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【谷粒商城】集群篇-k8s(4/4)

作者：互联网

【谷粒商城】集群篇-k8s(4/4)

目录

一、K8s快速入门

1）简介

2）架构

3）概念

4）快速体验

二、K8s集群安装

1）kubeadm

2）前置要求

3）部署步骤

4）环境准备

5）所有节点安装docker、kubeadm、kubelet、kubectl

6）部署k8s-master

7）安装POD网络插件（CNI）

8）加入kubenetes的Node节点

9）入门操作kubernetes集群

三、docker深入

四、K8s细节

1、kubectl文档

2、资源类型

3、格式化输出

命令参考

service的意义

Ingress

安装kubernetes可视化界面——DashBoard

kubesphere

1、简洁

2、安装前提提交

 

版权

一、K8s快速入门

1）简介

kubernetes简称k8s。是用于自动部署，扩展和管理容器化应用程序的开源系统。
中文官网：https://kubernetes.io/Zh/
中文社区：https://www.kubernetes.org.cn/
官方文档：https://kubernetes.io/zh/docs/home/
社区文档：https://docs.kubernetes.org.cn/

部署方式的进化：

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时光回溯

让我们回顾一下为什么 Kubernetes 如此有用。

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传统部署时代：

早期，各个组织机构在物理服务器上运行应用程序。无法为物理服务器中的应用程序定义资源边界，这会导致资源分配问题。 例如，如果在物理服务器上运行多个应用程序，则可能会出现一个应用程序占用大部分资源的情况， 结果可能导致其他应用程序的性能下降。 一种解决方案是在不同的物理服务器上运行每个应用程序，但是由于资源利用不足而无法扩展， 并且维护许多物理服务器的成本很高。

虚拟化部署时代：

作为解决方案，引入了虚拟化。虚拟化技术允许你在单个物理服务器的 CPU 上运行多个虚拟机（VM）。 虚拟化允许应用程序在 VM 之间隔离，并提供一定程度的安全，因为一个应用程序的信息 不能被另一应用程序随意访问。

虚拟化技术能够更好地利用物理服务器上的资源，并且因为可轻松地添加或更新应用程序 而可以实现更好的可伸缩性，降低硬件成本等等。

每个 VM 是一台完整的计算机，在虚拟化硬件之上运行所有组件，包括其自己的操作系统。

容器部署时代：

容器类似于 VM，但是它们具有被放宽的隔离属性，可以在应用程序之间共享操作系统（OS）。 因此，容器被认为是轻量级的。容器与 VM 类似，具有自己的文件系统、CPU、内存、进程空间等。 由于它们与基础架构分离，因此可以跨云和 OS 发行版本进行移植。

容器因具有许多优势而变得流行起来。下面列出的是容器的一些好处：

image-20200503105948619

image-20200503110101659

2）架构

（1）整体主从方式

image-20200503110244940

image-20200503110350256

（2）master节点架构

image-20200503110458806

image-20200503110631219

image-20200503110732773

（3）Node节点架构

image-20200503110804361

image-20200503111032457

3）概念

image-20200503112551188

image-20200503112627449

image-20200503112723747

image-20200503112810938

image-20200503113055314

image-20200503113619233

image-20200503113701902

4）快速体验

（1）安装minikube

https://github.com/kubernetes/minikube/releases
下载minikuber-windows-amd64.exe 改名为minikube.exe
打开virtualBox，打开cmd
运行
minikube start --vm-driver=virtualbox --registry-mirror=https://registry.docker-cn.com
等待20分钟即可。

（2）体验nginx部署升级

  1. 提交一个nginx deployment
    kubectl apply -f https://k8s.io/examples/application/deployment.yaml

  2. 升级 nginx deployment
    kubectl apply -f https://k8s.io/examples/application/deployment-update.yaml

  3. 扩容 nginx deployment

二、K8s集群安装

1）kubeadm

kubeadm是官方社区推出的一个用于快速部署kuberneters集群的工具。
这个工具能通过两条指令完成一个kuberneters集群的部署

创建一个master节点

$ kuberneters init

将一个node节点加入到当前集群中

$ kubeadm join <Master节点的IP和端口>

2）前置要求

一台或多台机器，操作系统Centos7.x-86_x64
硬件配置：2GB或更多RAM，2个CPU或更多CPU，硬盘30GB或更多
集群中所有的机器之间网络互通
可以访问外网，需要拉取镜像
禁止Swap分区

3）部署步骤

  1. 在所有的节点上安装Docker和kubeadm
  2. 不是Kubernetes Master
  3. 部署容器网络插件
  4. 部署Kubernetes Node，将节点加入Kubernetes集群中
  5. 部署DashBoard web页面，可视化查看Kubernetes资源

image-20200503144120720

4）环境准备

（1）准备工作

image-20200503175351320

image-20200503180202640

网卡1是NAT，用于虚拟机与本机访问互联网。网卡2是仅主机网络，虚拟机内部共享的虚拟网络

（2）启动三个虚拟机

下面是vagrantfile，使用它来创建三个虚拟机，分别为k8s-node1，k8s-node2和k8s-node3.

Vagrant.configure("2") do |config|
   (1..3).each do |i|
        config.vm.define "k8s-node#{i}" do |node|
            # 设置虚拟机的Box
            node.vm.box = "centos/7"

            # 设置虚拟机的主机名
            node.vm.hostname="k8s-node#{i}"

            # 设置虚拟机的IP
            node.vm.network "private_network", ip: "192.168.56.#{99+i}", netmask: "255.255.255.0"

            # 设置主机与虚拟机的共享目录
            # node.vm.synced_folder "~/Documents/vagrant/share", "/home/vagrant/share"

            # VirtaulBox相关配置
            node.vm.provider "virtualbox" do |v|
                # 设置虚拟机的名称
                v.name = "k8s-node#{i}"
                # 设置虚拟机的内存大小
                v.memory = 4096
                # 设置虚拟机的CPU个数
                v.cpus = 4
            end
        end
   end
end

vagrant ssh xxx进入到系统后
# vagrant ssh k8s-node1
su root 密码为vagrant

vi /etc/ssh/sshd_config

修改
PermitRootLogin yes 
PasswordAuthentication yes

所有的虚拟机设为4核4G

service sshd restart

192.168.56.100:22

关于在"网络地址转换"的连接方式下，三个节点的eth0，IP地址相同的问题。

**问题描述：**查看k8s-node1的路由表：

# 查看默认的网卡
[root@k8s-node1 ~]# ip route show
default via 10.0.2.2 dev eth0 proto dhcp metric 100 

10.0.2.0/24 dev eth0 proto kernel scope link src 10.0.2.15 metric 100 

192.168.56.0/24 dev eth1 proto kernel scope link src 192.168.56.100 metric 101

能够看到路由表中记录的是，通过端口eth0进行数据包的收发。

分别查看k8s-node1，k8s-node2和k8s-node3的eth0所绑定的IP地址，发现它们都是相同的，全都是10.0.2.15，这些地址是供kubernetes集群通信用的，区别于eth1上的IP地址，是通远程管理使用的。

