Kubernetes入门，使用minikube 搭建本地k8s 环境

这是一篇 K8S 的 HelloWorld,在学习K8S官方文档时搭建环境搭建的一个记录，照着文档下来还是比较顺利的。

一、安装kubectl

下载 kubectl
curl -LO "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"

下载 checksum
curl -LO "https://dl.k8s.io/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl.sha256"

检查sha265sum
arvin@ubuntu:~$ echo "$(<kubectl.sha256) kubectl" | sha256sum --check
kubectl: OK

安装
sudo install -o root -g root -m 0755 kubectl /usr/local/bin/kubectl

安装结果
arvin@ubuntu:~$ kubectl version --client
Client Version: version.Info{Major:"1", Minor:"21", GitVersion:"v1.21.1", GitCommit:"5e58841cce77d4bc13713ad2b91fa0d961e69192", GitTreeState:"clean", BuildDate:"2021-05-12T14:18:45Z", GoVersion:"go1.16.4", Compiler:"gc", Platform:"linux/amd64"}

二、安装minikube

minikube是本地的Kubernetes，致力于使Kubernetes易于学习和开发。

 下载minikube
 curl -LO https://storage.googleapis.com/minikube/releases/latest/minikube-linux-amd64
 安装
 sudo install minikube-linux-amd64 /usr/local/bin/minikube

三、启动minikube

minikube start

四、碰到的问题

1.提示docker 驱动不能与管理员权限一起使用

arvin@ubuntu:~$ sudo minikube start

minikube v1.20.0 on Ubuntu 20.10

Automatically selected the docker driver. Other choices: none, ssh

The "docker" driver should not be used with root privileges.

If you are running minikube within a VM, consider using --driver=none:

https://minikube.sigs.k8s.io/docs/reference/drivers/none/

Exiting due to DRV_AS_ROOT: The "docker" driver should not be used with root privileges.

2.提示docker 没有权限

arvin@ubuntu:~$ minikube start

minikube v1.20.0 on Ubuntu 20.10

Unable to pick a default driver. Here is what was considered, in preference order:

podman: Not installed: exec: "podman": executable file not found in $PATH

virtualbox: Not installed: unable to find VBoxManage in $PATH

vmware: Not installed: exec: "docker-machine-driver-vmware": executable file not found in $PATH

docker: Not healthy: "docker version --format {{.Server.Os}}-{{.Server.Version}}" exit status 1: Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Get http://%2Fvar%2Frun%2Fdocker.sock/v1.24/version: dial unix /var/run/docker.sock: connect: permission denied

kvm2: Not installed: exec: "virsh": executable file not found in $PATH

Exiting due to DRV_NOT_DETECTED: No possible driver was detected. Try specifying --driver, or see https://minikube.sigs.k8s.io/docs/start/

查阅docker 手册

The docker daemon binds to a Unix socket instead of a TCP port. By

default that Unix socket is owned by the user root and other users can

only access it using sudo. The docker daemon always runs as the root

user.

If you don’t want to use sudo when you use the docker command, create

a Unix group called docker and add users to it. When the docker daemon

starts, it makes the ownership of the Unix socket read/writable by the

docker group.

解决办法

arvin@ubuntu:~$ sudo groupadd docker    #添加docker用户组
groupadd: group 'docker' already exists
arvin@ubuntu:~$ sudo gpasswd -a $USER docker #将登陆用户加入到docker用户组中
Adding user arvin to group docker
arvin@ubuntu:~$ newgrp docker  #更新用户组

五、运行minikube

成功启动

arvin@ubuntu:~$ minikube start
  minikube v1.20.0 on Ubuntu 20.10
  Automatically selected the docker driver. Other choices: none, ssh
  Starting control plane node minikube in cluster minikube
  Pulling base image ...
  Downloading Kubernetes v1.20.2 preload ...
    > preloaded-images-k8s-v10-v1...: 491.71 MiB / 491.71 MiB  100.00% 3.31 MiB
    > index.docker.io/kicbase/sta...: 358.10 MiB / 358.10 MiB  100.00% 1.39 MiB
  minikube was unable to download gcr.io/k8s-minikube/kicbase:v0.0.22, but successfully downloaded kicbase/stable:v0.0.22 as a fallback image
  Creating docker container (CPUs=2, Memory=2200MB) ...
  This container is having trouble accessing https://k8s.gcr.io
  To pull new external images, you may need to configure a proxy: https://minikube.sigs.k8s.io/docs/reference/networking/proxy/
  Preparing Kubernetes v1.20.2 on Docker 20.10.6 ...
     Generating certificates and keys ...
     Booting up control plane ...
     Configuring RBAC rules ...
  Verifying Kubernetes components...
     Using image gcr.io/k8s-minikube/storage-provisioner:v5
  Enabled addons: storage-provisioner, default-storageclass
  Done! kubectl is now configured to use "minikube" cluster and "default" namespace by default

