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Ubuntu Server 20.04 on ThinkPad W520
10 years ago, I would dream for a ThinkPad W520 laptop: imagine 4 cores, 8 threads, 32GB memory and 160GB SSD in 2012! I saw one of these old battleship-class laptops Gumtree the other day so I bought it without much hesitation – It’s still very good as a mini server even in 2022. In…
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How to Use YAML as Data Source in Terraform
I love how DRY and lean YAML can be, since I started to learn Ansible years ago. Recently I wanted to provision MySQL user privileges right after the database instance provisioned in Google Cloud SQL. I used petoju/mysql Terraform provider to get the job done, it’s a community provider but seemed to be quite popular.…
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Monitoring as Code with Grafana
TL;DR: I used Grafana Helm charts and ArgoCD to deploy dashboards as code. I’ve been using Grafana to build dashboards for years, both at work and as a hobby. A dashboard was created by hand for monitoring my garage Kubernetes cluster. Since I’ve adopted gitOps with ArgoCD a few years ago, what about going forward…
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How to Connect to Cloud SQL via SSH
TL;DR: here’s a handy bash script which can connect to a private Cloud SQL instance(MySQL in this case) via a bastion host. Prerequisites: Google Cloud SQL instance with mTLS certs provisioned Google Cloud SDK installed(the gcloud command) a bash shell(better be V5.0+) OpenSSH and MySQL CLI installed Google Cloud SQL is an RDB as a…
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A Load Balancer for Cloud SQL Replicas
TL;DR: As of Aug 2022, there’s no out of box load balancing for Google Cloud SQL read replicas. So I built one for MySQL replicas with HAProxy with the ability to dynamically reload when number of replicas has changed. It will be quite straight forward to run a few HAProxy pods in Kubernetes as a…
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How to Use a Local Persistent Volume
TL;DR: A local persistent volume in a Kubernetes cluster is a persistent volume allocated in a certain node. Any pod mounting the volume will be automatically scheduled in the same node. Since it’s limited to 1 node, clearly it can’t be used as a high-availability solution, but hey, it’s quite Ok to use it for…
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How to Build Multi-Arch Docker Images for MacBook M1
At work, I currently use a MacBook Pro with an Intel chipset and some of my colleagues have upgraded to ones with M1 chipset which is of arm64 or aarch64 architecture. Then expectedly I need to build some Docker images for both architectures. I’ve done some multi-arch Docker stuff before so this is not really…
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How To Renew Certificates in Kubernetes Clusters, Revisited
There is a lot of TLS certificates used by the core of a Kubernetes cluster and a popular one is the client-server pair used by kubectl to authenticate to the cluster control plane. In my previous notes on how to renew certificates in a Kubernetes cluster with kubeadm, I found that the steps are quite…