[root@k8s-node1 ~]# ip addr
...
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 52:54:00:8a:fe:e6 brd ff:ff:ff:ff:ff:ff
    inet 10.0.2.15/24 brd 10.0.2.255 scope global noprefixroute dynamic eth0
       valid_lft 84418sec preferred_lft 84418sec
    inet6 fe80::5054:ff:fe8a:fee6/64 scope link 
       valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 08:00:27:a3:ca:c0 brd ff:ff:ff:ff:ff:ff
    inet 192.168.56.100/24 brd 192.168.56.255 scope global noprefixroute eth1
       valid_lft forever preferred_lft forever
    inet6 fe80::a00:27ff:fea3:cac0/64 scope link 
       valid_lft forever preferred_lft forever
[root@k8s-node1 ~]#

**原因分析：**这是因为它们使用是端口转发规则，使用同一个地址，通过不同的端口来区分。但是这种端口转发规则在以后的使用中会产生很多不必要的问题，所以需要修改为NAT网络类型。

image-20200503184536343

解决方法：

image-20200503184919936

image-20200503185344246

刷新一下MAC地址

1网络是集群交互，2网络是宿主交互

image-20200503190101156

（3）设置Linux环境（三个节点都执行）

systemctl stop firewalld
systemctl disable firewalld

# linux默认的安全策略
sed -i 's/enforcing/disabled/' /etc/selinux/config
setenforce 0

swapoff -a #临时关闭
sed -ri 's/.*swap.*/#&/' /etc/fstab #永久关闭
free -g #验证，swap必须为0

查看主机名：

hostname

如果主机名不正确，可以通过“hostnamectl set-hostname <newhostname> :指定新的hostname”命令来进行修改。

vi /etc/hosts
10.0.2.4 k8s-node1
10.0.2.5 k8s-node2
10.0.2.6 k8s-node3

将桥接的IPV4流量传递到iptables的链：

cat > /etc/sysctl.d/k8s.conf <<EOF

net.bridge.bridge-nf-call-ip6tables = 1

net.bridge.bridge-nf-call-iptables = 1

EOF

应用规则：

sysctl --system

疑难问题：遇见提示是只读的文件系统，运行如下命令

mount -o remount rw /

yum -y install ntpupdate

ntpupdate time.window.com #同步最新时间

5）所有节点安装docker、kubeadm、kubelet、kubectl

Kubenetes默认CRI（容器运行时）为Docker，因此先安装Docker。

（1）安装Docker

1、卸载之前的docker

sudo yum remove docker \
                  docker-client \
                  docker-client-latest \
                  docker-common \
                  docker-latest \
                  docker-latest-logrotate \
                  docker-logrotate \
                  docker-engine

2、安装Docker -CE

sudo yum install -y yum-utils \
device-mapper-persistent-data \
lvm2
# 设置docker repo的yum位置
sudo yum-config-manager \
    --add-repo \
    https://download.docker.com/linux/centos/docker-ce.repo
    
    # 安装docker，docker-cli
sudo yum -y install docker-ce docker-ce-cli containerd.io

3、配置docker加速

sudo mkdir -p /etc/docker
sudo tee /etc/docker/daemon.json <<-'EOF'
{
  "registry-mirrors": ["https://ke9h1pt4.mirror.aliyuncs.com"]
}
EOF
sudo systemctl daemon-reload
sudo systemctl restart docker

4、启动Docker && 设置docker开机启动

systemctl enable docker

基础环境准备好，可以给三个虚拟机备份一下；

image-20200503192940651

（2）添加阿里与Yum源

cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF

更多详情见： https://developer.aliyun.com/mirror/kubernetes

（3）安装kubeadm，kubelet和kubectl

yum list|grep kube

安装

yum install -y kubelet-1.17.3 kubeadm-1.17.3 kubectl-1.17.3

开机启动

systemctl enable kubelet && systemctl start kubelet

查看kubelet的状态：

systemctl status kubelet

查看kubelet版本：

[root@k8s-node2 ~]# kubelet --version
Kubernetes v1.17.3

6）部署k8s-master

（1）master节点初始化

在Master节点上，创建并执行master_images.sh

#!/bin/bash

images=(
	kube-apiserver:v1.17.3
    kube-proxy:v1.17.3
	kube-controller-manager:v1.17.3
	kube-scheduler:v1.17.3
	coredns:1.6.5
	etcd:3.4.3-0
    pause:3.1
)

for imageName in ${images[@]} ; do
    docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName
#   docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName  k8s.gcr.io/$imageName
done

查看100的内部通信端口

2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 08:00:27:7e:dd:f5 brd ff:ff:ff:ff:ff:ff
    inet 10.0.2.4/24 brd 10.0.2.255 scope global noprefixroute dynamic eth0
       valid_lft 512sec preferred_lft 512sec
    inet6 fe80::a00:27ff:fe7e:ddf5/64 scope link
       valid_lft forever preferred_lft forever

初始化kubeadm

kubeadm init \
--apiserver-advertise-address=10.0.2.4 \
--image-repository registry.cn-hangzhou.aliyuncs.com/google_containers \
--kubernetes-version   v1.17.3 \
--service-cidr=10.96.0.0/16  \
--pod-network-cidr=10.244.0.0/16

