Open-Gridview - the FOSS Out-Gridview

The Story

I've been a Microsoft SysAdmin for a long time before switching for Linux. During which, I scripted a lot in PowerShell.
PowerShell has several "output" functions like Out-File (which passes the input to a file), Out-Null etc.
One of these functions was Out-Gridview which tabularizes its input and …

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Using a global lock in Chef

The Story

Our dev team is currently using a Snowflake-like ID generation scheme that looks like this:
snowflake diagram
(Diagram by Elad Rosenhim, architect and companion at Dynamic Yield. See his post about distributed keys and how to survive managing an HBase cluster)

Those familiar with MongoDB might notice this structure …

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Enhancing Packer Templates with eRuby

The Problem

Packer is a great tool for creating machine images, and I'm using it to create EC2 AMIs.
My issue with it is that Packer is using JSON for input, and JSON is very inflexible. For instance, you can't:

  • Write comments (there was an issue open for two years …
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Listing Chef Cookbook Licenses

As part of a compliance check for our company, I was required to print the name/version of all FOSS proejcts I'm using.
Most of it was digging around Gemfiles and setup.pys, which isn't that interesting. The neat part was this snippet to extract license information from …

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Writing Complex Scripts in HBase Shell

The Story

HBase installations include a shell for running arbitrary commands.
For instance, if you want to view all of your snapshots, you can do something like:

[me@server ~]$ hbase shell
HBase Shell; enter 'help<RETURN>' for list of supported commands.
Type "exit<RETURN>" to leave the HBase Shell
Version …
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Running Inline DSL in ChefSpec

The Problem

I have a pet Chef cookbook in charge of managing SELinux policies in Linux machines (Take a look).
Until today I got along fine without testing, because the cookbook barely had any logic to be tested. The only test I had (contributed by someone) just made sure the …

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Generating known_hosts file using Chef

The Story

This post relates to my previous post. I was trying to create a script to amend my known_hosts file (where SSH keeps fingerprints of all of the servers it connected to in the past, to prevent MitM attacks) with SSH keys collected by Chef. This benefits me in …

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Merging known_hosts files

The Story

Some time ago, some colleague rebuilt several servers and reused their names (think sql1,sql2 etc).
Obviously the new servers had different SSH server keys than the old ones, so my known_hosts file was out of date.
I considered manually removing the old key fingerprints, but decided that …

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Managing AWS Security Groups with Piculet

The Problem

One of the first things I noticed when starting to work with AWS is that security groups are very hard to maintain:

  • Name and description are immutable - One can't modify the name/description of a Security Group after it's created
  • Groups contain magical constants - There is no place …
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