Arshad Mehmood is a Software Engineer at SAP SE in Germany and founder of Kookydroid, specializing in Go, Kubernetes, DevOps, self-hosted systems, and Android development.https://preview.arshadmehmood.com/en-ushttps://preview.arshadmehmood.com/development/introducing-vault-linker/https://preview.arshadmehmood.com/development/introducing-vault-linker/Automatically link note titles in Obsidian vaults with the rebranded Vault Linker CLI and community plugin.Thu, 17 Sep 2026 00:00:00 GMThttps://preview.arshadmehmood.com/devops/complete-guide-to-ssh-from-basics-to-advanced/https://preview.arshadmehmood.com/devops/complete-guide-to-ssh-from-basics-to-advanced/Master SSH from connection basics to advanced file transfers. Learn authentication methods, key management, remote command execution, and security best practices.Wed, 01 Apr 2026 00:00:00 GMThttps://preview.arshadmehmood.com/devops/how-fail2ban-locked-me-out-of-my-own-server-traefik-authentik/https://preview.arshadmehmood.com/devops/how-fail2ban-locked-me-out-of-my-own-server-traefik-authentik/A real incident report: I got my own IP banned after enabling Fail2ban with Traefik and Authentik, lost SSH access, recovered via provider console, and fixed my configuration.Wed, 01 Apr 2026 00:00:00 GMThttps://preview.arshadmehmood.com/personal/we-all-played-destiny-but-bungie-played-us-all/https://preview.arshadmehmood.com/personal/we-all-played-destiny-but-bungie-played-us-all/After more than seven years, 1,000+ Grandmaster Nightfall clears, and thousands of hours in Destiny 2, this is my goodbye letter to a game Bungie slowly turned into an extraction machine.Fri, 27 Mar 2026 00:00:00 GMThttps://preview.arshadmehmood.com/software/chatgpt-secretly-sharing-conversations-within-projects-privacy-investigation/https://preview.arshadmehmood.com/software/chatgpt-secretly-sharing-conversations-within-projects-privacy-investigation/A detailed investigation revealing how ChatGPT's Projects feature shares conversation context between separate chats, despite users having memory settings disabled.Thu, 23 Oct 2025 00:00:00 GMThttps://preview.arshadmehmood.com/development/avoiding-race-conditions-in-go/https://preview.arshadmehmood.com/development/avoiding-race-conditions-in-go/Learn how to use Go's sync/atomic package to eliminate race conditions when working with concurrent goroutines. A practical guide with real-world examples.Fri, 05 Sep 2025 00:00:00 GMThttps://preview.arshadmehmood.com/development/obsidian-notes-linker-open-source/https://preview.arshadmehmood.com/development/obsidian-notes-linker-open-source/Introducing Obsidian Notes Linker - an open-source tool to automatically create bidirectional links between your Obsidian notes. Boost your knowledge management workflow.Tue, 28 Jan 2025 00:00:00 GMThttps://preview.arshadmehmood.com/devops/setup-prometheus-exporter-jenkins/https://preview.arshadmehmood.com/devops/setup-prometheus-exporter-jenkins/To monitor Jenkins with Prometheus, we need to expose Jenkins metrics. Jenkins has a built-in Prometheus metrics endpoint that we can enable. Install Prometheus Metrics Plugin 1. Go to Jenkins Dashboard → Manage Jenkins…Fri, 11 Oct 2024 00:00:00 GMThttps://preview.arshadmehmood.com/devops/setup-sonarqube-exporter-jenkins/https://preview.arshadmehmood.com/devops/setup-sonarqube-exporter-jenkins/To monitor SonarQube metrics with Prometheus, we can use the SonarQube Prometheus Exporter plugin or the built-in web API metrics endpoint. Method 1: SonarQube Prometheus Exporter Plugin Install the Plugin 1. Download…Fri, 11 Oct 2024 00:00:00 GMThttps://preview.arshadmehmood.com/devops/setup-sonarqube-jenkins/https://preview.arshadmehmood.com/devops/setup-sonarqube-jenkins/SonarQube