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Selenium grid on Kubernetes

This post continues from where we left off on the Minikube guide. If you do not already have a Kubernetes cluster, you should read that first.

Selenium Grid allows you to build a cluster of Selenium nodes. Today we will create a Selenium cluster with 1 hub and 4 nodes …


Nginx throw HTTP 503 maintenance JSON for all requests

I found this technique after stumbling on Aaron Parecki's blog. You can read his post here:

Lets pretend you have an API and you need to turn on maintenance for a major change. All your …


Build RPM or DEB packages for Node.js using Jenkins and FPM

This blog post assumes you already have:

  • a Jenkins master and none or many build servers
  • FPM installed on the build servers
  • Node.js installed on the build servers

I add jenkins-build.sh in the root of the Node.js code repo:

# example usage: JOB_NAME=example-api BUILD_NUMBER=101 bash jenkins-build …

Register Super Powers with Pyramid add_request_method

The Pyramid web application framework uses a request object to hold state regarding an inbound HTTP connection. A view must accept a request object as the first argument which makes it always available to our views and templates.

This behavior rocks, but Pyramid makes it even better by allowing us …


My first Systemd Service Script and Override

At work we mostly run Centos and I have some NodeJS services to deploy. I feel most familiar with Ubuntu / Upstart so this post serves as my notes on systemd.

In this contrived example, we define a service for our taco-api application. The taco-api source code lives in /opt/taco-api …


Set static hostname for RHEL Centos 7 on AWS

This took me about 2 hours to figure out, hopefully it saves you time.

/etc/sysconfig/network:

HOSTNAME=desired-hostname.example.com

/etc/hostname:

desired-hostname.example.com

/etc/cloud/cloud.cfg:

preserve_hostname: true

If I swallow lots of air will I be lighter?

After dinner tonight, Carter, my four year old asked me, "If I swallow lots of air will I be lighter?". I thought about the question for a moment and then told him it depends on what surrounds you.

If you are surrounded by:
  • air and you swallow lots of air …

Output all instance identifiers of an AWS VPC to JSON

At work today I needed an easy way to collect private IP addresses of every instance in one of our production VPCs.

I ended up adding a tool to http://botoform.com to perform this task.

bf --profile <aws_profile> dump <vpc_name_tag> instances --output-format json

For example:

bf --profile customer3 dump …

Migrating from WordPress to Pelican

Five hints to save time during your migration from WordPress.


Boto3 get main route table

Library work around.


List all installed package names in Python

You only need a two lines of code to access package names and versions.


Filtering AWS resources with Boto3

References to take you from filtering novice to expert.


Working with botocore's ~/.aws/config

Don't reinvent the wheel, use Botocores Config facilities for work with AWS.


A Python script which searches for available interpreters


Migrating libvirt KVM guest to SmartOS KVM guest

Stop worrying and replace your Linux hypervisor with SmartOS.


Setting region programmatically in Boto3


Securely publish Jenkins build artifacts on Salt Master

Your project deserves an asset pipeline.


Set postgres user password on PostgreSQL SmartOS Zone


Risk, Process, and Balance

The operations of a company will have intrinsic risk. Risk occurs each time we decide to take an action or an inaction. This means that anything we choose to do, or not do, has associated risk.

An organization which has an unhealthy aversion to risk has a much higher chance …


autofs /net automount stopped working

So autofs randomly stopped working on one of my Ubuntu hosts (this issue has been found on Arch as well so its most likely a change upstream). I found this error in the logs:

attempting to mount entry /net/freenas.example.net
get_exports: lookup(hosts): exports lookup failed for freenas …

Custom Rundeck HipChat notification templates

Today I built a GUI and workflow around Ansible using Rundeck. Tonight I started diving into sending HipChat notifications and after a bit of research, I managed to create a custom notification template for each Rundeck project.

Modify your project's configuration file, on Ubuntu it was in /var/rundeck/projects …


Build release pipelines on S3 with s3p

This weekend I finished my first sprint on s3p which is a Python library and CLI application that manages release pipelines on AWS S3. I put a lot of effort into the readme.rst file, so look there for usage and examples.

