Test Kitchen Tricks

September 2, 2014August 31, 2015 Josh Reichardt 27 Comments

I have been working a lot with Chef and Test kitchen lately and thus have learned a few interesting tricks when running tests with these tools. Test Kitchen is one of my favorite tools when working with Chef configuration management because it is very easy to use and has a number of powerful features that make testing things in Chef simple and easy.

Test Kitchen itself sits on top of Vagrant and Virtualbox by default so to get started with the most basic usage example of Test Kitchen you will need to have Vagrant installed along with a few other items.

Vagrant (your distribution)
Virtualbox (again with your distribution)
Ruby 1.9 or higher + ruby gems

Then to install Test Kitchen.

gem install test-kitchen

That’s pretty much it. The official docs have some pretty detailed usage and in fact I have learned many of the tricks that I will be writing about today from the docs.

Once you are comfortable with Test Kitchen you can begin leveraging some of the more powerful features, which is what the remainder of this post will cover. There is a great talk given by the creator of test kitchen at this year’s Chefconf by the creator of Test Kitchen about some of the lessons learned and cool things that you can do with the tool. If you haven’t already seen it, it is worth a watch.

Anyway, let’s get started.

1) Fuzzy matching

This one is great for the lazy people out there. It basically allows you match a certain unique part of a command instead of typing out an entire command. So for example, you can just type in a partial name for a command to return the desired full command. Since Test Kitchen uses regular expression matching, this can be a very powerful feature.

2) Custom drivers

One reason that Test Kitchen is so flexible is because it can leverage many different plugins and drivers. And, since it is open source, if there is functionality missing from a driver you can simply write your own. Currently there is an awesome list of drivers available for Test Kitchen to use, and a wide variety of options available to hopefully suit most testing scenarios.

Of course, there are others as well. These just happen to be the drivers that I have tried and can verify. There is even support for alternate configuration management tool testing, which can be handy for those that are not using Chef specifically. For example there is a salt driver available.

3) .kitchen.local.yml

This is a nice handy little bit that is often overlooked but allows a nice amount of control by overriding the default .kitchen.yml configuration file with specific options. So for example, if you are using the ec2 driver in your configuration but need to test locally with Vagrant you can simply drop a .kitchen.local.yml on your dev machine and override the driver (and any other settings you might need to change). I have created the following .kitchen.local.yml for testing on a local Vagrant box using 32 bit Ubuntu to highlight the override capabilities of Test Kitchen.

driver: 
 name: vagrant 
 
platforms: 
 - name: ubuntu-1310-i386 
 - name: ubuntu-1404-i386

4) Kitchen diagnose

An awesome tool for diagnosing issues with Test Kitchen. Running the diagnose will give you lots of juicy info about what your test machines are doing (or should be doing) and a ton of configuration information about them. Basically, if something is misbehaving this is the first place you should look for clues.

If you want to blast info and settings for all your configurations, just run the following,

kitchen diagnose

5) Concurrency

If you have a large number of systems that need to have tests run on them then running your Test Kitchen tests in parallel is a great way to speed up your total testing time. Turning on concurrency is pretty straight forward, just add the “-c” flag and the number of instances to run on (the default is 9999).

kitchen converge -c 5

6) Verbose logging

This one can be helpful if your kitchen run is failing with no real clues or helpful information provided by the diagnose command. It seems obvious but getting this one to work gave me some trouble initially. To turn on verbosity simply add the debug flag to your test kitchen command.

So for example, if you want to converge a node with verbosity turned on, you would use this command.

kitchen converge -l debug

I recommend taking a look at some or all of these tricks to help improve your integration testing with Test Kitchen. Of course as I stated, all of this is pretty well documented. Even if you are already familiar with this tool, sometimes it just helps to have a refresher to remind you of a great tool and to jar your memory. Let me know if you have any other handy tricks and I will be sure to post them here.

Transitioning from bash to zsh

August 16, 2014August 31, 2015 Josh Reichardt 1 Comment

I have know about zsh for a long time now but have never really had a compelling reason to switch my default shell from bash until just recently, I have been hearing more and more people talking about how powerful and awesome zsh is. So I thought I might as well take the dive and get started since that’s what all the cool kids seem to be doing these days. At first I thought that changing my shell was going to be a PITA with all the customizations and idiosyncrasies that I have grown accustomed to using bash but I didn’t find that to be the case at all when switching to zsh.

