diff --git a/docs/reference/modules/discovery/zen.asciidoc b/docs/reference/modules/discovery/zen.asciidoc index cbe8ad13dd2..e68350515ea 100644 --- a/docs/reference/modules/discovery/zen.asciidoc +++ b/docs/reference/modules/discovery/zen.asciidoc @@ -56,9 +56,15 @@ The unicast discovery uses the <> module to perform As part of the ping process a master of the cluster is either elected or joined to. This is done automatically. The -`discovery.zen.ping_timeout` (which defaults to `3s`) allows for the -tweaking of election time to handle cases of slow or congested networks -(higher values assure less chance of failure). Once a node joins, it +`discovery.zen.ping_timeout` (which defaults to `3s`) determines how long the node +will wait before deciding on starting an election or joining an existing cluster. +Three pings will be sent over this timeout interval. In case where no decision can be +reached after the timeout, the pinging process restarts. +In slow or congested networks, three seconds might not be enough for a node to become +aware of the other nodes in its environment before making an election decision. +Increasing the timeout should be done with care in that case, as it will slow down the +election process. +Once a node decides to join an existing formed cluster, it will send a join request to the master (`discovery.zen.join_timeout`) with a timeout defaulting at 20 times the ping timeout.