Kubernetes

I read Learning Kubebuilder. It was a concise and well-organized resource that taught me a lot. My impression after reading is that Custom Resources (CRs) have high flexibility, making them tempting to create, but carelessly increasing their number makes them unmanageable. I felt it’s probably best to adopt them only for issues that fundamentally cannot be realized without CRs, and to create and use them minimally. For example, regarding the MarkdownView used as an example here, in reality it would be better to realize it with a combination of standard resources rather than a CR....

I tried https://github.com/kelseyhightower/kubernetes-the-hard-way on QEMU/KVM, so I’ll leave a log here. The original text assumes GCP, but this time I built it on local QEMU/KVM. Version List kubernetes-the-hard-way bf2850974e19c118d04fdc0809ce2ae8a0026a27 Kubernetes 1.12.0 containerd Container Runtime 1.2.0-rc.0 gVisor 50c283b9f56bb7200938d9e207355f05f79f0d17 CNI Container Networking 0.6.0 etcd v3.3.9 CoreDNS v1.2.2 1. Preparation Until getting the VM image and starting it. # Prepare VM image $ http_dir=http://ftp.jaist.ac.jp/pub/Linux/Fedora/releases/30/Cloud/x86_64/images $ wget $http_dir/Fedora-Cloud-Base-30-1.2.x86_64.qcow2 $ virt-customize -a /var/lib/libvirt/images/Fedora-Cloud-Base-30-1.2.x86_64.qcow2 \ --run-command 'yum remove cloud-init* -y' \ --root-password password:root $ cd /var/lib/libvirt/images/ $ for i in 0 1 2 ; do \ sudo cp ....

I read Kubernetes Complete Guide and will leave some notes here. I’m summarizing commands and mechanisms that I wasn’t usually conscious of. If you want to create small images, base them on scratch or alpine When both ENTRYPOINT and CMD are set, $ENTRYPOINT $CMD is executed Multi-stage build: You can process only in a build-specific container and copy the artifacts to an execution-specific container CNCF sets project maturity in three stages: “Graduated”, “Incubating”, and “Sandbox” When building on-premises, instance sizes on AWS or GCP can be used as a guide Flannel: Configures an overlay network between nodes There is a kubernetes playground provided by Docker, Inc....