注：

执行结果：

[root@k8s-node1 opt]# kubeadm init \
> --apiserver-advertise-address=10.0.2.15 \
> --image-repository registry.cn-hangzhou.aliyuncs.com/google_containers \
> --kubernetes-version   v1.17.3 \
> --service-cidr=10.96.0.0/16  \
> --pod-network-cidr=10.244.0.0/16
W0503 14:07:12.594252   10124 configset.go:202] WARNING: kubeadm cannot validate component configs for API groups [kubelet.config.k8s.io kubeproxy.config.k8s.io]
[init] Using Kubernetes version: v1.17.3
[preflight] Running pre-flight checks
        [WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
[preflight] Pulling images required for setting up a Kubernetes cluster
[preflight] This might take a minute or two, depending on the speed of your internet connection
[preflight] You can also perform this action in beforehand using 'kubeadm config images pull'
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Starting the kubelet
[certs] Using certificateDir folder "/etc/kubernetes/pki"
[certs] Generating "ca" certificate and key
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [k8s-node1 kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 10.0.2.15]
[certs] Generating "apiserver-kubelet-client" certificate and key
[certs] Generating "front-proxy-ca" certificate and key
[certs] Generating "front-proxy-client" certificate and key
[certs] Generating "etcd/ca" certificate and key
[certs] Generating "etcd/server" certificate and key
[certs] etcd/server serving cert is signed for DNS names [k8s-node1 localhost] and IPs [10.0.2.15 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [k8s-node1 localhost] and IPs [10.0.2.15 127.0.0.1 ::1]
[certs] Generating "etcd/healthcheck-client" certificate and key
[certs] Generating "apiserver-etcd-client" certificate and key
[certs] Generating "sa" key and public key
[kubeconfig] Using kubeconfig folder "/etc/kubernetes"
[kubeconfig] Writing "admin.conf" kubeconfig file
[kubeconfig] Writing "kubelet.conf" kubeconfig file
[kubeconfig] Writing "controller-manager.conf" kubeconfig file
[kubeconfig] Writing "scheduler.conf" kubeconfig file
[control-plane] Using manifest folder "/etc/kubernetes/manifests"
[control-plane] Creating static Pod manifest for "kube-apiserver"
[control-plane] Creating static Pod manifest for "kube-controller-manager"
W0503 14:07:30.908642   10124 manifests.go:225] the default kube-apiserver authorization-mode is "Node,RBAC"; using "Node,RBAC"
[control-plane] Creating static Pod manifest for "kube-scheduler"
W0503 14:07:30.911330   10124 manifests.go:225] the default kube-apiserver authorization-mode is "Node,RBAC"; using "Node,RBAC"
[etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests"
[wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests". This can take up to 4m0s
[apiclient] All control plane components are healthy after 22.506521 seconds
[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.18" in namespace kube-system with the configuration for the kubelets in the cluster
[upload-certs] Skipping phase. Please see --upload-certs
[mark-control-plane] Marking the node k8s-node1 as control-plane by adding the label "node-role.kubernetes.io/master=''"
[mark-control-plane] Marking the node k8s-node1 as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[bootstrap-token] Using token: sg47f3.4asffoi6ijb8ljhq
[bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles
[bootstrap-token] configured RBAC rules to allow Node Bootstrap tokens to get nodes
[bootstrap-token] configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
[bootstrap-token] configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
[bootstrap-token] configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
[bootstrap-token] Creating the "cluster-info" ConfigMap in the "kube-public" namespace
[kubelet-finalize] Updating "/etc/kubernetes/kubelet.conf" to point to a rotatable kubelet client certificate and key
[addons] Applied essential addon: CoreDNS
[addons] Applied essential addon: kube-proxy
#表示kubernetes已经初始化成功了
Your Kubernetes control-plane has initialized successfully!

To start using your cluster, you need to run the following as a regular user:

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

You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
  https://kubernetes.io/docs/concepts/cluster-administration/addons/

Then you can join any number of worker nodes by running the following on each as root:

kubeadm join 10.0.2.15:6443 --token sg47f3.4asffoi6ijb8ljhq \
    --discovery-token-ca-cert-hash sha256:81fccdd29970cbc1b7dc7f171ac0234d53825bdf9b05428fc9e6767436991bfb 
[root@k8s-node1 opt]#

由于默认拉取镜像地址k8s.cr.io国内无法访问，这里指定阿里云仓库地址。可以手动按照我们的images.sh先拉取镜像。

地址变为：registry.aliyuncs.com/googole_containers也可以。
科普：无类别域间路由（Classless Inter-Domain Routing 、CIDR）是一个用于给用户分配IP地址以及在互联网上有效第路由IP数据包的对IP地址进行归类的方法。
拉取可能失败，需要下载镜像。

运行完成提前复制：加入集群的令牌。

（2）测试Kubectl（主节点执行）

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

详细部署文档：https://kubernetes.io/docs/concepts/cluster-administration/addons/

 kubectl get nodes #获取所有节点

目前Master状态为notready。等待网络加入完成即可。

journalctl -u kubelet #查看kubelet日志

kubeadm join 10.0.2.4:6443 --token bt3hkp.yxnpzsgji4a6edy7 \
    --discovery-token-ca-cert-hash sha256:64949994a89c53e627d68b115125ff753bfe6ff72a26eb561bdc30f32837415a

7）安装POD网络插件（CNI）

在master节点上执行按照POD网络插件

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

以上地址可能被墙，可以直接获取本地已经下载的flannel.yml运行即可(https://blog.csdn.net/lxm1720161656/article/details/106436252 可以去下载)，如：

[root@k8s-node1 k8s]# kubectl apply -f  kube-flannel.yml    
podsecuritypolicy.policy/psp.flannel.unprivileged created
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
daemonset.apps/kube-flannel-ds-amd64 created
daemonset.apps/kube-flannel-ds-arm64 created
daemonset.apps/kube-flannel-ds-arm created
daemonset.apps/kube-flannel-ds-ppc64le created
daemonset.apps/kube-flannel-ds-s390x created
[root@k8s-node1 k8s]#

同时flannel.yml中指定的images访问不到可以去docker hub找一个wget yml地址
vi 修改yml 所有amd64的地址修改了即可
等待大约3分钟
kubectl get pods -n kube-system 查看指定名称空间的pods
kubectl get pods -all-namespace 查看所有名称空间的pods

$ ip link set cni0 down 如果网络出现问题，关闭cni0，重启虚拟机继续测试
执行watch kubectl get pod -n kube-system -o wide 监控pod进度
等待3-10分钟，完全都是running以后继续

查看命名空间：

[root@k8s-node1 k8s]# kubectl get ns
NAME              STATUS   AGE
default           Active   30m
kube-node-lease   Active   30m
kube-public       Active   30m
kube-system       Active   30m
[root@k8s-node1 k8s]#

[root@k8s-node1 k8s]# kubectl get pods --all-namespaces       
NAMESPACE     NAME                                READY   STATUS    RESTARTS   AGE
kube-system   coredns-546565776c-9sbmk            0/1     Pending   0          31m
kube-system   coredns-546565776c-t68mr            0/1     Pending   0          31m
kube-system   etcd-k8s-node1                      1/1     Running   0          31m
kube-system   kube-apiserver-k8s-node1            1/1     Running   0          31m
kube-system   kube-controller-manager-k8s-node1   1/1     Running   0          31m
kube-system   kube-flannel-ds-amd64-6xwth         1/1     Running   0          2m50s
kube-system   kube-proxy-sz2vz                    1/1     Running   0          31m
kube-system   kube-scheduler-k8s-node1            1/1     Running   0          31m
[root@k8s-node1 k8s]#

查看master上的节点信息：

[root@k8s-node1 k8s]# kubectl get nodes
NAME        STATUS   ROLES    AGE   VERSION
k8s-node1   Ready    master   34m   v1.17.3   #status为ready才能够执行下面的命令
[root@k8s-node1 k8s]#

最后再次执行，并且分别在“k8s-node2”和“k8s-node3”上也执行这里命令：

kubeadm join 10.0.2.4:6443 --token bt3hkp.yxnpzsgji4a6edy7 \
    --discovery-token-ca-cert-hash sha256:64949994a89c53e627d68b115125ff753bfe6ff72a26eb561bdc30f32837415a

