DevOps Stuff's

DevOps Daily: 2 Mins Do you know about init containers in kubernetes? Think of it as a setup steps for your main applciation pod, preparing the environment, dependencies, or configuration that your main app needs. Init containers runs before your main application container…

Which one of the following details is not part of a "Linux inode"? #linux #filesystem #devops #sre #devopsinterview

DevOps Diaries: In my initial days of #Kubernetes, when I was learning fundaments (still learning..) , I really like the simplicity and use cases of kubernetes "labels" feature. Annotations, on the other hand, always felt a bit unnecessary to me. Why have a separate thing?…

DevOps Diaries: 🤔Do you know everyone can create files in Linux /tmp directory , but only the owner can delete them? Let’s see how that works, ls -ld /tmp drwxrwxrwt 10 root root 4096 Oct 2 12:00 /tmp Normally, in a world-writable dir (rwxrwxrwx), anyone could delete…

DevOps Diaries: Back in my early Linux admin days, sometimes I saw random processes getting killed with no warning. Logs showed Out of memory: Kill process 1234 (mysqld). I was like - "why is Linux randomly killing stuff? 🤔 The truth: it wasn’t random at all. - OOM-Killer…

DevOps Diaries: lets discuss about SYN attack today!! Here’s why this attacks works… Phase1: During TCP Handshake process, When a server gets a SYN, it creates a half-open connection and places it in the SYN queue. -----> It replies with SYN+ACK and waits for the…

90% of DevOps/SRE engineers (including me at first 😅) ended up choosing the wrong answer in my recent poll - I told you it was a tricky one! The question was simple: (output of below command in bash) - name="abc" && echo $name{1..3}.txt Most people expected the output to be: -…

DevOps Diaries: In most interviews, when I trigger discussion about Kubernetes internals, I notice many engineers assume the kube-apiserver directly talks to the kubelet and instructs it what to do. But that’s not really how it works… - When you apply a Pod manifest, the API…

DevOps Diaries: I was reading about the process lifecycle in Linux and found something interesting - thought to share with all of you. When Linux create a process using a fork (), child process gets a copy of the parent’s memory. But here is the trick: Linux does not actually…

DevOps Diaries: Do you know about the Linux feature “Capabilities”? Introduced after Linux kernel 2.2 (1999), it has become a core security component in modern systems (containers, Kubernetes, cloud infra) let me try to explain, The old problem: Back in the day, Linux…

AWS Lambda internals are very interesting, Do you want to know How it working under the hood? Check out my medium post - medium.com/aws-in-plain-e… #lambda #aws #devops #sre #devopsinterview

DevOps Diaries: Back in my early Linux admin days, I saw processes in top showing >100% CPU. I was like: Arey yaar, what is happening? How single process can use more than 100% CPU :-( Later I understood that 100% means only one core fully busy. Example, On a 4-core…

DevOps Diaries: Do you know why your shell history sometimes misses commands after a crash or reboot? 🤔 Because bash (and most shells) don’t write history to disk immediately, they keep it in memory during the session and only flush it to ~/.bash_history when the shell exits…

DevOps Diaries: In Linux do you know why files in /proc often show 0 size? 🤔 - Because /proc isn’t real storage. It’s a virtual filesystem created by the kernel. - When you run cat /proc/cpuinfo or cat /proc/meminfo, nothing is read from disk. Instead, the kernel generates…

DevOps Diaries: Most of us use Kubernetes in production, but only a few know about seccomp. (Linux kernel security feature) Think of it this way: 1) iptables - filters network traffic. 2) seccomp - filters system calls from containers to the Linux kernel. Let's see how it…

DevOps Diaries: Early in my DevOps journey, I once deleted a 5GB log file from a production server to quickly free up space. To my surprise, df -h still showed the disk as full. No errors, no warning : just no space reclaimed. That’s when I learned one of the most important…

DevOps Interview Question of the Day - Scenario: You have a multi-tenant Kubernetes cluster where multiple teams run workloads. A team reports that their Pods are stuck in Pending despite sufficient CPU and memory resources available in the cluster. After investigating, you…

Question - What is the output of below one-liner in BASH name="abc" && echo $name{1..3}.txt 💀Only top 1% Linux Pro can answer this question. #DevOps #Linux #interviewquestions

When systems break, how do you troubleshoot?  here are the 3 main styles. 🔧⚙️ 1. Data Collector – Follows a systematic approach, collects detailed information, follow standard check list one by one, Reliable, but sometimes slower. 2. Educated Guesser – Relies on intuition…

When systems break, how do you troubleshoot?  here are the 3 main styles. 1. Data Collector – Follows a systematic approach, collects detailed information, follow standard check list one by one, Reliable, but sometimes slower. 2. Educated Guesser – Relies on intuition and past…