The main purpose of s3p is to use …


Dealing with pagination in Python

So I'm working with an API (AWS ElastiCache) that offers mandatory pagination of results. I need to get all results, so I took some time to work out this logic.

def combine_results(function, key, marker=0, **kwargs):
    """deal with manditory pagination of AWS result descriptions"""
    results = []
    while marker != None:
        result …

Turn python dict into a key=value string and back again

I'm currently refactoring a script that tags AWS resources and I came up with this one liner to generate pretty output. It basically turns {'tag1':'value1','tag2':'value2'} into tag1=value1, tag2=value2. Here is the code:

', '.join(['='.join(key_value) for key_value in {'a':'1','b':'2'}.items() ])

Oh and …


Migrating MongoDB from Ubuntu to SmartOS

I installed the mongodb 14.2.0 (uuid a5775e36-2a02-11e4-942a-67ae7a242985) dataset and launched a new zone. The zone automatically creates a username and password for admin and "quickbackup". You can find these passwords by running the following command inside the zone:

cat /var/svc/log/system-zoneinit\:default.log | grep -i mon …

Set Root Password SmartOS Percona MySQL Zone

I used project-fifo to launch the percona (14.2.0) MySQL dataset. I couldn't get into the MySQL instance so I reached out on IRC. Johngrasty, a friendly guy in the #smartos IRC channel, provided a command to display the randomly generated MySQL password emitted to the zone-init log:

cat …

Heka, World2!

This article expands on my “Hello World” for Heka blog post. Check that one out first if you are new to Heka.

In this guide we introduce using Heka over the network by utilizing two Hekad processes on localhost. For discussion purposes we name one of the Hekad processes "sender …


Mailpile Salt States for Ubuntu or Debian

I wrote these Salt States to install Mailpile on an Ubuntu host. Fun fact, it took me 20 minutes to write these states and they worked the first time I ran them. Disclaimer - I used a throw away server and wasn't concerned that buckets of packages were installed to the …


IRC Bot (Foxbot) runs canned remote executions using Salt Stack

I extended my IRC Bot Foxbot today to allow it to run canned remote executions on behalf of users in an IRC channel. This is only a prototype or proof-of-concept. Be very careful not to allow users to inject their own commands. Foxbot must be running on the Salt Master …


Filter Salt Stack Return Data Output

Sometimes you only want to see what has changed, and that is OK.

Create a file like this:

filter.py

#!/usr/bin/python

from json import loads
from json import dumps

import fileinput

stdin_lines = [line for line in fileinput.input()]

ret = loads(''.join(stdin_lines))

for minion_id, data in ret.items …

Replace the Nagios Scheduler and NRPE with Salt Stack

Note: I will update this post as I progress.

So the idea is to use Salt Stack's remote execution to communicate with all nodes and run the Nagios checks and collect the return output instead of using the NRPE client/service protocol. This reduces the number of agents running on …


Configuration Management and the Golden Image

When operations first became a thing, system administrators stood up servers using a base image from their favourite distribution. Things were done manually. Some administrators created their own distros, some wrote customised shell scripts to be run once-and-only-once to provision software and settings. This method worked, but it was slow …


Automatic Backups

My tools for creating automatic backups for various systems


tar-back

tar-back is a backup utility to tar and gzip target filesystems.
It supports a custom retention, filter exclusions, and backup directory.

I use tar-back in combination with cron to perform regular backups of all localhost filesystems into /archive/fs. I then have a central long term storage server that collects …


mysql-back

mysql-backis a backup utility script to dump (backup) and gzip every MySQL database on a host.

I use mysql-back in combination with cron to perform regular database dumps of MySQL servers to the /archive/db partition on localhost. I then have a central long term storage server that collects …


The Three Deployment Management Strategies

There are three deployment management strategies that could be used to maintain a system. Each has pros and cons which I outline in this document.

run once

A proceedure that is run once and only once to setup a system's configuration values and settings. A semaphore or flag generally blocks …


Heka, World!

This post serves as a "Hello World" for the data collection and processing software called Heka. Heka is written in Go and was open sourced by Mozilla, the same fabulous group that brings us Firefox!

I intend to use Heka to replace Logstash agents by sending logs directly to ElasticSearch …


sensu-salt

A while back I explained how to Create your own fleet of servers with Digital Ocean and salt-cloud. Today I will extend that post and show how I deployed a test environment for Sensu, an open source monitoring framework.

Before I test out new infrastructure software, I always attempt to …


Backup all virtual machines on a SmartOS hypervisor with smart-back.sh

This post will explain how to create a cronjob to backup of every virtual machine on a SmartOS hypervisor.

