[SPARK-15994][MESOS] Allow enabling Mesos fetch cache in coarse executor backend

Mesos 0.23.0 introduces a Fetch Cache feature http://mesos.apache.org/documentation/latest/fetcher/ which allows caching of resources specified in command URIs.

This patch:
- Updates the Mesos shaded protobuf dependency to 0.23.0
- Allows setting `spark.mesos.fetcherCache.enable` to enable the fetch cache for all specified URIs. (URIs must be specified for the setting to have any affect)
- Updates documentation for Mesos configuration with the new setting.

This patch does NOT:
- Allow for per-URI caching configuration. The cache setting is global to ALL URIs for the command.

Author: Charles Allen <charles@allen-net.com>

Closes #13713 from drcrallen/SPARK15994.

1 files changed, 7 insertions, 2 deletions

diff --git a/docs/running-on-mesos.md b/docs/running-on-mesos.md
index 77b06fcf33..923d8dbebf 100644
--- a/docs/running-on-mesos.md
+++ b/docs/running-on-mesos.md
@@ -506,8 +506,13 @@ See the [configuration page](configuration.html) for information on Spark config
     since this configuration is just a upper limit and not a guaranteed amount.
   </td>
 </tr>
-
-
+<tr>
+  <td><code>spark.mesos.fetcherCache.enable</code></td>
+  <td><code>false</code></td>
+  <td>
+    If set to `true`, all URIs (example: `spark.executor.uri`, `spark.mesos.uris`) will be cached by the [Mesos fetcher cache](http://mesos.apache.org/documentation/latest/fetcher/)
+  </td>
+</tr>
 </table>
 
 # Troubleshooting and Debugging