DevOps

What is Kafka Schema Registry? When working with Apache Kafka, one of the common challenges is handling the format of messages being passed between producers and consumers. Imagine a producer writing events in one format and a consumer expecting another — chaos! That’s where Kafka Schema Registry comes to the rescue. Schema Registry is a separate service that stores and manages schemas (usually Avro, but also JSON Schema or Protobuf). Instead of just sending raw JSON or binary, producers register the schema once, and consumers can retrieve it to make sure the data they read matches the expected format. ...

What is CI/CD and Why DevOps Engineers Need It If you’ve ever deployed an application manually — copying files, restarting services, and fixing unexpected issues at 2 AM — you know the pain. That’s where CI/CD comes in. It’s not just buzzwords, but one of the core practices in DevOps. Breaking It Down CI (Continuous Integration) Developers merge their code frequently (ideally daily) into a shared repo. Automated pipelines check if the new code builds, tests pass, and nothing is broken. ...

What is a Helm Subchart and How to Use It When you start using Helm to manage applications in Kubernetes, you’ll quickly discover that not everything should live in a single chart. Sometimes, an application depends on other components — like a database, cache, or monitoring tool. This is where subcharts come into play. What is a Subchart? A subchart is simply another Helm chart that lives inside the charts/ directory of your main chart. It’s a way to define dependencies. For example, your app may need Redis. Instead of reinventing the wheel, you include the Redis Helm chart as a subchart. ...

ETCD ID Mismatch in Kubernetes ETCD is the key-value store used by Kubernetes to keep cluster state. Sometimes you may see the following error in ETCD logs: 2025-11-11 12:13:10.134330 E | rafthttp: request cluster ID mismatch (got fc5dec74b3dcf6fa want 4e38d7b9b94fe83c) It usually happens when a member of the ETCD cluster has a different ID than what the cluster expects. Causes Restoring a backup incorrectly. Copying ETCD data directories between nodes. Node reinstallation without cleaning old ETCD state. Cluster misconfiguration after scaling or failover. How to Fix Step 1: Identify the problem member ...

Helm Error: UPGRADE FAILED - Another Operation in Progress When working with Helm in Kubernetes, you might encounter the following error: Error: UPGRADE FAILED: another operation (install/upgrade/rollback) is in progress This usually happens when a Helm release is already in the middle of an action, but another upgrade or rollback is triggered. Common Pending States Helm releases can get stuck in several states: pending-install — Helm started installing, but something went wrong before it finished. pending-upgrade — Helm tried to upgrade, but the process didn’t complete. pending-rollback — A rollback started but got stuck in the middle. These states prevent you from running another helm upgrade or helm rollback. ...