provides continuous inspection of code quality through static analysis. Let's integrate it with Jenkins for automated code quality checks. Run SonarQube with Docker Start SonarQube using Docker: Wait for…Fri, 11 Oct 2024 00:00:00 GMThttps://preview.arshadmehmood.com/devops/setup-dynamic-jenkins-agents-kubernetes/https://preview.arshadmehmood.com/devops/setup-dynamic-jenkins-agents-kubernetes/Learn how to configure Jenkins to dynamically create agents in a Kubernetes cluster using Kind. Step-by-step guide to scalable CI/CD infrastructure.Thu, 10 Oct 2024 00:00:00 GMThttps://preview.arshadmehmood.com/devops/setup-prometheus-grafana-docker/https://preview.arshadmehmood.com/devops/setup-prometheus-grafana-docker/Quick guide to setting up Prometheus and Grafana monitoring stack using Docker. Get your metrics collection and visualization running in minutes.Thu, 10 Oct 2024 00:00:00 GMThttps://preview.arshadmehmood.com/devops/devops-journey/https://preview.arshadmehmood.com/devops/devops-journey/Join my DevOps learning journey as I build a complete CI/CD pipeline using Jenkins, Docker, Kubernetes, Prometheus, and Grafana. A hands-on approach to mastering DevOps practices.Mon, 23 Sep 2024 00:00:00 GMThttps://preview.arshadmehmood.com/development/big-o-cheatsheet-time-complexity-pdf/https://preview.arshadmehmood.com/development/big-o-cheatsheet-time-complexity-pdf/Big-O cheat sheet already provides a PDF, but its not good enough for me and also not in Landscape mode. So, I made a better one which you can download below: Download BigO Cheatsheet Landscape PDFWed, 09 Nov 2022 00:00:00 GMThttps://preview.arshadmehmood.com/hardware/accesing-seagate-com-terminal-with-arduino-mega-as-ttl-adapter-and-putty/https://preview.arshadmehmood.com/hardware/accesing-seagate-com-terminal-with-arduino-mega-as-ttl-adapter-and-putty/Accessing Seagate Hardrive Recovery/Diagnostics Ports: The ports are shown here: These ports need to be connected to a USB to TTL Adapter. In my previous post How to use Arduino mega as a USB TTL Adapter, I wrote about…Mon, 01 Nov 2021 00:00:00 GMThttps://preview.arshadmehmood.com/hardware/use-arduino-mega-as-ttl-adapter/https://preview.arshadmehmood.com/hardware/use-arduino-mega-as-ttl-adapter/Using any Arduino as a USB to TTL Adapter is very easy. Just need to connect the reset pin with grnd pin to bypass the ATmega chip. The Rx and Tx pins can then be used as a normal USB to TTL Adapter. Below are some…Mon, 01 Nov 2021 00:00:00 GMThttps://preview.arshadmehmood.com/tutorial/install-mysql-and-allow-remote-connection-over-ssh-ubuntu/https://preview.arshadmehmood.com/tutorial/install-mysql-and-allow-remote-connection-over-ssh-ubuntu/Install MySQL: After creating root user, login as root: To create and grant access to a user to a specific db use: Replace all the quotes(') parts and db.table with your relevant information. IP would be the server IP…Thu, 28 May 2020 00:00:00 GMThttps://preview.arshadmehmood.com/development/my-first-open-source-android-library/https://preview.arshadmehmood.com/development/my-first-open-source-android-library/I have a lot of Android applications and a long time ago, I thought to cross promote my apps from insid my app. The first idea was to directly link to the Google play store page of my developer account, but I wanted…Wed, 28 Aug 2019 00:00:00 GMThttps://preview.arshadmehmood.com/development/using-rxjs-subject-for-cross-component-communication-in-angular/https://preview.arshadmehmood.com/development/using-rxjs-subject-for-cross-component-communication-in-angular/Earlier I posted about child to parent communication in angular, today we will take a look at cross component interaction in angular using Subject from the rxjs