In high availability mode, two vCenter Single Sign-On nodes work with the same database, data, and user stores to ensure that vCenter Single Sign-On is not a single point of failure.

This procedure upgrades an existing vCenter Server that was installed with a high availability vCenter Single Sign-On deployment.

You can upgrade vCenter Single Sign-On in a high availability installation without taking all vCenter Single Sign-On nodes offline at the same time. While the first Single Sign-On node is being upgraded, the load balancer will redirect all requests to the second node. After the first node is successfully upgraded, you can upgrade the second node.

vCenter Server can continue running while you upgrade vCenter Single Sign-On. Logged in users can continue accessing vCenter Server and related solutions that are connected to vCenter Single Sign-On during the upgrade. However, vCenter Server, the vSphere Web Client, and vCenter Inventory Service cannot be started while the first Single Sign-On node is offline.


vCenter Server 5.5 supports connection between vCenter Server and vCenter Server components by IP address only if the IP address is IPv4-compliant. To connect to a vCenter Server system in an IPv6 environment, you must use the fully qualified domain name (FQDN) or host name of the vCenter Server. The best practice is to use the FQDN, which works in all cases, instead of the IP address, which can change if assigned by DHCP.

Review the topics in Preparing for the Upgrade to vCenter Server.

See Prerequisites for the vCenter Server Upgrade

Verify that the load balancer in your existing vCenter Single Sign-On high availability deployment is configured as described in VMware Knowledge Base articles 2034157 and 2033588 .


Upgrade the first node in a vCenter Single Sign-On installation for high availability.


Upgrade an additional vCenter Single Sign-On node for an existing high availability vCenter Single Sign-On installation.


After you upgrade both nodes of a 5.1.x vCenter Single Sign-On high availability deployment to version 5.5, reconfigure the load balancer.


The vSphere Web Client lets you connect to a vCenter Server system to manage your vSphere deployment through a browser.


You can use Custom Install to upgrade vCenter Single Sign-On, vCenter Inventory Service, and vCenter Server separately to customize the location and configuration of the components.


You can upgrade vCenter Server separately after installing vCenter Single Sign-On, and upgrading Inventory Service.