Kubernetes（k8s）是自动化容器操作的开源平台，基于这个平台，你可以进行容器部署，资源调度和集群扩容等操作。如果你曾经用过Docker部署容器，那么可以将Docker看成Kubernetes底层使用的组件，Kubernetes是Docker的上层封装，通过它可以很方便的进行Docker集群的管理。今天我们使用minikube在单机上进行Kubernetes集群的部署，目的是让我们对k8s有个初步的认识。
安装docker
首先安装docker环境，不详细说明了，网上资料一大堆，可以参考官方安装文档
Mac: https://docs.docker.com/docker-for-mac/install/
Ubuntu: https://docs.docker.com/engine/installation/linux/docker-ce/ubuntu/
CentOS: https://docs.docker.com/engine/installation/linux/docker-ce/centos/
当然，如果上面所有方法你都失败了，也可以尝试直接下载binary可执行文件，然后启动docker即可 https://docs.docker.com/engine/installation/linux/docker-ce/binaries/
安装Minikube
Mac
# 如未安装cask，自行搜索 brew安装cask
brew cask install minikube
minikube -h
Linux
# 下载v0.24.1版本
curl -Lo minikube https://storage.googleapis.com/minikube/releases/v0.24.1/minikube-linux-amd64 && chmod +x minikube && sudo mv minikube /usr/local/bin/
# 也可以下载最新版，但可能和本文执行环境不一致，会有坑
curl -Lo minikube https://storage.googleapis.com/minikube/releases/latest/minikube-linux-amd64 && chmod +x minikube && sudo mv minikube /usr/local/bin/
minikube -h
安装Kubectl
kubectl即kubernetes的客户端，通过他可以进行类似docker run等容器管理操作
curl -Lo kubectl https://storage.googleapis.com/kubernetes-release/release/$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl && chmod +x kubectl && sudo mv kubectl /usr/local/bin/
kubectl -h
启动程序
启动minikube
sudo minikube start
首次启动会下载localkube，下载过程可能会失败，会有如下提示，重试几次即可
Starting local Kubernetes v1.8.0 cluster...
Starting VM...
Downloading Minikube ISO
64.70 MB / 140.01 MB [====================>-----------------------] 46.21% 14s
E0105 14:06:03.884826 10434 start.go:150] Error starting host: Error attempting to cache minikube ISO from URL: Error downloading Minikube ISO: failed to download: failed to download to temp file: failed to copy contents: read tcp 10.0.2.15:47048->172.217.24.16:443: read: connection reset by peer.
================================================================================
An error has occurred. Would you like to opt in to sending anonymized crash
information to minikube to help prevent future errors?
To opt out of these messages, run the command:
minikube config set WantReportErrorPrompt false
================================================================================
Please enter your response [Y/n]:
如果下载成功，但是报了诸如VBoxManage not found这样的错误，如下
Starting local Kubernetes v1.8.0 cluster...
Starting VM...
Downloading Minikube ISO
140.01 MB / 140.01 MB [============================================] 100.00% 0s
E0105 14:10:00.035369 10474 start.go:150] Error starting host: Error creating host: Error executing step: Running precreate checks.
: VBoxManage not found. Make sure VirtualBox is installed and VBoxManage is in the path.
Retrying.
E0105 14:10:00.035780 10474 start.go:156] Error starting host: Error creating host: Error executing step: Running precreate checks.
: VBoxManage not found. Make sure VirtualBox is installed and VBoxManage is in the path
================================================================================
An error has occurred. Would you like to opt in to sending anonymized crash
information to minikube to help prevent future errors?
To opt out of these messages, run the command:
minikube config set WantReportErrorPrompt false
================================================================================
Please enter your response [Y/n]:
解决办法是安装 VirtualBox【对于windows或者mac】 再重新启动；当然如果你是Linux，也可以执行如下命令启动minikube，此时就不需要安装VirtualBox了。
因为minikube默认需要虚拟机来初始化kunernetes环境，但Linux是个例外，可以追加–vm-driver=none参数来使用自己的环境，说明见https://github.com/kubernetes/minikube#quickstart
# linux 下独有，不依赖虚拟机启动
sudo minikube start --vm-driver=none
# 如果是Mac or Windows，安装VirtualBox后再重新start即可
sudo minikube start
如果安装了虚拟机，或者使用了–vm-driver=none参数，并且下载完毕，会有如下提示运行成功
Starting local Kubernetes v1.8.0 cluster...
