Thursday, October 20, 2016

Hawkular OpenShift Agent is Born

A new Hawkular agent has been published on - Hawkular OpenShift Agent.

It is implemented in Go and the main use case for which it was created is to be able to collect metrics from OpenShift pods. The idea is you run Hawkular OpenShift Agent (HOSA) on an OpenShift node and HOSA will listen for pods to come up and down on the node. As pods come online, the pods will tell the agent what (if any) metrics should be collected. As pods go down, the agent will stop collecting metrics from all endpoints running on that pod.

Today, only Prometheus endpoints (using either the binary or text protocol) can be scraped with Jolokia endpoints next on the list to be implemented. So HOSA will be able to support collecting metrics from either type of endpoint in the near future.

For more information - how to build and configure it - refer to the Hawkular OpenShift Agent README.

Monday, October 17, 2016

Pulling in a Go Dependency From a Fork, Branch, or Github PR using Glide

While writing a Go app, I decided to use Glide as the dependency management system (I tried Godep first, but even on the first day of using it, my dependencies were getting screwed up, lost, builds would mysteriously break - so I decided to switch to Glide, which seems much better).

I was using the Hawkular Go Client library because I needed to write metric data to Hawkular Metrics. So in my glide.yaml, I had this:
- package:
  - metrics
Which simply tells Glide that I want to use the latest master of the client library (I'm not using a versioned library yet. I guess I should start doing that).

Anyway, I needed to add a feature to the Hawkular Go Client. So I forked the git repository, created a branch in my fork where I implemented the new feature, and submitted a Github pull request from my own branch. Rather than wait for the PR to be merged, I wanted Glide to pull in my own branch in my forked repo so I could immediately begin using the new feature. It was as simple as adding three lines to my glide.yaml and running "glide update":
- package:
  vcs: git
  ref: issue-8

  - metrics
This tells Glide that the Hawkular Go client package is now located at a different repository (my fork located at under a branch called "issue-8".

Running "glide update" pulled in the Hawkuar Go client from my fork's branch and placed it in my vendors/ directory. I can now start using my new feature in my Go app without waiting for the PR to be merged. Once the PR is merged, I can remove those three lines, "glide update" again, and things should be back to normal.

Wednesday, October 5, 2016

Installing Open Shift Origin and Go for a Development Environment

The Hawkular team is doing some work to develop a Hawkular Agent for running within an Open Shift environment. Since the Go Programming Language ("Go") seems to be the language de jour and many things within the Open Shift infrastructure is developed in Go, the first attempt at this new Hawkular Agent will also be implemented in Go.

Because of this, I needed to get a development environment up and running that included both Open Shift and Go. This blog is simply my notes on how I did this.


Go isn’t necessary to install and run Open Shift, but because I want to write a Go application, I need it.


* Create the directory where Go is to be installed

   mkdir $HOME/bin/go-install (this is where Go will be installed)

* Create the Go workspace (GOPATH will end up pointing to here)

   mkdir $HOME/source/go
   mkdir $HOME/source/go/bin
   mkdir $HOME/source/go/pkg
   mkdir $HOME/source/go/src

* Download go package from

   cd /tmp

* Unpack the tar in the $HOME/bin/go-install - should end up inside a subdirectory "go"

   cd $HOME/bin/go-install
   tar xzvf /tmp/go*.tar.gz

* Set up your shell environment so you can run Go
** Put the following Inside .bashrc 

   export GOROOT=${HOME}/bin/go-install/go
   export PATH=${PATH}:${GOROOT}/bin
   export GOPATH=${HOME}/source/go

* Make sure Go is working before going on - run “go version” to confirm. I like to log completely out and then back in again so my bash script gets loaded for all my shells.


* Download and install guru

   cd $HOME/bin/go-install/go/bin
   go get
   go build

** The above puts the "guru" executable in your current directory (which should be $HOME/bin/go-install/go/bin)

* Download and install gocode

   cd $HOME/bin/go-install/go/bin
   go get
   go build

** The above puts the "gocode" executable in your current directory (which should be $HOME/bin/go-install/go/bin)

* Download and install godef

   cd $HOME/bin/go-install/go/bin
   go get
   go build

** The above puts the "godef" executable in your current directory (which should be $HOME/bin/go-install/go/bin)

* Download and install godep

   cd $HOME/bin/go-install/go/bin
   go get
   go build

** The above puts the "godep" executable in your current directory (which should be $HOME/bin/go-install/go/bin)

* If you use Eclipse, install GoClipse:
** Plugin Site:
** Make sure the GoClipse configuration knows where your Go installation is along with your guru, gocode, and godef executables. See the Go configuration settings in Eclipse preferences.