Create the following bash script in /opt/smart-back.sh:

#!/usr/bin/bash

# Backup all virtual machines on a SmartOS hypervisor
# Author:  russell@ballestrini.net
# Website: http://russell.ballestrini.net/

# Backup directory …

Simplify deployments with Upstart and uWSGI

As you know from my previous post, I recently deleted LinkPeek.com and after struggling to get it back online, I vowed to start utilizing configuration management. During this exercise, I noticed that the architecture I use in production seems overly complicated.

The current production deployment stack:

  • Nginx listen on …

Postfix Salt State Formula


Control a MongoDB collection in configuration management

This post explains how to use configuration management (Salt Stack) to completely control a MongoDB collection. In our example we want to control a store's collection of plans.

First we create a JSON representation of the collection.

mongodb/plan.json:

{
  "_id" : { "$oid" : "4ef8b9e2be329f491d98f74b" },
  "cost" : 20, "description" : "development",
  "name" : "good", "count …

Configuration Management vs Remote Execution

It's about time to learn the difference.


Understanding Salt Stack user and group management

This state will create a user:

russell:
  user:
    - present

This state will create a user and a group. This also makes the user part of the group, and handles creating the group first:

russell:
  group:
    - present
  user:
    - present
    - groups:
      - russell
    - require:
      - group: russell

This state handles user and group generation …


Create your own fleet of servers with Digital Ocean and salt-cloud

Have you heard about Digital Ocean? They offer a polished user interface, KVM guests with SSD storage, and an API to interact with a cloud of hypervisors. API integration got you down? Don't worry, salt-cloud has already integrated Digital Ocean among it's list of providers! The rest of this post …


Add a custom header to all Salt managed files using pillar and jinja templates

Salt-stack (salt) provides a solution for centralized configuration management and remote execution. One of the most basic things Salt provides is the ability to manage the contents of a file or a directory of files. Using Salt we can dictate the state of our minions and as a result we …


Honey! I just DELETED LinkPeek.com

During the day I am an ops sys-admin. During the night I am a husband, father of two, and a CEO of a bootstrapped start-up. After launch, my first project was to schedule regular backups of user data and archive off-site. My goal was to create backups but never need …


virt-back's Domfetcher class returns doms from libvirt API


Prevent a certain program from running too long in bash

Update - I opensourced this script here: bash kira

I came up this this script to kill certain programs after they run for too long. This works like similar to a timeout. Warning this script is pretty harsh and kills the program.

#!/bin/bash
PROGRAM=replace-with-program-name
PIDSFILE=/tmp/kill-these.pids

for …

Always attempt to scale vertically first

I spent the weekend fretting because one of my servers was basically being DOS'd by paying customers. During the outage I started thinking about the best way to scale and how I could make the code-base more efficient.

Linux top reported high load, in the 20's. Eventually I figured out …


High load on web server after updating from Ubuntu 10.04 to Ubuntu 12.04 LTS

Charts that show the load difference.


How to rescue logs and config from a failed Citrix NetScaler App Gateway

Today our production Citrix NetScaler broke. The box wouldn't boot and our only backup copy of the config was on the NetScaler itself.

Being the only Unix guy around I attempted to help out the admins working the outage. I SSH'd into the development NetScaler and noticed it runs on …


Trouble mounting filesystem on KVM guest after reboot

Just found this out the hard way...

It looks like the attachment of /KVMROOT/guest-dev-app.img on guest-dev did not persist when the KVM host rebooted for patching.

As it appears the virsh attach-disk command works a lot like the mount command.

In order to have a disk attachment persist …


Zenoss or Nagios monitoring of HTTPS using client certificate authentication

I recently needed to monitor an HTTPS API for response time and availability. At first I planned to just use the Nagios check_http command.

After gathering more requirements I learned that the API was protected by client certificate authentication. After some research I quickly found that no solution existed to …


Webmaster tools alerted issue turned out Pylon session files flooded inodes


A system administrators guide to installing and maintaining multiple python environments

Some operating systems depend on a specific version of python to function properly. For example, Yum on Redhat Enterprise Linux 5 (RHEL5) depends on python 2.4.3. This version of python lacks support from many utilities …


virt-back: restoring from backups

In a perfect world we should create backups but never need them. Although this statement holds truth, creating guest backups provides many more benefits.

The most common reasons system administrators restore from a virt-back guest backup:

  • recovering from data corruption
  • recovering deleted files
  • recovering from a virus infection
  • recovering from …

virt-back: a python libvirt backup utility for kvm xen virtualbox

backup your virtual maching guests.



© Russell Ballestrini.