16 February 2017

Dev Ops Story

In Dev-Ops, it’s not uncommon to have many slave nodes. In a particular case, although the majority of my clients system is Unix based, a segment of test nodes require Windows.

Dev-Ops looks heavily at automation, but done while thinking like a developer/software engineer while approaching the configuration of many nodes to have the specified setup. That means dev-ops workers tend to want tools that integrate somewhat with the way they work with code and tools for manipulating code.

Automating in Linux has a set of tools Chef, Puppet and Ansible are some cases. Ansible is used there for the Linux system due to it being python based, matching the majority of the site code, it’s ability to be used without the target system requiring installation of an agent, and to a lesser degree the galaxy roles ecosystem.

What Is PDQ

PDQ is an automated installation and configuration system for multiple Windows nodes. It uses a central server to manage many nodes, and uses Windows specific mechanisms for remote secure access - the equivalent of a secure shell on Linux machines.

It will install packages in quiet/UI free modes (it can not point and click on UI’s). It can run powershell or other commands to make changes.

It also stores installers in a package repository - an advantage over ansible where you’d need a separate system like Artifactory to store those. It’s installation steps, wizard driven, will automagically whizz the file over to the target system before running the setup command.

It has some conditionals, and is 32/64 bit aware so different tasks can be run when things don’t match up.

Like ansible, it has an inventory management system with a UI tool to set this up. Running things is done through a different UI, where steps can be configured and targeted at systems.

Where it could be improved

Source control/versioning

Ansible scripts are plain text scripts - they are yaml files, resource files and the rare python extension. As such, the whole setup is version controlled in git (pick source control of your choice here). This makes it easy to have an audit of changes, to roll back the script (not necessarily role back what happened when it ran) and use commits to infer why a certain change was made and when.

Adding the ability to store the configuration (not perhaps the database of exe’s and zip’s acocmpanying this) and scripts in git, svn or a choice of source control tools would make this a tool much more compatible with a dev-ops way of working.

Editors

There is a built-in spot for adding powershell and other scripts. This is great, as being able to make ad-hoc scripts part of a deployment is essential. However, the editors are not particularly developer friendly - they appear to be simply notepad. Embedding something like scintilla, or one of the other common editor tools would make a difference - where there would be syntax highlighting, it would understand block-indenting (selection of a chunk of lines and indenting or dedenting the lot) and a few of the simpler IDE manipulations that are common.

File manipulations

Ansible has some simple things like “line in file” and modules specifically for dealing with this. Since some tools come with a configuration file, having some quick tools, perhaps following the wizard style of the rest of PDQ, to perform these would save a bit of repetition. As it stands - you will need to build your own, probaby using powershell or similar.

Conditionals

As mentioned above, there are simple conditionals based on bitness and the presence of a file. Some more powerful conditions would help though.

A starting point would be “if pattern is in file” - detecting a text pattern in a file, regex capable. Another would be to base it on what a last step did. Perhaps if the last step made a change. Now this may be being coloured by my ansible experience, where a step can register a “changed” result, and then a later step can use this result to determine if it will run as well. A very common example, suitable also to the windows experience would be “if this file was modified, then restart service ".

A simple text representation

This is perhaps a biggie. Wizards are useful - they are a handy way to quickly throw stuff together and reduce a learning curve. However, dev-ops, being development/code oriented do like to be able to use text-editor to fine tune things. Having a plain-text representation for the system makes this possible.

This also feeds into the first point about source control - plain text works well with source control systems. It can be diff’d, it can have lines associated with a particular source control commit.

I would suggest some system like yaml, json or XML. Although INI files could do this - they are perhaps a little simplistic to represent the rich activity configuration available in PDQ. Round tripping between the two would allow workers to stay in their comfort zone perhaps - although text usually allows for operations more advanced than a UI would be able to represent.

In Conclusion

PDQ is a powerful tool and is simple to use. It appears that some pure ops/IT/admin workers really like this tool, and use it. It is not a free tool, and perhaps there are free tools that better suit the dev-ops way of doing things. Chef, Puppet and Ansible have some windows support. The chocolatey package manager may eliminate having to fuss around finding the installers for at least common free-to-download packages.

Since this system is prefered by ops, making it perhaps more developer friendly will allow the two groups to work more closely together or curse each other less, and continue to use the PDQ tool throughout.



blog comments powered by Disqus