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How to Upgrade Istio the Git-Ops Way
Istio 1.17 has been running really well in my Garage Kubernetes lab, but I thought it’s time to give it an upgrade. It was installed and configured using istioctl utility last time when I bootstrapped the cluster. Since I’ve automated a lot of Kubernetes resources using ArgoCD I would like to upgrade Istio the git-ops…
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How to Calculate Proportions Using 2 Metrics in Prometheus
Recently I needed to improve an alert defined using Prometheus Alert Manager to trigger when less than half of the minimum replicas are up, eg. I had a look at existing metrics collected by kube-state-metrics in my Kubernetes cluster, the number of replicas running well could be queried with the kube_pod_status_ready metric and the number…
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An Easy Way to Build GitHub Actions Workflows
TL; DR: I found it not so convenient to look up GitHub’s official docs when traversing objects in GHA(GitHub Actions), ie. what’s in github.event object? So using a few steps now all the data structures are available to me. 🙂
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A Simple and Interactive Decoder for Kubernetes Secrets
TL; DR: Here’s a simple shell function which can decode Kubernetes secrets interactively and should work in any Bash and compatible environments. Requirements: Here’s the code. This can be chained together with other commands too, eg. on a Mac, I can do Then the decoded content of selected secret key will be put into clipboard.…
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How Much Did I Pay for Electricity, Petrol and Gas in 2023?
Am I one of those minimalists? No. The secret is, I paid 0 for petrol and gas – I have no need of them since I fully electrified my home. Here are the milestones of my journey to full electrification: I suspended my gas account in May 2023 and the process costed me $88. With…
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A GKE Issue: Metadata Service Is Unreachable In Nodes
Recently I encountered some errors in a GKE cluster where a lot of pods were stuck at crash loop backoff state, which means the pods couldn’t recover on their own. When taking a closer look, I saw errors like: It’s a DNS issue then. However when I created a pod and ran some DNS tests…
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ArgoCD, Jsonnet and Tanka in 2024
A few years ago, I got to know Jsonnet and I loved it at first sight. I used a nice little tool called tanka to manage my Jsonnet manifests and I got them working together with ArgoCD, and finally I re-deployed my blog using this combo. Everything worked like a charm, until… Recently I upgraded…
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How to Enable Compression in Istio Ingress Gateway
TL; DR: here’s a code snippet to turn on gzip compression for Istio’s ingress gateway, using Envoy filter. Tested with Istio 1.16 and Kubernetes 1.26. To test it with curl: 🙂