How to identify which Daemon Process is writing to the file - unix

I need to identify a daemon process that is writing to a log file periodically. The problem is that I dont have any idea which process is doing the job, and I need to show some progress to the client by tomorrow. Anybody has any clue?
I have already sorted out the daemon processes running in the system with the help of the PPID. Any help would be appreciated.
Also I think it is possible (rarely) for a daemon not to have a PPID as 1. How can we find it out then?

Try the fuser command on your log file, which will display the PIDs of processes using it.
Example:
$ fuser file.log
file.log: 3065

lsof gives a list of open files with the processes.
So lsof | grep <filename> should help you.

You can use auditctl.
# sudo apt-get install auditd
# sudo /sbin/auditctl -w /path/to/file -p war -k hosts-file
-w watch /etc/hosts
-p warx watch for write, attribute change, execute or read events
-k hosts-file is a search key.
# sudo /sbin/ausearch -f /path/to/file | more
Gives output such as
type=UNKNOWN[1327] msg=audit(1459766547.822:130): proctitle=2F7573722F7362696E2F61706163686532002D6B007374617274
type=PATH msg=audit(1459766547.822:130): item=0 name="/path/to/file" inode=141561 dev=08:00 mode=0100444 ouid=33 ogid=33 rdev=00:00 nametype=NORMAL
type=CWD msg=audit(1459766547.822:130): cwd="/"
type=SYSCALL msg=audit(1459766547.822:130): arch=c000003e syscall=2 success=yes exit=41 a0=7f3c23034cd0 a1=80000 a2=1b6 a3=8 items=1 ppid=24452 pid=6797 auid=42949672
95 uid=33 gid=33 euid=33 suid=33 fsuid=33 egid=33 sgid=33 fsgid=33 tty=(none) ses=4294967295 comm="apache2" exe="/usr/sbin/apache2" key="hosts-file"

Related

Can't see Elasticsearch daemon

I'm trying to run elasticsearch as a daemon on a server.
I have run this command:
./bin/elasticsearch -d -p somefilename
but I can't find any proof of the daemon actually running, since ps -e | grep elastic does not produce any output. How can I see the process?
Elasticsearch runs on JVM. to see the PID of elasticsearch, you can use "jps" command.
with "ps ef" , only you can see java related process.
if you insist on using ps you can try this:
ps axms |grep -i elasticsearch
"axms" option show the details of all process.

How do I turn off wget proxy?

I had been using a proxy for a long time. Now I need to remove it. I have forgotten how I have added the proxy to wget. Can someone please help me get back to the normal wget where it doesn't use any proxy. As of now, I'm using
wget <link> --proxy=none
But I'm facing a problem when I'm installing using a pre-written script. It's painstaking to search all through the scripts and change each command.
Any simpler solution will be very much appreciated.
Thanks
Check your
~/.wgetrc
/etc/wgetrc
and remove proxy settings.
Or use wget --no-proxy command line option to override them.
In case your OS is alpine/busybox then the wget might vary from the one used by #Logu.
There the correct command is
wget --proxy off http://server:port/
Running wget --help outputs:
/ # wget --help
BusyBox v1.31.1 () multi-call binary.
Usage: wget [-c|--continue] [--spider] [-q|--quiet] [-O|--output-document FILE]
[-o|--output-file FILE] [--header 'header: value'] [-Y|--proxy on/off]
[-P DIR] [-S|--server-response] [-U|--user-agent AGENT] [-T SEC] URL...
Retrieve files via HTTP or FTP
--spider Only check URL existence: $? is 0 if exists
-c Continue retrieval of aborted transfer
-q Quiet
-P DIR Save to DIR (default .)
-S Show server response
-T SEC Network read timeout is SEC seconds
-O FILE Save to FILE ('-' for stdout)
-o FILE Log messages to FILE
-U STR Use STR for User-Agent header
-Y on/off Use proxy

How to debug php-fpm performance?