First and foremost, I used a tool called oh-my-zsh to help with the transition. If you haven’t heard about it yet, oh-my-zsh aims to be a sort of framework for zsh. This project is a nice clean way to get started with zsh because it give you a nice set of defaults out of the the box without having to do much configuration or tweaking and I found that many of my little tricks and shortcuts were already baked in to to oh-my-zsh, along with a ton of other settings and customizations that I did not have using bash.

From their github page:

oh-my-zsh is an open source, community-driven framework for managing your ZSH configuration. It comes bundled with a ton of helpful functions, helpers, plugins, themes, and few things that make you shout…

Here are just a few of the improvement that zsh/oh-my-zsh offer:

Improved tab completion
persistent history across all shells
Easy to use plugin system
Easy to use theme system
Autocorrect

The most obvious difference that I have noticed is the improved, out of the box tab completion, which I think should be enough on its own to convince you! On top of that, most of my tricks and customizations were already turned on with oh-my-zsh. Another nice touch is that themes and plugins come along as part of the package, which is really nice for easing the transition.

So after spending an afternoon with zsh I am convinced that it is the way to go (at least for my own workfolw). Of course there are always caveats and hiccups along the way as I’ve learned there are with pretty much everything.

Tuning up tmux

Out of the box, my tmux config uses the default shell, which happens to be bash. So I needed to modify my ~/.tmux.conf to reflect the switch over the zsh. It is a pretty straight forward change but is something that you will need to make note of kif you use tmux and are transitioning in to using zsh.

set-option -g default-shell /usr/bin/zsh

I am using Ubuntu 14.04, so my zsh is installed to /usr/bin/zsh. The other thing that you will need to do is make sure you kill any stale tmux processes after updating to zsh. I found one running in the background that was blocking me from using the new coonfig.

Goodies

There is a nice command cheat sheet for zsh. Take some time to learn these shortcuts and aliases, they are great time savers and are very usefull.

oh-my-zsh comes bundled up with a large number of goodies. At the time of this writing there were 135 plugins as well as a variety of themes. You can check the plugins wiki page for descriptions for the various plugins. To turn on a specific plugin you will need to add it to your ~/.zshrc config file. Find the following line in your config.

plugins=(git)

and add plugins separated by spaces

plugins (git vagrant chef)

You will need to reload the config for the changes to be picked up.

source ~/.zshrc

Most themes are hosted on the wiki, but there is also a web site dedicated to displaying the various themes, which is really cool. It does a much better job of showing differences between various themes. You can check it out here. Themes function in a similar way to plugins. If you want to change your theme, edit your ~/.zshrc file and select the desired them.

ZSH_THEME="clean"

You will need to reload your config for this option as well.

source ~/.zshrc

Conclusion

If you haven’t already made the switch to zsh I recommend that you at least experiment and play around with it before you make any final decisions. You may be set in your ways and happy with bash or any other shell that you are used to but for me, all the awesomeness changed my opinion and decide to reevaluate my biases. If you’re worried about making the switchin, using oh-my-zsh makes the transition so painless there is practically no reason not to try it out.

This post is really just the tip of the iceberg for the capabilities of this shell, I just wanted to expose readers to all of its glory. Zsh offers so much more power and customization than I have covered in this post and is an amazing productivity tool with little learning overhead.

Let me know if you have any awesome zsh tips or tweaks that folks should know about.

Uchiwa dashboard for Sensu

August 12, 2014August 31, 2015 Josh Reichardt 9 Comments

Recently the new Uchiwa dashboard redesign for Sensu was released, and it is awesome. It’s hard to describe how much of a leap forward this most recent release is, but it finally feels like Sensu is as “complete” and polished product as other open source and commercial products that exist. And if you haven’t heard of Sensu yet you are missing out. As described on the website sensuapp.org. Sensu is an open source monitoring framework. Instead of the traditional monolithic type of monitoring solutions (cough Nagios cough) that typically come to mind, the design of Sensu allows for a more more scalable and distributed approach to monitoring which hasn’t really been done before and offers a number of benefits, including a variety of dashboards to choose from.

