toic.org - Entries for the category Monitoring

Apache monitoring tool ApTop beta released

Wed, 12 Dec 2012 23:34:19 +0000

This is my first public publish to PyPi, without further delays, here is the full project description

ApTop

ApTop ia a top(1) alike monitoring utility for Apache.

Being daily involved in monitoring system load in shared environment I find it lacking proper tool for monitoring Apache behavior in real time. Granted there are some tools for this job, they are usually of limited options for some monitoring needs.

ApTop was written as a hobby project in python for debugging purposes while investigating several system load situations caused by web applications in shared hosting environment.

ApTop is still an early beta release with some known bugs, nevertheless it still provides a great starting point in monitoring Apache. Every feedback and feature request at this point is more than welcomed.

Description

ApTop will show near real time Apache active working proceses and virtual host connections. By default sleeping / waiting for connections slots will be filtered out.

ApTop is also displaying several screens

Dashboard or Home screen

This screen displays some relevant informations gathered from apache-status page. It is by default sorted by shortest last apache access time "SS" and it displays only active connections. Displayed fields are the same as in server-status page, so you can find detailed explanation for their meaning at the bottom of server-status page.

Displayed fields are:

PID - OS process ID M - Mode of operation CPU - CPU usage, number of seconds SS - Seconds since beginning of most recent request< Req - Milliseconds required to process most recent request Conn - Kilobytes transferred this connection Acc - Number of accesses this connection / this child / this slot Client - Remote client VHost - Local virtualhost Request - Request method and partial URL

Count by vhosts screen

This screen displays virtualhosts in order by highest count of active connections along with connection count.

Very useful for detecting high traffic sites.

Count by clients screen

This screen displays clients in order by highest count of active connections along with connection count.

Very useful for detecting resource exhausters.

Requirements

ApTop should work just fine on any unix based system with python standard packages and lxml.

Make sure you have libxml2 libxslt libxslt-devel libxml2-devel packages instaleld prior to building lxml:

For RHEL based distro you can install those with

yum install libxml2 libxslt libxslt-devel libxml2-devel

After that you can install lxml python package with easy_install lxml or pip install lxml

ApTop is using Apaches mod_status with ExtendedStatus On for gathering data. Please ensure that mod_status is enabled and proper status url is defined in aptop.conf There are some concernes regarding enabled ExtendedStatus On, but I think this links covers this nicely.

Instalation

These installation options are for RHEL based distros, adjust accordingly.

yum install libxml2 libxslt libxslt-devel libxml2-devel python-setuptools

Now you can do

easy_install ApTop

easy_install https://bitbucket.org/btoic/aptop/get/master.tar.gz

You can now run aptop.py

Configuration

ApTop has some built in default configuration directives, but it will also look first in ~/.aptop.conf and than /etc/aptop.conf for overrides.

ApTop uses .ini style configuration files and main cofniguration options should be placed after [aptop] section.

By default ApTop will use http://localhost/server-status url for grabbing data to display, and with default refresh rate of 5 seconds.

Available configuration options:

status_url = URL

This configuration option will require you to enter valid mod_status status url for server you wish to monitor. This defaults to http://localhost/server-status Note that Apache should have ExtendedStatus conf option set to On

refresh = seconds

This option will control ApTop default refresh interval. It defaults to 5 seconds and can't be lower than 1 second.

You can even monitor the remote systems if they granted you access rights to theirs server-status URL. In the future ApTop will provide options to save remote monitored servers to its configuration.

Runtime options

While running ApTop responds to following options:

H - display main screen

V - display vhosts by conn. count

c - display clients by conn. count

R - reverse the current sort order

I - toggle active/inactive slots

Aditional links

http://toic.org

https://bitbucket.org/btoic/aptop

Munin centralized monitoring on Centos

Fri, 09 Oct 2009 19:56:24 +0000

Munin is a great tool for performance graphing your servers, by default it will graph resources on localhost, however if you wish to monitor multiple servers from single location, then you must deploy a central Munin server.

Having central graphs mean you can have central hub of data about performance of your systems. This can later be better presented, viewed and analyzed,

Let's begin setting up a central server

To get things started we will need one server for centralized graphs. For start this can be a low budget dedicated server or a small vps, if you have large amount of monitored nodes, and large amout of metrics on them, then you will probably want to invest in better disks. Updating huge amounts of rrd files and regenerating html an graphs can be disk IO intensive with large instalations.

Installing munin

This will be a minimal install for a central munin server. I'm using a small vps with minimal centos 5 install.