[root@k8s-node1 opt]# kubectl get nodes;
NAME        STATUS     ROLES    AGE   VERSION
k8s-node1   Ready      master   47m   v1.17.3
k8s-node2   NotReady   <none>   75s   v1.17.3
k8s-node3   NotReady   <none>   76s   v1.17.3
[root@k8s-node1 opt]#

监控pod进度

# 在master执行
watch kubectl get pod -n kube-system -o wide

等到所有的status都变为running状态后，再次查看节点信息：

[root@k8s-node1 ~]#  kubectl get nodes;                         
NAME        STATUS   ROLES    AGE     VERSION
k8s-node1   Ready    master   3h50m   v1.17.3
k8s-node2   Ready    <none>   3h3m    v1.17.3
k8s-node3   Ready    <none>   3h3m    v1.17.3
[root@k8s-node1 ~]#

8）加入kubenetes的Node节点

在node节点中执行，向集群中添加新的节点，执行在kubeadm init 输出的kubeadm join命令；
确保node节点成功：
token过期怎么办
kubeadm token create --print-join-command

9）入门操作kubernetes集群

1、在主节点上部署一个tomcat

kubectl create deployment tomcat6 --image=tomcat:6.0.53-jre8

获取所有的资源：

[root@k8s-node1 k8s]# kubectl get all
NAME                           READY   STATUS              RESTARTS   AGE
pod/tomcat6-7b84fb5fdc-cfd8g   0/1     ContainerCreating   0          41s

NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
service/kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP   70m

NAME                      READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/tomcat6   0/1     1            0           41s

NAME                                 DESIRED   CURRENT   READY   AGE
replicaset.apps/tomcat6-7b84fb5fdc   1         1         0       41s
[root@k8s-node1 k8s]#

kubectl get pods -o wide 可以获取到tomcat部署信息，能够看到它被部署到了k8s-node3上了

[root@k8s-node1 k8s]# kubectl get all -o wide
NAME                           READY   STATUS              RESTARTS   AGE   IP       NODE        NOMINATED NODE   READINESS GATES
pod/tomcat6-5f7ccf4cb9-xhrr9   0/1     ContainerCreating   0          77s   <none>   k8s-node3   <none>           <none>

NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE   SELECTOR
service/kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP   68m   <none>

NAME                      READY   UP-TO-DATE   AVAILABLE   AGE   CONTAINERS   IMAGES               SELECTOR
deployment.apps/tomcat6   0/1     1            0           77s   tomcat       tomcat:6.0.53-jre8   app=tomcat6

NAME                                 DESIRED   CURRENT   READY   AGE   CONTAINERS   IMAGES               SELECTOR
replicaset.apps/tomcat6-5f7ccf4cb9   1         1         0       77s   tomcat       tomcat:6.0.53-jre8   app=tomcat6,pod-template-hash=5f7ccf4cb9

查看node3节点上，下载了哪些镜像：

[root@k8s-node3 k8s]# docker images
REPOSITORY                                                       TAG             IMAGE ID       CREATED         SIZE
registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy   v1.17.3         ae853e93800d   14 months ago   116MB
quay.io/coreos/flannel                                           v0.11.0-amd64   ff281650a721   2 years ago     52.6MB
registry.cn-hangzhou.aliyuncs.com/google_containers/pause        3.1             da86e6ba6ca1   3 years ago     742kB
tomcat                                                           6.0.53-jre8     49ab0583115a   3 years ago     290MB

查看Node3节点上，正在运行的容器：

[root@k8s-node3 k8s]# docker ps
CONTAINER ID   IMAGE                                                            COMMAND                  CREATED              STATUS              PORTS     NAMES
8a197fa41dd9   tomcat                                                           "catalina.sh run"        About a minute ago   Up About a minute             k8s_tomcat_tomcat6-5f7ccf4cb9-xhrr9_default_81f186a8-4805-4bbb-8d77-3142269942ed_0
4074d0d63a88   registry.cn-hangzhou.aliyuncs.com/google_containers/pause:3.1    "/pause"                 2 minutes ago        Up 2 minutes                  k8s_POD_tomcat6-5f7ccf4cb9-xhrr9_default_81f186a8-4805-4bbb-8d77-3142269942ed_0
db3faf3a280d   ff281650a721                                                     "/opt/bin/flanneld -…"   29 minutes ago       Up 29 minutes                 k8s_kube-flannel_kube-flannel-ds-amd64-vcktd_kube-system_31ca3556-d6c3-48b2-b393-35ff7d89a078_0
be461b54cb4b   registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy   "/usr/local/bin/kube…"   30 minutes ago       Up 30 minutes                 k8s_kube-proxy_kube-proxy-ptq2t_kube-system_0e1f7df3-7204-481d-bf15-4b0e09cf0c81_0
88d1ab87f400   registry.cn-hangzhou.aliyuncs.com/google_containers/pause:3.1    "/pause"                 31 minutes ago       Up 31 minutes                 k8s_POD_kube-flannel-ds-amd64-vcktd_kube-system_31ca3556-d6c3-48b2-b393-35ff7d89a078_0
52be28610a02   registry.cn-hangzhou.aliyuncs.com/google_containers/pause:3.1    "/pause"                 31 minutes ago       Up 31 minutes                 k8s_POD_kube-proxy-ptq2t_kube-system_0e1f7df3-7204-481d-bf15-4b0e09cf0c81_0

在node1上执行：

[root@k8s-node1 k8s]# kubectl get pods
NAME                       READY   STATUS    RESTARTS   AGE
tomcat6-7b84fb5fdc-cfd8g   1/1     Running   0          5m35s

[root@k8s-node1 k8s]# kubectl get pods --all-namespaces
NAMESPACE     NAME                                READY   STATUS    RESTARTS   AGE
default       tomcat6-7b84fb5fdc-cfd8g            1/1     Running   0          163m
kube-system   coredns-546565776c-9sbmk            1/1     Running   0          3h52m
kube-system   coredns-546565776c-t68mr            1/1     Running   0          3h52m
kube-system   etcd-k8s-node1                      1/1     Running   0          3h52m
kube-system   kube-apiserver-k8s-node1            1/1     Running   0          3h52m
kube-system   kube-controller-manager-k8s-node1   1/1     Running   0          3h52m
kube-system   kube-flannel-ds-amd64-5xs5j         1/1     Running   0          3h6m
kube-system   kube-flannel-ds-amd64-6xwth         1/1     Running   0          3h24m
kube-system   kube-flannel-ds-amd64-fvnvx         1/1     Running   0          3h6m
kube-system   kube-proxy-7tkvl                    1/1     Running   0          3h6m
kube-system   kube-proxy-mvlnk                    1/1     Running   0          3h6m
kube-system   kube-proxy-sz2vz                    1/1     Running   0          3h52m
kube-system   kube-scheduler-k8s-node1            1/1     Running   0          3h52m
[root@k8s-node1 ~]#

