How to Run Go on OpenShift

OpenShift is a great PaaS offering by Red Hat. At the moment Go is not currently on the supported platform list. However Red Hat have kindly provided a DIY cartridge to run whatever you want on the platform. As Go is one of my favourite languages I thought I'd put together a template that can be used to deploy a basic Go application.

0. Create a OpenShift account. Go to http://openshift.redhat.com to create an account.

1. Install the OpenShift client tools.

   cd /etc/yum.repos.d
   sudo wget https://openshift.redhat.com/app/repo/openshift.repo
   sudo yum install rhc

2. Create a new domain

   rhc-create-domain --namespace your-namespace --rhlogin your-login

3. Create a new application

   rhc-create-app --app your-appname --type diy-0.1 --rhlogin your-login

4. Add this as an upstream repository

   git remote add upstream -m master git://github.com/gcmurphy/golang-openshift.git
   git pull -s recursive -X theirs upstream master

5. Build the source and copy the output to your bin directory (updated for Go version 1)

   cd server
   go build
   mv server ../bin

6. Push to your OpenShift repository

   git commit -a -m "My first go + openshift application"
   git push

7. You are good to Go! You can read more about the OpenShift DIY cartridge here.

A note on cross compiling

This skeleton project depends on the fact that the OpenShift images that are deployed are running on Linux x86_64 virtual machines. However the OpenShift toolkit is available for both Windows and Mac OSX. In order to use this toolkit on these platforms the following additional steps need to be used to create a cross compiler for the non Linux development environments:

1. Get the latest release of the Go source code.

   wget http://go.googlecode.com/files/go1.0.1.src.tar.gz

2. Extract the source code and compile it, targeting the Linux platform and architecture

   tar xzvf go*.tar.gz
   cd go/src
   CGO_ENABLED=0 GOOS=linux GOARCH=amd64 ./make.bash

3. If everything worked you should see:

   Installed Go for linux/amd64 in Your build directory
   Installed commands in Your build directory/bin

4. Try to build the project now using the go compiler we just created

   cd golang-openshift/server
   CGO_ENABLED=0 GOOS=linux GOARCH=amd64 ~/xcompile/go/bin/go build

The output file will run on a Linux AMD64 box but not locally which is a bit of an annoyance. The alternative would be to create a copy of the Go runtime on the Linux machine and compile the code remotely.