a managed host to a vCenter Server system.

Procedure

  1. Navigate to Home > Hosts and Clusters and select a host.
  2. Right-click the host and select Connection > Connect from the pop-up menu.
    When the managed host’s connection status to vCenter Server is changed, the statuses of the virtual machines on that managed host are updated to reflect the change.

How Do You Reconnect ESXi Hosts After Changes to the vCenter Server SSL Certificate

vCenter Server uses an SSL certificate to encrypt and decrypt host passwords stored in the vCenter Server database. If the certificate is replaced or changed, vCenter Server cannot decrypt host passwords, and therefore cannot connect to managed hosts. If vCenter Server fails to decrypt a host password, the host is disconnected from vCenter Server.

You must reconnect the host and supply the login credentials, which are encrypted and stored in the database using the new certificate.