First let's setup elrepo:

rpm -Uvh http://download.fedora.redhat.com/pub/epel/5/i386/epel-release-5-3.noarch.rpm

Now we need to install munin and munin-node (if you wish to monitor this host as well):

yum install -y munin munin-node

by default munin will put its html files into /var/www/html/munin folder If you wish to move that to another place, now is your time. For the sake of simplicity I'll just leave it where it is. Of course we will need apache to access munin html files, so if you don't have apache installed do:

yum install -y httpd

now start the apache:

service httpd start

If you left everything as it is munin html should be available at: http://yourhostname.com/munin/ You may notice that there is nothing there yet, just wait until we configure all other hosts. start the munin-node on this host (if you installed it):

service munin-node start

Make sure your cron is runing:

service crond status

and let's go configure those other hosts.

Installing munin-node

Installing on cPanel

Since lot's of my servers to monitor are with cPanel installed there is an easy way to install munin.

Login to your whm go to: Manage plugins, now find Munin, click a check box, scroll down and click save. After the munin is installed it should appear in your whm at the bottom of the navigation. Go and check up if the munin is installed correctly.

Installing trough cPanel will install munin-node and munin, you can disable the munin graphing later if you like.

Installing on non cPanel

We can install munin on Centos trough Elrepo. first we will setup elrepo:

rpm -Uvh http://download.fedora.redhat.com/pub/epel/5/i386/epel-release-5-3.noarch.rpm

and then install a munin-node:

yum install -y munin-node

voila... let's configure nodes on remote servers now.

Configuring munin-node on remote hosts

For both cPanel and non-cPanel servers all we need to do is add allowed host in munin-node.conf:

nano /etc/munin/munin-node.conf

add at the end of the file:

allow ^192\.168\.0\.20$

where 192.168.0.20 is the IP address of you central munin server. restart the munin-node:

service munin-node restart

If you have firewall installed on that host (and I hope you do), allow the incoming tcp port 4949 for the IP of the central node.

In csf add the following line:

tcp:in:d=4949:s=192.168.0.20

to your /etc/csf/csf.allow file

or just run:

iptables -A INPUT -p tcp -s 192.168.0.2 --dport 4949 -m state --state NEW,ESTABLISHED -j ACCEPT

Modify this to your firewall, and don't forget to replace 192.168.0.20 with your munin server IP. Now everything should be ready for data collection from central server

Configuring munin server

We need to configure munin conf file on our central server to collect data from remote servers:

nano /etc/munin/munin.conf

If you didn't change any locations of html files and munin datastore you realy don't need to change that in the conf file.

What we are interested with are the host sections. You will notice there is configuration for our localhost You can change its name now, leave the address field as it is.

To add up a new host just add:

[myhost.mydomain.com]
address 192.168.0.10
use_host_name yes

change the 192.168.0.10 with the IP of the server you wish to monitor. you can now add as many host you like. Make sure that you have enabled outgoing connections on tcp port 4949 on your central munin server. After a while the first results should start to appear.

Configuring multi host display graphs

The real benefit of having all the host graphs and data on one place is you can easily make multi host graphs and compare the loads on the servers. This could help you grasp a bigger picture of individual server workloads and give you an idea what to improve and how to load balance between the machines.

Here is one of the example graphs, showing apache request per second. If the machines were the same hardware configuration that would give indications that some of the machines have higher hit rate and we would need to rewrite our load balancing.

We could do the same thing with load graphs and see which servers have the spikes, and distribute the workload on some less loaded servers.

So how do we configure this?

First you need to find out rrd's name of the data you wish to put on the graph.

for example apache accesses per second:

cd /var/lib/munin/yourdomain.com

ls -lh in the directory and you will find out what data is available to munin. in case of the apache accesses data we will have few files named:

hostname.domainname.com-apache_accesses-accesses80-d.rrd hostname2.domainname.com-apache_accesses-accesses80-d.rrd

what we are interested with are those fields (marked in red) after the domain name separated by dash. Ok let's write a conf in munin.conf for this two hosts:

nano /etc/munin/munin.conf

Go under the host definitions in your conf file and add:

[domainname.com;Totals] update no apacheaccess.graph_title Apache access side by side apacheaccess.graph_order hostname=hostname.domainname.com:apache_accesses.accesses80 hostname1=hostname1.domainname.com.com:apache_accesses.accesses80

Notice the red lines, they are the same as rrd filenames red parts we saw earlier, just replace dash with dot. Green text is to disable updates for this domain declaration since updates are already done at the host declaration in the conf file. Blue is the graph representation name, followed by title in the first line and data in second.

This way you can make all the side by side graphs for all the data munin collected in rrd files. After the changes wait for a next munin update and enjoy the graphs