从前面看到tomcat部署在Node3上，现在模拟因为各种原因宕机的情况，将node3关闭电源，观察情况。

docker stop执行的时候，docker ps发现又有新的容器了，这是k8s又新建了，所以选择关机node3

[root@k8s-node1 k8s]# kubectl get nodes
NAME        STATUS     ROLES    AGE   VERSION
k8s-node1   Ready      master   79m   v1.17.3
k8s-node2   Ready      <none>   41m   v1.17.3
k8s-node3   NotReady   <none>   41m   v1.17.3

得等个几分钟才能容灾恢复

[root@k8s-node1 k8s]# kubectl get pods -o wide
NAME                       READY   STATUS        RESTARTS   AGE     IP           NODE        NOMINATED NODE   READINESS GATES
tomcat6-5f7ccf4cb9-clcpr   1/1     Running       0          4m16s   10.244.1.2   k8s-node2   <none>           <none>
tomcat6-5f7ccf4cb9-xhrr9   1/1     Terminating   1          22m     10.244.2.2   k8s-node3   <none>           <none>

2、暴露nginx访问

在master上执行

kubectl expose deployment tomcat6 --port=80 --target-port=8080 --type=NodePort

pod的80映射容器的8080；server会带来pod的80

查看服务：

[root@k8s-node1 k8s]# kubectl get svc
NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)        AGE
kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP        93m
tomcat6      NodePort    10.96.7.78   <none>        80:30055/TCP   8s

[root@k8s-node1 k8s]# kubectl get svc -o wide
NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)        AGE     SELECTOR
kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP        103m    <none>
tomcat6      NodePort    10.96.7.78   <none>        80:30055/TCP   9m38s   app=tomcat6

浏览器输入：http://192.168.56.100:30055/ ，可以看到tomcat首页

输入下面命令可以看到pod和封装pod 的service，pod是部署产生的，部署还有一个副本

[root@k8s-node1 ~]# kubectl get all
NAME                           READY   STATUS    RESTARTS   AGE
pod/tomcat6-5f7ccf4cb9-clcpr   1/1     Running   0          4h12m

NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)        AGE
service/kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP        5h37m
service/tomcat6      NodePort    10.96.7.78   <none>        80:30055/TCP   4h3m

NAME                      READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/tomcat6   1/1     1            1           4h30m

NAME                                 DESIRED   CURRENT   READY   AGE
replicaset.apps/tomcat6-5f7ccf4cb9   1         1         1       4h30m

3、动态扩容测试

kubectl get deployment

[root@k8s-node1 ~]# kubectl get deployment
NAME      READY   UP-TO-DATE   AVAILABLE   AGE
tomcat6   2/2     2            2           11h
[root@k8s-node1 ~]#

应用升级： kubectl set image (–help查看帮助)
扩容：kubectl scale --replicas=3 deployment tomcat6

[root@k8s-node1 ~]# kubectl scale --replicas=3 deployment tomcat6
deployment.apps/tomcat6 scaled
[root@k8s-node1 ~]# kubectl get pods -o wide
NAME                       READY   STATUS    RESTARTS   AGE     IP           NODE        NOMINATED NODE   READINESS GATES
tomcat6-5f7ccf4cb9-clcpr   1/1     Running   0          4h23m   10.244.1.2   k8s-node2   <none>           <none>
tomcat6-5f7ccf4cb9-jbvr4   1/1     Running   0          9s      10.244.2.3   k8s-node3   <none>           <none>
tomcat6-5f7ccf4cb9-ng556   1/1     Running   0          9s      10.244.2.4   k8s-node3   <none>           <none>

[root@k8s-node1 ~]# kubectl get svc -o wide
NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)        AGE     SELECTOR
kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP        5h48m   <none>
tomcat6      NodePort    10.96.7.78   <none>        80:30055/TCP   4h15m   app=tomcat6

扩容了多份，所有无论访问哪个node的指定端口，都可以访问到tomcat6

http://192.168.56.101:30055/

http://192.168.56.102:30055/

缩容：kubectl scale --replicas=2 deployment tomcat6

[root@k8s-node1 ~]# kubectl scale --replicas=1 deployment tomcat6
deployment.apps/tomcat6 scaled

[root@k8s-node1 ~]# kubectl get pods -o wide
NAME                       READY   STATUS    RESTARTS   AGE     IP           NODE        NOMINATED NODE   READINESS GATES
tomcat6-5f7ccf4cb9-clcpr   1/1     Running   0          4h32m   10.244.1.2   k8s-node2   <none>           <none>

[root@k8s-node1 ~]# kubectl get all
NAME                           READY   STATUS    RESTARTS   AGE
pod/tomcat6-5f7ccf4cb9-clcpr   1/1     Running   0          4h33m

NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)        AGE
service/kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP        5h58m
service/tomcat6      NodePort    10.96.7.78   <none>        80:30055/TCP   4h24m

NAME                      READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/tomcat6   1/1     1            1           4h51m

NAME                                 DESIRED   CURRENT   READY   AGE
replicaset.apps/tomcat6-5f7ccf4cb9   1         1         1       4h51m

4、以上操作的yaml获取
参照k8s细节

5、删除
kubectl get all

[root@k8s-node1 ~]# kubectl get all
NAME                           READY   STATUS    RESTARTS   AGE
pod/tomcat6-5f7ccf4cb9-clcpr   1/1     Running   0          4h33m

NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)        AGE
service/kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP        5h58m
service/tomcat6      NodePort    10.96.7.78   <none>        80:30055/TCP   4h24m

NAME                      READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/tomcat6   1/1     1            1           4h51m

NAME                                 DESIRED   CURRENT   READY   AGE
replicaset.apps/tomcat6-5f7ccf4cb9   1         1         1       4h51m
#删除deployment.apps/tomcat6 
[root@k8s-node1 ~]# kubectl delete deployment.apps/tomcat6
deployment.apps "tomcat6" deleted
#查看剩余的资源
[root@k8s-node1 ~]# kubectl get all
NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)        AGE
service/kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP        6h
service/tomcat6      NodePort    10.96.7.78   <none>        80:30055/TCP   4h26m
# 此时没有了部署，但是有service，没有pod只有service也是没有对应的服务的

# 查看pod信息
[root@k8s-node1 ~]# kubectl get pods
No resources found in default namespace.

kubectl delete deploye/nginx
kubectl delete service/nginx-service

三、docker深入

四、K8s细节

1、kubectl文档

​ https://kubernetes.io/zh/docs/reference/kubectl/overview/

2、资源类型

https://kubernetes.io/zh/docs/reference/kubectl/overview/#资源类型

3、格式化输出

https://kubernetes.io/zh/docs/reference/kubectl/overview/

所有 kubectl 命令的默认输出格式都是人类可读的纯文本格式。要以特定格式向终端窗口输出详细信息，可以将 -o 或 --output 参数添加到受支持的 kubectl 命令中。

