deployment介绍和使用

什么是deployment

deployment是对pods和ReplicaSet的定义，定义了pods和ReplicaSet的定义和实现方式等。
如下为deployment的定义

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.12.2
        ports:
        - containerPort: 80

metadata 指明了服务名为nginx-deployment, 标签为nginx, 

spec指定了pod的副本为3个，每个pod容器镜像为ngix:1.12.2, 容器端暴漏的端口为80
接下来我们启动deployment

kubectl create -f deployment_nginx.yml

会显示：”nginx-deployment deployment has been created” 

我们执行

kubectl get deployment

查看deployment状态 

NAME               DESIRED   CURRENT   UP-TO-DATE   AVAILABLE  AGE  
nginx-deployment      3          3        3            3        9s

可以看到deployment启动了三个pod，并且三个pod都是可用的。 

kubectl get rs

可以看到ReplicaSet的状态为启动了3个pod，都是就绪状态 

接下来可以查看下pod

kubectl get pods

显示deployment详细信息 

kubectl get deployment -o wide

我们也可以更新deployment的image 

kubectl set image deployment nginx-deployment nginx=nginx:1.1.13

我们可以回滚deployment版本 

kubectl rollout undo deployment nginx-deployment

查看deployment的历史信息 

kubectl rollout history deployment nginx-deployment

将deployment服务暴露出去 

kubectl expose deployment nginx-deployment --type=NodePort

终端会提示服务已经暴露出去 

service nginx-deployment  exposed

我们接下来查看下service信息 

kubectl get svc

会显示服务映射的端口和地址 

安装kubeadm

基于ubuntu配置k8s环境

hostnamectl set-hostname k8s-master

设置好后可以查看下我们的配置 

tail /etc/hosts

查看防火墙状态 

sudo apt-get install ufw

关闭临时分区 

swapoff -a

更新https 

apt-get update && apt-get install -y apt-transport-https

获取gpg 

curl -fsSL https://mirrors.aliyun.com/kubernetes/apt/doc/apt-key.gpg | apt-key add -

新增源 

add-apt-repository "deb [arch=amd64] https://mirrors.aliyun.com/kubernetes/apt/ kubernetes-xenial main"

更新apt

apt-get update

查看1.15最新版本

apt-cache madison kubelet kubectl kubeadm |grep '1.15.4-00'         //查看1.15的最新版本

安装指定版本的工具 

apt install -y kubelet=1.15.4-00 kubectl=1.15.4-00 kubeadm=1.15.4-00        //安装指定的版本

kubelet禁用swap 

tee /etc/default/kubelet <<-'EOF'
KUBELET_EXTRA_ARGS="--fail-swap-on=false"
EOF

systemctl daemon-reload && systemctl restart kubelet

 初始化k8s

kubeadm init \
  --kubernetes-version=v1.15.4 \
  --image-repository registry.aliyuncs.com/google_containers \
  --pod-network-cidr=10.24.0.0/16 \
  --ignore-preflight-errors=Swap

在当前账户下执行，kubectl配置调用

mkdir -p $HOME/.kube
cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
chown $(id -u):$(id -g) $HOME/.kube/config

使用fannel的overlay网络实现多节点pod通信 

kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

查看pods信息 

kubectl get pods -A

配置dashboard 

kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/v2.0.0-beta4/aio/deploy/recommended.yaml

配置后查看pod信息

get pods -A

查看namespaces信息

kubectl get namespaces

可以查看所有的namespaces信息 

设置好网络模式后，接下来查看下apiserver暴露的地址

kubectl cluster-info

显示如下

Kubernetes master is running at https://172.17.0.9:6443
Heapster is running at https://172.17.0.9:6443/api/v1/namespaces/kube-system/services/heapster/proxy
KubeDNS is running at https://172.17.0.9:6443/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy
monitoring-grafana is running at https://172.17.0.9:6443/api/v1/namespaces/kube-system/services/monitoring-grafana/proxy
monitoring-influxdb is running at https://172.17.0.9:6443/api/v1/namespaces/kube-system/services/monitoring-influxdb/proxy

如果外网访问，换成外网地址就行了。 

我自己dashboard的访问地址:

https://81.68.86.146:6443/api/v1/namespaces/kubernetes-dashboard/services/https:kubernetes-dashboard:/proxy/

因为访问dashboard需要权限 

1.创建服务账号
首先创建一个叫admin-user的服务账号，并放在kube-system名称空间下：

# admin-user.yaml
apiVersion: v1
kind: ServiceAccount
metadata:
  name: admin-user
  namespace: kube-system

执行kubectl create命令： 

kubectl create -f admin-user.yaml

2.绑定角色 

默认情况下，kubeadm创建集群时已经创建了admin角色，我们直接绑定即可：

# admin-user-role-binding.yaml
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
  name: admin-user
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
- kind: ServiceAccount
  name: admin-user
  namespace: kube-system

执行kubectl create命令： 

kubectl create -f  admin-user-role-binding.yaml

3.获取Token 

现在我们需要找到新创建的用户的Token，以便用来登录dashboard：

kubectl -n kube-system describe secret $(kubectl -n kube-system get secret | grep admin-user | awk '{print $
1}')

4 制作证书 

k8s默认启动了证书验证，我们创建证书

# 生成client-certificate-data
grep 'client-certificate-data' ~/.kube/config | head -n 1 | awk '{print $2}' | base64 -d >> kubecfg.crt
# 生成client-key-data
grep 'client-key-data' ~/.kube/config | head -n 1 | awk '{print $2}' | base64 -d >> kubecfg.key
# 生成p12
openssl pkcs12 -export -clcerts -inkey kubecfg.key -in kubecfg.crt -out kubecfg.p12 -name "kubernetes-client"

然后我们将kubecfg.p12 copy到windows双击安装证书即可。 

然后chrome 打开地址：

https://81.68.86.146:6443/api/v1/namespaces/kubernetes-dashboard/services/https:kubernetes-dashboard:/proxy/

单节点k8s,默认pod不被调度在master节点,需要设置去污点

kubectl taint nodes --all node-role.kubernetes.io/master-     //去污点，master节点可以被调度

输出如下

node/k8s-master untainted

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