Mathias Lafeldt mlafeldt

Read and understand https://help.github.com/articles/signing-commits-using-gpg/
Configure Git to sign all the commits, see https://github.com/mlafeldt/dotfiles/commit/f4554f0a122145509da5cdf4180037b3bc13b0ab
Install gpg-agent (we don't want to enter a password for each commit)

brew install gpg-agent

wget https://apt.dockerproject.org/repo/pool/main/d/docker-engine/docker-engine_1.11.1-0~trusty_amd64.deb
sudo dpkg -i docker-engine_1.11.1-0~trusty_amd64.deb
sudo apt-get -y -f install

Nomad Resilience Testing with Vagrant

Based on https://github.com/hashicorp/nomad/tree/master/demo/vagrant, I did some resilience testing to figure out how reliable Nomad's periodic jobs are.

Test scenario

I used this minimal periodic job, which executes a shell script every minute:

# example.nomad

First of all, install Homebrew itself.

As the tap is a private Git repo, you need to generate a GitHub token with repo scope and then add this token to your ~/.netrc file like this:

machine github.com
  login <your GitHub user>
  password <your GitHub token>

Service metrics

I would strongly suggest having your services expose basic metrics themselves. At a bare minimum, for a web service you should probably expose metrics like response times and error rates—vital if your server isn’t fronted by a web server that is doing this for you. But you should really go further. For example, our accounts service may want to expose the number of times customers view their past orders, or your web shop might want to capture how much money has been made during the last day.

Semantic Monitoring

We can try to work out if a service is healthy by, for example, deciding what a good CPU level is, or what makes for an acceptable response time. If our monitoring system detects that the actual values fall outside this safe level, we can trigger an alert— something that a tool like Nagios is more than capable of.

However, in many ways, these values are one step removed from what we actually want to track—namely, is the system working? The more complex the interactions

	require "stringex"

	desc "Create a new letter"
	task :new_letter, :title do \|t, args\|
	title = args[:title] \|\| "New Letter"
	num = File::basename(Dir['letters/*'].last)[0,3].to_i + 1
	filename = "letters/%03d-%s.md" % [num, title.to_url]
	date = Time.now.strftime("%Y-%m-%d")

	puts "==> Creating new letter: #{filename}"

	- name: "Build and push Docker images"
	sudo: yes
	command: "java -jar /opt/jenkins/jenkins-cli.jar -s http://127.0.0.1:8080 build {{ item }} -f"
	args:
	creates: "/var/lib/jenkins/jobs/{{ item }}/workspace"
	with_items:
	- CLI
	- Deployer
	- Foo
	- Bar

	package main

	import (
	"log"
	"os"

	"github.com/hashicorp/vault/api"
	"github.com/hashicorp/vault/builtin/credential/github"
	)

	require 'stringex'

	POSTS_DIR = '_posts'
	BUILD_DIR = '_site'
	DEPLOY_DIR = '_deploy'
	DEPLOY_BRANCH = 'master'

	def git(*args)
	sh 'git', *args
	end

	$ docker images quay.io/mlafeldt/chef-runner
	REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE
	quay.io/mlafeldt/chef-runner rpm b524faf0fe69 42 hours ago 830.3 MB
	quay.io/mlafeldt/chef-runner deb d26c1d8dc51c 42 hours ago 622.9 MB

	$ docker push quay.io/mlafeldt/chef-runner
	The push refers to a repository [quay.io/mlafeldt/chef-runner] (len: 2)
	Sending image list
	Pushing repository quay.io/mlafeldt/chef-runner (2 tags)
	Image 511136ea3c5a already pushed, skipping