19 Sep 09 Server Monitoring with Munin
I finally got around to investigating server monitoring tools, and came across Munin. This tool allows you to monitor various nodes in your network, and it generates pretty graphs for a wide variety of system parameters. You install munin-node software on the machines you wish to monitor. The node software gathers statistics which are collected periodically by a munin master agent, which produces the nice graphs that you can view with a web browser.
Installing it was easy with Ubuntu, as packages already exist for it. It was a simple “sudo apt-get install munin munin-node.” The Ubuntu package set me up for running both the master and node software on the same machine. I then had to edit the /etc/munin/munin.conf to change a few paths around, notably where to put the generated HTML files. One hitch that stumped me for a few minutes was a permissions problem on the path to the location of the HTML files. The Ubuntu package creates a new munin user, so make sure all directories on the path to the HTML files have an “x” bit for world. Once that was sorted I started seeing data after 5 minutes for a variety of things including CPU load, MySQL statistics, and filesystem usage. Awesome! I decided to put Apache Basic Authorization password protection on the directory where the report files live, as it is sensitive data that I wouldn’t want just anyone to see.
Below is an example graph, one of about 50 (!) that are available right out of the box. Plugins exist and can be created for a wide variety of other parameters as well. In addition, Munin can notify you by email if parameters get out of range. See the Munin home page for more examples and information.
Munin MySQL Graph
Munin looks like a very useful tool to keep an eye on your server. Thanks to the Munin team for this great piece of software!
Tags: monitoring, munin, Server, tools
15 May 09 Server Upgrade, A Slight Return
I started having some pretty serious doubts that I could bring the current server down, get it re-imaged, and then put everything back within a few hours. A major goof or unforseen gotcha could bring the site down for days, which wouldn’t be good for my stress level. So after talking to my old PHP pal Evaders, I decided to follow his recent course of action and rent a second server and then migrate to it at my leisure. This has the added bonus that the latest entry level server packages from my host feature slightly faster processors and double the RAM compared to what I have now. And since I apparently can click through my own affiliate link, it really shouldn’t cost a whole lot. I’ll just be renting two servers for a short period. Once I get everything setup and moved over I can turn off the old one.
So last night I placed an order for another server, and within hours it was ready to go. The first step will be to re-image it from CentOS 5 to Ubuntu 8.04 LTS. Here we go! This should be very interesting.
29 Apr 09 Server Migration Is Go…
Well I’ve been doing some reading and thinking, and I think I have mentally prepared myself to re-image the server with Ubuntu 8.04 LTS. Everything seems to be manageable without Plesk. I did some reading, and discovered the default Mail Transfer Agent (MTA – I learned a new acronym!) in Ubuntu is Postfix. I started reading their online documentation, and at first I found it quite inscrutable. I kind of panicked and ordered a book on Postfix. But after reading the docs some more, it is starting to make sense, and seems quite easy to configure it to just forward email. I’m glad I bought the book though. It hasn’t arrived yet, but I’m sure it will be handy down the road. I don’t currently have a need for locally hosted mailboxes, spam filters, etc. One thing I can definitely appreciate: administering mail for a large network is very complicated. My use case is pretty simple though, I hope.
I did some poking around on my Ubuntu equipped laptop. Configuring Apache should be easy. They made support for virtual hosts very easy right out of the box by how they arranged the configuration files.
So right now I am taking some notes about what to backup, making lists of databases, database users, collations, etc., all in preparation for RI-Day (Re-Imaging Day). I’ve got lots of stuff to juggle. I surprised myself by how much custom stuff I added in little over a year, and it will take some time to get it set back up on the new server. Therefore I am going to have to give myself a lot of time to do this. I’m thinking Memorial Day weekend would be a good target as I have some additional days off around then.
I think it will be a very good step to move to Ubuntu and I’m looking forward to it! I’m curious as to how my host has customized the image. Surely they have some things like DNS and SSH configured, otherwise no one could remotely login and administer it out of the box. But did they also setup mail? I guess I’ll find out.
25 Apr 09 Server Migration?
I’ve been renting a dedicated server from 1&1 Hosting (yes that’s my affiliate link) for a little over a year now. I’ve been very happy with it, it has allowed me to run several websites, host an IRC server, a TeamSpeak server, Subversion, and Trac. I even very briefly ran a Call of Duty server on it! It is currently running Fedora Core 6, which was old even when I got it a year ago. I’ve been itching to re-image it to something that is supported, and I think I’m finally going to do it. It makes sense to get this done before I go live with SG101 2.0. The only question now is what OS should I go with?
A year ago there wasn’t very many OS options with 1&1. Now, they have 17 variants, including CentOS, openSUSE, Debian, and Ubuntu, with various permutations of the Plesk control panel. I think the safe choice here is to switch to CentOS 5 with Plesk 9. This distribution is currently very similar to FC6 and comes with a newer version of Plesk, which I rely on a lot. However, it would be very cool to run Ubuntu 8.04 LTS, since that is also what I am developing with on my laptop. I think it would minimize surprises to have the same OS on both production and development. And, I’d really like to use at least Python 2.5. FC6 and CentOS 5 are still using Python 2.4.
Unfortunately, 1&1 does not offer Plesk with this configuration. Hmmm, can I take the training wheels off and manage a server without Plesk? Here are the things that Plesk makes easy for me with their web GUI:
- Creation of domains and subdomains.
- Managing the mail server.
- Rotating Apache server logs.
- Easy access to phpMyAdmin.
- Quick dashboard like status for how much memory and disk space I am using.
- Webstats.
- Maybe some things I don’t know about? This frightens me.
So the question becomes, can I manage these things without Plesk? Let’s see:
- Apache. I’ve had to heavily customize the Apache configuration files generated by Plesk in order to get Python apps running. I think I’m comfortable now with Apache, and I can just save off the Plesk configuration files for future reference. I don’t anticipate any problems with this.
- Mail. This is a big mystery to me. I didn’t even know the server was running QMail until last night. Fortunately, I don’t make heavy use of the mail server. I only use it for simple redirects. I have about 10 or so redirects. Getting the equivalent functionality running under Ubuntu may require some research on my part.
- Log rotation. I’m sure I could come up with some cron jobs to handle log rotation. I assume Plesk is using cron for this, and perhaps I can see how it is doing it.
- phpMyAdmin. I’m pretty sure I can just install phpMyAdmin myself using an Ubuntu package.
- Server stats. Not a huge loss, I can use the command line to get the same information.
- Webstats. I could probably install this myself, but to be honest, I don’t really look at these that much.
- The unknown. It should be “interesting” to find out what I am missing. Gulp.
So after thinking long and hard about this, I think going with Ubuntu will be a good choice for the long term. Having similar production and development environments will be important. Ubuntu 8.04 LTS still has (I think) about 4 years left for server support, and there should be a migration path to the next LTS release.
However leaving Plesk behind will require me to become more of a server geek. This, I don’t actually mind, as I am enjoying learning all this stuff slowly over time. I can practice some of these things on my laptop before I make the big switch. I need to figure out the mail server thing, and doing a dry run of moving the MySQL databases from production to my development server.
Another important question is when to do this? Ideally I will want to give myself plenty of time, perhaps over a long weekend. It will mean downtime for the current hosted websites. And it will probably be pretty nerve wracking. 
I’ll be thinking about these things and blogging about them over the course of the next few days.
