Installing or updating VMware tools on a clustered guest server might cause brief interruptions to vital system services and indicators that are closely watched by NCS. As a result, the guest server might be fenced during the process. To avoid such problems, you must stop NCS on a node before you install or update VMware tools on it. You can start NCS on the node after you have successfully installed or updated VMware tools.
Alternatively, you can put the whole cluster in maintenance mode before you install or update VMware tools on the clustered guest servers, and disable maintenance mode afterwards. However, if something goes wrong with VMware tools update or installation, the cluster might be left in a unknown state, and you might need to reboot some nodes in order to bring the cluster out of maintenance mode.