This is a continuation from What OS for Docker host? (Part 2).
CoreOS
Reading about my plight and having experienced problems with Docker on Alpine Linux, Jan Hapke recommended CoreOS unless one needs CIFS. Since I didn’t know anything about CIFS, I assumed I didn’t need it. So I pulled down another ISO and burned another disc. The installation process was fairly simple and I’d already learned my lesson about specifying authorized keys at install time during my Rancher OS exploration. I was a little surprised that the installer didn’t ask me if I really wanted to reformat my hard drive–I knew it would and admittedly did use sudo, but usually for such potentially disastrous consequences most installers ask if you really want to lose all the data on the drive . . .
The install went fairly quickly and I was able to ssh into my machine using my key. I checked and the Docker version was at 1.8.3–I had installed the “stable” version of CoreOS so it makes sense that it doesn’t have the very latest and greatest. I ran a few Docker containers and everything worked smoothly and as I would want.
Then came wireless networking setup. I couldn’t. Searching a bit found others also wanted to use wireless with CoreOS, but the solution seems to involved manually finding the correct drivers and then reconfiguring and building the kernel. That was something I wasn’t too keen to try. And so I decided that I wouldn’t use CoreOS.
Snappy
While searching for operating systems to try, I came across a couple articles mentioning Ubuntu Core which is known as “Snappy” and is apparently “designed for Docker”. Since I still had CoreOS running on the laptop, the install consisted of running:
wget http://releases.ubuntu.com/15.04/ubuntu-15.04-snappy-amd64-generic.img.xz unxz -c ubuntu-15.04-snappy-amd64-generic.img.xz | sudo dd of=/dev/sdX bs=32M
After that, since I had just run dd over the hard drive, things were understandably in a very bad state, so I forced a restart of the machine. Surprisingly Snappy booted up fine and I was able to SSH into it using the default user name and password (both “ubuntu”).
Installing Docker was pretty easy once I realized that the system didn’t have apt-get. Using the Snappy way, I ran:
sudo snappy install docker
This gave me version 1.6.2 of Docker. I tried running “sudo snappy update docker” but it just seemed to update ubuntu-core. When I went to install Docker directly from docker.io, I discovered that not only does Snappy not come with wget or curl, it doesn’t even seem to have an easy way to install those tools (though some people have found complicated ways to install them). Since I just wanted to fetch a single file, and had Docker, I mounted a volume, spun up a container, and fetched the Docker install script into the mounted directory. I then exited the container and tried to run the script. The script seemed to think that Snappy is like normal Ubuntu and tried to run apt-get. It failed miserably. With an ancient version of Docker and difficulty adding the most basic of utilities, I didn’t even want to try taking on the beast that is wireless. And so I decided that I wouldn’t use Snappy.
I had thought that this post would have two parts, but obviously that didn’t work out. The story continues (and hopefully finds a happy ending) in part 3.
If you are going down the route of picking leaner hosts then……What i would say is that worrying about the setup of the host too much above obviously working with docker and being thinish, is something ive since simplified by never really using the host, but using a docker container set up with all the crap as and when i need it and so it keeps my messy ‘host’setup in its own container. Its a little like docker in docker but better in my opinion most of the time. Any sharing of files etc, goes through here. It tends to keep me a lot happier. When virtualized it definitely makes sense , anyway, i think……although maybe im wromg?