Starting VM...
Getting VM IP address...
Moving files into cluster...
Downloading localkube binary
148.25 MB / 148.25 MB [============================================] 100.00% 0s
0 B / 65 B [----------------------------------------------------------] 0.00%
65 B / 65 B [======================================================] 100.00% 0sSetting up certs...
Connecting to cluster...
Setting up kubeconfig...
Starting cluster components...
Kubectl is now configured to use the cluster.
===================
WARNING: IT IS RECOMMENDED NOT TO RUN THE NONE DRIVER ON PERSONAL WORKSTATIONS
The 'none' driver will run an insecure kubernetes apiserver as root that may leave the host vulnerable to CSRF attacks
When using the none driver, the kubectl config and credentials generated will be root owned and will appear in the root home directory.
You will need to move the files to the appropriate location and then set the correct permissions. An example of this is below:
sudo mv /root/.kube $HOME/.kube # this will write over any previous configuration
sudo chown -R $USER $HOME/.kube
sudo chgrp -R $USER $HOME/.kube
sudo mv /root/.minikube $HOME/.minikube # this will write over any previous configuration
sudo chown -R $USER $HOME/.minikube
sudo chgrp -R $USER $HOME/.minikube
This can also be done automatically by setting the env var CHANGE_MINIKUBE_NONE_USER=true
Loading cached images from config file.
启动一个容器服务
# kube-nginx999 是要定义的容器名称 nginx:latest表明要用nginx镜像 --port=80表明容器对外暴露80端口
sudo kubectl run kube-nginx999 --image=nginx:latest --port=80
> deployment "kube-nginx999" created
查看状态
sudo kubectl get pods
NAME READY STATUS RESTARTS AGE
nginx999-55f47cb99-46nm8 1/1 containerCreating 0 38s
稍等一分钟左右，如果你的服务一直是containerCreating状态，没有变化，那就是创建实例出现问题，如下方法查看log
sudo minikube logs
日志中出现 failed pulling image… 则是因为镜像拉取失败导致服务创建失败，原因？GFW嘛！服务在拉取自身需要的gcr.io/google_containers/pause-amd64:3.0镜像时失败了，如下报错。
Jan 05 03:52:58 minikube localkube[3624]: E0105 03:52:58.952990 3624 kuberuntime_manager.go:632] createPodSandbox for pod "nginx666-864b85987c-kvdpb_default(b0cc687d-f1cb-11e7-ba05-080027e170dd)" failed: rpc error: code = Unknown desc = failed pulling image "gcr.io/google_containers/pause-amd64:3.0": Error response from daemon: Get https://gcr.io/v2/: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)
解决方法：用本地镜像替代
原理就是使用阿里云的镜像下载到本地，然后命名为minikube使用的gcr.io的同名镜像，替代远端镜像即可
# 下载阿里云镜像
docker pull registry.cn-hangzhou.aliyuncs.com/google-containers/pause-amd64:3.0
# 本地命名为 gcr.io/google_containers/pause-amd64:3.0
docker tag registry.cn-hangzhou.aliyuncs.com/google-containers/pause-amd64:3.0 gcr.io/google_containers/pause-amd64:3.0
重新启动服务
增加 –image-pull-policy=IfNotPresent 参数，表明优先使用本地镜像，不从远端拉取
sudo kubectl run kube-nginx999 --image=nginx:latest --port=80 --image-pull-policy=IfNotPresent
如果提示已经存在，换个名字重新执行即可。这时候查看服务状态应该是如下Running状态代表创建成功，但此时还不能访问容器
sudo kubectl get pods
NAMESPACE NAME READY STATUS RESTARTS AGE
default kube-nginx999-77867567f5-48czx 1/1 Running 2 16h
发布服务
sudo kubectl expose deployment kube-nginx999 --type=NodePort
> service "kube-nginx999" exposed
查看服务地址
sudo minikube service kube-nginx999 --url
> http://127.0.0.1:30690
上面命令展示的地址即启动的nginx容器服务地址，访问 http://127.0.0.1:30690 即可出现nginx首页，服务成功启动！
PS: 访问http://localhost:30690是不可以的。
dashboard 管理后台
dashboard是kubernetes提供的容器服务管理后台，可视化界面，用来进行机器负载，集群管理，镜像扩容，配置数据等相关操作
启动dashboard
# 会打印出管理后台地址
sudo minikube dashboard --url
# 或者用下面写法，会自动打开默认浏览器，但我的一直失败，没有打开默认浏览器，没关系，执行后自己打开也行
sudo minikube dashboard
但初次会报下面的两种错误之一
# 1
Could not find finalized endpoint being pointed to by kubernetes-dashboard: Error validating service: Error getting service kubernetes-dashboard: services "kubernetes-dashboard" not found
# 2
Waiting, endpoint for service is not ready yet...
