DEV Community: crazyoptimist

How to clean up disk space on Ubuntu server

crazyoptimist — Sat, 29 May 2021 05:44:00 +0000

If you are running your own cloud instances and use them for development purposes, their capacities would probably be limited and sometimes you might notice that the disk space is too low.

TL;DR

Remove unnecessary system packages and package caches

sudo apt-get --purge autoremove
sudo apt-get autoclean
sudo apt-get clean

Remove system log except for the last 3 days

Check it first:

journalctl --disk-usage

sudo journalctl --vacuum-time=3d

Actually it grows day by day, so you can create a cron script to clean up journal logs once a month for example, or can configure it to use limited amount of disk space by setting SystemMaxUse=50M in /etc/systemd/journald.conf. Then reload conf:

sudo systemctl restart systemd-journald

Clean up snap

Check it first:

du -h /var/lib/snapd/snaps

This is a bash script.

#!/bin/bash
# Removes old revisions of snaps
# CLOSE ALL SNAPS BEFORE RUNNING THIS
set -eu
snap list --all | awk '/disabled/{print $1, $3}' |
    while read snapname revision; do
        snap remove "$snapname" --revision="$revision"
    done

Please add more in the comment section if you have another ones.

Happy coding! :)

How to Use Git Rebase in a Practical Situation

crazyoptimist — Wed, 14 Oct 2020 20:15:55 +0000

Imagine that there are two pull requests open on a project repository.
Each change has its own branch like this:

master
feature/add-base64-endpoint
feature/add-user-agent-endpoint

The challenge is to use git rebase to add both changes to master. When you finished, your master branch should have three commits in the following order:

feat: add user-agent endpoint

feat: add base64 endpoint

init

Okay, let’s go!

git clone repo_url
git status
git checkout feature/add-base64-endpoint
git rebase master
git status
git checkout master
git merge feature/add-base64-endpoint
git status
git checkout feature/add-user-agent-endpoint
git rebase master

Oops! You should see rebase conflict!
You need to check the conflicted parts and fix it. Fortunately VS Code provides some great hints for you to do that.
I personally use Vim as my IDE because I'm a huge fan of Vim!
Do not forget to check if the code base is functionable even after you resolve the conflicts, i.e. all the tests should be green, app should be functional eventually.
Once you finish resolving conflicts, follow these steps:

git add .
git rebase --continue
git checkout master
git status
git checkout master
git merge feature/add-user-agent-endpoint
git status
git log

Boom! You must be done!
Happy gitting! 😉

How to Make a Swap Space Using a Swap File in Linux

crazyoptimist — Wed, 07 Oct 2020 04:13:32 +0000

This article has been ported from my personal blog
You might have been stuck in memory leak when building some kinda javascript-heavy frontend apps like Vue or React on a cloud server itself. Just for serving built artifacts, we do not need large instances, but still the building process is always hungry for more memory you know.
Below is how to resolve such specific problem.
Oh, this is not the case if you already have a dedicated(partitioned) swap space, it's a better option in any case but in most cases, we will be playing with servers without a swap patition.
Okay, let's get started.
As a general rule, calculate swap space according to the following:

Amount of physical RAM	Recommended swap space
2 GB or less	2 * `Amount of physical RAM`
More than 2 GB, less than 32 GB	4 GB + (`Amount of physical RAM` – 2 GB)
32 GB or more	1 * `Amount of physical RAM`

Important Note: Swap sapce should never be less than 32 MB!

Steps

Create a swap file

sudo dd if=/dev/zero of=/swapfile bs=128M count=YOUR_COUNT

In the above command, bs is block size which should be less than the available memory at that moment.
bs * YOUR_COUNT will be your swap file size, for example, bs=128M count=32 means your swap file will be 4096 MB in size.

Update the read and write permissions for the swap file

sudo chmod 600 /swapfile

Set up a Linux swap area

sudo mkswap /swapfile

Make the swap file available for immediate use by adding the swap file to swap space

sudo swapon /swapfile

Verify that the procedure was successful:

sudo swapon -s

Enable the swap file at boot time by editing the `/etc/fstab` file

sudo vim /etc/fstab

Add the following line at the end of the file:

/swapfile swap swap defaults 0 0

That's it.
Happy coding!

DEPLOY YOUR WEB APPLICATIONS IN A MINUTE - MADE WITH 💖 FOR DOCKERISTS

crazyoptimist — Tue, 08 Sep 2020 01:29:40 +0000

As a software engineer or a DevOps engineer, you may come up with boring tasks frequently, one of which is setting up a new cloud environment for deployment of your awesome web apps/micro services.

Using the following script, you will lose the dull pain. Just grab the script and run it with bash, then you will get the complete environment with docker/docker-compose and nginx which are all on the latest stable version.

Note: This is just for Ubuntu Bionic/Focal. Buzz me anytime in case you want to get the same one for any other distro, I'd love to help!

Happy containerizing! 🐋

Originally posted on my blog here.