A method is provided for a plug-in manager in a virtual machine (VM) system to install or update a plug-in at a web client server in the VM system. The plug-in extends the web client server with a user interface element to interact with a management entity implemented as a VM in the VM system. The method includes receiving, from the management entity, a request to register or update the plug-in, wherein the request includes an address and authentication information for the management entity, recording the address and the authentication information, transmitting, to the web client server, an instruction to install or update the plug-in, receiving, from the plug-in at the web client server, a request for the address and the authentication information for the management entity, and transmitting, to the plug-in at the web client server, the address and the authentication information for the management entity.