Explorations - computing, research, etc.

TLDR; If you are having trouble with docker build and ephemeral port ranges, we can use iptables to solve the issue: $ sudo iptables -t nat -I POSTROUTING -p tcp -m tcp --sport 32768:61000 -j MASQUERADE --to-ports 49152-61000 I have written previously abo…

When we create an AWS Code Deploy deployment group via Terraform or CloudFormation and integrate with an Auto Scaling Group, it also by default creates an initial lifecycle hook which ensuresthat a new code deployment gets triggered when a scale-out event…

Much has been written (and asked) on the topic of hard links and soft links (a.k.a symbolic links) on Linux.

I wanted to create a new SSL certificate for IIS hosted ASP.NET framework application.

Fedora Scientific brings together the most useful open source scientific and numerical tools atop the goodness of the KDE desktop environment.

My task at hand was simple.

Welcome to this new blog post!

If you are trying to introduce flyway to an existing database with the schemas and tables already created, you may find flyway baseline command useful.

Let’s say you have made a few changes to a file and only want to stage only some of those changes for commit.

In a previous post, I shared that we are going to have Fedora Scientific Vagrant boxes with the upcoming Fedora 29 release.

While attempting to use flyway for SQL server schema migrations, I was consistently getting an error of the form Found non-empty schema xxx ithout metadata table!

While working on creating a template file for a Go project, I wanted to better understand how to work with data in Go templates as available via the html/template package.

I wanted to download the prometheus binary using curl.

In this post, we learn how we can make use of docker’s user namespacing feature on Linux in a CI/build environment to avoid running into permission issues.

AWS Route 53 private hosted zones enable you to have private DNS names which only resolve from your VPC.

In this post, I discuss a problem (and its solution) I encountered while working with AWS (Amazon Web Services) Network ACLs, docker containers and ephemeral port ranges.

AWS lambda functions look deceptively simple.

I went into working with Windows docker containers after having been worked with docker on Linux exclusively.

I have been working with PowerShell for three months now, and my approach to using it has been pretty much google and trial - copying things, modifying things till they work and learning new things on the way.

In my new post on the CodeShip blog, I discuss configuring terraform with a consul remote backend.

I am very excited to share that sometime back the Fedora project gave the go ahead on my idea of making Fedora Scientific available as Vagrant boxes starting with Fedora 29.

The video for my PyCon talk - “Counter, Gauge, Oh My!”

A few weeks back I wrote a analyser for Apache Thrift IDL in Python.

In a couple of days, on Saturday, I will be delivering my PYCON US talk titled Counter, Gauge, Upper 90 - Oh my!.

Fedora 28 is out and I am happy to share that after a few releases of no Fedora Scientific, we are back.

Introduction The ping program is one of the most common programs which is used to check the “aliveness” of a host and a typical execution looks as follows: $ ping 127.0.0.1 -c 1 -4 PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data. 64 bytes from 127.0.0.1:…

Introduction I recently learned about Cloudflare’s 1.1.1.1 DNS service.

Fedora 28 beta was announced recently and I am happy to say Fedora Scientific is back.

In this post, we will see how we can implement the AWS assume role functionality which allows an IAM role to be able to obtain temporary credentials to access a resource otherwise only accessible by another IAM role.

In my earlier post, Quick and dirty debian packages for your Go application I shared a recipe building DEB packages for Go applications.

In this post, we will see a demo of sorted sets in redis.

At work, I learned about how Right-to-Left Override was being used to make actually malicious files to look harmless.

After a fair number of furious impatient attempts to try and use specific git commits of third party packages in my Python software, I finally have been able to make it work.

The Freelancer.com REST API is powered by a number of backend services.

GCC's C compiler allows you to define various variable attributes.

When writing programs in Python (CPython), you have access to data types such as a int, str, tuple, list and a dict.

In the last two articles (Data in CPython and Data in C), as it turned out, I discussed two fundamental points in each language: What happens in an assignment operation (such as a=2)?

In C, the data you use in your programs will usually fall into one of the three basic categories: int, char and float.

math.h provides basic mathematical functions as part of the C standard library and are also usable from C++.

In this post, we will learn about a quick and easy workflow for building and deploying your golang applications as Debian packages.

In an earlier article, Monitoring Your Synchronous Python Web Applications Using Prometheus, I discussed a limitation of using the Python client for prometheus.

In this article, we will explore the Python programming language as a tool to retrieve various information about a system running Linux.

First, I installed openvpn: $ sudo dnf -y install openvpn Then, I used the following systemd unit file from here to create a systemd service for creating a new VPN connection on Fedora 27: $ cat /etc/systemd/system/openvpn@.service [Unit] Description=Open…

If you are running your server applications via supervisord on a Linux distro running systemd, you may find this post useful.

When using Terraform’s aws_security_group_rule with EC2 classic, you may get an error saying that the source security group doesn’t exist, even though it does.

I use vim as my occasional text editor, especially when I am working on small projects or just editing a text document.

It is common knowledge that programs written in high level languages have to be translated into a low level language using programs referred to as translators.

If you are getting the “Too many connections” error, couple of things worth checking on the MySQL server: mysql> show processlist; ..

As of yesterday, this blog is automatically being published via Travis CI.

I had to rotate a few video frames using iMovie.