Product Perfect

Augeas is a configuration editing tool and scripting language for manipulating configuration files programmatically. It was first introduced in 2007 by Red Hat engineer David Lutterkort as part of the Puppet software suite. Augeas uses a tree structure to represent system configurations, allowing developers to manage complex systems with ease. The language's name originates from Greek mythology, referencing King Augeas who had an enormous stable cleaned by Hercules - symbolizing its ability to handle large-scale tasks efficiently. Its unique approach has been recognized in various technical publications such as "Automating Linux and Unix System Administration" (Springer-Verlag New York Inc., 2008).

Ask the right questions secure the right Augeas talent among an increasingly shrinking pool of talent.

First 20 minutes

General Augeas app knowledge and experience

The first 20 minutes of the interview should seek to understand the candidate's general background in Augeas application development, including their experience with various programming languages, databases, and their approach to designing scalable and maintainable systems.

How would you install Augeas on a Linux system?

You would use the package manager for your specific Linux distribution. For example, on Ubuntu, you would use the command 'sudo apt-get install augeas-tools'.

What are the main components of Augeas?

The main components of Augeas are the Augeas library, lenses, and the augtool command-line interface.

Describe the difference between Augeas and other configuration management tools.

Augeas is unique in its use of lenses, which are modules that define how a configuration file is mapped to the tree and back. This allows Augeas to edit files in a controlled manner, preserving comments and formatting.

How would you use Augeas to modify a configuration file?

You would use the 'set' command in augtool, specifying the path to the node you want to modify and the new value. For example, 'set /files/etc/ssh/sshd_config/PermitRootLogin no'.

What are lenses in Augeas and what is their purpose?

Lenses are modules in Augeas that define how a configuration file is mapped to the tree and back. They allow Augeas to edit files in a controlled manner, preserving comments and formatting.

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What you’re looking for early on

Does the candidate have a solid understanding of Augeas?

Has the candidate demonstrated experience with Puppet?

Can the candidate write and understand Augeas lenses?

Does the candidate show good problem-solving skills?

Next 20 minutes

Specific Augeas development questions

The next 20 minutes of the interview should focus on the candidate's expertise with specific backend frameworks, their understanding of RESTful APIs, and their experience in handling data storage and retrieval efficiently.

Describe the difference between 'set' and 'setm' commands in Augeas.

'set' is used to modify a single node, while 'setm' is used to modify multiple nodes that match a given path expression.

How would you use Augeas to add a new node to a configuration file?

You would use the 'set' command in augtool, specifying the path to the new node and its value. If the node does not exist, it will be created.

What are the steps to create a custom lens in Augeas?

Creating a custom lens involves defining the lens in a .aug file, testing it with augparse, and then installing it in the lenses directory.

Describe the difference between 'ins' and 'set' commands in Augeas.

'ins' is used to insert a new node at a specific location in the tree, while 'set' is used to modify the value of an existing node or create a new node if it does not exist.

How would you use Augeas to delete a node from a configuration file?

You would use the 'rm' command in augtool, specifying the path to the node you want to delete. For example, 'rm /files/etc/ssh/sshd_config/PermitRootLogin'.

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At this point, a skilled Augeas engineer should demonstrate strong problem-solving abilities, proficiency in Augeas programming language, and knowledge of software development methodologies. Red flags include lack of hands-on experience, inability to articulate complex concepts, or unfamiliarity with standard coding practices.

Digging deeper

Code questions

These will help you see the candidate's real-world development capabilities with Augeas.

What does this simple Augeas command do?
augtool print /files/etc/hosts
This command prints the contents of the /etc/hosts file as seen by Augeas.
What does this Augeas command do?
augtool set /files/etc/hosts/1/ipaddr 192.168.0.1
This command sets the IP address of the first entry in the /etc/hosts file to 192.168.0.1.
What does this Augeas command do?
augtool rm /files/etc/hosts/*[ipaddr='192.168.0.1']
This command removes all entries in the /etc/hosts file that have an IP address of 192.168.0.1.
What does this Augeas command do?
augtool defvar myhosts /files/etc/hosts/*[ipaddr=~regexp('.*\.0\.1$')]
This command defines a variable 'myhosts' that refers to all entries in the /etc/hosts file that have an IP address ending in '.0.1'.

Wrap-up questions

Final candidate for Augeas Developer role questions

The final few questions should evaluate the candidate's teamwork, communication, and problem-solving skills. Additionally, assess their knowledge of microservices architecture, serverless computing, and how they handle Augeas application deployments. Inquire about their experience in handling system failures and their approach to debugging and troubleshooting.

What are the steps to integrate Augeas with Puppet?

Integrating Augeas with Puppet involves installing the augeasproviders_core module, and then using the 'augeas' resource type in your Puppet manifests.

Describe the difference between 'defvar' and 'defnode' commands in Augeas.

'defvar' is used to define a variable that references a node, while 'defnode' is used to define a variable and ensure that the node it references exists.

How would you use Augeas to modify a configuration file without losing comments and formatting?

You would use the 'set' command in augtool, specifying the path to the node you want to modify and the new value. Augeas will preserve comments and formatting by default.

Augeas application related

Product Perfect's Augeas development capabilities

Beyond hiring for your Augeas engineering team, you may be in the market for additional help. Product Perfect provides seasoned expertise in Augeas projects, and can engage in multiple capacities.

Augeas Consultive assessments

Augeas Application Conversion Assessment Augeas Application Integration Assessment Augeas Data & Database Integration Assessment

Custom Augeas development projects

Custom Augeas App Conversion Augeas Custom App Development Process App UI Design for Augeas Facelifts

Hiring guide for Augeas Engineers

Augeas Developer Hiring Guide

What you’re looking for early on

The ideal back-end app developer

What you’re looking to see on the Augeas engineer at this point.

Augeas Consultive assessments

Custom Augeas development projects