percentile apache server request response times

I needed a hack to quickly find the 95th percentile of apache request response times. For example I needed to be able to say that “95% of our apache requests are served in X milliseconds or less.” In the apache2 config the LogFormat directive had %D (the time taken to serve the request, in microseconds) as the last field. Meaning the last field of each log line would be the time it took to serve the request. This would make it easy to pull out with $NF in awk

# PCT=.95; NR=`cat access.log | wc -l `; cat /var/log/apache2/access.log | awk '{print $NF}' | sort -rn | tail -n+$(echo "$NR-($NR*$PCT)" |bc | cut -d. -f1) |head -1
938247

In this case 95% of the apache requests were served in 938 milliseconds or less (WTF?!). Then run on an aggregated group of logs, or change the date/time range to just run for logs on a particular day, or for multiple time periods.

Note: I couldn’t get scale to work here in bc for some reason.

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use netstat to monitor receive queue Recv-Q

# i=0; while true; do i=$(($i+1)); echo $i ==============================; netstat -natlp | grep ^tcp | sort -nk1 | awk '{ if($2 != 0) {print}}' ; sleep 1;  done;
1 ==============================
2 ==============================
3 ==============================
4 ==============================
5 ==============================
tcp      100      0 10.0.3.167:22           198.21.8.23:53477       ESTABLISHED 99304/sshd: fordodone
6 ==============================
7 ==============================
8 ==============================
9 ==============================
tcp    43520      0 10.0.3.167:53877        10.0.9.55:3306          ESTABLISHED 119789/mysqldump
10 ==============================
11 ==============================
12 ==============================
13 ==============================
14 ==============================
15 ==============================
16 ==============================
tcp6       1      0 10.0.3.167:80           198.21.8.23:65114       CLOSE_WAIT  3880/apache2    
17 ==============================
18 ==============================
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convert dmesg timestamp to date time

If you have messages in dmesg that log the event time as “seconds since last boot”, it can be difficult to tell when they happened. Here’s an example of one of these messages:

# tail -1 /var/log/dmesg
[8969653.483175] poorcoding.php[14798]: segfault at 7f2efca36ed0 ip 00007f2efca36ed0 sp 00007f2efaf0be98 error 14
#

You could use something like this to parse out the timestamp and convert it to a date:

# date --date=@$((`date +%s --date="\`who -b | awk '{print $3" "$4}'\`"` + `dmesg | tail -1 | awk '{print $1}' | sed -e 's/\[//g' -e 's/\..*//g'`))
Thu Nov  5 01:21:53 PDT 2015
#

If your application logs to kern.log, it uses timestamps as well as seconds since uptime, so the error will already have a timestamp on it

Aug 14 09:57:59 myhostname kernel: [8969653.483177] poorcoding.php[14800]: segfault at 7f2efca36ec8 ip 00007f2efca36ec8 sp 00007f2ef10c4e98 error 14

TODO: make a quick function; convert all the messages not just a tailed or greped one;

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docker get list of tags in repository

The native docker command has an excellent way to search the docker hub repository for an image. Just use docker search <search string> to look in their registry.

# docker search debian
NAME                          DESCRIPTION                                     STARS     OFFICIAL   AUTOMATED
ubuntu                        Ubuntu is a Debian-based Linux operating s...   2338      [OK]       
debian                        Debian is a Linux distribution that's comp...   763       [OK]       
google/debian                                                                 47                   [OK]
neurodebian                   NeuroDebian provides neuroscience research...   12        [OK]       
jesselang/debian-vagrant      Stock Debian Images made Vagrant-friendly ...   4                    [OK]
eboraas/debian                Debian base images, for all currently-avai...   3                    [OK]
armbuild/debian               ARMHF port of debian                            3                    [OK]
mschuerig/debian-subsonic     Subsonic 5.1 on Debian/wheezy.                  3                    [OK]
fike/debian-postgresql        PostgreSQL 9.4 until 9.0 version running D...   2                    [OK]
maxexcloo/debian              Docker base image built on Debian with Sup...   1                    [OK]
kalabox/debian                                                                1                    [OK]
takeshi81/debian-wheezy-php   Debian wheezy based PHP repo.                   1                    [OK]
webhippie/debian              Docker images for debian                        1                    [OK]
eeacms/debian                 Docker image for Debian to be used with EE...   1                    [OK]
reinblau/debian               Debian with usefully default packages for ...   1                    [OK]
mariorez/debian               Debian Containers for PHP Projects              0                    [OK]
opennsm/debian                Lightly modified Debian images for OpenNSM      0                    [OK]
konstruktoid/debian           Debian base image                               0                    [OK]
visono/debian                 Docker base image of debian 7 with tools i...   0                    [OK]
nimmis/debian                 This is different version of Debian with a...   0                    [OK]
pl31/debian                   Basic debian image                              0                    [OK]
idcu/debian                   mini debian os                                  0                    [OK]
sassmann/debian-chromium      Chromium browser based on debian                0                    [OK]
sassmann/debian-firefox       Firefox browser based on debian                 0                    [OK]
cloudrunnerio/debian                                                          0                    [OK]

We can see the official debian repository right at the top. Unfortunately there’s no way to see what tags and images are available for us to pull down and deploy. However, there is a way to query the registry for all the tags in a repository, returned in JSON format. You can use a higher level programming language to get the list and parse the JSON for you. Or you can just use a simple one-liner:

# wget -q https://registry.hub.docker.com/v1/repositories/debian/tags -O -  | sed -e 's/[][]//g' -e 's/"//g' -e 's/ //g' | tr '}' '\n'  | awk -F: '{print $3}'
latest
6
6.0
6.0.10
6.0.8
6.0.9
7
7.3
7.4
7.5
7.6
7.7
7.8
7.9
8
8.0
8.1
8.2
experimental
jessie
jessie-backports
oldstable
oldstable-backports
rc-buggy
sid
squeeze
stable
stable-backports
stretch
testing
unstable
wheezy
wheezy-backports

