I have been upgrading some VMware clusters lately and I figured I would put together some steps that you should normally follow when doing so. This post is more of a guideline rather than being very detailed as compared to my other posts. With that said, let’s get started

1. The first thing that you normally update should be vCenter and it is a good idea to always take a snapshot of the VM before doing so. If everything goes as planned then you can safely delete the snapshot once you are done.

2. Once vCenter is upgraded you want to upgrade VMware update manager(VUM) next if you have it installed. If you have other VMware appliances then these should be upgraded as well.

3. The next component that gets upgrade is your ESXi hosts.

Note 1: We can have different version of hosts in the same cluster but we must make sure that the hardware matches so that we can vMotion across them.

When upgrading hosts you want to place them in maintenance mode to migrate the VMs off it. Once there are no VMs on a host, I like to move it outside of the cluster and upgrade it then bring it back into the cluster once I am done with the process.

Note 2: It is a good idea to get the network information and the iSCSI initiator name before upgrading or doing a clean install of a host to a newer version.

4. I disable HA and DRS on a cluster before starting since when I join a host back into the cluster I don’t like VMs to move to it automatically before I test it first.

5. When I upgrade a host I like to remove it from vCenter since I prefer doing a clean install.

6. When the host comes up we want to set it up with the following:

root password

Management interfaces

IP address, Mask, Gateway

DNS Servers and DNS Names

Custom DNS suffix

Set a static entry in DNS that points to the host IP address.

Run test and make sure that everything works fine

7. Add the host back into vCenter and assign it an ESXi license. Do not add it back to the cluster yet but just add it to the data center.

8. Start configuring the settings on the host.

Time Servers

Standard Switches




VMKernel Ports





Fault Tolerance

Shared Storage

Software iSCSI adapter

Put in the old IQN or give the new IQN access to your LUNs in your storage appliance.

Bind your iSCSI VMKernel ports for MPIO

Add the iSCSI address of your storage under dynamic discovery

Refresh the storage and wait for LUNs to show up

Configure the path selection policy on each LUN

At this point in time you should be able to bring the host back into the cluster. Once it is back in the cluster you want to vMotion a VM over and make sure that it works.

9. Create a host profile from this host as it will be used going forward for the other hosts. Make sure to attach this profile to the cluster once you have no old ESXi versions of host in this cluster.

10. You should be able to enable DRS once all the host in the cluster are running the same version.

11. The next step deals with migrating from the old VMFS-3 file system over to the new one. It is recommended to create a new LUN in the storage appliance and use VMFS-5 for the new file system. Once this is done and all the hosts can see the storage then you should do a storage vMotion from the old volumes over to the new ones. Delete the old volumes when you are done.

If you are deleting a volume then you should follow the following guidelines.

      1. No virtual machines reside on the datastore.
      2. The datastore is not part of a datastore cluster.
      3. The datastore is not managed by VMware vSphere Storage DRS.
      4. Storage I/O control is disabled
      5. The datastore is not used for vSphere HA heartbeat.

12. Don’t forget to upgrade VMware tools on the VMs as this is always a good thing to do. You can also upgrade the VM hardware if you need it.

13. If you are using vSphere Distributed Switches then these should also be upgraded.

This should be a good guideline for a typical upgrade process. If I find more things then I will edit this post to point out those extra steps. Thank you for reading this article and feel free to leave any comments below.

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