--- title: JobTracker High Availability (HA) in MR1 author: admin type: post date: 2013-12-30T15:02:46+00:00 url: /jobtracker-high-availability-ha-in-mr1/ tumblr_gethue_permalink: - http://gethue.tumblr.com/post/71637613809/jobtracker-high-availability-ha-in-mr1 tumblr_gethue_id: - 71637613809 sf_thumbnail_type: - none sf_thumbnail_link_type: - link_to_post sf_detail_type: - none sf_page_title: - 1 sf_page_title_style: - standard sf_no_breadcrumbs: - 1 sf_page_title_bg: - none sf_page_title_text_style: - light sf_background_image_size: - cover sf_social_sharing: - 1 sf_sidebar_config: - left-sidebar sf_left_sidebar: - Sidebar-2 sf_right_sidebar: - Sidebar-1 sf_caption_position: - caption-right slide_template: - default categories: - Browsing ---
When the Job Tracker goes down, Hue cannot display the Jobs in File Browser or submit to the correct cluster.
In MR1, Hadoop can support two Job Trackers, a master Job Tracker that can fail over to a standby Job Tracker and hence provide Job Tracker HA. Let’s see how [Hue 3.5][1] and [CDH5beta1][2] (and probably CDH4.6) can take advantage of this. Note: in MR1 Hue is using a [plugin][3] to communicate with the Job Tracker. This can be configured in CDH or Hadoop 0.23 / 1.2.0 ([MAPREDUCE-461][4]). We configure two Job Trackers in the [hue.ini][5]: {{< highlight bash >}}[hadoop] ... [[mapred_clusters]] [[[default]]] \# Enter the host on which you are running the Hadoop JobTracker jobtracker_host=host-1 \# Whether to submit jobs to this cluster submit_to=True [[[ha-standby]]] \# Enter the host on which you are running the Hadoop JobTracker jobtracker_host=host-2 \# Whether to submit jobs to this cluster submit_to=True {{< /highlight >}} And that’s it! Hue will communicate with the available Job Tracker automatically! Notice that in the case of Oozie jobs, Oozie will try to re-submit the job but will need a logical name ([HUE-1631][6]). To enable this in Hue, specify it in each MapReduce cluster, e.g.: {{< highlight bash >}}[hadoop] [[mapred_clusters]] [[[default]]] \# JobTracker logical name. \## logical_name=MY_NAME {{< /highlight >}} As usual feel free to comment on the [hue-user][7] list or[@gethue][8]! [1]: http://gethue.tumblr.com/post/69115755563/hue-3-5-and-its-redesign-are-out [2]: http://www.cloudera.com/content/support/en/documentation/cdh5-documentation/cdh5-documentation-v5-latest.html [3]: http://cloudera.github.io/hue/docs-3.5.0/manual.html#_configure_mapreduce_0_20_mr1 [4]: https://issues.apache.org/jira/browse/MAPREDUCE-461 [5]: https://github.com/cloudera/hue/blob/master/desktop/conf.dist/hue.ini#L336 [6]: https://issues.cloudera.org/browse/HUE-1631 [7]: http://groups.google.com/a/cloudera.org/group/hue-user [8]: https://twitter.com/gethue