I recently started preparing for deploying our localstre.am codebase to an actual server. So, that means I’m currently having a lot of fun picking up some new skills and playing system administrator (and being aware of my short comings there). World plus dog seems to be recommending using either Chef or Puppet for this and since I know few good people that are into puppet in a big way and since I’ve seen it used in Nokia, I chose the latter.
After getting things to a usable state, I have a few observations that come from my background of having engineered systems for some time and having a general gut feeling about stuff being acceptable or not that I wanted to share.
- The puppet syntax is weird. It’s a so-called ruby DSL that tries to look a bit like json and only partially succeeds. So you end up with a strange mix of : and => depending on the context. I might be nit picking here but I don’t think this a particularly well designed DSL. It feels more like a collection of evolved conventions for naming directories and files that happen to be backed by ruby. The conventions, naming, etc. are mostly non sensical. For example the puppet notion of a class is misleading. It’s not a class. It doesn’t have state and you don’t instantiate it. No objects are involved either. It’s more close to a ruby module. But in puppet, a module is actually a directory of puppet stuff (so more like a package). Ruby leaks through in lots of places anyway so why not stick with the conventions of that language? For example by using gems instead of coming up with your own convoluted notion of a package (aka module in puppet). It feels improvised and gobbled together. Almost like the people who built this had no clue what they were doing and changed their minds several times. Apologies for being harsh if that offended you BTW .
- The default setup of puppet (and chef) assumes a lot of middleware that doesn’t make any sense whatsoever for most smaller deployments (or big deployments IMNSHO). Seriously, I don’t want a message broker anywhere near my servers any time soon, especially not ActiveMQ. The so-called masterless (puppet) or solo (chef) setups are actually much more appropriate for most people. They are more simple and have less moving parts. That’s a good thing when it comes to deployments.
- It tries to be declarative. This is mostly a good thing but sometimes it is just nice to have an implicit order of things following from the order in which you specify things. Puppet forces you to be explicit about order and thus ends up being very verbose about this. Most of that verbosity is actually quite pointless. Sometimes A really comes before B if I specify it in that order in one file.
- It’s actually quite verbose compared to the equivalent bash script when it comes to basic stuff like for example starting a service, copying a file from a to b, etc. Sometimes a “cp foo bar; chmod 644 bar” just kinda does the trick. It kind of stinks that you end up with these five line blobs for doing simple things like that. Why make that so tedious?
- Like maven and ant in the Java world it, it tries to be platform agnostic but only partially succeeds. A lot of platform dependencies creep in any way and generally puppet templates are not very portable. Things like package names, file locations, service names, etc. end up being platform specific anyway.
- Speaking of which, puppet is more like ant than like maven. Like ant, all puppet does is provide the means to do different things. It doesn’t actually provide a notion of a sensible default way that things are done that you then customize, which is what maven does instead. Not that I’m a big fan of maven but with puppet you basically have to baby sit the deployment and worry about all the silly little details that are (or should be) bog standard between deployments: creating users, setting up & managing ssh keys, ensuring processes run with the appropriate restrictions, etc. This is a lot of work and like a lot of IT stuff it feels repetitive and thus is a good candidate for automation. Wait … wasn’t puppet supposed to be that solution? The puppet module community provides some reusable stuff but its just bits and pieces really and not nearly enough for having a sensible production ready setup for even the simplest of applications. It doesn’t look like I could get much value out of that community.
So, I think puppet at this stage is a bit of a mixed bag and I still have to do a lot of work to actually produce a production ready system. Much more than I think is justified by the simplicity of real world setups that I’ve seen in the wild. Mostly running a ruby or java application is not exactly rocket science. So, why exactly does this stuff continue to be so hard & tedious despite a multi billion dollar industry trying to fix this for the last 20 years or so?
I don’t think puppet is the final solution in devops automation. It is simply too hard to do things with puppet and way too easy to get it wrong as well. There’s too much choice, a lack of sensible policy, and way too many pitfalls. It being an improvement at all merely indicates how shit things used to be.
Puppet feels more like a tool to finish the job that linux distributors apparently couldn’t be bothered to do in arbitrary ways than like a tool to produce reliable & reproducible production quality systems at this point and I could really use a tool that does the latter without the drama and attitude. What I need is sensible out of the box experience for the following use case: here’s a war file, deploy that on those servers.
Anyway, I started puppetizing our system last week and have gotten it to the point where I can boot a bunch of vagrant virtual machines with the latest LTS ubuntu and have them run localstre.am in a clustered setup. Not bad for a week of tinkering but I’m pretty sure I could have gotten to that point without puppet as well (possibly sooner even). And, I still have a lot of work to do to setup a wide range of things that I would have hoped would be solved problems (logging, backups, firewalls, chroot, load balancing a bog standard, stateless http server, etc). Most of this falls in the category of non value adding stuff that somebody simply has to do. Given that we are a two person company and I’m the CTO/server guy, that would be me.
I of course have the benefit of hindsight from my career in Nokia where I watched Nokia waste/invest tens of millions on deploying simple bog standard Java applications (mostly) to servers for a few years. It seems simple things like “given a war file, deploy the damn thing to a bunch of machines” get very complicated when you grow the number of people involved. I really want to avoid needing a forty people ops team to do stupid shit like that.
So, I cut some corners. My time is limited and my bash skills are adequate enough that I basically only use puppet to get the OS in a usable enough state that I can hand off to to a bash script to do the actual work of downloading, untarring, chmodding, etc. needed to get our application running. Not very puppet like but at least it gets the job done in 40 lines of code or so without intruding too much on my time. In those 40 lines, I install the latest sun jdk (tar ball), latest jruby (another tar ball), our code base, and the two scripts to start elastic search and our jetty/mizuno based app server.
What would be actually useful is reusable machine templates for bog standard things like php and ruby capable servers, java tomcat servers, apache load balancers, etc with sensible hardened configurations, logging, monitoring, etc. The key benefit would be inheriting from a sensible setup and only changing the bits that actually need changing. It seems that is too much to ask for at this point and consequently hundreds of thousands of system administrators (or the more hipster devops if you are so inclined) continue to be busy creating endless minor variations of the same systems.