library. We can declare the subject inside our component…Wed, 24 Jul 2019 00:00:00 GMThttps://preview.arshadmehmood.com/tutorial/how-to-auto-renew-letsencrypt-ssl-certificate-using-certbot/https://preview.arshadmehmood.com/tutorial/how-to-auto-renew-letsencrypt-ssl-certificate-using-certbot/Let's Encrypt is awesome! They offer free ssl certificates for three months and also a auto renewal bot which updates the certificates for you when it is about to expire. Automated renewal If you don't have any server…Fri, 19 Apr 2019 00:00:00 GMThttps://preview.arshadmehmood.com/tutorial/duolingo-streak-repair-hack-100-percent-working/https://preview.arshadmehmood.com/tutorial/duolingo-streak-repair-hack-100-percent-working/Earlier I wrote about the same topic here. Well after trying other methods I found out that is very easy to repair a lost streak. No more pressure! Better still, this method even works to repair your very old lost…Tue, 16 Apr 2019 00:00:00 GMThttps://preview.arshadmehmood.com/development/generate-unigrams-bigrams-trigrams-ngrams-etc-in-python/https://preview.arshadmehmood.com/development/generate-unigrams-bigrams-trigrams-ngrams-etc-in-python/Learn how to generate n-grams (unigrams, bigrams, trigrams) in Python using NLTK and custom functions. Complete guide for text processing and NLP tasks.Fri, 15 Mar 2019 00:00:00 GMThttps://preview.arshadmehmood.com/tutorial/how-to-download-whatsapp-status-of-your-friends-on-iphone-and-android-without-any-app/https://preview.arshadmehmood.com/tutorial/how-to-download-whatsapp-status-of-your-friends-on-iphone-and-android-without-any-app/I will show you a method to download/save WhatsApp status photos and videos of your friends/contacts from your phone without installing any app. The only downside is that you require (temporary) access to a computer.…Wed, 19 Dec 2018 00:00:00 GMThttps://preview.arshadmehmood.com/personal/is-it-possible-to-use-machine-learning-in-clash-of-clans/https://preview.arshadmehmood.com/personal/is-it-possible-to-use-machine-learning-in-clash-of-clans/If you are living under a rock for the past few years, then you probably don't know about Clash of Clans. Clash of Clans is a strategy game for Android and iOS, published by Supercell back in 2012. I've been playing it…Mon, 03 Dec 2018 00:00:00 GMThttps://preview.arshadmehmood.com/development/change-parent-component-values-in-angular-with-viewcontainerref/https://preview.arshadmehmood.com/development/change-parent-component-values-in-angular-with-viewcontainerref/Well there are many ways of parent child communication and interaction in angular, e.g. @Input binding, setter, ngOnChanges(), EventEmitter, via local variable, @ViewChild(), via a service, and so on... We will look at…Wed, 28 Nov 2018 00:00:00 GMThttps://preview.arshadmehmood.com/security/estrongs-es-file-explorer-file-manager-is-always-tracking-you/https://preview.arshadmehmood.com/security/estrongs-es-file-explorer-file-manager-is-always-tracking-you/Es File Explorer File Manager was one the best File managers for Android for the past few years. But they have definitely killed the goose that layed the golden eggs, by adding ads to users lockscreens, without their…Mon, 29 Oct 2018 00:00:00 GMThttps://preview.arshadmehmood.com/security/strange-requests-broke-nginx-server/https://preview.arshadmehmood.com/security/strange-requests-broke-nginx-server/Since the last month I am developing a Node.js application with Vue.js and recently, I bought a server and uploaded my still in development site there. I deployed my test application to the server just one week ago and…Sat, 29 Sep 2018 00:00:00 GMThttps://preview.arshadmehmood.com/tutorial/how-to-delete-files-from-heroku-repo/https://preview.arshadmehmood.com/tutorial/how-to-delete-files-from-heroku-repo/It's