Re: Significance of PID files
When a daemon process is started, the process ID of the process is captured in a pid file. It is used for following purposes: - During a daemon startup, the existence of pid file is used to determine that the process is already running. - When a daemon is stooped, hadoop scripts sends kill TERM signal to the process ID captured in pid file for graceful shutdown. After a timeout, if the process still exists, kill -9 is sent for forced shutdown. For more details, see the relevant code in http://svn.apache.org/repos/asf/hadoop/common/trunk/hadoop-common-project/hadoop-common/src/main/bin/hadoop-daemon.sh On Fri, Jul 4, 2014 at 10:00 AM, Vijaya Narayana Reddy Bhoomi Reddy vijay.bhoomire...@gmail.com wrote: Hi, Can anyone please explain the significance of the pid files in Hadoop i.e. purpose and usage etc? Thanks Regards Vijay -- http://hortonworks.com/download/ -- CONFIDENTIALITY NOTICE NOTICE: This message is intended for the use of the individual or entity to which it is addressed and may contain information that is confidential, privileged and exempt from disclosure under applicable law. If the reader of this message is not the intended recipient, you are hereby notified that any printing, copying, dissemination, distribution, disclosure or forwarding of this communication is strictly prohibited. If you have received this communication in error, please contact the sender immediately and delete it from your system. Thank You.
Re: Significance of PID files
At Daemon level. Thanks, Giridhar. On Fri, Jul 4, 2014 at 11:03 AM, Vijaya Narayana Reddy Bhoomi Reddy vijay.bhoomire...@gmail.com wrote: Vikas, Its main use is to keep one process at a time...like one one datanode at a any host - Can you please elaborate in a more detail? What is meant by one process at a time? At what level does a pid file come into picture i.e. is it at a deamon level, job level, task level etc? Thanks Vijay On 4 July 2014 10:36, Vikas srivastava vikas_srivas...@apple.com wrote: Paid files used to store the pic if particular process. Its main use is to keep one process at a time...like one one datanode at a any host On Jul 4, 2014 10:00 AM, Vijaya Narayana Reddy Bhoomi Reddy vijay.bhoomire...@gmail.com wrote: Hi, Can anyone please explain the significance of the pid files in Hadoop i.e. purpose and usage etc? Thanks Regards Vijay
Significance of PID files
Hi, Can anyone please explain the significance of the pid files in Hadoop i.e. purpose and usage etc? Thanks Regards Vijay
Re: Significance of PID files
Vikas, Its main use is to keep one process at a time...like one one datanode at a any host - Can you please elaborate in a more detail? What is meant by one process at a time? At what level does a pid file come into picture i.e. is it at a deamon level, job level, task level etc? Thanks Vijay On 4 July 2014 10:36, Vikas srivastava vikas_srivas...@apple.com wrote: Paid files used to store the pic if particular process. Its main use is to keep one process at a time...like one one datanode at a any host On Jul 4, 2014 10:00 AM, Vijaya Narayana Reddy Bhoomi Reddy vijay.bhoomire...@gmail.com wrote: Hi, Can anyone please explain the significance of the pid files in Hadoop i.e. purpose and usage etc? Thanks Regards Vijay
