How to Rollback an ESXi host from 6.5 to 6.0?
In many scenarios we need to rollback our ESXi server to previous update/version. ESXi has the inbuilt feature from where rollback is possible. It is quite simple you just need to SSH host and reboot the host from GUI and select the recovery options (Shift + R).
But before you go for rollback here are few points that needs to be considered first as reverting ESXi host is only valid if the host was updated using these methods:
- VIB installation or removal
- Profile installation or removal
- ESXi host update using VMware Update Manager
- Updated from a ISO
On the Live environments where reverting is required, put the host into maintenance mode by vmotion the VMs to other hosts.
On issue where ESXi host stuck at boot loop.
In case host doesn’t go on recovery option, you can check Recovery Mode for a previous version, you can check the boot banks for additional builds. Run below command from SSH for boot config file:
tail -2 /*bootbank/boot.cfg
Output of this command will be as given in below figure
As we can see here, the primary boot bank contains ESXi 6.5 code and the alternate boot bank contains ESXi 6.0 code.
If you are using full features of vSphere 6.5 make sure you check compatibility against vSphere 6.0. Two things which must be checked prior reverting from 6.5 to 6.0 are VMFS and virtual machine hardware versions.
- VMFS 6: VMFS 6 was introduced with vSphere 6.5. However, vSphere 6.0 utilized VMFS 5. If you created a VMFS 6 version with ESXi 6.5, you will not be able to access the datastore after rollback.
- VM Hardware Version: vSphere 6.5 also introduced version 13 virtual machine hardware. Version 13 hardware is not compatible with ESXi 6.0. Version 11 or lower is compatible. However, there are a few supported options for downgrading virtual machine hardware versions.
- In the console screen of the ESXi host, press Ctrl+Alt+F2 to see the Direct Console User Interface (DCUI) screen.
- Login with Root account.
- Press F12 to go into boot options and then Press F11 to restart the host.
- Watch the console, when ESXi host start booting you will see two booting options at bottom right corner as given in below figure:
- Press Shift+R in order to go for rollback to previous version.
- After pressing Shift+R you will see another screen with Hypervisors as below:
- Press Y to continue
Once ESXi gets reverted to previous version there are chances when it will not connect automatically in vcenter. Try connecting the host manually by Right Click > Connect.
Exit Maintenance Mode.
NOTE: Before doing any rollback in production environment, make sure you check all the given pre-requisites, better to check with VMware support.(Pre-requisites may differ from Infrastructure to Infrastructure). Ensure to take a good backup of ESXi host configuration before rollback.