###### tags: `Ubuntu` `Kubernetes` `microk8s`

# 在 Ubuntu 19.10 上使用 microk8s 來架構 Kubernetes 服務

## 安裝

$ snap install microk8s --classic
$ snap list microk8s
Name      Version  Rev  Tracking  Publisher   Notes
microk8s  v1.16.2  993  stable    canonical✓  classic

$ sudo usermod -a -G microk8s $USER
$ newgrp microk8s #暫時先取得群組權限，重新啟動系統後就不需要執行這個指令了。

## 查看狀態

$ microk8s.status
microk8s is running
addons:
cilium: disabled
dashboard: disabled
dns: disabled
fluentd: disabled
gpu: disabled
helm: disabled
ingress: disabled
istio: disabled
jaeger: disabled
knative: disabled
linkerd: disabled
metrics-server: disabled
prometheus: disabled
rbac: disabled
registry: disabled
storage: disabled

$ microk8s.kubectl get nodes
NAME   STATUS   ROLES    AGE     VERSION
9527   Ready    <none>   6m16s   v1.16.2

$ microk8s.kubectl get services
NAME         TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)   AGE
kubernetes   ClusterIP   10.152.183.1   <none>        443/TCP   6m31s

## 使用 dashboard

https://microk8s.io/docs/addon-dashboard

$ microk8s.enable dashboard
Applying manifest
serviceaccount/kubernetes-dashboard created
service/kubernetes-dashboard created
secret/kubernetes-dashboard-certs created
secret/kubernetes-dashboard-csrf created
secret/kubernetes-dashboard-key-holder created
configmap/kubernetes-dashboard-settings created
role.rbac.authorization.k8s.io/kubernetes-dashboard created
clusterrole.rbac.authorization.k8s.io/kubernetes-dashboard created
rolebinding.rbac.authorization.k8s.io/kubernetes-dashboard created
clusterrolebinding.rbac.authorization.k8s.io/kubernetes-dashboard created
deployment.apps/kubernetes-dashboard created
service/dashboard-metrics-scraper created
deployment.apps/dashboard-metrics-scraper created
service/monitoring-grafana created
service/monitoring-influxdb created
service/heapster created
deployment.apps/monitoring-influxdb-grafana-v4 created
serviceaccount/heapster created
clusterrolebinding.rbac.authorization.k8s.io/heapster created
configmap/heapster-config created
configmap/eventer-config created
deployment.apps/heapster-v1.5.2 created

If RBAC is not enabled access the dashboard using the default token retrieved with:

token=$(microk8s.kubectl -n kube-system get secret | grep default-token | cut -d " " -f1)
microk8s.kubectl -n kube-system describe secret $token

In an RBAC enabled setup (microk8s.enable RBAC) you need to create a user with restricted
permissions as shown in:
https://github.com/kubernetes/dashboard/blob/master/docs/user/access-control/creating-sample-user.md

先把 token 找出來等一下要用

$ token=$(microk8s.kubectl -n kube-system get secret | grep default-token | cut -d " " -f1)
$ microk8s.kubectl -n kube-system describe secret $token
Name:         default-token-kk2mz
Namespace:    kube-system
Labels:       <none>
Annotations:  kubernetes.io/service-account.name: default
              kubernetes.io/service-account.uid: 3f2b6305-fa1e-4e7a-ab24-a727253b216e

Type:  kubernetes.io/service-account-token

Data
====
ca.crt:     1103 bytes
namespace:  11 bytes
token:      eyJhbGciOiJSUzI1NiIsImtpZCI6IlBPS1dvZDJWbzN6bms4QnRtbzg3U2RpQmdFNHFVVGdwV21YMU1qN3hhek0ifQ.eyJpc3MiOiJrdWJlcm5ldGVzL3NlcnZpY2VhY2NvdW50Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9uYW1lc3BhY2UiOiJrdWJlLXN5c3RlbSIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VjcmV0Lm5hbWUiOiJkZWZhdWx0LXRva2VuLWtrMm16Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9zZXJ2aWNlLWFjY291bnQubmFtZSI6ImRlZmF1bHQiLCJrdWJlcm5ldGVzLmlvL3NlcnZpY2VhY2NvdW50L3NlcnZpY2UtYWNjb3VudC51aWQiOiIzZjJiNjMwNS1mYTFlLTRlN2EtYWIyNC1hNzI3MjUzYjIxNmUiLCJzdWIiOiJzeXN0ZW06c2VydmljZWFjY291bnQ6a3ViZS1zeXN0ZW06ZGVmYXVsdCJ9.htCICXMXK_pVnd9XwJRNHAtXlgrjJQilfarEPv2RAqScJOkhD_fymWVuABYUnja_I3D4foXQ_MoxQGxUdAgjeIRz0ZcTiMRoAQcBTFQxCstNz7xVMeWz6Rfh1nd9YSXlr0LmzRY4sEPWLalyH48OtqePjVQGTlIUaLEfvzlG4aE0oWt_PiiMw8DlC3AKhYk_tyxdm34OjOBOfUiBINg1_-0DdAeLREU8dTvofOrY_jbIWGZDIiGlFjmlndpH1D_meF4l5KwgAtoQfayhTfkLXD6VL7BGoPz-74Q0ENhRLHnsHKvr6wl6a3aYaCyL-4I0x8DT2lb9Y0pe0d5M8qqm7A

啟動 proxy 後可以透過 http://127.0.0.1:8001/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:/proxy/ 這個網址跟上面找到的 token 來登入

$ microk8s.kubectl proxy --accept-hosts=.* --address=0.0.0.0

## 參考文件

* https://www.inwinstack.com/2018/04/17/what-is-kubernetes-part1/
* https://microk8s.io/docs/