Pre-requisites for Obtaining the “Outside View” of VMs by connecting to a vCenter Server
- Ensure that the remote agent has IP connectivity to the vCenter server.
- Ensure that the remote agent has web access to the webport (port 80/443) configured for the vCenter server.
All the tests that the remote agent executes should be configured with the IP address of vCenter, and the name and password of a user with Administrator or Virtual Machine Administrator privileges to vCenter. However, if owing to security constraints, you cannot expose the credentials of the administrator, then, you can configure the tests with the credentials of a user with ‘Read-only’ privileges to vCenter. For this purpose, you can assign the Read-only role to a local/domain user to vCenter. To know how to do this, refer to Section of this document.
vCenter servers too terminate user sessions based on timeout periods. The default timeout period is 30 mins. When you stop a remote agent, sessions currently in use by the remote agent will remain open for this timeout period until vCenter times out the session. If the remote agent is restarted within the timeout period, it will open a new set of sessions. If you want the remote agent to close already existing sessions on vCenter before it opens new sessions, then, when monitoring a vSphere/ESX server via vCenter, you can optionally configure the tests with the credentials of a user with permissions to View and Terminate Sessions (from vCenter 4.1, this is called the View and stop sessions permission) on vCenter. To know how to grant this permission to a user to vCenter, refer to Section Creating a Special Role on vCenter and Assigning the Role to a Local/Domain User of this document.
When the remote agent is started/restarted, it first attempts to connect to the vCenter server and terminate all existing sessions for the user whose credentials have been provided for the tests. This is done to ensure that unnecessary sessions do not remain established in the vCenter server for the session timeout period. Ideally, you should create a separate user account with the required credentials and use this for the test configurations. If you provide the credentials for an existing user for the test configuration, when the remote agent starts/restarts, it will close all existing sessions for this user (including sessions you may have opened using the Virtual Infrastructure client). Hence, in this case, you may notice that your VI client sessions are terminated when the remote agent starts/restarts.
- VI APIs are memory-intensive, and therefore, while monitoring ESX servers using vCenter, the default memory setting of 128 MB will not be sufficient for the eG agent to pull out the required metrics. The maximum memory setting of the eG agent should hence be increased to any value between 256 MB and 1024 MB, but the exact value will depend upon the number of ESX servers being managed by the vCenter in your environment. Refer to Increasing the Memory Settings of the eG Agent that Monitors ESX Servers to know how to alter the memory settings of the eG agent.