语法

kubectl [command] [TYPE] [NAME] -o=<output_format>
  • 1

根据 kubectl 操作，支持以下输出格式：

Output formatDescription
-o custom-columns=使用逗号分隔的自定义列列表打印表。
-o custom-columns-file=使用 `` 文件中的自定义列模板打印表。
-o json输出 JSON 格式的 API 对象
`-o jsonpath=打印 jsonpath 表达式定义的字段
-o jsonpath-file=打印 `` 文件中 jsonpath 表达式定义的字段。
-o name仅打印资源名称而不打印任何其他内容。
-o wide以纯文本格式输出，包含任何附加信息。对于 pod 包含节点名。
-o yaml输出 YAML 格式的 API 对象。

示例

在此示例中，以下命令将单个 pod 的详细信息输出为 YAML 格式的对象：

kubectl get pod web-pod-13je7 -o yaml
  • 1

请记住：有关每个命令支持哪种输出格式的详细信息，请参阅 kubectl 参考文档。

–dry-run：

–dry-run=‘none’: Must be “none”, “server”, or “client”. If client strategy, only print the object that would be

sent, without sending it. If server strategy, submit server-side request without persisting the resource.

值必须为none，server或client。如果是客户端策略，则只打印该发送对象，但不发送它。如果服务器策略，提交服务器端请求而不持久化资源。

也就是说，通过–dry-run选项，并不会真正的执行这条命令。

[root@k8s-node1 ~]# kubectl create deployment tomcat6 --image=tomcat:6.0.53-jre8 --dry-run -o yaml

W0504 03:39:08.389369    8107 helpers.go:535] --dry-run is deprecated and can be replaced with --dry-run=client.
apiVersion: apps/v1
kind: Deployment
metadata:
  creationTimestamp: null
  labels:
    app: tomcat6
  name: tomcat6
spec:
  replicas: 1
  selector:
    matchLabels:
      app: tomcat6
  strategy: {}
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: tomcat6
    spec:
      containers:
      - image: tomcat:6.0.53-jre8
        name: tomcat
        resources: {}
status: {}
[root@k8s-node1 ~]#

实际上我们也可以将这个yaml输出到文件，然后使用kubectl apply -f来应用它

#输出到tomcat6.yaml 
[root@k8s-node1 ~]# kubectl create deployment tomcat6 --image=tomcat:6.0.53-jre8 --dry-run -o yaml >tomcat6.yaml
W0504 03:46:18.180366   11151 helpers.go:535] --dry-run is deprecated and can be replaced with --dry-run=client.

#修改副本数为3
[root@k8s-node1 ~]# cat tomcat6.yaml 
apiVersion: apps/v1
kind: Deployment
metadata:
  creationTimestamp: null
  labels:
    app: tomcat6
  name: tomcat6
spec:
  replicas: 3     #修改副本数为3
  selector:
    matchLabels:
      app: tomcat6
  strategy: {}
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: tomcat6
    spec:
      containers:
      - image: tomcat:6.0.53-jre8
        name: tomcat
        resources: {}
status: {}

#应用tomcat6.yaml 
[root@k8s-node1 ~]# kubectl apply -f tomcat6.yaml 
deployment.apps/tomcat6 created
[root@k8s-node1 ~]#

查看pods：

[root@k8s-node1 ~]# kubectl get pods  
NAME                       READY   STATUS    RESTARTS   AGE
tomcat6-7b84fb5fdc-5jh6t   1/1     Running   0          8s
tomcat6-7b84fb5fdc-8lhwv   1/1     Running   0          8s
tomcat6-7b84fb5fdc-j4qmh   1/1     Running   0          8s
[root@k8s-node1 ~]#

查看某个pod的具体信息：

[root@k8s-node1 ~]# kubectl get pods tomcat6-7b84fb5fdc-5jh6t  -o yaml

apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: "2020-05-04T03:50:47Z"
  generateName: tomcat6-7b84fb5fdc-
  labels:
    app: tomcat6
    pod-template-hash: 7b84fb5fdc
  managedFields:
  - apiVersion: v1
    fieldsType: FieldsV1
    fieldsV1:
      f:metadata:
        f:generateName: {}
        f:labels:
          .: {}
          f:app: {}
          f:pod-template-hash: {}
        f:ownerReferences:
          .: {}
          k:{"uid":"292bfe3b-dd63-442e-95ce-c796ab5bdcc1"}:
            .: {}
            f:apiVersion: {}
            f:blockOwnerDeletion: {}
            f:controller: {}
            f:kind: {}
            f:name: {}
            f:uid: {}
      f:spec:
        f:containers:
          k:{"name":"tomcat"}:
            .: {}
            f:image: {}
            f:imagePullPolicy: {}
            f:name: {}
            f:resources: {}
            f:terminationMessagePath: {}
            f:terminationMessagePolicy: {}
        f:dnsPolicy: {}
        f:enableServiceLinks: {}
        f:restartPolicy: {}
        f:schedulerName: {}
        f:securityContext: {}
        f:terminationGracePeriodSeconds: {}
    manager: kube-controller-manager
    operation: Update
    time: "2020-05-04T03:50:47Z"
  - apiVersion: v1
    fieldsType: FieldsV1
    fieldsV1:
      f:status:
        f:conditions:
          k:{"type":"ContainersReady"}:
            .: {}
            f:lastProbeTime: {}
            f:lastTransitionTime: {}
            f:status: {}
            f:type: {}
          k:{"type":"Initialized"}:
            .: {}
            f:lastProbeTime: {}
            f:lastTransitionTime: {}
            f:status: {}
            f:type: {}
          k:{"type":"Ready"}:
            .: {}
            f:lastProbeTime: {}
            f:lastTransitionTime: {}
            f:status: {}
            f:type: {}
        f:containerStatuses: {}
        f:hostIP: {}
        f:phase: {}
        f:podIP: {}
        f:podIPs:
          .: {}
          k:{"ip":"10.244.2.7"}:
            .: {}
            f:ip: {}
        f:startTime: {}
    manager: kubelet
    operation: Update
    time: "2020-05-04T03:50:49Z"
  name: tomcat6-7b84fb5fdc-5jh6t
  namespace: default
  ownerReferences:
  - apiVersion: apps/v1
    blockOwnerDeletion: true
    controller: true
    kind: ReplicaSet
    name: tomcat6-7b84fb5fdc
    uid: 292bfe3b-dd63-442e-95ce-c796ab5bdcc1
  resourceVersion: "46229"
  selfLink: /api/v1/namespaces/default/pods/tomcat6-7b84fb5fdc-5jh6t
  uid: 2f661212-3b03-47e4-bcb8-79782d5c7578
spec:
  containers:
  - image: tomcat:6.0.53-jre8
    imagePullPolicy: IfNotPresent
    name: tomcat
    resources: {}
    terminationMessagePath: /dev/termination-log
    terminationMessagePolicy: File
    volumeMounts:
    - mountPath: /var/run/secrets/kubernetes.io/serviceaccount
      name: default-token-bxqtw
      readOnly: true
  dnsPolicy: ClusterFirst
  enableServiceLinks: true
  nodeName: k8s-node2
  priority: 0
  restartPolicy: Always
  schedulerName: default-scheduler
  securityContext: {}
  serviceAccount: default
  serviceAccountName: default
  terminationGracePeriodSeconds: 30
  tolerations:
  - effect: NoExecute
    key: node.kubernetes.io/not-ready
    operator: Exists
    tolerationSeconds: 300
  - effect: NoExecute
    key: node.kubernetes.io/unreachable
    operator: Exists
    tolerationSeconds: 300
  volumes:
  - name: default-token-bxqtw
    secret:
      defaultMode: 420
      secretName: default-token-bxqtw
status:
  conditions:
  - lastProbeTime: null
    lastTransitionTime: "2020-05-04T03:50:47Z"
    status: "True"
    type: Initialized
  - lastProbeTime: null
    lastTransitionTime: "2020-05-04T03:50:49Z"
    status: "True"
    type: Ready
  - lastProbeTime: null
    lastTransitionTime: "2020-05-04T03:50:49Z"
    status: "True"
    type: ContainersReady
  - lastProbeTime: null
    lastTransitionTime: "2020-05-04T03:50:47Z"
    status: "True"
    type: PodScheduled
  containerStatuses:
  - containerID: docker://18eb0798384ea44ff68712cda9be94b6fb96265206c554a15cee28c288879304
    image: tomcat:6.0.53-jre8
    imageID: docker-pullable://tomcat@sha256:8c643303012290f89c6f6852fa133b7c36ea6fbb8eb8b8c9588a432beb24dc5d
    lastState: {}
    name: tomcat
    ready: true
    restartCount: 0
    started: true
    state:
      running:
        startedAt: "2020-05-04T03:50:49Z"
  hostIP: 10.0.2.4
  phase: Running
  podIP: 10.244.2.7
  podIPs:
  - ip: 10.244.2.7
  qosClass: BestEffort
  startTime: "2020-05-04T03:50:47Z"