Sensu touts itself as a “monitoring router”, which is a much more intuitive approach to monitoring once your wrap your head around the concept and leave the monolithic idea alone. For example, you can plug in different components to your monitoring solution very easily with Sensu, and you aren’t tied to one solution. If you need graphing and analytics you can choose from any number of existing solutions, Graphite, hosted Graphite, DataDog, NewRelic, etc. and more importantly, if something isn’t working as well as you’d like you can simply rip it out the component that isn’t working in favor of something that fits your needs better. Meaning it adds flexibility. no more hammering square blocks in to round holes. Sensu also offers nice scalability features, since all of the pieces are loosely coupled you don’t need to worry about scaling the entire beast, you can pick and choose which pieces to scale and when. Sensu itself is also scalable. Since the backbone of Sensu relies on RabbitMQ (soon to be opened up to other message queueing services), the busier it gets, simply cluster or add nodes to your RabbitMQ cluster. Granted, RabbitMQ isn’t exactly the easiest thing to scale, but it is possible.

With its distributed nature, Sensu by default is just a monitor. In the beginning, that meant either writing your own dashboard to communicate with Sensu server or using the default dashboard. As the ecosystem has evolved, the default dashboard has not been able to keep up with the evolution of Sensu and the needs of those using it.

Traditionally in the monitoring world, if you are not familiar, design and usability have not exactly been high priorities with regards to dashboards, graphics and GUI’s in the majority of tools that exist. Although that fact is changing somewhat with some of the newer cloud tools like DataDog and NewRelic, the only problem is that those solution are commercial and can become expensive. The bane of the open source solutions, at least for me, is how ugly the dashboards and user experiences have been (the Sensu default dashboard was an exception). But, the latest release of Uchiwa for Sensu has really changed the game in my opinion. It is much more modern and elegant.

We have gone from this:

To this:

Which one would you rather use? It is much easier to use and is much more elegant. The main dashboard (pictured above) gives a nice 1,000 ft view of what is going on in your environment. It is easy to quickly check the dashboard for any issues going on in your environment.

In addition to the home view, there is a nice checks view to get a glimpse of pretty much everything that’s going on in your environment. Sometimes with a large number of checks it is very easy to forget what exactly is happening so this is a nice way to double check.

As well, there is another similar view for checking clients. One small but very nice piece of info here is that it will display the Sensu client version for each host. If there are any issues with a host it is easy to tell from here.

You can also drill down in to any of these hosts to get a better picture of what exactly is going on. It will show you exactly which checks are being run for the host as well as some other very hand information.

From this page you can even select an individual check and see exactly how it is set up and behaving. It is easy to silence a single alert of all alerts for a client. Just click on the sound icon in any context to silence or unsilence an alert or an entire client. This has been handy for minimizing alert spam when doing maintenance on specific hosts.

One last handy feature is the info page. From here you can check out some of the Sensu server info as well as Uchiwa settings. This is also good for troubleshooting.

That pretty much covers the highlights of the new UI. As I have said, I am very excited for this release because this is an awesome GUI and there are going to be some really interesting improvements and additions in the future for Uchiwa which will make it an even stronger and more compelling reason to make the switch to Sensu and Uchiwa if you haven’t already.

If you have direct questions about the post, you comment here. Otherwise, the best place to get help with most of this stuff is probably the #sensu channel on IRC. That’s where the majority of the project contributors hang out. You can check out the Uchiwa code as well if you’d like over on Github. If you ever have issues with the dashboard that is the place to go, I would suggest browsing through the issues and if you can’t find a solution then create a new issue. Don’t hesitate to jump in to any of the discussions either. The author is very friendly and helpful and is very quick to respond to issues. One final helpful resource is the Sensu docs. Make sure you are looking at the correct version of Sensu according to the documentation, there are still enough changes occurring that the docs still have some differences between them and can get new users fumbled up.

7 useful but hard to remember Linux commands

August 9, 2014August 31, 2015 Josh Reichardt 22 Comments

I have found myself using these commands over and over so I decided I’d take the time to go ahead and document them for future me as well as readers because I find these commands pretty useful. I just always manage to forget them, hence the title of the post. The smart thing to do would be to create aliases for these commands but I have just been too lazy and some of them are run across different servers so it isn’t always a convenient option.

Anyway, let’s go ahead and run through the commands before I forget…

1) du -ah / | sort -n -r | head -n 50

This one is really handy for debugging space issues. It will list the top 50 files according to file size, with the largest at the top of the list.Notice the “/” will specify the location to search so you can easily modify this one to search different locations, like “/var/log” for example if you are having trouble with growing log files.

1.5) du -sh /*

This will quickly give you an idea of how how your disk space has been allocated. Definitely handy when you are troubleshooting.

