Server load balancing using a fair weighted hashing technique

摘要

A fair weighted-hashing technique may be used in load balancing among a group of modules. In one implementation, a device may maintain a table that relates how incoming client resource requests are to be distributed among the modules. The device may update the table, in response to an indication that an additional module, associated with a module identifier, is to be included in the group of modules. The updating may include determining a number of entries to add to the table for the additional module, calculating a first hash value for each of the number of entries, and modifying the table by writing the module identifier to one or more sequential entries of the table, beginning at an index into the table corresponding to the first hash value.

主权项

1. A method comprising:
maintaining, by a device, a table that indicates how incoming client resource requests are to be distributed among a plurality of modules; updating the table, by the device and based on an indication that an additional module, associated with a module identifier, is to be included in the plurality of modules, by:
determining a number of entries to add to the table for the additional module,calculating a first hash value for each entry of the number of entries, andmodifying the table by writing the module identifier to one or more sequential entries of the table,
an index, of a first entry of the one or more sequential entries, corresponding to the first hash value; updating the table, by the device and based on an indication to remove a particular module of the plurality of modules,
a particular module identifier, of the particular module, being associated with the indication to remove the particular module,updating the table based on the indication to remove the particular module including:
overwriting entries, in the table corresponding to the particular module identifier, with a previous entry in the table; and looking up, by the device, one of the plurality of modules to handle a particular incoming client resource request, based on a second hash value obtained from information in the particular incoming client resource request,
the second hash value being used as an index into the table to lookup a module identifier of the one of the plurality of modules to handle the particular incoming client resource request.