Kubernetes

Links

• Kubernetes: https://kubernetes.io/

  • Deployments: https://kubernetes.io/docs/concepts/workloads/controllers/deployment/

• kubectl

  • Doc: https://kubernetes.io/docs/reference/kubectl/overview/

  • Install and Set Up kubectl: https://kubernetes.io/docs/tasks/tools/install-kubectl/

• minikube

  • Doc: https://minikube.sigs.k8s.io/

  • GitHub: kubernetes/minikube

Commands

• Minikube commands: https://minikube.sigs.k8s.io/docs/commands/

  • Start local Kubernetes: minikube start

  • Stop local Kubernetes cluster: minikube stop

  • Get status of local Kubernetes: minikube status

  • Start old version (1.15.0 for example): minikube start -p aged --kubernetes-version=v1.15.0

  • list services: minikube service list

  • get Kubernetes URL for a service: minikube service <resource_name>

  • start the dashboard: minikube dashboard

  • get minikube version: minikube version

• kubectl Commands: https://kubernetes.io/docs/reference/kubectl/overview/

  • get info about the cluster: kubectl cluster-info

  • Get version of k8s: kubectl version

  • display all pods across all namespaces: kubectl get pods -A

  • display state of resource: kubectl describe service <resource_name>

  • display infos of resource: kubectl get services <resource_name>

  • delete deployment: kubectl delete deployment <deployment_name>

  • namespace commands

    • List namespaces: kubectl get namespace

    • Create namespace: kubectl create namespace <namespace_name>

Installation

• install Minikube: https://minikube.sigs.k8s.io/docs/start/

• install KVM: https://help.ubuntu.com/community/KVM/Installation

First starts looks like this:

$ minikube start
😄  minikube v1.13.0 on Ubuntu 18.04
✨  Automatically selected the kvm2 driver
💾  Downloading driver docker-machine-driver-kvm2:
    > docker-machine-driver-kvm2.sha256: 65 B / 65 B [-------] 100.00% ? p/s 0s
    > docker-machine-driver-kvm2: 13.81 MiB / 13.81 MiB  100.00% 1.13 MiB p/s 1
💿  Downloading VM boot image ...
    > minikube-v1.13.0.iso.sha256: 65 B / 65 B [-------------] 100.00% ? p/s 0s
    > minikube-v1.13.0.iso: 173.73 MiB / 173.73 MiB  100.00% 1.61 MiB p/s 1m48s
👍  Starting control plane node minikube in cluster minikube
💾  Downloading Kubernetes v1.19.0 preload ...
    > preloaded-images-k8s-v6-v1.19.0-docker-overlay2-amd64.tar.lz4: 486.28 MiB
🔥  Creating kvm2 VM (CPUs=2, Memory=2200MB, Disk=20000MB) ...
🐳  Preparing Kubernetes v1.19.0 on Docker 19.03.12 ...
🔎  Verifying Kubernetes components...
🌟  Enabled addons: default-storageclass, storage-provisioner
💡  kubectl not found. If you need it, try: 'minikube kubectl -- get pods -A'
🏄  Done! kubectl is now configured to use "minikube" by default

Helm

The package manager for Kubernetes

• https://helm.sh/

• Install: https://docs.helm.sh/docs/intro/install/

• Commands

  • add a chart repository (example): $ helm repo add stable https://kubernetes-charts.storage.googleapis.com/

  • list the charts you can install: helm search repo stable

If install fails with Error: cannot re-use a name that is still in use the --replace flag can be used.

Post Setup Examples

After setup:

$ kubectl get pods -A
NAMESPACE              NAME                                        READY   STATUS    RESTARTS   AGE
kube-system            coredns-f9fd979d6-r2vhj                     1/1     Running   2          3h49m
kube-system            etcd-minikube                               1/1     Running   2          3h49m
kube-system            kube-apiserver-minikube                     1/1     Running   2          3h49m
kube-system            kube-controller-manager-minikube            1/1     Running   2          3h49m
kube-system            kube-proxy-tnk8g                            1/1     Running   2          3h49m
kube-system            kube-scheduler-minikube                     1/1     Running   2          3h49m
kube-system            storage-provisioner                         1/1     Running   5          3h49m
kubernetes-dashboard   dashboard-metrics-scraper-c95fcf479-b92v2   1/1     Running   2          3h45m
kubernetes-dashboard   kubernetes-dashboard-5c448bc4bf-tttfg       1/1     Running   2          3h45m