命令参考

https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands#create

service的意义

3、Service的意义
1、部署一个nginx
kubectl create deployment nginx --image=nginx

2、暴露nginx访问
kubectl expose deployment nginx --port=80 --type=NodePort

统一应用访问入口，
Service管理一组Pod
防止Pod失联（服务发现）、定义一组Pod的访问策略
现在我们使用NodePort的方式暴露，这样访问每个节点的端口，都可以访问各个Pod,如果节点宕机，就会出现问题。

前面我们通过命令行的方式，部署和暴露了tomcat，实际上也可以通过yaml的方式来完成这些操作。

#这些操作实际上是为了获取Deployment的yaml模板
[root@k8s-node1 ~]#  kubectl create deployment tomcat6 --image=tomcat:6.0.53-jre8 --dry-run -o yaml >tomcat6-deployment.yaml
W0504 04:13:28.265432   24263 helpers.go:535] --dry-run is deprecated and can be replaced with --dry-run=client.
[root@k8s-node1 ~]# ls tomcat6-deployment.yaml
tomcat6-deployment.yaml
[root@k8s-node1 ~]#

修改“tomcat6-deployment.yaml”内容如下：

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: tomcat6
  name: tomcat6
spec:
  replicas: 3
  selector:
    matchLabels:
      app: tomcat6
  template:
    metadata: 
      labels:
        app: tomcat6
    spec:
      containers:
      - image: tomcat:6.0.53-jre8
        name: tomcat

#部署
[root@k8s-node1 ~]# kubectl apply -f tomcat6-deployment.yaml
deployment.apps/tomcat6 configured


#查看资源
[root@k8s-node1 ~]# kubectl get all
NAME                           READY   STATUS    RESTARTS   AGE
pod/tomcat6-7b84fb5fdc-5jh6t   1/1     Running   0          27m
pod/tomcat6-7b84fb5fdc-8lhwv   1/1     Running   0          27m
pod/tomcat6-7b84fb5fdc-j4qmh   1/1     Running   0          27m

NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
service/kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP   14h

NAME                      READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/tomcat6   3/3     3            3           27m

NAME                                 DESIRED   CURRENT   READY   AGE
replicaset.apps/tomcat6-7b84fb5fdc   3         3         3       27m
[root@k8s-node1 ~]#

kubectl expose deployment tomcat6 --port=80 --target-port=8080 --type=NodePort  --dry-run -o yaml

apiVersion: v1
kind: Service
metadata:
  creationTimestamp: null
  labels:
    app: tomcat6
  name: tomcat6
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 8080
  selector:
    app: tomcat6
  type: NodePort
status:
  loadBalancer: {}

将这段输出和“tomcat6-deployment.yaml”进行拼接，表示部署完毕并进行暴露服务：

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: tomcat6
  name: tomcat6
spec:
  replicas: 3
  selector:
    matchLabels:
      app: tomcat6
  template:
    metadata: 
      labels:
        app: tomcat6
    spec:
      containers:
      - image: tomcat:6.0.53-jre8
        name: tomcat
---
apiVersion: v1
kind: Service
metadata:
  creationTimestamp: null
  labels:
    app: tomcat6
  name: tomcat6
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 8080
  selector:
    app: tomcat6
  type: NodePort

部署并暴露服务

[root@k8s-node1 ~]# kubectl apply -f tomcat6-deployment.yaml
deployment.apps/tomcat6 created
service/tomcat6 created

查看服务和部署信息

[root@k8s-node1 ~]# kubectl get all
NAME                           READY   STATUS    RESTARTS   AGE
pod/tomcat6-7b84fb5fdc-dsqmb   1/1     Running   0          4s
pod/tomcat6-7b84fb5fdc-gbmxc   1/1     Running   0          5s
pod/tomcat6-7b84fb5fdc-kjlc6   1/1     Running   0          4s

NAME                 TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
service/kubernetes   ClusterIP   10.96.0.1       <none>        443/TCP        14h
service/tomcat6      NodePort    10.96.147.210   <none>        80:30172/TCP   4s

NAME                      READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/tomcat6   3/3     3            3           5s

NAME                                 DESIRED   CURRENT   READY   AGE
replicaset.apps/tomcat6-7b84fb5fdc   3         3         3       5s
[root@k8s-node1 ~]#

