Specifications

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The installation path of the previous version of vCenter Server must be compatible with the installation
requirements for Microsoft Active Directory Application Mode (ADAM/AD LDS). The installation path
cannot contain any of the following characters: non-ASCII characters, commas (,), periods (.),
exclamation points (!), pound signs (#), at signs (@), or percentage signs (%). If your previous version of
vCenter Server does not meet this requirement, you must perform a clean installation of vCenter Server.
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Back up the SSL certificates that are on the vCenter Server system before you upgrade to vCenter
Server 5.5. The default location of the SSL certificates is %allusersprofile%\Application
Data\VMware\VMware VirtualCenter.
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Make sure that SSL certificate checking is enabled for all vSphere HA clusters. If certificate checking is
not enabled when you upgrade, HA will fail to configure on the hosts. Select Administration > vCenter
Server Settings > SSL Settings > vCenter requires verified host SSL certificates. Follow the
instructions to verify each host SSL certificate and click OK.
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If the vCenter Server 4.x environment that you are upgrading includes Guided Consolidation 4.x,
uninstall Guided Consolidation before upgrading to vCenter Server 5.5.
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Before the vCenter Server installation, in the Administrative Tools control panel of the vCenter Single
Sign-On instance that you will register vCenter Server to, verify that the following services are started:
VMware Certificate Service, VMware Directory service , VMware Identity Manager Service, VMware
KDC service, and tcruntime-C-ProgramData-VMware-cis-runtime-VMwareSTSService.
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You must log in as a member of the Administrators group on the host machine, with a user name that
does not contain any non-ASCII characters.
Network Prerequisites
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Verify that DNS reverse lookup returns a fully qualified domain name when queried with the IP
address of the vCenter Server. When you upgrade vCenter Server, the installation of the web server
component that supports the vSphere Web Client fails if the installer cannot look up the fully qualified
domain name of the vCenter Server from its IP address. Reverse lookup is implemented using PTR
records. To create a PTR record, see the documentation for your vCenter Server host operating system.
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If you use DHCP instead of a manually assigned (static) IP address for vCenter Server, make sure that
the vCenter Server computer name is updated in the domain name service (DNS). Test this is by
pinging the computer name. For example, if the computer name is host-1.company.com, run the
following command in the Windows command prompt:
ping host-1.company.com
If you can ping the computer name, the name is updated in DNS.
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Ensure that the ESXi host management interface has a valid DNS resolution from the vCenter Server
and all vSphere Web Clients. Ensure that the vCenter Server has a valid DNS resolution from all ESXi
hosts and all vSphere Web Clients.
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If you will use Active Directory as an identity source, verify that it is set up correctly. The DNS of the
vCenter Single Sign-On Server host machine must contain both lookup and reverse lookup entries for
the domain controller of the Active Directory. For example, pinging mycompany.com should return the
domain controller IP address for mycompany. Similarly, the ping -a command for that IP address
should return the domain controller hostname. Avoid trying to correct name resolution issues by
editing the hosts file. Instead, make sure that the DNS server is correctly set up. For more information
about configuring Active Directory, see the Microsoft Web site. Also, the system clock of the vCenter
Single Sign-On Server host machine must be synchronized with the clock of the domain controller.
Chapter 3 Preparing for the Upgrade to vCenter Server
VMware, Inc. 49