These instructions will install Open Shift in a virtual machine. So you need to get Vagrant and VirtualBox first before doing anything. And of course Vagrant needs Ruby 2 so you need that before anything. Then you install the Open Shift image.

Note that you may have to change your BIOS settings to enable virtualization. To avoid a VERR_VMX_MSR_ALL_VMX_DISABLED error, I had to do this on my Lenovo laptop in the Security->Virtualization section of the BIOS settings.

These notes follow the instructions found at

(October 5, 2016: Note that the instructions there tell you to not use Vagrant 1.8.5 nor VirtualBox 5.1 - unfortunately, they tell you this all the way at the bottom after the instructions. So if you start at the top and work your way down, you will be frustrated beyond belief until you decide to skip all the way to the bottom and realize this. I emailed the folks maintaining that page to put those notices at  the top so people can see these warnings before they start downloading the wrong stuff.)


If you already have Ruby 2+ installed, you can skip this. This will install RVM and then use that to install Ruby 2. If you skip this step, make sure you have a Ruby 2 installation available before going on to installing and running Vagrant.

* Download and install RVM and Ruby
** You need to accept the GPG key for RVM and install RVM

   gpg2 --keyserver hkp:// --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3
   curl -L | bash -s stable
   rvm autolibs packages

** Now install Ruby 2

   rvm install 2.3.0
   rvm use --default 2.3.0
   ruby -v


* Download and install Vagrant .rpm

   cd /tmp

   rpm -i vagrant_*.rpm
   vagrant version


* Download and install Virtual Box
** You must grab it from the Oracle yum repo - we first must add that repo to our system:

   sudo wget -P /etc/yum.repos.d

** If anything goes wrong during the install, you'll want to update your system and reboot - so you may want to do this now:

    dnf update

** Make sure the kernel version is expected - these should output the same version string - otherwise, reboot

   rpm -qa kernel | sort -V | tail -n 1

   uname -r

** Install VirtualBox now

   dnf install VirtualBox-5.0

I ran into some problems when I tried to run VirtualBox before I realized I needed to download VirtualBox from the Oracle yum repo. If you download from, say, RPMFusion, these instructions may not work (they did not for me). If you run into problems, you might have to install some additional packages via dnf (such as kernel-devel, kernel-headers, dkms) and perform some additional magic which I do not know which explains why I received a Dreadful grade on my O.W.L. exam.


* Go to an empty directory where you want to prepare your Vagrantfile

   mkdir ${HOME}/openshift

   cd ${HOME}/openshift

* Create a Vagrant file that initializes the OpenShift image.

   vagrant init openshift/origin-all-in-one

* Run Open Shift inside a VM within VirtualBox
   vagrant up --provider=virtualbox

At this point you should have an OpenShift environment running. If any errors occur, a log message should tell you how you can proceed.

You will want to download the Open Shift command line client "oc". Rather than regurgitate the instructions here, simply log into Open Shift using the default "admin" user (password "admin") and go to and follow the instructions there to download, install, and use "oc".

Note that you can SSH into your VM by executing "vagrant ssh"

The Open Shift self-signed certificate found at "/var/lib/origin/openshift.local.config/master/ca.crt" can be used to authenticate clients.


Should you wish to upgrade the Open Shift VM in the future, the following steps should do it.

* Go to the directory where you ran the VM:

   cd ${HOME}/openshift

* Update the image

   vagrant box update --box openshift/origin-all-in-one

* Destroy and re-create the VM environment

   vagrant destroy --force
   vagrant up --provider=virtualbox


Should you wish to remove the Open Shift VM in the future, the following steps should do it.

* Go to the directory where your Vagrantfile is

   cd ${HOME}/openshift

* Remove Open Shift VM

   vagrant halt
   vagrant destroy --force
   vagrant box remove --force openshift/origin-all-in-one