Terraform has emerged as one of the top open source infrastructure as code (IaC) tools, since its initial release by Hashicorp back in 2014.

The design philosophy behind the tool is to have declarative, and stateful representation for the underlying IT infrastructure (whether it be on public, on-premise, or hybrid cloud), which in turns simplify the control, collaboration, and auditing of the cloud resources.

The classical example to show the main idea creating a VM:

Problem

Sometimes, when working with docker engine on CI systems, certain type of errors could arise from the challenging restrictions in the environment. This is typical due the inherent server-client architecture in docker.

Here’s one of the problems that I’ve seen recently. When a client is connecting to dockerd in order to build an image or pull external images:

failed to prepare a4mv4dh8qcq283c7x47a4nwpg: devmapper: Thin Pool has 161986 free data blocks which is less than minimum required 163840 free data blocks. Create more free space in thin pool or use dm.min_free_space option to change behavior

Using universally unique identifiers (UUIDs) for exposed resource identifiers is more secure, and convenient for database distribution. It is relatively simple to configure Active Record to generate UUID primary keys in migrations.

Setup

Here are the steps:

1. Setup the default generation inside config/application.rb:

    # config/application.rb
   
    module SampleApp
      class Application < Rails::Application
        ...
        # Change the primary key
        # default type to UUIDs.
        config.generators do |g|
          g.orm :active_record,
                primary_key_type: :uuid
        end
      end
    end
   

In many times you may need to optimze rapidly a bunch of images at your hands. There are handy utilities that can help you reduce image sizes with simple commands in the terminal. The following lists some of these tools:

1. OptiPNG: Advanced PNG Optimizer:

Get it for Mac OS X:

brew install optipng

For Linux Ubuntu:

apt-get install optipng

To optimize an image, run:

optipng <img-name>.png

In the past week, I have been deploying a Sinatra app to AWS Elastic Beanstalk. In development environment, everything was working just fine, but when I published the application and tested it in production, I encountered a weird problem in one of the templates that was supposed to be supporting uft-8 text without any issues.

Symptoms

The error was appearing in one of the .erb view files that contains a textarea field. When it is populated with a non English text at the server, the application crashes with 500 code. Here’s a fragment of the error stack trace: