Kubernetes簡介
Kubernetes是一個用于管理容器化的工作負(fù)載和服務(wù)的便攜式宰翅、可擴展的開源平臺，有助于聲明式配置和自動化铸敏。Kubernetes有一個龐大且快速生長的生態(tài)系統(tǒng)杆融，服務(wù)、支持和工具已廣泛應(yīng)用柏副。
谷歌于2014年將Kubernetes項目開源。通常簡稱k8s蚣录。
環(huán)境搭建
安裝環(huán)境為 ubuntu 16.04割择。
docker
確保docker服務(wù)已安裝并正常運行，檢查方法為執(zhí)行docker run hello-world萎河，能看到運行結(jié)果荔泳。kubectl
kubectl是kubernetes的命令行工具，通過它進行k8s集群資源監(jiān)控虐杯；新建玛歌、刪除、修改組件厦幅；部署和管理應(yīng)用沾鳄。
- 安裝
# ubuntu可使用snap安裝
sudo snap install kubectl
# check是否安裝成功
kubectl version
- 配置
配置文件通常位置~/.kube/config，配置信息包括：context确憨、user、cluster瓤的、cert等休弃。
# 查看集群信息
kubectl cluster-info
- Minikube
Minikube 是一個使我們很容易在本地運行 kubernetes 的工具，他是通過在本機 VM 里運行一個單節(jié)點 kubernetes 集群圈膏，這對于新手想了解和學(xué)習(xí) kubernetes 提供了很大的幫助塔猾。
- Linux安裝without VM
curl -Lo minikube https://storage.googleapis.com/minikube/releases/latest/minikube-linux-amd64 && chmod +x minikube
curl -Lo kubectl https://storage.googleapis.com/kubernetes-release/release/$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl && chmod +x kubectl
export MINIKUBE_WANTUPDATENOTIFICATION=false
export MINIKUBE_WANTREPORTERRORPROMPT=false
export MINIKUBE_HOME=$HOME
export CHANGE_MINIKUBE_NONE_USER=true
mkdir $HOME/.kube || true
touch $HOME/.kube/config
export KUBECONFIG=$HOME/.kube/config
sudo -E ./minikube start --vm-driver=none
# this for loop waits until kubectl can access the api server that Minikube has created
for i in {1..150}; do # timeout for 5 minutes
./kubectl get po &> /dev/null
if [ $? -ne 1 ]; then
break
fi
sleep 2
done
# kubectl commands are now able to interact with Minikube cluster
- 使用kubectl連接minikube并進行一些基本操作。Linux only稽坤。
$ minikube start
Starting local Kubernetes v1.7.5 cluster...
Starting VM...
SSH-ing files into VM...
Setting up certs...
Starting cluster components...
Connecting to cluster...
Setting up kubeconfig...
Kubectl is now configured to use the cluster.
$ kubectl run hello-minikube --image=k8s.gcr.io/echoserver:1.4 --port=8080
deployment "hello-minikube" created
$ kubectl expose deployment hello-minikube --type=NodePort
service "hello-minikube" exposed
# We have now launched an echoserver pod but we have to wait until the pod is up before curling/accessing it
# via the exposed service.
# To check whether the pod is up and running we can use the following:
$ kubectl get pod
NAME READY STATUS RESTARTS AGE
hello-minikube-3383150820-vctvh 1/1 ContainerCreating 0 3s
# We can see that the pod is still being created from the ContainerCreating status
$ kubectl get pod
NAME READY STATUS RESTARTS AGE
hello-minikube-3383150820-vctvh 1/1 Running 0 13s
# We can see that the pod is now Running and we will now be able to curl it:
$ curl $(minikube service hello-minikube --url)
CLIENT VALUES:
client_address=192.168.99.1
command=GET
real path=/
...
$ kubectl delete service hello-minikube
service "hello-minikube" deleted
$ kubectl delete deployment hello-minikube
deployment "hello-minikube" deleted
$ minikube stop
Stopping local Kubernetes cluster...
Machine stopped.
kubernetes dashboard
運行minikube dashboard丈甸，打開kubernetes dashboard糯俗，可以看到集群的負(fù)載、任務(wù)睦擂、Pods等莺琳。
好啦挫望，開啟k8s之旅吧～
kubernetes dashboard
后記（踩坑記）
kubernetes的坑真的一個接一個啊，最近一周都是失足少女狀態(tài)。
First of all稚补，Never try to set up an environment in windows.
Then，下面記錄了幾個印象深刻的坑勺三。
- 獲取kubernetes依賴鏡像
在minikube start時運行kubeadm init命令時隧膘，程序一直卡在那里，查詢journalctl日志后發(fā)現(xiàn)一直在拉取國外k8s.gcr.io的鏡像述呐，但國內(nèi)k8s.gcr.io鏡像被墻惩淳，所以就卡在那里了。
解決方法是自己在docker hub上用docker autobuild做了鏡像乓搬。當(dāng)然也可以去搜索別人已經(jīng)做好的鏡像黎泣，找到對應(yīng)版本就好了。
從別人那里fork過來的鏡像庫缤谎，自己改了一些docker源抒倚。https://github.com/treephie/docker-library
# 使用方法就是，先docker pull到本地坷澡，再docker tag成谷歌的地址和版本托呕。
docker pull treeph/kube-addon-manager
docker pull treeph/k8s-dns-dnsmasq-nanny-amd64
docker pull treeph/kubernetes-dashboard-amd64
docker pull treeph/kube-proxy-amd64
docker pull treeph/k8s-dns-sidecar-amd64
docker pull treeph/k8s-dns-kube-dns-amd64
docker pull treeph/pause-amd64
docker pull treeph/etcd-amd64
docker pull treeph/kube-scheduler-amd64
docker pull treeph/kube-controller-manager-amd64
docker pull treeph/kube-apiserver-amd64
docker tag treeph/kube-addon-manager:latest k8s.gcr.io/kube-addon-manager:v8.6
docker tag treeph/k8s-dns-dnsmasq-nanny-amd64:latest k8s.gcr.io/k8s-dns-dnsmasq-nanny-amd64:1.14.4
docker tag treeph/kubernetes-dashboard-amd64:latest k8s.gcr.io/kubernetes-dashboard-amd64:v1.8.1
docker tag treeph/kube-proxy-amd64:latest k8s.gcr.io/kube-proxy-amd64:v1.10.0
docker tag treeph/k8s-dns-sidecar-amd64:latest k8s.gcr.io/k8s-dns-sidecar-amd64:1.14.4
docker tag treeph/k8s-dns-kube-dns-amd64:latest k8s.gcr.io/k8s-dns-kube-dns-amd64:1.14.4
docker tag treeph/pause-amd64:latest k8s.gcr.io/pause-amd64:3.1
docker tag treeph/etcd-amd64:latest k8s.gcr.io/etcd-amd64:3.1.12
docker tag treeph/kube-scheduler-amd64:latest k8s.gcr.io/kube-scheduler-amd64:v1.10.0
docker tag treeph/kube-controller-manager-amd64:latest k8s.gcr.io/kube-controller-manager-amd64:v1.10.0
docker tag treeph/kube-apiserver-amd64:latest k8s.gcr.io/kube-apiserver-amd64:v1.10.0
# 完成后查看本地鏡像
treeph@treeph-VirtualBox:~$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
k8s.gcr.io/kube-addon-manager v8.6 e7ffc6793f17 7 hours ago 78.4 MB
k8s.gcr.io/k8s-dns-dnsmasq-nanny-amd64 1.14.4 a873e1b191b4 7 hours ago 41.4 MB
k8s.gcr.io/kubernetes-dashboard-amd64 v1.8.1 bb065852c246 23 hours ago 121 MB
k8s.gcr.io/kube-proxy-amd64 v1.10.0 064653de4df1 23 hours ago 97 MB
k8s.gcr.io/k8s-dns-sidecar-amd64 1.14.4 39798ae6e4ee 24 hours ago 41.8 MB
k8s.gcr.io/k8s-dns-kube-dns-amd64 1.14.4 10625de58167 24 hours ago 41.4 MB
k8s.gcr.io/pause-amd64 3.0 62eaddb725bb 24 hours ago 747 kB
k8s.gcr.io/pause-amd64 3.1 62eaddb725bb 24 hours ago 747 kB
k8s.gcr.io/etcd-amd64 3.1.12 1572aa534c99 4 days ago 193 MB
k8s.gcr.io/kube-scheduler-amd64 v1.10.0 bbd569e45bcb 4 days ago 50.4 MB
k8s.gcr.io/kube-controller-manager-amd64 v1.10.0 4afb144bd444 4 days ago 148 MB
k8s.gcr.io/kube-apiserver-amd64 v1.10.0 b59ed8fe408e 4 days ago 225 MB
更詳細的步驟參考這篇博文：https://www.cnblogs.com/ericnie/p/7749588.html
- Port 10250 is already in use
可能的導(dǎo)致原因是kubeadm init之前運行過，已經(jīng)做了一些配置频敛。
再次運行之前需要將之前的配置操作重置项郊，執(zhí)行kubeadm reset即可。
重置之后再重新minikube start或者kubeadm init斟赚，應(yīng)該就好了着降。
參考StackOverflow: https://stackoverflow.com/questions/41732265/how-to-use-kubeadm-to-create-kubernetest-cluster
- 執(zhí)行minikube命令報錯Permission denied
嘗試加sudo，如果成功執(zhí)行的話是權(quán)限問題拗军，minikube安裝成功后修改文件所屬和組權(quán)限任洞，從root改到普通用戶。
sudo chown -R $USER $HOME/.minikube
sudo chgrp -R $USER $HOME/.minikube
- dial tcp x.x.x.x:x. connection refused
檢查是否docker環(huán)境未好发侵，檢查方法是docker run hello-world交掏。
