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diff --git a/_drafts/ansible-and-chef.mdown b/_drafts/ansible-and-chef.mdown index 87b1000..2f65ea8 100644 --- a/_drafts/ansible-and-chef.mdown +++ b/_drafts/ansible-and-chef.mdown @@ -4,65 +4,88 @@ category: devops title: Where we talk about ansible and chef --- -I've been using Chef for some time now, but it was always via Vagrant, -so a few weeks ago I decided to get more familiar with it. Since a -friend of mine set up a Chef server for his own use and was OK to let -me use it for my own server, I put to profit the Thanksgiving weekend -to reinstall my Linode server with it. +I've been using [Chef](http://www.opscode.com/chef/) for some time now, but it was always via [Vagrant](http://vagrantup.com), +so a few weeks ago I decided to get more familiar with it. A friend +of mine had set up a Chef server for his own use and was OK to let me use +it for my personal server. There was a four days weekend for Thanksgiving +coming, so it was the perfect occasion to take a better look at it, +and to re-install my Linode server with Chef. And since it was a +really long weekend, I also decided to take a look at [ansible](http://ansible.cc), another +tool to push stuff to your server. I'm not going to talk about installation, configuration, set up and -all that kind of stuff, there's enough blog posts, articles and books -about that subject. Instead, I will focus on my experience and share -my (very valuable) opinion (because, clearly, the world deserve to -know what I think). +all that kind of stuff, there's enough material available around (blog +posts, articles, books, etc). Instead, I will talk about my +experience and share my (very valuable) opinion (because, clearly, the +world deserve to know what I think). ## Writing cookbooks for Chef For the few of you who don't know, cookbooks, in Chef's world, are a -group of files (templates, static files) and code to change the state -of your machine. +group of files (templates, static files) and code that are used to +automate your infrastructure. Usually, you'll create a cookbook for +each of your application (one for nginx, one for MySQL, etc). + +I've a few services on my server (git, gitolite, Jenkins, graphite, +collectd, phabricator, ...), and I wanted a coobook for each of them. +I've started by looking for the one already existing (there's a lot of +them on GitHub, on the +[opscode's account](https://github.com/opscode-cookbooks/)), and I tried to use +them without any modification. Usually, a cookbook will let you set +some configuration details in your role or node to override the +defaults it provides (like +the password for MySQL, or the path where to put logs). So what I did +was to set the interesting cookbook as a git submodule in my cookbook +repository. Unfortunately, for almost all of them, I had to give up +and import them in the repo, so I could edit and modify them. + +That's probably my biggest complaint with cookbooks: I doubt code +re-usability is possible. You can use a cookbook as a base for your +own version, but either they are too generic; or sometimes you need a +workaround; or they do way too many things. And as a result, you need to edit the +code to make them behave the way you want. + +In my opinion, developers/ops should just publish [LWRP](http://docs.opscode.com/essentials_cookbook_lwrp.html) (Lightweight +Resources and Providers) and templates, that's the only thing that I +can see as really re-usable (take a look at +[perl-chef](https://github.com/dagolden/perl-chef), I think that this one is a good +example). + +## Using ansible -I've a few services on my server: git, gitolite, Jenkins, graphite, -collectd and phabricator, and I wanted a coobook for all of them. -I've started by looking for some cookbooks on the web and try to use -them without any modification. Usually, I would fetch them as a -submodule in my cookbooks repository. But for all of them, I had to -give up and import them in the repo, so I could modify them. - -That's probably my biggest concern with cookbooks: I doubt code -re-usability is possible. Cookbooks should just provides LWRP -(Lightweight Resources and Providers), that's the only thing that I -can see as really re-usable. +ansible was a new tool for me. A few friends mentionned it to me last +October when I was at the [OSDC.fr](http://osdc.fr) and it was also suggested to me by a +colleague at work. -Another annoying thing, I've not found a way to run the chef-client -with only one specific cookbook (well, I was able to, by commenting -all the cookbooks except one in my role, but that's gross). +This tool is definitely less known that Chef, so I'll give a quick +introduction. In ansible world, you write "playbooks", which are the +orchestration language for the tool. That sounds very similar with +Chef, but the main difference is they are not actual code, but a +scenario with actions. -## Using Ansible +On the web site of the project, there's a quote saying: -ansible was a new tool for me. A few friends mentionned it to me last -October when I was at OSDC.fr and it was also suggested to me by a -colleague at work. +> You can get started in minutes. -~~~~~~ description of what ansible is -It's probably less known that Chef. +and for once, that's true. I only had to read the first page of the +documentation, and I was able to write a very simple playbook that I +was able to evolve very quickly to do something actually useful. -~~~~~~REWORK THAT PART -With ansible you write playbooks don't write code, you only write a description in -YAML. They don't encourage to share your entire playbooks, but -instead they incite you to write modules (in Python). (you can see modules as being -similar to LWRP in Chef's world). +Another difference with Chef is that they don't incite you to share +your playbooks, but instead to share your modules. Modules could be +compared to Chef's LWRP. They are Python code to do something +specific (like the [`pip`](http://ansible.cc/docs/modules.html#pip) module, to install Python package, or the +[`template`](http://ansible.cc/docs/modules.html#template)'s one). ## Chef vs Ansible -I've decided to stick to this: use Chef for my supporting application -(nginx, MySQL, etc) and ansible for my applications. +For now, I've decided to stick to this: use Chef for my supporting +application (nginx, MySQL, etc) and ansible for my own applications. So far, I prefer ansible to Chef. There's definitely less available -material about ansible on the net, but the quality is better, and it's -usually well organized. I've never spend more than 10 minutes looking -for something and to implement it. It can't say the same with Chef: -the wiki is confusing, there's way too many cookbooks available, their -quality is very disparate, etc. - +material about ansible on the net, but the quality is better, and the +main documentation is very (I insist on the *very*) well organized. I've never spend more than +10 minutes looking for something and to implement it. I can't say +the same with Chef: the wiki is confusing; there's way too many +cookbooks available; their quality is very disparate. |