查看kuberners 状态

minikube dashboard --url
  Verifying dashboard health ...
  Launching proxy ...
  Verifying proxy health ...
http://127.0.0.1:34235/api/v1/namespaces/kubernetes-dashboard/services/http:kubernetes-dashboard:/proxy/

六、部署Demo

创建一个develpment
kubectl create deployment hello-minikube --image=k8s.gcr.io/echoserver:1.4

kubectl expose deployment hello-minikube --type=NodePort --port=8080

arvin@ubuntu:~$ kubectl get services hello-minikube
NAME             TYPE       CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
hello-minikube   NodePort   10.96.129.107   <none>        8080:31559/TCP   46s

arvin@ubuntu:~$ minikube service hello-minikube
|-----------|----------------|-------------|---------------------------|
| NAMESPACE |      NAME      | TARGET PORT |            URL            |
|-----------|----------------|-------------|---------------------------|
| default   | hello-minikube |        8080 | http://192.168.49.2:30064 |
|-----------|----------------|-------------|---------------------------|
  Opening service default/hello-minikube in default browser...

发现网页无法访问
查看pod信息
arvin@ubuntu:~$ kubectl get pods  -o wide
NAME                              READY   STATUS             RESTARTS   AGE   IP           NODE       NOMINATED NODE   READINESS GATES
hello-minikube-6ddfcc9757-njfpc   0/1     ImagePullBackOff   0          13m   172.17.0.5   minikube   <none>           <none>

发现处于imagepullbackoff 状态
查看pod 详细描述
arvin@ubuntu:~$ kubectl describe pod
Name:         hello-minikube-6ddfcc9757-njfpc
Namespace:    default
Priority:     0
Node:         minikube/192.168.49.2
Start Time:   Wed, 19 May 2021 00:38:52 +0800
Labels:       app=hello-minikube
              pod-template-hash=6ddfcc9757
Annotations:  <none>
Status:       Pending
IP:           172.17.0.5
IPs:
  IP:           172.17.0.5
Controlled By:  ReplicaSet/hello-minikube-6ddfcc9757
Containers:
  echoserver:
    Container ID:
    Image:          k8s.gcr.io/echoserver:1.4
    Image ID:
    Port:           <none>
    Host Port:      <none>
    State:          Waiting
      Reason:       ImagePullBackOff
    Ready:          False
    Restart Count:  0
    Environment:    <none>
    Mounts:
      /var/run/secrets/kubernetes.io/serviceaccount from default-token-9rdjm (ro)
Conditions:
  Type              Status
  Initialized       True
  Ready             False
  ContainersReady   False
  PodScheduled      True
Volumes:
  default-token-9rdjm:
    Type:        Secret (a volume populated by a Secret)
    SecretName:  default-token-9rdjm
    Optional:    false
QoS Class:       BestEffort
Node-Selectors:  <none>
Tolerations:     node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
                 node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
  Type     Reason     Age                   From               Message
  ----     ------     ----                  ----               -------
  Normal   Scheduled  15m                   default-scheduler  Successfully assigned default/hello-minikube-6ddfcc9757-njfpc to minikube
  Normal   Pulling    12m (x4 over 15m)     kubelet            Pulling image "k8s.gcr.io/echoserver:1.4"
  Warning  Failed     12m (x4 over 14m)     kubelet            Failed to pull image "k8s.gcr.io/echoserver:1.4": rpc error: code = Unknown desc = Error response from daemon: Get https://k8s.gcr.io/v2/: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)
  Warning  Failed     12m (x4 over 14m)     kubelet            Error: ErrImagePull
  Warning  Failed     12m (x6 over 14m)     kubelet            Error: ImagePullBackOff
  Normal   BackOff    4m56s (x35 over 14m)  kubelet            Back-off pulling image "k8s.gcr.io/echoserver:1.4"

