1. A machine-implemented method, comprising: storing, at a network device, configuration commands of a previous request received from a particular user without applying the configuration commands on the network device until a first request to change a current operational state of the network device to reflect the configuration commands is received from the particular user; in response to receiving the first request to change the current operational state of the network device to reflect the configuration commands, assigning an exclusive lock to the particular user, wherein the exclusive lock prevents any other user who is not assigned the exclusive lock from changing the current operational state of the network device; changing, under the exclusive lock, the current operational state of the network device to reflect the configuration commands, wherein changing the current operational state includes applying the stored configuration commands to the current operational configuration of the network device; updating configuration history that describes a plurality of operational states of the network device to reflect the configuration commands; receiving a second request from a client to view a subset of the configuration history data, wherein the second request identifies the subset by an association with a particular period of time or a particular operational state of the network device; and transmitting the subset to the client.