Going by the book, the upgrade process is precisely defined and should be followed in a specified order and manner whenever possible. In real life, other options and challenges always exist that might come into play in your organization. If you want to upgrade to vSphere 5.1 with the least possible headaches, you should perform the following steps in their precise order:
- Upgrade vCenter
- Upgrade vSphere Client
- Upgrade vCenter Update Manager
- Upgrade Hosts
- Upgrade VMware Tools for VMs
- Upgrade Virtual Machine Hardware
Now let’s look at each of these steps a little closer and discuss some considerations and issues for each one.
VMware supports in-place upgrades to vSphere 5.1 on 64-bit systems from vCenter 4.x and vCenter Server 5.0. On average, you should expect your vCenter to be down for about 40 to 50 minutes. This includes reconnecting the database. During this time, your ESX/ESXi hosts and VMs will continue to function as normal. High Availability (HA) will still be functional if it is configured; but Distributed Resource Scheduler (DRS) will not function without vCenter.
Unlike earlier versions, vCenter Server 5.1 does not support directly migrating an existing vCenter Server to a new machine (physical or virtual) during an upgrade. In addition, if you are using Windows XP Professional x64 for your vCenter Server in 5.0, then you will need to choose a compatible server OS instead, because vSphere 5.1 does not support using Windows XP x64 as a vCenter Server.
As I mentioned before, you will have to make a decision in regard to your Single Sign On server when upgrading vCenter Server. There is a lot to be considered and known here, especially in a large organization. I would highly recommend that you search the latest links and forums regarding Single Sign On BEFORE you upgrade your vCenter! You can upgrade your vCenter in-place by installing the latest version from the vSphere Installation Manager (VIM) software package.
Upgrading vSphere Client
As part of the upgrade, you will install a new vSphere Client and a new vSphere Web Client. The difference is that in previous versions you were likely just installing the Web Client because it was there; but now you will actually begin to use it more. In fact, you will have to use it to take advantage of many of the new features that vSphere 5.1 offers, such as shared-nothing vMotion! You can upgrade both of these components in place using the VIM software package.
Upgrading vCenter Update Manager
While there are many ways to upgrade your hosts and VMs (interactive, scripted, and so on), the best method and the one with the fewest potential headaches is to use the vCenter Update Manager (VUM). The VUM for 5.1 can easily upgrade your 4.x and 5.0 ESXi hosts and even your 4.x ESX hosts! To take advantage of what VUM has to offer, you should upgrade VUM by installing the latest version from the VIM software package. VUM for vSphere 5.1 requires a 64-bit OS. If you are running an earlier version of VUM on a 32-bit platform, then you will have to do a new installation. After installing/upgrading VUM, you should also upgrade the VUM plug-in in your new vSphere Client. Again, I recommend that you read all of the latest release notes FIRST.
When you upgrade from ESX 4.x to ESXi 5.x, the upgrade process preserves as much of the ESX host configuration as possible. Because of the architectural differences between ESX 4.x and ESXi 5.x, many configuration files cannot be migrated. If a host contains customizations such as special VMware Infrastructure Bundles (VIBs) or drivers, this will further complicate the process. In addition, there are a significant number of firewall configuration changes and the firewall rulesets are replaced by new rulesets. Also, since the ESXi 5.x hosts will use more memory than the previous host, the Resource Pool settings might be sufficient for all VMs; especially if you are using all or close to all of the resources on the host. Additionally, network changes cannot be ignored, especially if you are upgrading from ESX 4.x to ESXi 5.x. In this case, the Service Console and Service Console port will be removed and replaced by a vmkernel port that is configured for Management. While it’s possible to upgrade your hosts in many ways (esxcli commands, scripted, auto deploy, and so on) using VUM will give you the best chance of having a functional ESXi 5.x host when the upgrade is finished.
Finally, you haven’t really successfully upgraded the hosts until they are reconnected to their respective managing vCenter Servers, and each host license is reapplied or upgraded. You should perform the following steps, after you have upgraded or migrated your hosts and BEFORE you upgrade your VMs.
- If vCenter Server manages the host, reconnect the host to the vCenter by right-clicking the host and selecting Connect.
- View the upgrade logs. You can use the vSphere Client to export the logs and view them for any anomalies that stand out. You don’t have to understand all of the verbose information to see something that just doesn’t seem proper, such as a storage error or an error affecting HA.
- Reapply the license or note the number of days that you still have in evaluation mode. You only have 60 days from the time you originally powered on the host. You can use the License Portal on the VMware page and your new vSphere Client to upgrade your license.
- Run the command esxcli storage claimrule convert on your vSphere CLI to convert any ESX 3.xstyle/adv/Disk/MaskLUNs LUN masks to the claim rule format used with ESXi 5.1.
Upgrading VMware Tools for VMs
VMware Tools is a suite of utilities that you can install in the OS of a VM. VMware Tools enhances the performance of the VM and makes many of the ease-of-use features possible, such as shutting down VMs without first logging in. In addition, VMware tools provides improved memory control, improved mouse performance, and synchronization of the clock on the VM with that of the host. This is still just a subset of the benefits provided by VMware Tools. Suffice it to say that VMware Tools should be installed whenever possible on all VMs.
Once you have VUM installed and upgraded, you can use VUM to easily upgrade the VMware Tools to match the current version of your host and the VMs that are supported on that type of host. In this example, you are upgrading the VMware Tools on the VMs to support the Version 9 virtual hardware that you will be upgrading to and using on the Version 9 VMs that will be on the ESXi 5.1 host. Even though you are planning ahead for the next version of virtual hardware, you should always update the VMware Tools first and then the virtual hardware.
With Windows and Linux operating systems, after you have upgraded the VMware Tools, you must reboot the system or at least re-load the network modules (in Linux). You should understand that Version 9 virtual hardware will only be compatible with ESXi 5.1 hosts. If you don’t plan to upgrade all of the hosts in a cluster, you might want to hold off on upgrading the VMs.
Upgrading Virtual Machine Hardware
The final step that you can perform with VUM is upgrading the VM hardware to match the host. If you have decided that you want to upgrade the VMs, and have already upgraded the VMware Tools, then you can select this option in VUM, and the virtual hardware on the VMs will be upgraded. You should, of course, plan for some downtime of the VMs during the upgrade of the VM hardware as well as during the upgrade of the VMware Tools. Once you are upgraded to vSphere 5.1, you should be able to update your VMware Tools on most of your VMs without downtime; as that is one of the new features!
What Should You Do After You Upgrade?
You will have other upgrade concerns if you are using the vCenter Appliance, which cannot be upgraded with the VUM but must be reinstalled and reconnected to your database. In addition, you may need to manually install or upgrade VMware Tools on Linux, Solaris, or Netware VMs. For more information about these additional upgrade steps, search for the pdf at vSphere Upgrade 5.1 – Documentation.
In addition, upgrade steps that you can take later on include upgrading your VMFS-3 datastores to VMFS-5 and upgrading your vSphere Distributed Switches. These are steps that do not have to be performed at the time of the initial upgrade but can be performed very quickly and easily once all your hosts are upgraded, the time is right, and there is a need for the new version. In fact, you may never elect to perform these upgrades on some of your datastores and switches.
The final thing that you should do is begin to enjoy the features and benefits available in your new vSphere 5.1 environment. To find all the latest information, simply search for What’s New in vSphere 5.1 and then follow the VMware links to pdfs and information pages. Don’t forget to upgrade the remainder of your environment when the time is right to take advantage of the latest that VMware has to offer!
Reproduced from Global Knowledge: Upgrading to ESXi 5.1 – Best Practices