frustrating when you push some code to Heroku and some files are just not deleted and Heroku serves you an old version of your code with a mix of new files. Well, worry no more! You can simply delete the old files…Sun, 16 Sep 2018 00:00:00 GMThttps://preview.arshadmehmood.com/tutorial/using-ledger-nano-s-as-a-u2f-device/https://preview.arshadmehmood.com/tutorial/using-ledger-nano-s-as-a-u2f-device/Skip right to, how to use it with Ledger Nano S What is U2F? U2F is an open authentication standard that enables Internet users to securely access any number of online services with one single security key instantly and…Fri, 14 Sep 2018 00:00:00 GMThttps://preview.arshadmehmood.com/security/always-keep-your-cryptocurrency-on-a-cold-storage-hardware-wallet/https://preview.arshadmehmood.com/security/always-keep-your-cryptocurrency-on-a-cold-storage-hardware-wallet/As with any type of currency or asset, you would always want to keep it in a safe place. Safe places are safe boxes in your home, banks, vaults, wallet and in the case of digital crypto currencies, a cold storage or a…Sat, 08 Sep 2018 00:00:00 GMThttps://preview.arshadmehmood.com/tutorial/build-and-deploy-gitlab-project-repository-to-firebase-hosting-with-continuous-integration/https://preview.arshadmehmood.com/tutorial/build-and-deploy-gitlab-project-repository-to-firebase-hosting-with-continuous-integration/Previously, I wrote a blog post on how to Deploy Angular App To Firebase Hosting and Deploy Gitlab Project/Repository to Heroku app with Continuous Integration in 5 minutes!. Now we will use Gitlab's Continuous…Thu, 30 Aug 2018 00:00:00 GMThttps://preview.arshadmehmood.com/development/my-first-open-source-repository-langur-translation-chat-bot/https://preview.arshadmehmood.com/development/my-first-open-source-repository-langur-translation-chat-bot/Sometime ago, I made a chatbot from translating one language to another called Langur. Today, I have decided to make it open source, so that people can learn from it and make chat bots easily. It's my very first open…Fri, 24 Aug 2018 00:00:00 GMThttps://preview.arshadmehmood.com/tutorial/deploy-angular-app-to-firebase-hosting/https://preview.arshadmehmood.com/tutorial/deploy-angular-app-to-firebase-hosting/Deploy Angular app to Firebase hosting Hosting an angular app on firebase is really easy. Prerequisites: Node and angular-cli. Steps: To deploy and app: 1. Create Angular App, or use already created Angular App. 2.…Mon, 20 Aug 2018 00:00:00 GMThttps://preview.arshadmehmood.com/personal/today-i-learned-to-share-knowledge/https://preview.arshadmehmood.com/personal/today-i-learned-to-share-knowledge/Today I learned, sharing code. Testing visibility.Sun, 19 Aug 2018 00:00:00 GMThttps://preview.arshadmehmood.com/personal/what-i-learnt-from-my-failed-incubator/https://preview.arshadmehmood.com/personal/what-i-learnt-from-my-failed-incubator/Ever since, I was in university, I was motivated to start my own company. In 2012, I graduated with Bachelor's degree from FAST National University, Islambad. Our university offered an incubator program and a couple of…Fri, 10 Aug 2018 00:00:00 GMThttps://preview.arshadmehmood.com/tutorial/deploy-gitlab-project-repository-to-heroku-app-with-continuous-integration-in-five-minutes/https://preview.arshadmehmood.com/tutorial/deploy-gitlab-project-repository-to-heroku-app-with-continuous-integration-in-five-minutes/I love Heroku and I love Gitlab. Both of them offer so much for free, which comes in handy when you're just testing applications. What I love even more is the Gitlab's Continuous Integration (GitLab CI/CD). Its just…Thu, 26 Jul 2018 00:00:00 