Sentinel command renaming: document it into sentinel.conf.

sentinel.conf

@@ -203,3 +203,22 @@ sentinel failover-timeout mymaster 180000
 
 sentinel deny-scripts-reconfig yes
 
+# REDIS COMMANDS RENAMING
+#
+# Sometimes the Redis server has certain commands, that are needed for Sentinel
+# to work correctly, renamed to unguessable strings. This is often the case
+# of CONFIG and SLAVEOF in the context of providers that provide Redis as
+# a service, and don't want the customers to reconfigure the instances outside
+# of the administration console.
+#
+# In such case it is possible to tell Sentinel to use different command names
+# instead of the normal ones. For example if the master "mymaster", and the
+# associated slaves, have "CONFIG" all renamed to "GUESSME", I could use:
+#
+# sentinel rename-command mymaster CONFIG GUESSME
+#
+# After such configuration is set, every time Sentinel would use CONFIG it will
+# use GUESSME instead. Note that there is no actual need to respect the command
+# case, so writing "config guessme" is the same in the example above.
+#
+# SENTINEL SET can also be used in order to perform this configuration at runtime.