From 6d4f0460a056c8ce4a036dcc0eb6efa10ede4488 Mon Sep 17 00:00:00 2001 From: Stavros Kontopoulos Date: Tue, 16 Aug 2016 19:33:07 +0300 Subject: [PATCH] doc --- docs/running-on-mesos.md | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/docs/running-on-mesos.md b/docs/running-on-mesos.md index a6ce34c761c82..173961deaadcb 100644 --- a/docs/running-on-mesos.md +++ b/docs/running-on-mesos.md @@ -207,6 +207,16 @@ The scheduler will start executors round-robin on the offers Mesos gives it, but there are no spread guarantees, as Mesos does not provide such guarantees on the offer stream. +In this mode spark executors will honor port allocation if such is +provided from the user. Specifically if the user defines +`spark.executor.port` or `spark.blockManager.port` in Spark configuration, +the mesos scheduler will check the available offers for a valid port +range containing the port numbers. If no such range is available it will +not launch any task. If no restriction is imposed on port numbers by the +user, ephemeral ports are used as usual. This port honouring implementation +implies one task per host if the user defines a port. In the future network +isolation shall be supported. + The benefit of coarse-grained mode is much lower startup overhead, but at the cost of reserving Mesos resources for the complete duration of the application. To configure your job to dynamically adjust to its