k8s单机版[ microk8s ]

k8s 的网页管理界面：dashboard

1， ubuntu16 安装microk8s

microk8s 是单机版的k8s集群，安装过程仅需2、3分钟，适合测试使用

wang@wang-GA-MA770T-UD3P:~/Downloads$  sudo snap install microk8s --classic
[sudo] password for wang: 
microk8s v1.13.0 from 'canonical' installed

wang@wang-GA-MA770T-UD3P:/home/wang# ls /snap/bin/
etcd.etcdctl  microk8s.enable    microk8s.status  microk8s.inspect   microk8s.stop
microk8s.istioctl microk8s.config   microk8s.kubectl  microk8s.ctr      microk8s.reset
etcdctl  microk8s.disable  microk8s.start

#配置环境变量
root@stack:/home/wang#  echo 'export PATH=$PATH:/snap/bin'>>~/.bashrc && source ~/.bashrc

# 如果之前安装了k8s, 需要覆盖之前的安装的 k8s 服务才能使用microk8s命令
wang@wang-GA-MA770T-UD3P: /snap/bin/$ ./microk8s.kubectl config view --raw > $HOME/.kube/config
# apiVersion: v1
# clusters:
# - cluster:
#     certificate-authority-data: Ek0TVRJeE9UQTBNelkwTjF
#   name: kubernetes
# - cluster:
#     certificate-authority: /root/.minikube/ca.crt
#     server: https://192.168.99.100:8443
#   name: minikube
# contexts:
# - context:
#     cluster: kubernetes
#     user: kubernetes-admin
#   name: kubernetes-admin@kubernetes
# - context:
#     cluster: minikube
#     user: minikube
#   name: minikube
# current-context: minikube
# kind: Config
# preferences: {}
# users:
# - name: kubernetes-admin
#   user:
#     client-certificate-data: LS0tLS1CRUdJTiBDRVJUSUZJQ0FURS0tL
#     client-key-data: LS0tLS1CRUdJTiBSU0EgUFJJVkFURSBLRVktLS
# - name: minikube
#   user:
#     client-certificate: /root/.minikube/client.crt
#     client-key: /root/.minikube/client.key
#####################################
# apiVersion: v1
# clusters:
# - cluster:
#     server: http://127.0.0.1:8080
#   name: microk8s-cluster
# contexts:
# - context:
#     cluster: microk8s-cluster
#     user: admin
#   name: microk8s
# current-context: microk8s
# kind: Config
# preferences: {}
# users:
# - name: admin
#   user:
#     username: admin
# 

a, 查看集群信息

#查看基本信息
wang@wang-GA-MA770T-UD3P:~/Downloads$ snap info microk8s
name:      microk8s
summary:   Kubernetes for workstations and appliances
publisher: Canonical✓
contact:   https://github.com/ubuntu/microk8s
license:   unset
description: |
  MicroK8s is a small, fast, secure, single node Kubernetes that installs on just about any Linux
  box. Use it for offline development, prototyping, testing, or use it on a VM as a small, cheap,
  reliable k8s for CI/CD. It's also a great k8s for appliances - develop your IoT apps for k8s and
  deploy them to MicroK8s on your boxes.
commands:
  - microk8s.config
  - microk8s.disable
  - microk8s.docker
  - microk8s.enable
  - microk8s.inspect
  - microk8s.istioctl
  - microk8s.kubectl
  - microk8s.reset
  - microk8s.start
  - microk8s.status
  - microk8s.stop
services:
  microk8s.daemon-apiserver:          simple, enabled, active
  microk8s.daemon-apiserver-kicker:   simple, enabled, active
  microk8s.daemon-controller-manager: simple, enabled, active
  microk8s.daemon-docker:             simple, enabled, active
  microk8s.daemon-etcd:               simple, enabled, active
  microk8s.daemon-kubelet:            simple, enabled, active
  microk8s.daemon-proxy:              simple, enabled, active
  microk8s.daemon-scheduler:          simple, enabled, active
  
#插件状态
wang@wang-GA-MA770T-UD3P:~/Downloads$ microk8s.status
microk8s is running
addons:
ingress: disabled
dns: disabled
metrics-server: disabled
istio: disabled
gpu: disabled
storage: disabled
dashboard: disabled
registry: disabled

