A new leap second will be introduced at the end of 2016. We have six months to get ready, but this time it may be easier than before as several timekeeping software have implemented some “leap smear” algorithm, which seems to be a very popular approach nowadays; e.g.: ntpd, the reference implementation for NTP, seems to have implemented leap smear from version 4.2.8p3 onward.
We’ll see how it goes. Until then… test!
After 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.
Here’s another quick post about docker, sorry again if it will come out a bit raw.
In my previous post I talked about my first experiments with docker. There was a number of unanswered questions at first, which got an answer through updates to the blog post during the following days. All but one. When talking about a containerized process that needs to log through syslog to an external server, the post concluded:
if the dockerized process itself needs to communicate with a syslog service “on board”, this may not be enough…
This 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😉
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.
Here’s the video of my ignite talk at Config Management Camp 2016: “the three legs of modern configuration management (…or maybe it’s four)”. The slides of the talk are also available on SpeakerDeck.
It didn’t take many hours for Luke Kanies to pick up my provocative blog post and express his disappointment:
I’m not going to complain for his words: if I was him I would have thought the same things, and maybe also written the same things. At the same time, it’s kind of funny that a lot of the inspiration for that post came from Luke himself. I’ll explain.
CFEngine, Puppet, Chef… and Ansible, Salt… and many others. We have loved them and we have hated them. It’s time we take a picture, because they may be gone in a few years time. This is the word — or the cry — that got out of too many Configuration Management practitioners at this year’s Config Management Camp.
Learning more of systemd has been on my agenda since the release of Debian 8 “Jessie”. With the new year I decided that I had procrastinated enough, I made a plan and started to study according to the plan. Today it was time for action: to verify my understanding of the documentation I read up to now, I decided to put together unit files for CFEngine. It was an almost complete success and the result is now on GitHub for everyone to enjoy. I would appreciate if you’d give them a shot and report back.
Main goals achieved:
- I successfully created three service unit files, one for each of CFEngine’s daemons: cf-serverd, cf-execd and cf-monitord; the units are designed so that if any of the daemon is killed for any reason, systemd will bring it back immediately.
- I successfully created a target unit file that puts together the three service units. When the cfengine3 target is started, the three daemons are requested to start; when the cfengine3 target is stopped, the three daemons are stopped. The cfengine3 target completely replaces the init script functionality.
Goal not achieved: I’ve given a shot at socket activation, so that the activation of cf-serverd was delayed until a connection was initiated to port 5308/TCP. That didn’t work properly: systemd tried to start cf-serverd but it died immediately, and systemd tried and tried again until it was too much. I’ll have to investigate if cf-serverd needs to support socket activation explicitly or if I was doing something wrong. The socket unit is not part of the distribution on GitHub but its content are reported here below. In case you spot any problem please let me know.