Deployment Automation

Couple months back I was asked to look into deployment process of a software developed using zope, the open source web framework for python. Deployment of this product is a quite complex process. The complete installation of this product on 6 servers takes about 5 days. It has 34 components to deploy.

Product is deployed using puppet master and puppet agent setup.

The puppet master runs on CentOS 6.8. This server has 8 cores and 8G memory. Puppet agent nodes run Windows 2012 R2. Deployment process involves setting up puppet master, puppet agents, prepare configuration files, extracting artifacts. Then log on to each windows machine to run start deploy each component.

This process is fine if there are 5 to 6 servers. But it will not scale up and becomes laborious work as number of servers increase. Growing business needs more efficient, robust and scalable product deployment solution.

Another challenge is to reduce deployment time and make it easy to deploy.

I started analyzing each process to understand pain area. I quickly learnt that activities like setting up puppet master, puppet agents, prepare configuration files, extract artifacts are all manual processes. After puppet infrastructure setup, deployment engineer manually logs on to each server using tool like remote desktop to setup puppet agents.

First , I decided to automate the manual processes. But I was told not to introduce any new technology and tools unless absolutely necessary. Since it is a python shop, I have chosen python for scripting, Jenkins for deployment automation and nginx is used as local package server.

I chose Jenkins to run slaves on each puppet agent node. Also I automated installation and setup puppet master and nginx. Jenkins job will pull the nginx, puppet master software and install them.

But setting up puppet agent and remote execution, I have to install jenkins on each windows server. Admin has to log on to each windows server at least once to setup jenkins slaves. To avoid this I chose to use winrm. Configuration is simple and done remotely. Pywinrm helped remote login to windows. This allowed me to download puppet agent software to each windows server, install them and handshake with puppet master remotely. Puppet agent setup and configuration also programmed to run in parallel. Python multiprocessing module was used to achieve this. This save good amount of time and effort. This whole activity was talking about 6 to 8 hours for an expert deployment engineer. Setting up of puppet agent on 6 servers has been reduced now to 3 mins.

For puppet master, yaml is used for configuration. Editing yaml was another area of concern. Only experienced deployment engineer used to edit those huge configuration files. I decided to generate these configuration file using spreadsheet, so that editing is simple and syntax can be verified as they are generated.

Now a job need to simplify yaml and puppet config generation. I captured information like servers and component mapping in a spreadsheet to generate yaml and puppet config needed for puppet. Thus editing spreadsheet is made easy and this spreadsheet is read using xlrd module. This job will now generate yaml and puppet config file in about few minutes.

Now I had to extract artifacts. In the manual process, artifact was extracted just before starting deployment. With concurrent process, this process is reduced to 10 minutes to extract all 34 components.

I grouped independent components and dependent and sub dependent components. I installed all independent components in parallel and then dependent components and worked on this order of installation and generated groups.

At this time everything is setup to start installing product components using pywinrm.

Jenkins job started, all processes spawned, logged onto windows as expected. Almost in first two minutes seen component started getting deployed. For my great surprise, all components deployed and application has come up in about 5 hours.

I did many testing, everything is working as expected and installation time is reduced by about 90%. This whole process is greatly simplified. Now anyone can edit spreadsheet to change configurations and install product.

With this I will have to look for optimization now. I will have to optimize database setup, zope setup.

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