发现是缺少镜像
minikube ssh
docker images 

arvin@ubuntu:~$ minikube ssh
Last login: Tue May 18 16:55:58 2021 from 192.168.49.1
docker@minikube:~$ docker images
REPOSITORY                                TAG        IMAGE ID       CREATED         SIZE
gcr.io/k8s-minikube/storage-provisioner   v5         6e38f40d628d   7 weeks ago     31.5MB
k8s.gcr.io/kube-proxy                     v1.20.2    43154ddb57a8   4 months ago    118MB
k8s.gcr.io/kube-controller-manager        v1.20.2    a27166429d98   4 months ago    116MB
k8s.gcr.io/kube-apiserver                 v1.20.2    a8c2fdb8bf76   4 months ago    122MB
k8s.gcr.io/kube-scheduler                 v1.20.2    ed2c44fbdd78   4 months ago    46.4MB
kubernetesui/dashboard                    v2.1.0     9a07b5b4bfac   5 months ago    226MB
k8s.gcr.io/etcd                           3.4.13-0   0369cf4303ff   8 months ago    253MB
k8s.gcr.io/coredns                        1.7.0      bfe3a36ebd25   11 months ago   45.2MB
kubernetesui/metrics-scraper              v1.0.4     86262685d9ab   13 months ago   36.9MB
k8s.gcr.io/pause  

发现没有我们刚才部署的镜像,这里我们下载一个镜像进行重新部署测试
下载镜像

docker@minikube:~$ docker pull cilium/echoserver
Using default tag: latest
latest: Pulling from cilium/echoserver
a6014dd53961: Pull complete
fedc7896051b: Pull complete
5500b395a348: Pull complete
880bf53d0210: Pull complete
94791026eeca: Pull complete
d51579691189: Pull complete
7fd34bf14970: Pull complete
4b12f3ef8e65: Pull complete
b0e3c31807a2: Pull complete
e0962580d825: Pull complete
46b541e4c252: Pull complete
Digest: sha256:d6bd1dee4502cc50a974a97563330b4caaa2ac5b00a20ad2b82f4aa0e25e14fe
Status: Downloaded newer image for cilium/echoserver:latest
docker.io/cilium/echoserver:latest

部署新的echoserver
kubectl create deployment testechoserver --image=cilium/echoserver
deployment.apps/testechoserver created

arvin@ubuntu:~$ kubectl expose deployment testechoserver --type=NodePort --port=8080
service/testechoserver exposed

查看部署状态
arvin@ubuntu:~$ kubectl get deployment
NAME             READY   UP-TO-DATE   AVAILABLE   AGE
hello-minikube   0/1     1            0           26m
testechoserver   1/1     1            1           2m12s

查看创建的服务
arvin@ubuntu:~$ kubectl get services testechoserver
NAME             TYPE       CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
testechoserver   NodePort   10.106.69.154   <none>        8080:32617/TCP   2m3s

设置端口转发
arvin@ubuntu:~$ kubectl port-forward service/testechoserver 7080:8080
Forwarding from 127.0.0.1:7080 -> 8080
Forwarding from [::1]:7080 -> 8080

使用curl 查看信息
arvin@ubuntu:~$ curl http://127.0.0.1:7080

Hostname: testechoserver-5668cd9764-jslfz

Pod Information:
	-no pod information available-

Server values:
	server_version=nginx: 1.13.3 - lua: 10008

Request Information:
	client_address=::ffff:127.0.0.1
	method=GET
	real path=/
	query=
	request_version=1.1
	request_scheme=http
	request_uri=http://127.0.0.1:8080/

Request Headers:
	accept=*/*
	host=127.0.0.1:7080
	user-agent=curl/7.68.0

Request Body:
	-no body in request-

七、管理集群

minikube 的一些命令

暂停集群而不影响部署的应用程序
minikube pause 

停止集群，相对应的是minikube start启动集群
minikube stop 

设置内存大小为2048MB，设置后创建新的集群会使用改配置
minikube config set memory 2048 

查看扩展插件信息
minikube addons list 

删除集群
minikube delete 

具体可根据minikube --help 查看学习