Webpages are loading very slow, it takes them around 6 seconds to even start sending the page data, which is then sent in a matter of 0.2 seconds and is generated in 0.19 seconds.
I doubt that it is caused by php or the browser, so the problem must be with the server which is handled by nginx and php5-fpm
A server admin said that indeed the problem was caused by a misconfigured fpm or nginx
How can I debug the cause of the slowdown?
Setup: php5.3, mysql5, linux, nginx, php5-fpm
This question is probably too broad for StackOverflow, as the question could span several pages and topics.
However if the question was just how do I do debug the performance of PHP-FPM then the answer would be much easier - use Strace and the script below.
#!/bin/bash
mkdir trc
rm -rf trc/*.trc
additional_strace_args="$1"
MASTER_PID=$(ps auwx | grep php-fpm | grep -v grep | grep 'master process' | cut -d ' ' -f 7)
summarise=""
#shows total of calls - comment in to get
#summarise="-c"
nohup strace -r $summarise -p $MASTER_PID -ff -o ./trc/master.follow.trc >"trc/master.$MASTER_PID.trc" 2>&1 &
while read -r pid;
do
if [[ $pid != $MASTER_PID ]]; then
#shows total of calls
nohup strace -r $summarise -p "$pid" $additional_strace_args >"trc/$pid.trc" 2>&1 &
fi
done < <(pgrep php-fpm)
read -p "Strace running - press [Enter] to stop"
pkill strace
That script will attach strace to all of the running php-fpm instances. Any requests to the web server that reach php-fpm will have all of their system calls logged, which will allow you to inspect which ones are taking the most time, which will allow you to figure out what needs optimising first.
On the other hand, if you can see from the Strace output that PHP-FPM is processing each request fast, it will also allow you to eliminate that as the problem, and allow you to investigate nginx, and how nginx is talking to PHP-FPM, which could also be the problem.
#Danack saved my life.
But I had to change the command to get the MASTER_PID:
MASTER_PID=$(ps auwx | grep php-fpm | grep -v grep | grep 'master process' | sed -e 's/ \+/ /g' | cut -d ' ' -f 2)

Problem with plink output

I'm using plink to run a command on a Unix remote machine.
The command is:
ls -1trd testegrep.txt |tail -1 |xargs tail -f| grep 's';
The way I'm sending this command is by using a file with a set of commands like:
plink.exe -ssh -t -l user -pw pwd tst.url.pt -m commands.out
When I run the command this way the plink does not receive any input. It seems that is waiting for input.
But if I run:
plink.exe -ssh -t -l user -pw pwd tst.url.pt "ls -1trd testegrep.txt |tail -1 |xargs tail -f| grep 's';"
I get the expected result.
I'm not using the plink with a file with the command because I choose so. I'm using a test automation software that allows me to run tests on remote hosts and this is the way the tool works.
Any thoughts on what is going wrong?
I tested the command you provided and it worked without problems.
Maybe the problem is related to:
The server's host key is not cached in the registry.
The path to the file is not correct.
The file is empty.
include server hostkey
most importantly, you need to include the unix profile using the -m paramater
You can include all your commands in the same file where the profile is kept also.
$Output = ((plink.exe -hostkey hostkey -l UNAME -i SSHKEY -P 22 -ssh server -batch -m PROFILE) | ? {$_ -ne ""})

I lost nginx.pid,it disappeared

Here is part of my nginx.conf:
pid /www/nginx0836/nginx.pid;
While I restart nginx, in several seconds I run ls /www/nginx0836 and it lists nginx.pid.
But after several seconds, running ls /www/nginx0836 again, nginx.pid is not listed.
Why?
By the way, nginx server works well and when I run
ps -ef | grep "nginx: master process" | grep -v "grep" | awk -F ' ' '{print $2}'
then I can see nginx pid.
try monitoring folder with incrond and log any changes with $# $# on that directory.
may be you will see something like puppet or an rsync deleting the pid file.
/www/nginx0836 IN_DELETE echo "$# $#"
it will log any delete event on directory
simpler than audit...
sorry the poor english
Try default configuration for nginx, you will find similar problem here

Resources