Docker 🐳

UPDATE 26/07/2015 In typical fashion, a few weeks after posting this Docker themselves released a much better version than mine, you can install it using the following commands; Update to CentOS 7 Docker install one-liner 1/2 curl -sSL https://get.docker.com/ | sh systemctl enable docker && systemctl start docker docker run hello-world What follows is the original, now mostly redundant post. It’s been a while since I touched the code for the one-liner Docker installer I wrote a while back. ...

After being nagged by the gaffer to try OpenShift Origin V3 I finally got round to running a test server using Vagrant on my Mac. I must say, going into this that the documentation at this stage is struggling a little to keep up with the development and these instructions are the results of much trial, error & Googling. Also, the product is very much still in active development and there have been several bugs, like this one↗ , which have caused the instructions below not to work. ...

Since I last properly [wrote about Docker](/2014/08/31/docker-fig-nginx-reverse-proxies-and-centos-7/“Docker, Fig, NGINX Reverse Proxies and CentOS 7”) a lot has changed. Docker have introduced some new command line tools which allow for easy orchestration of Docker instances, clusters and container management. These are; Docker Machine↗ — Allows you to easily deploy Docker instances to a lot of different platforms. Docker Compose↗ — A replacement for Fig↗ . Docker Swarm↗ — Native clustering for your Docker instances. Out of these three technologies, Swarm is not really suitable for production use so I won’t go into it in too much detail in this post. ...

Now the dev team at work↗ have moved over to using Docker we decided to have some fun. An internal system we use is based on Drupal7↗ , the development version of the site has a NGINX / PHP 5.4 container↗ running in front of it. We have been hearing alot about HHVM↗ so why not try building a container and seeing if it our codebase works? ...

When Docker 1.3↗ was released a few weeks ago I was interested in using the process injection docker exec functionality. Unfortunately, all of the repos which provide RPMs for Docker are out of date, the documentation suggests a manual installation↗ of the binary which is turns out to be straight forward: Installing Docker 1.3.x on CentOS 7 1/2 # Download the binary & set the permissions curl -L https://get.docker.com/builds/Linux/x86_64/docker-latest > /usr/bin/docker; chmod +x /usr/bin/docker # Download the systemd files curl -L https://raw.githubusercontent.com/docker/docker/master/contrib/init/systemd/docker.service > /usr/lib/systemd/system/docker.service curl -L https://raw.githubusercontent.com/docker/docker/master/contrib/init/systemd/docker.socket > /usr/lib/systemd/system/docker.socket # Enable & start the service systemctl enable docker systemctl start docker # Install Fig as well curl -L https://github.com/docker/fig/releases/download/1.0.0/fig-`uname -s`-`uname -m` > /usr/local/bin/fig; chmod +x /usr/local/bin/fig now to check it works: ...

On Friday DigitalOcean announced the availability↗ of CoreOS↗ on their platform. CoreOS is a very optimized Operating System which is designed to just run containers. While it has some very powerful clustering elements made up of …. etcd↗ fleet↗ systemmd↗ …. I decided my first step should be to do the opposite of every blog post I have read about CoreOS and run a single instance with the tools I am used to using. ...

I have been writing a lot about Docker↗ and how I have used it over the last several months so why another another post? Well, for a start it has a lot of momentum. Since Docker went 1.0 in June↗ there have been two further↗ releases↗ . Also, the ecosystem which has sprung up around Docker is keeping up the same pace as well. This means that there is always a lot of new shinny things to play with such as ….. ...

I have been installing and exposing SSH on most of the containers I have deployed, which I know is wrong. As I have been trying to do things in a more “devops” way I decided to do a little reading on how I can enter and leave running containers on my CentOS 7 instance without having to expose SSH or configure users. This is when I came across nsenter↗ & docker-enter↗ . As you can see from the following instructions and terminal session installing nsenter and then using docker-enter to connect to a running container is a breeze; ...