Edit on the availability zone config documentation (#2384)

Signed-off-by: Ken Haines <khaines@microsoft.com>

Author: khaines

docs/configuration/config-file-reference.md

@@ -540,7 +540,7 @@ lifecycler:
   [tokens_file_path: <string> | default = ""]
 
   # The availability zone of the host, this instance is running on. Default is
-  # the lifecycler ID.
+  # an empty string, which disables zone awareness for writes.
   # CLI flag: -ingester.availability-zone
   [availability_zone: <string> | default = ""]
 

pkg/ring/lifecycler.go

@@ -98,7 +98,7 @@ func (cfg *LifecyclerConfig) RegisterFlagsWithPrefix(prefix string, f *flag.Flag
 	f.StringVar(&cfg.Addr, prefix+"lifecycler.addr", "", "IP address to advertise in consul.")
 	f.IntVar(&cfg.Port, prefix+"lifecycler.port", 0, "port to advertise in consul (defaults to server.grpc-listen-port).")
 	f.StringVar(&cfg.ID, prefix+"lifecycler.ID", hostname, "ID to register into consul.")
-	f.StringVar(&cfg.Zone, prefix+"availability-zone", "", "The availability zone of the host, this instance is running on. Default is the lifecycler ID.")
+	f.StringVar(&cfg.Zone, prefix+"availability-zone", "", "The availability zone of the host, this instance is running on. Default is an empty string, which disables zone awareness for writes.")
 }
 
 // Lifecycler is responsible for managing the lifecycle of entries in the ring.