DevOps

Introduction etcd is a distributed key-value store that plays a critical role in Kubernetes by storing cluster configuration and state. When etcd runs into problems, it can cause cluster instability or downtime. This article covers common etcd errors, their underlying causes, and actionable solutions. 1. etcdserver: request timed out ❓ Cause Occurs when etcd members can’t communicate efficiently, often due to network issues or disk I/O latency. 🛠️ Solution Check disk performance: iostat -xz 1 Ensure etcd data is on SSD storage. Check network latency and connectivity between cluster members: ping <etcd-member-IP> 2. etcdserver: leader changed ❓ Cause This is often seen when leadership changes too frequently, indicating instability in the etcd cluster. ...

DDoS (Distributed Denial of Service) attacks are among the most common threats to cloud-native infrastructure and APIs. They can flood your services with traffic, exhausting resources and causing downtime. In this article, we’ll explore effective strategies to prevent and mitigate DDoS attacks — from rate limiting to cloud-based protections. 1. What Is a DDoS Attack? A DDoS attack occurs when a network of compromised machines sends overwhelming traffic to a target server or service, aiming to exhaust bandwidth or system resources. ...

Long-running queries can cause serious performance issues in PostgreSQL. Here’s how to automate their termination to keep your DB healthy. Why Kill Long-Running Queries? In real-world scenarios, long-running queries often: Lock tables or rows Exhaust memory or CPU Cause deadlocks Block migrations or monitoring tools Typical causes: Forgotten WHERE clauses Heavy reporting queries Hung jobs or broken clients How It Works We’ll use a Bash script to: Connect to PostgreSQL Detect queries older than 60 seconds Automatically terminate them Bash Script to Kill Long Queries 1. Define connection and timeout #!/bin/bash PG_CONN="postgres://user:pass@postgres-host/postgres-db" QUERY_TIMEOUT="60" PSQL_RUN="psql $PG_CONN -Atc" 2. Build the query QUERY="SELECT pid FROM pg_stat_activity WHERE now() - query_start > '${QUERY_TIMEOUT} seconds'::interval" 3. Run and kill echo "Checking for queries longer than $QUERY_TIMEOUT seconds..." pids=$(${PSQL_RUN} "$QUERY") for pid in $pids; do echo "Terminating PID $pid..." ${PSQL_RUN} "SELECT pg_terminate_backend($pid)" done Automate with Cron To run every 5 minutes: ...

The Horizontal Pod Autoscaler (HPA) in Kubernetes automatically scales the number of pods in a deployment or replica set based on observed resource usage, such as CPU or memory. This article breaks down how HPA works, when to use it, its pros and cons, and how to get started with it in your Kubernetes cluster. 1. What is HPA? HPA dynamically adjusts the number of pods in a Kubernetes workload (like a Deployment or StatefulSet) based on metrics from the Kubernetes Metrics Server. ...

Kubernetes Resource Management: LimitRange vs ResourceQuota Managing resources in Kubernetes is critical for ensuring fair usage, stability, and predictable performance in a multi-tenant cluster. Two powerful tools provided by Kubernetes for this purpose are LimitRange and ResourceQuota. This article explains what they are, their differences, and how to use them effectively. What is LimitRange? LimitRange is a Kubernetes policy object that sets default resource limits (CPU/memory) for containers in a namespace. ...