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Posted to common-user@hadoop.apache.org by Vijaya Narayana Reddy Bhoomi Reddy <vi...@gmail.com> on 2014/07/04 06:30:13 UTC
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
Posted by Suresh Srinivas <su...@hortonworks.com>.
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.bhoomireddy@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
>
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Re: Significance of PID files
Posted by Suresh Srinivas <su...@hortonworks.com>.
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.bhoomireddy@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
Posted by Suresh Srinivas <su...@hortonworks.com>.
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.bhoomireddy@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
Posted by Suresh Srinivas <su...@hortonworks.com>.
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.bhoomireddy@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.