Wrap that in a little bash script and you have an easy way to list the tags of a repository. Since a tag is just a pointer to a image commit multiple tags can point to the same image. Get fancy:

# wget -q https://registry.hub.docker.com/v1/repositories/debian/tags -O -  | sed -e 's/[][]//g' -e 's/"//g' -e 's/ //g' | tr '}' '\n' | sed -e 's/^,//' | sort -t: -k2 | awk -F[:,] 'BEGIN {i="image";j="tags"}{if(i!=$2){print i" : "j; i=$2;j=$4}else{j=$4" | "j} }END{print i" : "j}'
image : tags
06af7ad6 : 7.5
19de96c1 : wheezy | 7.9 | 7
1aa59f81 : experimental
20096d5a : rc-buggy
315baabd : stable
37cbf6c3 : testing
47921512 : 7.7
4a5e6db8 : 8.1
4fbc238a : oldstable-backports
52cb7765 : wheezy-backports
84bd6e50 : unstable
88dc7f13 : jessie-backports
8c00acfb : latest | jessie | 8.2 | 8
91238ddc : stretch
b2477d24 : stable-backports
b5fe16f2 : 7.3
bbe78c1a : 7.8
bd4b66c4 : oldstable
c952ddeb : squeeze | 6.0.10 | 6.0 | 6
d56191e1 : 6.0.8
df2a0347 : 8.0
e565fbbc : 7.4
e7d52d7d : sid
feb75584 : 7.6
fee2ea4e : 6.0.9

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wget monitor website download speed

# while true; do date | tr '\n' '-' | sed -e 's/-/ --- /'; wget http://testsite.com/fancy.pdf -O /dev/null 2>&1 | grep saved | awk -F"[()]" '{print $2}'; sleep 1s; done;
Thu Oct 30 15:18:26 PDT 2014 --- 1.25 MB/s
Thu Oct 30 15:18:28 PDT 2014 --- 1.20 MB/s
Thu Oct 30 15:18:29 PDT 2014 --- 958.95 KB/s
Thu Oct 30 15:18:31 PDT 2014 --- 1.36 MB/s
Thu Oct 30 15:18:32 PDT 2014 --- 873.98 KB/s
Thu Oct 30 15:18:33 PDT 2014 --- 1.38 MB/s
Thu Oct 30 15:18:35 PDT 2014 --- 261.90 KB/s
Thu Oct 30 15:18:37 PDT 2014 --- 1.38 MB/s
Thu Oct 30 15:18:38 PDT 2014 --- 360.14 KB/s
Thu Oct 30 15:18:40 PDT 2014 --- 1.37 MB/s
Thu Oct 30 15:18:42 PDT 2014 --- 427.06 KB/s
Thu Oct 30 15:18:44 PDT 2014 --- 1.37 MB/s
Thu Oct 30 15:18:45 PDT 2014 --- 397.54 KB/s
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Using find to act on files is very useful, but if the files that are found need different actions based on their filetype, it gets a bit trickier. For example there are some log files foo.log but after 10 days they get compressed to foo.log.gz. So you are finding regular text files, as well as gzipped text files. Extend your find with an -exec and a bash shell to determine what file extension it is, and to run the appropriate grep or zgrep based on that. Then run it through awk or whatever else to parse out what you need.

# find . -type f -name 'foo.log*' -exec bash -c 'if [[ $0 =~ .log$ ]]; then grep foobar $0; elif [[ $0 =~ .log.gz$ ]]; then zgrep foobar $0; fi' {} \; | awk '{if(/typea/)a++; if(/typeb/)b++; tot++} END {print "typea: "a" - "a*100/tot"%"; print "typeb: "b" - "b*100/tot"%"; print "typec: "tot-(a+b)" - "(tot-(a+b))*100/tot"%"; print "total: "tot;}'
typea: 5301 - 67.4771%
typeb: 2539 - 32.3192%
typec: 16 - 0.203666%
total: 7856
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monitor NetApp SnapMirror transfer speed

You may want to monitor the speed of a current snapmirror to get an idea of how fast the transfer is going. The speed might change throughout the day due to load, or disk bottleneck, etc. I started with this one-liner:

i=0;j=0; while true; do j=$i; i=`ssh toaster01 "snapmirror status -l volname" | grep Progress | awk '{print $2}'| cut -d \( -f2`; if [ $j -eq 0 ]; then sleep 1m; continue; fi; echo -n "$i-$j = ";echo "scale=2;($i-$j)/(1024*1024)" | bc | tr '\n' ' '; echo "GB/min"; sleep 1m; done;

Which lead to this short script:

#!/bin/bash
# FILE: netapp_sm_monitor.sh
# AUTHOR: For Do Done <fordodone@fordodone.com>
# DATE: 2014/03/26
# NOTES: 
# 

if [ $# -lt 2 ]
then
  echo ""
  echo "usage: netapp_sm_monitor.sh <filer> <srcvol> [-v]"
  echo ""
  exit
fi

i=0;
j=0; 

while true; 
do 
  j=$i; 
  i=`ssh $1 "snapmirror status -l $2" | grep Progress | awk '{print $2}'| cut -d \( -f2`; 
  if [ $j -eq 0 ]; 
    then 
    sleep 1m; 
    continue; 
  fi; 
  if [ "$3" == "-v" ]
  then
    echo -n "$i-$j = ";
  fi
  echo "scale=2;($i-$j)/(1024*1024)" | bc | tr '\n' ' '; echo "GB/min"; 
  sleep 1m; 
done;
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