3.2.4.1.3 Identifying an Active Node
A client can determine whether a computer is an active node in a cluster by first establishing an RPC connection to the computer, as specified in section 3.2.3.
For protocol version 2.0, if the connection succeeds, the client SHOULD conclude that the server is currently an active node in a cluster.
For protocol version 3.0, if the connection succeeds, the client SHOULD conclude that the server is a node in a cluster. However, in order to determine whether the server is an active node, the client SHOULD query the node state as specified in section 3.2.4.1.1.
If the RPC connection succeeded, the client SHOULD call the ApiCloseCluster (section 3.1.4.1.2 for protocol version 2, or 3.1.4.2.2 for protocol version 3) method to clean up any server context that is no longer needed.
If the client fails to establish an RPC connection, as specified in section 3.2.3, the client SHOULD conclude that the computer is not an active node in a cluster; however, the client SHOULD NOT conclude that the computer either is or is not configured as a node in a cluster.