[ 
https://issues.apache.org/jira/browse/HADOOP-13837?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Weiwei Yang updated HADOOP-13837:
---------------------------------
    Description: 
*Reproduce steps*

# Setup a hadoop cluster
# Stop resource manager : yarn --daemon stop resourcemanager
# Stop node manager : yarn --daemon stop nodemanager
WARNING: nodemanager did not stop gracefully after 5 seconds: Trying to kill 
with kill -9
ERROR: Unable to kill 20325

it always gets "Unable to kill <nm_pid>" error message, this gives user 
impression there is something wrong with the node manager process because it 
was not able to be forcibly killed. But in fact, the kill command works as 
expected.

This was because hadoop-functions.sh did not check process existence after kill 
properly. Currently it checks the process liveness right after the kill command

{code}
...
kill -9 "${pid}" >/dev/null 2>&1
if ps -p "${pid}" > /dev/null 2>&1; then
      hadoop_error "ERROR: Unable to kill ${pid}"
...
{code}

when resource manager stopped before node managers, it always takes some 
additional time until the process completely terminates. I tried to print 
output of {{ps -p <nm_pid>}} in a while loop after kill -9, and found following

{noformat}
16212 ?        00:00:11 java <defunct>
0
  PID TTY          TIME CMD
16212 ?        00:00:11 java <defunct>
0
  PID TTY          TIME CMD
16212 ?        00:00:11 java <defunct>
0
  PID TTY          TIME CMD
1
  PID TTY          TIME CMD
1
  PID TTY          TIME CMD
1
  PID TTY          TIME CMD
...
{noformat}

in the first 3 times of the loop, the process did not terminate so the exit 
code of {{ps -p}} are still {{0}}

*Proposal of a fix*

Firstly I was thinking to add a 

  was:
Reproduce steps

# Setup a hadoop cluster
# Stop resource manager : yarn --daemon stop resourcemanager
# Stop node manager : yarn --daemon stop nodemanager
WARNING: nodemanager did not stop gracefully after 5 seconds: Trying to kill 
with kill -9
ERROR: Unable to kill 20325

it always gets "Unable to kill <nm_pid>" error message, this gives user 
impression there is something wrong with the node manager process because it 
was not able to be forcibly killed. But in fact, the kill command works as 
expected.

This was because hadoop-functions.sh did not check process existence after kill 
properly. Currently it checks the process liveness right after the kill command

{code}
...
kill -9 "${pid}" >/dev/null 2>&1
if ps -p "${pid}" > /dev/null 2>&1; then
      hadoop_error "ERROR: Unable to kill ${pid}"
...
{code}

when resource manager stopped before node managers, it always takes some 
additional time until the process completely terminates. I tried to print 
output of {{ps -p <nm_pid>}} in a while loop after kill -9, and found following

{noformat}
16212 ?        00:00:11 java <defunct>
0
  PID TTY          TIME CMD
16212 ?        00:00:11 java <defunct>
0
  PID TTY          TIME CMD
16212 ?        00:00:11 java <defunct>
0
  PID TTY          TIME CMD
1
  PID TTY          TIME CMD
1
  PID TTY          TIME CMD
1
  PID TTY          TIME CMD
...
{noformat}

in the first 3 times of the loop, the process did not terminate so the exit 
code of {{ps -p}} are still {{0}}


> Process check bug in hadoop_stop_daemon of hadoop-functions.sh
> --------------------------------------------------------------
>
>                 Key: HADOOP-13837
>                 URL: https://issues.apache.org/jira/browse/HADOOP-13837
>             Project: Hadoop Common
>          Issue Type: Bug
>          Components: scripts
>            Reporter: Weiwei Yang
>            Assignee: Weiwei Yang
>         Attachments: HADOOP-13837.01.patch, HADOOP-13837.02.patch, 
> HADOOP-13837.03.patch, HADOOP-13837.04.patch, check_proc.sh
>
>
> *Reproduce steps*
> # Setup a hadoop cluster
> # Stop resource manager : yarn --daemon stop resourcemanager
> # Stop node manager : yarn --daemon stop nodemanager
> WARNING: nodemanager did not stop gracefully after 5 seconds: Trying to kill 
> with kill -9
> ERROR: Unable to kill 20325
> it always gets "Unable to kill <nm_pid>" error message, this gives user 
> impression there is something wrong with the node manager process because it 
> was not able to be forcibly killed. But in fact, the kill command works as 
> expected.
> This was because hadoop-functions.sh did not check process existence after 
> kill properly. Currently it checks the process liveness right after the kill 
> command
> {code}
> ...
> kill -9 "${pid}" >/dev/null 2>&1
> if ps -p "${pid}" > /dev/null 2>&1; then
>       hadoop_error "ERROR: Unable to kill ${pid}"
> ...
> {code}
> when resource manager stopped before node managers, it always takes some 
> additional time until the process completely terminates. I tried to print 
> output of {{ps -p <nm_pid>}} in a while loop after kill -9, and found 
> following
> {noformat}
> 16212 ?        00:00:11 java <defunct>
> 0
>   PID TTY          TIME CMD
> 16212 ?        00:00:11 java <defunct>
> 0
>   PID TTY          TIME CMD
> 16212 ?        00:00:11 java <defunct>
> 0
>   PID TTY          TIME CMD
> 1
>   PID TTY          TIME CMD
> 1
>   PID TTY          TIME CMD
> 1
>   PID TTY          TIME CMD
> ...
> {noformat}
> in the first 3 times of the loop, the process did not terminate so the exit 
> code of {{ps -p}} are still {{0}}
> *Proposal of a fix*
> Firstly I was thinking to add a 



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]

Reply via email to