#节点状态
wang@wang-GA-MA770T-UD3P:~/Downloads$ microk8s.kubectl get nodes
NAME                  STATUS   ROLES    AGE     VERSION
wang-ga-ma770t-ud3p   Ready       8m47s   v1.13.0

#服务状态
wang@wang-GA-MA770T-UD3P:~/Downloads$ microk8s.kubectl get services
NAME         TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)   AGE
kubernetes   ClusterIP   10.152.183.1           443/TCP   8m58s

b，通过webui 管理k8s集群：登录dashboard

wang@wang-GA-MA770T-UD3P:~/Downloads$ microk8s.enable dns
Enabling DNS
Applying manifest
service/kube-dns created
serviceaccount/kube-dns created
configmap/kube-dns created
deployment.extensions/kube-dns created
Restarting kubelet
[sudo] password for wang: 
DNS is enabled

# 开启dashboard服务
# create -f https://raw.githubusercontent.com/kubernetes/dashboard/master/aio/deploy/recommended/kubernetes-dashboard.yaml
wang@wang-GA-MA770T-UD3P:~/Downloads$ microk8s.enable dashboard
Enabling dashboard
secret/kubernetes-dashboard-certs created
serviceaccount/kubernetes-dashboard created
deployment.apps/kubernetes-dashboard created
service/kubernetes-dashboard created
service/monitoring-grafana created
service/monitoring-influxdb created
service/heapster created
deployment.extensions/monitoring-influxdb-grafana-v4 created
serviceaccount/heapster created
configmap/heapster-config created
configmap/eventer-config created
deployment.extensions/heapster-v1.5.2 created
dashboard enabled

# 创建用户，获取登录密钥
#创建登录用的账户
cat  > dashboard-adminuser.yaml < dashboard-adminuser-roleBind.yaml <
## Annotations:  kubernetes.io/service-account.name: admin-user
##               kubernetes.io/service-account.uid: b1cb7e10-06bb-11e9-a37b-1c6f65287c2d
## 
## Type:  kubernetes.io/service-account-token
## 
## Data
## ====
## ca.crt:     1094 bytes
## namespace:  11 bytes
## token:      eyJhbGciOiJSUzI1NiIsImtpZCI6IiJ9.eyJpc3MiOiJrdWJlcm5ldGVzL3NlcnZpY2VhY2NvdW50Iiwia3ViZ........

#开启api 代理服务， 监听8001端口， web访问会使用到此端口
wang@wang-GA-MA770T-UD3P:~/Downloads$ microk8s.kubectl proxy
Starting to serve on 127.0.0.1:8001

c, 访问dashboard页面报错503

http://localhost:8001/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:/proxy/

{
 "kind": "Status",
 "apiVersion": "v1", 
 "metadata": {}, 
 "status": "Failure", 
 "message": "no endpoints available for service \"kubernetes-dashboard\"",
 "reason": "ServiceUnavailable", 
 "code": 503 
 }
 #=====原因
 wang@wang-GA-MA770T-UD3P:~/Downloads$ microk8s.kubectl get pods --namespace kube-system
 NAME                                              READY   STATUS              RESTARTS   AGE
heapster-v1.5.2-6bc7c4965d-9qbsb                  0/4     ContainerCreating   0          32m
kube-dns-6ccd496668-5wdsl                         0/3     ContainerCreating   0          33m
kubernetes-dashboard-654cfb4879-rtrw6             0/1     ContainerCreating   0          32m
monitoring-influxdb-grafana-v4-6679c46745-hplwv   0/2     ContainerCreating   0          32m

#======解决
wang@wang-GA-MA770T-UD3P:~/Downloads$ sudo docker pull lhcalibur/pause-amd64
[sudo] password for wang: 
Using default tag: latest
latest: Pulling from lhcalibur/pause-amd64
a3ed95caeb02: Pull complete 
f11233434377: Pull complete 
Digest: sha256:40cd7088fd930f1e8939aaa5d5b8bdf6b214bda7eb22070cf20f5094b6863191
Status: Downloaded newer image for lhcalibur/pause-amd64:latest

wang@wang-GA-MA770T-UD3P:~/Downloads$ sudo docker tag lhcalibur/pause-amd64:latest gcr.io/google_containers/pause-amd64:3.0

wang@wang-GA-MA770T-UD3P:~/Downloads$ microk8s.kubectl get pods --namespace kube-system
NAME                                              READY   STATUS    RESTARTS   AGE
heapster-v1.5.2-64874f6bc6-pbt5k                  4/4     Running   0          25m
kube-dns-6ccd496668-5wdsl                         3/3     Running   1          78m
kubernetes-dashboard-654cfb4879-rtrw6             1/1     Running   0          78m
monitoring-influxdb-grafana-v4-6679c46745-hplwv   2/2     Running   0          78m

