Pre-requisites for Obtaining the “Outside View” of VMs by directly connecting to the target vSphere/ESX Server
- Ensure that the remote agent has IP connectivity to the vSphere/ESX server.
- Ensure that the remote agent has web access to the web services interface (port 80/443) of the vSphere/ESX server.
Configure all the tests that the remote agent executes with the name and password of the root user to the vSphere/ESX server. However, if, owing to security constraints, you cannot use root user permissions, you can alternatively configure the tests with the credentials of a user who has been assigned the ‘Read-only’ role. To see how you can create such a user on the ESX server, refer to Section Creating a New User with Read-Only Privileges to the ESX Server of this document.
vSphere/ESX servers 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 vSphere/ESX 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 before it opens new sessions, then you would have to configure all the tests with the credentials of an vSphere/ESX user with permissions to View and Terminate Sessions (from vSphere 4.1, this is called the View and stop sessions permission). To know how to grant this permission to a vSphere/ESX user, refer to Creating a Special Role on an ESX Server and Assigning the Role to a New User to the Server
Sometimes, the VMware VI SDK may cache the hardware status metrics it collects and provide the test with the cached results. This may cause the eG agent to receive obsolete hardware status information from the SDK. This is also the reason why, you may at times notice a mismatch between the hardware status reported by the eG agent and by the vSphere client. To ensure that the eG agent always reports the current hardware status, you should configure the eG agent to obtain the hardware metrics from the VMware VI SDK only after the SDK resets the cache to clear its contents, and then refreshes the cache so that the latest hardware status information is fetched into it. To enable the eG agent to make the reset and refresh SDK calls, the esx user and esx password parameters must be configured with the credentials of a user with Change Settings privilege.
- VI APIs are memory-intensive, and therefore, while monitoring ESX servers in an agentless manner, the default memory setting of 128 MB will not be sufficient for the remote agent to pull out the required metrics. The maximum memory setting of the remote 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 monitored 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.