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Beyond the Tutorial: The Real-World Debugging Challenges

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Beyond the Tutorial: The Real-World Debugging Challenges This article is a cautionary tale and a practical guide. It walks a developer through a series of common, real-world errors that they will encounter when deploying their first operator. The tone is direct, empathetic, and focuses on the problem-solving process.

  1. The Build Process: make and the Missing Rule The first challenge was not with Kubernetes but with the build tool itself. The Problem: When you ran make install, the make command returned No rule to make target ‘install’. This was a crucial lesson in understanding that a successful Kubernetes workflow starts with a disciplined, reliable build process. The make command’s sole job is to read a Makefile and execute a specific rule. The error meant the recipe was either missing or had a typo. The Fix: The solution was to create a Makefile with a correctly defined install rule. This rule is a declarative recipe that tells make how to build and install our Custom Resource Definitions (CRDs). It encapsulates the complexity of the underlying kubectl commands, ensuring that our installation process is both repeatable and reliable.

  2. The API Limit: CRD Bloat This was a major, real-world bug that demonstrated a crucial limitation of the Kubernetes API. The Problem: When you ran make install, you received the error metadata.annotations: Too long: must have at most 262144 bytes. This was a hard limit in the Kubernetes API itself, not a bug in our code. The Diagnosis: The controller-gen tool, which is used by your Makefile to generate our Custom Resource Definition (CRD), was automatically generating a massive, detailed schema of our custom resource and trying to store it in an annotation, which caused the CRD to exceed the 256KB size limit. The Solution: The solution was to tell controller-gen to truncate the long descriptions. This is a necessary and standard step when working with complex CRDs. The Makefile’s manifests rule is refactored to use the crd:maxDescLen=0 flag, which tells the tool to truncate the descriptions that are causing the size bloat.

  3. The Missing Image: ImagePullBackOff This was a classic Kubernetes debugging scenario that tested our understanding of the relationship between Docker and Kubernetes. The Problem: The Kubernetes pods were in an ImagePullBackOff state, even though the image was successfully loaded into the kind cluster. This was a crucial lesson in understanding that our local Docker registry and the kind cluster’s internal registry are two different things. Kubernetes was looking for the image in a public registry (docker.io/library), but it was not there. The Fix: The solution was to use the kind load docker-image command to explicitly load the image into the kind cluster’s internal registry. This made the image available to all the worker nodes, allowing the pods to start correctly.

  4. A Broken Connection: exec: “crictl”: executable file not found in $PATH This was a quick, but important, debugging exercise. The Problem: When you ran docker exec … crictl images, you received an error that the crictl command was not found. The root cause was a simple typographical error. You had typed critcl instead of crictl. The Fix: The solution was simply to correct the tyAsk customer to check firewall that udp traffic is allowed on 1434 port from trino host to their sql host.