You can use either esxcli or vicfg-hostops to enter/exit maintenance mode.

esxcli

• Enter: esxcli system maintenanceMode set --enable true
• Exit: esxcli system maintenanceMode set --enable false

vicfg-hostops

• Enter: vicfg-hostops --operation enter
• Exit: vicfg-hostops --operation exit

Note that you can use vicfg-hostops --operation info to check whether the host is finished with entering maintenance mode or is still busy.

PowerCLI

After connecting to the host or vCenter server:

• Enter: Get-VMHost <name-of-host> | Set-VMHost -State Maintenance
• Exit: Get-VMHost <name-of-host> | Set-VMHost -State Connected

When attempting to register the vSphere Replication appliance to the PSC, you may encounter this error:

Error
Server returned 'request expired' less than 0 seconds after request was issued, but it shouldn't have expired for at least 600 seconds.

On the appliance, look in the log file /opt/vmware/hms/logs/hms.log: if you see messages similar to the following, the time of the replication appliance and the PSC may not be in sync.

/opt/vmware/hms/logs/hms.log
2017-01-14 06:57:00.694 ERROR com.vmware.vim.sso.client.impl.SoapBindingImpl [main] (..client.impl.SoapBindingImpl) | SOAP faultjavax.xml.ws.soap.SOAPFaultException: The time now Wed Jan 18 12:27:31 MST 2017 does not fall in the request   ...