Freaks City

A production alert came in at midnight while the on-call engineer was asleep. After connecting to the environment, it became clear that one microservice was experiencing a steady increase in file descriptor usage, eventually leading to an OutOfMemoryError and service crash. This microservice establishes SSH connections during operation, and sin ...

Problem Description When running Kafka consumers in production, you may encounter the following error patterns: Client-side logs: The provided member is not known in the current generation i/o timeout Server-side logs (broker): [GroupCoordinator 0]: Sending empty assignment to member watermill-xxx of group-name for generation 14 with no errors ...

Essential Linux Commands for System Inspection A collection of frequently used commands for system monitoring and maintenance. System Shutdown, Reboot, and Session Control Command Purpose shutdown -h now Power off immediately shutdown -h +10 Schedule shutdown after 10 minutes shutdown -h 11:00 Shutdown at 11:00 shutdown -c Cancel a ...

SQL Execution Error E-3113 on long string columns in 2.1.x Symptom SELECT statements fail with [E-3113] string column length after upgrading to 2.1.0 or 2.1.1. Fix Raise the session variable parallel_pipeline_task_num. On a 32-core / 256 GB node: SET parallel_pipeline_task_num = 16; -- or 32 JDBC catalog connection exhaustion Symptom Can not ...

Dedicated Service User Creation Creating a dedicated Kafka runtime user isolates the service from your primary system account to avoid permission conflicts and environment pollusion. This step is optional but strongly recommended for production and test environments. # Create dedicated kafka service user, you will be prompted to set a password ...

Diagnostic Workflow: The Three Core Techniques When troubleshooting issues in a Kubernetes cluster—such as unresponsive nodes, crashing Pods, or network failures—it's essential to move beyond surface-level symptoms. A structured diagnostic approach significantly improves resolution speed and accuracy. The following three techniques form the fou ...

Installation Methods System Preparation Before installing MySQL, verify existing installations using: rpm -qa | grep -i mysql Stop services and remove previous installations: ps -ef | grep mysql rpm -e --nodeps package_name For dependency conflicts: rpm -ev package_name --nodeps rpm -e --noscripts package_name Clean remaining directories: fi ...

Understanding CPU Utilization in MySQL High CPU usage often indicates underlying performance issues. Analyzing resource consumption helps identify bottlenecks and optimize server operations. MySQL can cause CPU spikes due to inefficient queries, IO bottlenecks, or configuration issues. CPU States Explained $ top top - 10:24:03 up 36 days, 28 mi ...

When the Docker client attempts to reach the daemon through the local Unix socket at /var/run/docker.sock, the server may be unresponsive even if the service appears configured. Initial attempts to launch the daemon through the system's service manager fail immediately: admin@node-01:~$ sudo systemctl start docker Job for docker.service failed ...

When deploying Istio on manually provisioned Kubernetes clusters, control plane components frequently fail to initialize due to DNS resolution timeouts and webhook connectivity issues. These problems typically stem from control plane nodes being unable to reach CoreDNS or cluster services from host network contexts. Prerequisites: DNS and Contr ...