Hi, Sumona:
      It's a bug in Spark old version, In spark 1.6.0, it is fixed.
      After the application complete, spark master will load event log to memory, and it is sync because of actor. If the event log is big, spark master will hang a long time, and you can not submit any applications, if your master memory is to small, you master will die!
      The solution in spark 1.6 is not very good, the operation is async, and so you still need to set a big java heap for master.

------------------ 原始邮件 ------------------
发件人: "Shixiong(Ryan) Zhu";<shixiong@databricks.com>;
发送时间: 2016年3月1日(星期二) 上午8:02
收件人: "Sumona Routh"<sumosha2@gmail.com>;
抄送: "user@spark.apache.org"<user@spark.apache.org>;
主题: Re: Spark UI standalone "crashes" after an application finishes

Do you mean you cannot access Master UI after your application completes? Could you check the master log?

On Mon, Feb 29, 2016 at 3:48 PM, Sumona Routh <sumosha2@gmail.com> wrote:
Hi there,
I've been doing some performance tuning of our Spark application, which is using Spark 1.2.1 standalone. I have been using the spark metrics to graph out details as I run the jobs, as well as the UI to review the tasks and stages.

I notice that after my application completes, or is near completion, the UI "crashes." I get a Connection Refused response. Sometimes, the page eventually recovers and will load again, but sometimes I end up having to restart the Spark master to get it back. When I look at my graphs on the app, the memory consumption (of driver, executors, and what I believe to be the daemon (spark.jvm.total.used)) appears to be healthy. Monitoring the master machine itself, memory and CPU appear healthy as well.

Has anyone else seen this issue? Are there logs for the UI itself, and where might I find those?