Forem: Vishal Srikanth

Service management in Linux

Vishal Srikanth — Sun, 07 Apr 2024 14:17:33 +0000

People who use Linux do know how to start/stop services with the front-end command line utilities like systemctl but they don’t really appreciate the stuff that happens behind the scenes just to start a service that you want to be already started.

In this blogpost, let me tell you all how service management happens in Linux operating systems, so you might appreciate this wonderful aspect of Linux.

Operating systems manage applications and services for you that run in foreground and background. Windows does in its own way. But Linux, the rock solid operating system for servers does this in a way that’s so awesome.

If you didn’t know how a system gets booted up, let me tell you in a nutshell.
First off, when you press that little plastic button on your machine, it starts with the whooshing sound of cooling fans. Then the system goes through something known as POST_(Power-On-Self-Test) process which is actually a set of diagnostic tests that a computer runs every time it's powered on to make sure all of its components are working properly. Next, the BIOS _(if it’s an older system) or UEFI (newer ones use this) starts up, which then look for the boot files especially the kernel. The kernel kicks in and starts the services.

But how does the kernel know the services it has to start, the ones it has to start on-boot , the ones which you wanna start on-demand?

That’s where a service management system comes into play!

Service management system is the one that actually starts up the services on-boot. I’m saying services but that doesn’t just include applications like MySQL, Apache web server engines. But the word services encompasses the networking stack, Storage I/O service, LVM ,NFS, anything you could think of.

Think of it. You just have an on-demand application like Firefox installed but without the TCP/IP networking stack started, can you even get anywhere? Or you have a hard-drive installed. If you can’t perform any I/O operations on it, what’s the purpose then?
Kernel deals with the hardware interaction. These service management systems deal with the running of software on top of the kernel. These are so important that if you’d close this process system, the entire system would crash.

With Linux, there are two service management systems which are Sysinit and systemd, namely.

Sysint is the good, old guy who’s been around for a long time. His birth dates back to the good, old 80’s when pure Unix, Slackware systems were present. Don’t get me wrong. Slackware is still there but the last release was actually in 2016. The last version is the SysVinit (you gotta pronounce it like System-Five-init).
Systemd is the new kid in the block. Actually ,he’s prevalent from the year 2010. systemd does things way better, faster than sysinit but there are some gotchas to systemd as well.

I hope you understood how services and applications are managed in Linux. In the next blogpost, let’s take a look at how these two systems manage things in their own way.

Till then, be happy and keep learning. See ya!

The need for configuration management software in the current landscape of IT infrastructure

Vishal Srikanth — Thu, 21 Mar 2024 10:36:26 +0000

Just like how the clown pops up in the movie "IT" and terrifies the audience, managing IT infrastructure was a similar experience for system administrators until now. How did it change? Let me tell you.

(Source:imgflip.com)

Configuration management software is one of the set of infrastructure automation tools that system administrators and DevOps engineers use to manage the huge IT infrastructure of their organizations.

Twenty years back , system administrators who would manage Windows or Linux machines had to go to each and every machine and configure them. Be it changing the IP address to re-installing the whole operating system of machines.

Some years later, system administrators started to remotely manage the machines using telnet which was an unsecure protocol that could be easily captured by packet sniffers such as Wireshark. Then, they started using the more secure protocol (i.e) SSH. Even though they could manage all the machines from little cubicles in their offices, they had to still connect to thousands of machines one by one. This introduced configuration errors especially where the configuration might not be applied to a machine as desired. Yes, system administrators are humans, so it did introduce human errors where the sleepy administrator could apply faulty configuration to the machines and wreck them all.

Then, with the rise of programming seeping its way into system administration, admins would write little scripts in PowerShell (if it was a Windows machine) or Bash (in case of Linux machines) and manage them. This eased their pain but to a extent, as they had to still loop over to every machine and execute them by their IP address or hostname of the machines.
Now, its 2024. With the emergence of cloud computing and microservice architecture, managing thousands of these little minions (another cute nickname for machines in my glossary :D) is just pure hell if we had to do it in the above mentioned ways. Thankfully, great people came with the idea of configuration management software.

Right now, in the market we have a lot of tools such as Salt (a.k.a SaltStack), Puppet, Chef, Ansible. Cloud vendors have their proprietary solutions as well. But in the end, one must win in this shark tank, right?

It’s Ansible that wins. But why did this guy win? What’s the secret to his success. I will tell you in the next post.

Till then, be curious and keep learning!

Readers, a huge "thank you" for reading my post till the end.

A blast to the past!

Vishal Srikanth — Tue, 19 Mar 2024 08:39:15 +0000

Coming up with the idea of starting a blog wasn't easy. Seriously, I did lack the motivation. But here I am, with my new blog. So, to start off with, let me give you a backstory of how I got to dabble with computers.
Back then in the early 2000s, this young boy coming from a small town on a hill didn't have access to computers. But then as savior(s), came these Internet café or browsing centers (that's how we used to call them!) .Boys of my age, including me would flock to these centers just to play an hour of a game that many of my readers would have guessed it by now which is Grand Theft Auto Vice City. The owner of those centers made a huge fortune out of our hard-earned money. (actually, we had to earn it hard by buttering our parents for that...hahaha!)

As time passed by like this, I came to my home after a small vacation at my aunt's house in another hill town. To my surprise, I was welcomed by this shiny all-black desktop sitting on top of our 20 year old wooden table that was kinda like a inheritance of my dad. Computers in my age were all this beige or white-colored, fat, beeping AMD Athlon powered computers that still looked cool but not as cool as my new complete black desktop that boasted a powerful latest generation Core 2 Duo (hey, it was "latest" and "powerful" back in my day) dual-core processor with a single gigabyte of RAM running Windows XP. I went bonkers looking at my new desktop.

Then, I started to fiddle, mess around with the computer by myself learning how to navigate, open and close files and folders, install applications and games etc.

As time went by, I was getting pretty good at using computers that I developed a strong passion for them. So, there was this monthly magazine called "Digit" and "Chip" here in India that I became an avid reader of, since I got an old issue from the nearby library. The magazine was a deep, technical magazine that had all sorts of computer related stuff that I wanted to know, from hardware to software.

Going on with my story, we had to move to another area of my hometown. My dad took the decision of setting up a DSL internet connection at home which was slow compared to today's standards (but hey, something is better than nothing!) Then I got introduced to YouTube where I started to watch tech-related channels like Linus Tech Tips, GamersNexus and video-game related channels like IGN. I gained thrice the knowledge about computers than I had before, watching these videos.

Skip forward. Here I am, with my under-graduate degree in Computer Science and Engineering with the same old passion that I had.