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/// @startDocuBlock JSF_get_admin_server_role
/// @brief Get to know whether this server is a Coordinator or DB-Server
///
/// @RESTHEADER{GET /_admin/server/role, Return role of a server in a cluster}
///
/// @RESTDESCRIPTION
///
/// Returns the role of a server in a cluster.
/// The role is returned in the *role* attribute of the result.
/// Possible return values for *role* are:
/// - *COORDINATOR*: the server is a coordinator in a cluster
/// - *PRIMARY*: the server is a primary database server in a cluster
/// - *SECONDARY*: the server is a secondary database server in a cluster
/// - *UNDEFINED*: in a cluster, *UNDEFINED* is returned if the server role cannot be
///    determined. On a single server, *UNDEFINED* is the only possible return
///    value.
///
/// @RESTRETURNCODES
///
/// @RESTRETURNCODE{200}
/// Is returned in all cases.
/// @endDocuBlock
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