2) git checkout — .

I don’t use this one very often, which is probably why I manage to forget it so easily. But I really like it. Sometimes I will be working on a git repo across different machines at the same time and will run in to conflicts committing to the repo or more likely I committed changes on one machine and just need to pull down the newest changes but can’t since I have made modifications. For those scenarios you can run the above command quickly reset your git changes quickly and easily.

3) tmux kill-window -t 3

i use tmux for my terminal and window manager on all my workstations and love it. If you haven’t heard of it, take a look here. Sometimes the sessions can get stuck so it becomes necessary to close the window without destroying the tmux session. Again, this doesn’t happen very often so it is sometimes hard for me to remember the exact syntax but this one is a handy little trick for managing tmux windows and sessions.

4) grep -r “text”

I know, I should really have this one memorized by now. I am trying to remember but I don’t find myself using this one all that often even though it is really powerful and useful. This will essentially search through every file recursively and spit out the text pattern that you feed to it.

5) kill $(pgrep process)

This one is handy when there are a large number of stuck processes and you need to blow them all out with one command. For example if the chrome browser ever gets stuck with a million tabs open, there are likely a large number of processes all with the same – or similar names. If you pass all or part of the process name in to this command pgrep will find them and kill will destroy them

6) docker rm $(docker ps -a -q)

I have been using Docker more and more recently and every once in awhile I find myself with a large number of dead Docker processes that need to be cleaned up. This command will blow out all of these stale processes at once. This is nice because Docker processes take up a large amount of disk space and often times can fill up your drives without you being aware. I have been able to reclaim large amounts of disk space with this command.

7) watch -n 10 df -ah

This is another good one for checking disk space issues. It will update you every ten seconds with the disk utilization of the system. Pretty straight forward but a great tool to help troubleshooting space issues.

That’s all I have for now, there are lots more but these are the most useful ones that I find myself forgetting the most often, hopefully this post will serve as a nice reminder. If you have any cool or useful commands that you would like to share feel free to comment and I will update the post to include them.

Recover a Grafana dashboard

July 24, 2014August 31, 2015 Josh Reichardt 15 Comments

Grafana uses Elasticsearch (optionally) to store its dashboards. If you ever migrate your Graphite/Grafana servers or simply need to grab all of your dashboards from the old server then you will likely be looking for them in Elasticsearch. Luckily, migrating to a new server and moving the dashboards is and uncomplicated and easy to do process. In this post I will walk through the process of moving Grafana dashboards between servers.

This guide assumes that Elasticsearch has been installed on both old and new servers. The first thing to look at is your current Grafana config. This is the file that you probably used to set up your Grafana environment originally. This file resides in the directory that you placed your Grafana server files in to, and is named config.js. There is a block inside this config file that tells Elasticsearch where to save dashboards, which by default is called “grafana-dashboards” which should look something like this:

/**
 * Elasticsearch index for storing dashboards
 *
 */
 grafana_index: "grafana-dash-orig",

Now, if you still have access to the old server it is merely a matter of copying this Elasticsearch directory that houses your Grafana dashboard over to the new location. By default on an Ubuntu installation the Elasticsearch data files get placed in to the following path:

/var/lib/elasticsearch/elasticsearch/nodes/0/indices/grafana-dashboards

Replace “0” with the node if this is a clustered Elasticsearch instance, otherwise you should see the grafana-dashboard directory. Simply copy this directory over to the new server with rsync or scp and put it in a temporary location for the time being (like /tmp for example). Rename the existing grafana-dashboards directory to something different, in case there are some newly created dashboards that you would like to retrieve. Then move the original dashboards (from the old server) from the /tmp directory in to the above path, renaming it to grafana-dashboard. The final step is to chown the directory and its contents. The steps for accomplishing this task are similar to the following.

On the old host:

cd /var/lib/elasticsearch/elasticsearch/nodes/0/indices/
rsync -avP -e ssh grafana-dashbaords/ user@remote_host:/tmp/

On the new host:

cd /var/lib/elasticsearch/elasticsearch/nodes/0/indices/
mv grafana-dashboards grafana-dash-orig
mv /tmp/grafana-dashboards ./grafana-dashboards
chown -R elasticsearch:elasticsearch grafana-dashboards

You don’t even need to restart the webserver or Elasticsearch for the old dashboards to show up. Just reload the page and bam. Dashboards.