Photo by Guillaume Bolduc on Unsplash

Anyone in my LinkedIn network knows last year I became a Certified Kubernetes Application Developer. After about 4 years working actively on Kubernetes day by day, this certification was a great recognition of my studies.
This is why I decided to start a new post series, describing what I’ve learned about containers and their use cases. Topics will be:

* Basic concepts
* Use cases
* Unix background
* Namespaces
* Control Groups
* chroot
* Implementations
* Docker
* containerd
* Docker commands
* Orchestration and Docker Swarm
* Kubernetes
* Architecture…

Photo by Guillaume Bolduc on Unsplash

Anyone in my LinkedIn network knows last year I became a Certified Kubernetes Application Developer. After about 4 years working actively on Kubernetes day by day, this certification was a great recognition of my studies.
This is why I decided to start a new post series, describing what I’ve learned about containers and their use cases. Topics will be:

* Basic concepts
* Use cases
* Unix background
* Namespaces
* Control Groups
* chroot
* Implementations
* Docker
* containerd
* Docker commands
* Orchestration and Docker Swarm
* Kubernetes
* Architecture…

Photo by Mika Baumeister on Unsplash

The simplest tool you could use to perform some data analysis is Microsoft Excel. If you have few structured data and you need to order them, filter them or graph them, Excel is perfect.
Obviously, Excel is not a Big Data tool, as you could crash the process using it with lots and lots of data.

Sometimes you cannot leverage the UI tools to order data in ascending or descending order, so you need to use Excel’s advanced built-in functions.
To order your data in a new sheet in descending way, you could use LARGE function (in Italian version, GRANDE)…


Photo by Leon Wu on Unsplash

Writing my BSc thesis I discovered LaTeX, a software used to prepare documents looking like a book. LaTeX, in fact, is a very good typography software, that allows users to write plain texts and then, with the help of some markup tags, split the text in chapter and section, add styles (bold, italics, etc.), cross-references, citations, etc.

At the beginning I used a TeX distribution called MikTeX, because I used a Windows OS. Step by step, as soon as I understood how much powerful this software is, I started to use TeX Live on Unix OS.
Those two distributions have…


Photo by James Lee on Unsplash

We are continuously looking for an application always available. More our application will be available, more we could get new customers and increase our revenue.
But an application cannot be always available.

As we know, if you perform an update adding new features or fixing bug, you will cause an outage because old TCP connections to your server will be closed and no new connections will be accepted until the server will be up and running again. This is why we always look for high availability.
But also high availability is a paradox, because the same maintenance operations are mandatory. Even…


Photo by Yancy Min on Unsplash

If you use Git as source code management tool, you probably use a plugin for your favorite IDE or a desktop application. Anyway, sometimes you need to use the CLI to perform some tricky commands.

Here you could find my personal tricks for Git CLI I learned during my work (or too late to be used in my day-by-day job).

Undo last commit

Sometimes you need to undo your last commit, because you need to remove a file from that or to avoid commit some secrets. In that case, git reset is the command you need to run.

If you would like to…


Photo by Sai Kiran Anagani on Unsplash

In my day-by-day job, I started to use lots of BASH commands to debug network issues, and I did never not many of them. This is why I decided to write here all those commands and how do I use usually.

This is a series. Here the table of contents:

  1. dig
  2. ping
  3. whois
  4. openssl
  5. nslookup
  6. traceroute and mtr
  7. iptables
  8. network configuration and statistics (this story)
  9. tcpdump

Another sets of useful CLI commands for network issues debugging are related to the network configuration from a network interface point of view and also from a ARP table point of view.
There are few…


Photo by Tracy Adams on Unsplash

Sometimes you need to use different SSH keys to connect to different remote hosts. You could be a little bit lazy and you don’t want to remember which is the right SSH key to use.
The best way is to configure your SSH agent in order to use the right SSH key based on the host, using a configuration file named.ssh/config.

This is a simple textfile with a well-known syntax.
For example, if you would like to connect to host bar.example.com using SSH key id_rsa_bar and user bar, and also connect to host foo.example.com


Photo by Sai Kiran Anagani on Unsplash

In my day-by-day job, I started to use lots of BASH commands to debug network issues, and I did never not many of them. This is why I decided to write here all those commands and how do I use usually.

This is a series. Here the table of contents:

  1. dig
  2. ping
  3. whois
  4. openssl
  5. nslookup
  6. traceroute and mtr
  7. iptables (this story)
  8. network configuration and statistics
  9. tcpdump

Sometimes you could notice from some IPs you cannot receive any packet, or you could not reach out some IPs. This means you probably have a firewall inside your machine or outside your machine…


Photo by Sai Kiran Anagani on Unsplash

In my day-by-day job, I started to use lots of BASH commands to debug network issues, and I did never not many of them. This is why I decided to write here all those commands and how do I use usually.

This is a series. Here the table of contents:

  1. dig
  2. ping
  3. whois
  4. openssl
  5. nslookup
  6. traceroute and mtr (this story)
  7. iptables
  8. network configuration and statistics
  9. tcpdump

A new chapter in my personal network debug toolkit: network hop analysis.

Sometimes your packets seem to be lost somewhere in the Net and you would like to understand exactly where. …

Gabriele de Capoa

Software engineer, wanna-be data scientist

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