Configuration management

An update to cf-keycrypt

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I have published a small update to cf-keycrypt, so that it’s now easier to compile the tool on Debian systems and it’s compatible with CFEngine 3.15. You can find it here.

For those who don’t know the tool, I’ll try to explain what it is in a few words. The communication between CFEngine agents on clients and the CFEngine server process on a policy hub is encrypted. The key pairs used to encrypt/decrypt the communication are created on each node, usually at installation time or manually with a specific command. cf-keycrypt is a tool that takes advantage of those keys to encrypt and decrypt files, so that they are readable only on the nodes that are supposed to use them. The fact that the keys are created on the nodes themselves eliminates the need to distribute the keys securely.

cf-keycrypt was created years ago by Jon Henrik Bjørnstad, one of the founders of CFEngine (the company). The code has finally landed the CFEngine core sources as cf-secret, but it’s not part of the current stable releases. I had an hard time trying to compile it, but I made it with good help from the CFEngine help mailing list. I decided to give the help back to the community, publishing my updates and opening a pull request to the original code.  Until it’s merged, if it ever will, you can find my fork on my github.

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Down the rabbit hole: installing software

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Preface

This article is about using configuration management to install software on your own computers (e.g. your laptops, or the computers used by your family and relatives) and how the complexity of this task is easy to overlook, no matter if you are a newbie or an expert.

If you already know about configuration management and how it makes sense to use it at a small scale like, again, your own computers or your family’s, you can just skip at the section “New job, new setup”.

If you already know about configuration management and you are asking yourself why it should make sense to use it at a small scale, I suggest that you start a section earlier, at Personal configuration management”.

If you are new to configuration management, or you wonder what could be difficult in installing software on a set of systems, I suggest that you read the whole article.

In any case, happy reading!

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The future of configuration management (again), and a suggestion

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cfgmgmtcamp-logoI have attended the Config Management Camp in Gent this year, where I also presented the talk “Promise theory: from configuration management to team leadership“. A thrilling experience, considering that I was talking about promise theory at the same conference and in the same track where Mark Burgess, the inventor of promise theory, was holding one of the keynotes!

The quality of the conference was as good as always, but my experience at the conference was completely different from the past. Last time I attended, in 2016, I was actively using CFEngine and that shaped in both the talks I attended and the people that I hanged on with the most. This year I was coming from a different work environment and a different job: I jumped a lot through the different tracks and devrooms, and talked with many people with a very different experience than mine. And that was truly enriching. I’ll focus on one experience in particular, that led me to see what the future of configuration management could be.

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Perl to go

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I have been using Perl for more than 20 years now, seen Perl 4 bow out and Perl 5 come in and develop in that fantastic language that has helped me uncountable times in my professional life. During those years I’ve also considered learning another language, but I have been unable to take a stand for a long time.

And there came Go and the hype around Go, just like years ago there was a lot of hype around Java. But while whatever written in Java I came across was a big, heavy and slow memory eater, most of the tools I came across that were written in Go were actually good stuff — OK, still a bit bloated in size, but they actually worked. The opportunity came, and I finally gave Go a shot.

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cf-deploy v2 released

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Update: this article refers to the third version of cf-deploy. For the latest release, check the github repository.

Errata corrige: it’s actually v3! This is what happens when you don’t publish updates for your software for too long…

github-logo I took some time this weekend to release an update for cf-deploy. You have now the option to override the configuration hardcoded in the script by means of environment variables. Check the README for the details.

If you don’t know what cf-deploy is, that’s fair 😉 In two words, it’s a Makefile and a Perl front-end to it that makes it easier to pack together a set of files for a configuration management tools and send them to a distribution server. Designed with git and CFEngine in mind, it’s general enough that you can easily adapt it to any version control system and any configuration management tool by simply modifying the Makefile. If it sounds interesting, you are welcome to read Git repository and deployment procedures for CFEngine policies on this same blog. Enjoy!

 

cfengine-tap now on GitHub

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github-logo Back from the holiday season, I have finally found the time to publish a small library on GitHub. It’s called cfengine-tap and can help you writing TAP-compatible tests for your CFEngine policies.

TAP is the test anything protocol. It is a simple text format that test scripts can use to print out the results and test suites can consume. Originally born in the Perl world, it is now supported in many other languages.

Using this library it’s easier to write test suites for your CFEngine policies. Since it’s publicly available on GitHub and published under a GPL license, you are free to use it and welcome to contribute and make it better (please do).

Enjoy!

How I configure a docker host with CFEngine

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DockerAfter some lengthy busy times I’ve been able to restart my work on Docker. Last time I played with some containers to create a Consul cluster using three containers running on the same docker host — something you will never want to do in production.

And the reason why I was playing with a Consul cluster on docker was that you need a key/value store to play with overlay networks in Docker, and Consul is one of the supported stores. Besides, Consul is another technology I wanted to play with since the first minute I’ve known it.

To run an overlay network you need more than one Docker host otherwise it’s pretty pointless. That suggested me that it was time to automate the installation of a Docker host, so that I could put together a test lab quickly and also maintain it. And, as always, CFEngine was my friend. The following policy will not work out of the box for you since it uses a number of libraries of mine, but I’m sure you’ll get the idea.

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A dockerized policy hub

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DockerThis is a quick post, apologies in advance if it will come out a bit raw.

I’ve been reading about docker for a while and even attended the day of docker in Oslo. I decided it was about time to try something myself to get a better understanding of the technology and if it could be something useful for my use cases.

As always, I despise the “hello world” style examples so I leaned immediately towards something closer to a real case: how hard would it be to make CFEngine’s policy hub a docker service? After all it’s just one process (cf-serverd) with all its data (the files in /var/cfengine/masterfiles) which looks like a perfect fit, at least for a realistic test. I went through the relevant parts of the documentation (see “References” below) and I’d say that it pretty much worked and, where it didn’t, I got an understanding of why and how that should be fixed.

Oh, by the way, a run of docker search cfengine will tell you that I’m not the only one to have played with this 😉

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The future of configuration management – mini talks

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On March 7th I was at the DevOps Norway meetup where both Jan Ivar Beddari and me presented an extended version of the ignite talks we held at Config Management Camp in February. The talks were streamed and recorded through Hangouts and the recording is available on YouTube.

The meeting gave me the opportunity to explain in a bit more detail my viewpoint about why we need a completely new design for our configuration management tools. I had tried already in a blog post that caused some amount of controversy and it was good to get a second chance.

I’d recommend you watch both Jan Ivar’s talk and mine, but if you’re interested only in my part then you can check out here:

And don’t forget to check out the slides, both Jan Ivar’s and mine.