GMThttps://preview.arshadmehmood.com/personal/peoples-energy-and-surrounding-yourself-with-the-best-people/https://preview.arshadmehmood.com/personal/peoples-energy-and-surrounding-yourself-with-the-best-people/You are the average of five people you spend the most time with, according to Jim Rohn. And we are influenced more by our environment than we think. What kind people you are around with, will make you their average. So,…Mon, 23 Jul 2018 00:00:00 GMThttps://preview.arshadmehmood.com/tutorial/how-to-use-gitlab-after-enabling-two-factor-authentication-2fa/https://preview.arshadmehmood.com/tutorial/how-to-use-gitlab-after-enabling-two-factor-authentication-2fa/You should always try to use Two-Factor Authentication whenever possible, as, it adds another layer of protection and security. A few days ago, I also enabled 2FA in Gitlab. Everything worked fine, until I pushed my…Thu, 12 Jul 2018 00:00:00 GMThttps://preview.arshadmehmood.com/personal/whats-your-developer-identity/https://preview.arshadmehmood.com/personal/whats-your-developer-identity/We have many identities, identity for work, identity for friends and a different identity for home. But, I want to write about the developer identity, what is your software developer identity? I recently read a blog…Wed, 11 Jul 2018 00:00:00 GMThttps://preview.arshadmehmood.com/personal/the-most-fulfilling-2-i-made-and-my-android-developer-journey/https://preview.arshadmehmood.com/personal/the-most-fulfilling-2-i-made-and-my-android-developer-journey/I started my Android developer journey back in 2008-2009 when Android was not very commonly know. I used to live in a small apartment in Islamabad,Pakistan at that time and I was also doing my bachelor's in computer…Mon, 11 Jun 2018 00:00:00 GMThttps://preview.arshadmehmood.com/cryptocurrency/ledger-nano-s-update/https://preview.arshadmehmood.com/cryptocurrency/ledger-nano-s-update/Hardware wallets are the safest and most convenient way to store cryptocurrency. The good thing about Ledger Nano S is that the private keys of your wallets are never shared. After waiting for a long time, I recieved my…Tue, 13 Mar 2018 00:00:00 GMThttps://preview.arshadmehmood.com/tutorial/duolingo-lost-streak-repair-hack/https://preview.arshadmehmood.com/tutorial/duolingo-lost-streak-repair-hack/Update: I have posted an updated and easy method for the hack here You had a streak of 100 days or even more and you just lost it! Shit happens! I understand your sadness of losing a streak. It also happened to me, once…Mon, 05 Mar 2018 00:00:00 GMThttps://preview.arshadmehmood.com/development/langur-language-translation-bot/https://preview.arshadmehmood.com/development/langur-language-translation-bot/Since, I am living in Germany. I have to learn the German language. Somewhow, I came up with this idea of translating text messages of whatever you type into the chat, I thought it would make my life easier. You can get…Wed, 21 Feb 2018 00:00:00 GMThttps://preview.arshadmehmood.com/android/auto-update-android-sqlite-database-version/https://preview.arshadmehmood.com/android/auto-update-android-sqlite-database-version/You may be familiar with the onUpgrade(SQLiteDatabase, int, int) method of the SQLiteOpenHelper class, which is called in your database helper class whenever your database version changes to a higher version. It is a…Sun, 28 Jan 2018 00:00:00 GMThttps://preview.arshadmehmood.com/personal/hello-world/https://preview.arshadmehmood.com/personal/hello-world/Hello World. The first letters you usually type when you begin some new program, to test it is working properly. Earlier I had thought of posting only software development related stuff here on my blog but now, I have…Sat, 27 Jan 2018 00:00:00 GMT