Waiting, endpoint for service is not ready yet...
如果查看log的话，会找到和pause一样的错误，即在镜像拉取的时候失败，解决方法如下，将所有kubernetes需要的镜像全部用阿里源下载到本地，然后命名为gcr.io…，来让minikube不从远端下载
如果不确定应该将tag重命名为什么的话，可以执行sudo grep ‘image:’ -R /etc/kubernetes看到默认情况下需要的镜像名以及版本号，对应去 https://dev.aliyun.com/search.html 搜索下载，然后命名为上面配置中定义的tag即可，当然，你可以在阿里云下载1.1然后重命名为1.2也没关系，差几个小版本不会有太大影响。
docker pull registry.cn-hangzhou.aliyuncs.com/google-containers/kubernetes-dashboard-amd64:v1.7.1
docker tag registry.cn-hangzhou.aliyuncs.com/google-containers/kubernetes-dashboard-amd64:v1.7.1 gcr.io/google_containers/kubernetes-dashboard-amd64:v1.8.0
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kube-addon-manager:v6.4-beta.2
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-addon-manager:v6.4-beta.2 gcr.io/google-containers/kube-addon-manager:v6.4-beta.2
docker pull registry.cn-shenzhen.aliyuncs.com/gcrio/k8s-dns-kube-dns-amd64:latest
docker tag registry.cn-shenzhen.aliyuncs.com/gcrio/k8s-dns-kube-dns-amd64:latest gcr.io/google_containers/k8s-dns-kube-dns-amd64:1.14.5
docker pull registry.cn-hangzhou.aliyuncs.com/google-containers/k8s-dns-dnsmasq-nanny-amd64:1.14.5
docker tag registry.cn-hangzhou.aliyuncs.com/google-containers/k8s-dns-dnsmasq-nanny-amd64:1.14.5 gcr.io/google_containers/k8s-dns-dnsmasq-nanny-amd64:1.14.5
docker pull registry.cn-hangzhou.aliyuncs.com/google-containers/k8s-dns-sidecar-amd64:1.14.5
docker tag registry.cn-hangzhou.aliyuncs.com/google-containers/k8s-dns-sidecar-amd64:1.14.5 gcr.io/google_containers/k8s-dns-sidecar-amd64:1.14.5
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/storage-provisioner:v1.8.1
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/storage-provisioner:v1.8.1 gcr.io/k8s-minikube/storage-provisioner:v1.8.1
然后重启minikube
sudo minikube stop
sudo minikube start [--vm-driver=none] # linux没装virtualbox的情况下需要加上后面的参数
再次执行
sudo minikube dashboard --url
> http://127.0.0.1:30000/
访问 http://127.0.0.1:30000/ 即可看到操作后台
写在最后
如果你下载工具时提示下载错误，基本上就是因为GFW，所以如果你有本地ss能够科学上网的话，可以在终端里执行下面命令，让 curl wget等命令也会走代理，加快下载
export http_proxy='socks5:127.0.0.1:1080'
有个坑，执行完以后访问 127.0.0.1 也是会走代理，这时候当然要换一个tab访问即可。