###异常的情况如下：
 Warning  FailedCreatePodSandBox  101s                   kubelet, stack     Failed create pod sandbox: rpc error: code = Unknown desc = failed to get sandbox image "k8s.gcr.io/pause:3.1": 
 failed to pull image "k8s.gcr.io/pause:3.1": failed to resolve image "k8s.gcr.io/pause:3.1": no available registry endpoint:
 failed to do request: Head https://k8s.gcr.io/v2/pause/manifests/3.1: dial tcp 74.125.204.82:443: i/o timeout

再次访问： http://localhost:8001/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:/proxy/

登录后即可进入管理界面

d, 部署nginx服务报错：Get https://registry-1.docker.io/v2/: net/http: request canceled while waiting for connection (Client.Timeout

nginx-deployment.yaml

apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  selector:
    matchLabels:
      app: nginx
  replicas: 1 # tells deployment to run 2 pods matching the template
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.7.9
        ports:
        - containerPort: 80

创建deployment后，pod状态异常

wang@wang-GA-MA770T-UD3P:~/Downloads$ microk8s.kubectl get pods
NAME                                READY   STATUS             RESTARTS   AGE
nginx-deployment-76bf4969df-sr8m4   0/1     ImagePullBackOff   0          49m

wang@wang-GA-MA770T-UD3P:~/Downloads$ microk8s.kubectl describe pod nginx-deployment-76bf4969df-sr8m4 
Name:               nginx-deployment-76bf4969df-sr8m4
Namespace:          default
Priority:           0
PriorityClassName:  
Node:               wang-ga-ma770t-ud3p/192.168.1.12
Start Time:         Sun, 23 Dec 2018 23:12:37 +0800
Labels:             app=nginx
                    pod-template-hash=76bf4969df
Annotations:        
Status:             Pending
IP:                 10.1.1.25
Events:
  Type     Reason          Age                    From                          Message
  ----     ------          ----                   ----                          -------
  Normal   Scheduled       49m                    default-scheduler             Successfully assigned default/nginx-deployment-76bf4969df-sr8m4 to wang-ga-ma770t-ud3p
  Normal   Pulling         46m (x2 over 49m)      kubelet, wang-ga-ma770t-ud3p  pulling image "nginx:1.7.9"
  Warning  Failed          45m (x2 over 46m)      kubelet, wang-ga-ma770t-ud3p  Error: ErrImagePull
  Warning  Failed          45m                    kubelet, wang-ga-ma770t-ud3p  Failed to pull image "nginx:1.7.9": rpc error: code = Unknown desc = Error response from daemon: Get https://registry-1.docker.io/v2/: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)
  Normal   SandboxChanged  45m (x7 over 46m)      kubelet, wang-ga-ma770t-ud3p  Pod sandbox changed, it will be killed and re-created.
  Normal   BackOff         45m (x6 over 46m)      kubelet, wang-ga-ma770t-ud3p  Back-off pulling image "nginx:1.7.9"

2, centos 7 安装microk8s

# 安装 snap
yum -y install epel-release
yum -y install yum-plugin-copr
yum -y copr enable ngompa/snapcore-el7
yum -y install snapd
systemctl enable --now snapd.socket
ln -s /var/lib/snapd/snap /snap

# snap 安装 microk8s
snap install microk8s --classic
snap info microk8s

#配置 microk8s环境变量
[root@node2 ~]# ls /var/lib/snapd/snap/bin
microk8s.config   microk8s.enable    microk8s.kubectl  microk8s.status
microk8s.ctr      microk8s.inspect   microk8s.reset    microk8s.stop
microk8s.disable  microk8s.istioctl  microk8s.start
[root@node2 ~]# echo 'export PATH=$PATH:/var/lib/snapd/snap/bin'>>/etc/profile ; source /etc/profile

# 创建别名： snap alias microk8s.kubectl kubectl