访问node1，node1和node3的30172端口：

[root@k8s-node1 ~]# curl -I http://192.168.56.{100,101,102}:30172/
HTTP/1.1 200 OK
Server: Apache-Coyote/1.1
Accept-Ranges: bytes
ETag: W/"7454-1491118183000"
Last-Modified: Sun, 02 Apr 2017 07:29:43 GMT
Content-Type: text/html
Content-Length: 7454
Date: Mon, 04 May 2020 04:35:35 GMT

HTTP/1.1 200 OK
Server: Apache-Coyote/1.1
Accept-Ranges: bytes
ETag: W/"7454-1491118183000"
Last-Modified: Sun, 02 Apr 2017 07:29:43 GMT
Content-Type: text/html
Content-Length: 7454
Date: Mon, 04 May 2020 04:35:35 GMT

HTTP/1.1 200 OK
Server: Apache-Coyote/1.1
Accept-Ranges: bytes
ETag: W/"7454-1491118183000"
Last-Modified: Sun, 02 Apr 2017 07:29:43 GMT
Content-Type: text/html
Content-Length: 7454
Date: Mon, 04 May 2020 04:35:35 GMT

[root@k8s-node1 ~]#

Ingress

通过Ingress发现pod进行关联。基于域名访问
通过Ingress controller实现POD负载均衡
支持TCP/UDP 4层负载均衡和HTTP 7层负载均衡

步骤：
（1）部署Ingress controller

执行“k8s/ingress-controller.yaml”

[root@k8s-node1 k8s]# kubectl apply -f ingress-controller.yaml 
namespace/ingress-nginx created
configmap/nginx-configuration created
configmap/tcp-services created
configmap/udp-services created
serviceaccount/nginx-ingress-serviceaccount created
clusterrole.rbac.authorization.k8s.io/nginx-ingress-clusterrole created
role.rbac.authorization.k8s.io/nginx-ingress-role created
rolebinding.rbac.authorization.k8s.io/nginx-ingress-role-nisa-binding created
clusterrolebinding.rbac.authorization.k8s.io/nginx-ingress-clusterrole-nisa-binding created
daemonset.apps/nginx-ingress-controller created
service/ingress-nginx created
[root@k8s-node1 k8s]#

查看

[root@k8s-node1 k8s]# kubectl get pods --all-namespaces
NAMESPACE       NAME                                READY   STATUS              RESTARTS   AGE
default         tomcat6-7b84fb5fdc-dsqmb            1/1     Running             0          16m
default         tomcat6-7b84fb5fdc-gbmxc            1/1     Running             0          16m
default         tomcat6-7b84fb5fdc-kjlc6            1/1     Running             0          16m
ingress-nginx   nginx-ingress-controller-9q6cs      0/1     ContainerCreating   0          40s
ingress-nginx   nginx-ingress-controller-qx572      0/1     ContainerCreating   0          40s
kube-system     coredns-546565776c-9sbmk            1/1     Running             1          14h
kube-system     coredns-546565776c-t68mr            1/1     Running             1          14h
kube-system     etcd-k8s-node1                      1/1     Running             1          14h
kube-system     kube-apiserver-k8s-node1            1/1     Running             1          14h
kube-system     kube-controller-manager-k8s-node1   1/1     Running             1          14h
kube-system     kube-flannel-ds-amd64-5xs5j         1/1     Running             2          13h
kube-system     kube-flannel-ds-amd64-6xwth         1/1     Running             2          14h
kube-system     kube-flannel-ds-amd64-fvnvx         1/1     Running             1          13h
kube-system     kube-proxy-7tkvl                    1/1     Running             1          13h
kube-system     kube-proxy-mvlnk                    1/1     Running             2          13h
kube-system     kube-proxy-sz2vz                    1/1     Running             1          14h
kube-system     kube-scheduler-k8s-node1            1/1     Running             1          14h
[root@k8s-node1 k8s]#

这里master节点负责调度，具体执行交给node2和node3来完成，能够看到它们正在下载镜像

image-20200504124608258

（2）创建Ingress规则

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: web
spec:
  rules:
  - host: tomcat6.kubenetes.com
    http:
       paths: 
          - backend: 
              serviceName: tomcat6
              servicePort: 80

[root@k8s-node1 k8s]# touch ingress-tomcat6.yaml
#将上面的规则，添加到ingress-tomcat6.yaml文件中
[root@k8s-node1 k8s]# vi  ingress-tomcat6.yaml  
 
[root@k8s-node1 k8s]# kubectl apply -f ingress-tomcat6.yaml 
ingress.extensions/web created
[root@k8s-node1 k8s]#

修改本机的hosts文件，添加如下的域名转换规则：

192.168.56.102 tomcat6.kubenetes.com

测试: http://tomcat6.kubenetes.com/

并且集群中即便有一个节点不可用，也不影响整体的运行。

安装kubernetes可视化界面——DashBoard

1、部署DashBoard

$ kubectl appy -f  kubernetes-dashboard.yaml

文件在“k8s”源码目录提供

2、暴露DashBoard为公共访问

默认DashBoard只能集群内部访问，修改Service为NodePort类型，暴露到外部

kind: Service
apiVersion: v1
metadata:
  labels:
    k8s-app: kubernetes-dashboard
  name: kubernetes-dashboard
  namespace: kube-system
spec:
  type: NodePort
  ports:
    - port: 443
      targetPort: 8443
      nodePort: 3001
  selector:
    k8s-app: kubernetes-dashboard

访问地址：http://NodeIP:30001

3、创建授权账号

$ kubectl create serviceaccount dashboar-admin -n kube-sysem

$ kubectl create clusterrolebinding dashboar-admin --clusterrole=cluter-admin --serviceaccount=kube-system:dashboard-admin

$ kubectl describe secrets -n kube-system $( kubectl -n kube-system get secret |awk '/dashboard-admin/{print $1}' )

使用输出的token登录dashboard

image-20200504153630775

kubesphere

默认的dashboard没啥用，我们用kubesphere可以打通全部的devops链路，kubesphere集成了很多套件，集群要求比较高
https://kubesphere.io

kuboard也很不错，集群要求不高
https://kuboard.cn/support/

1、简洁

kubesphere是一款面向云原声设计的开源项目，在目前主流容器调度平台kubernets智商构建的分布式多用户容器管理平台，提供简单易用的操作界面以及向导式操作方式，在降低用户使用容器调度平台学习成本的同时，极大降低开发、测试、运维的日常工作的复杂度。

2、安装前提提交

1、安装helm（master节点执行）

helm是kubernetes的包管理器。包管理器类似于在Ubuntu中使用的apt，centos中的yum或者python中的pip一样，能够快速查找，下载和安装软件包。Helm有客户端组件helm和服务端组件Tiller组成，能够将一组K8S资源打包统一管理，是查找、共享和使用为Kubernetes构建的软件的最佳方式。

1）安装

curl -L https://git.io/get_helm.sh|bash

由于被墙的原因，使用我们给定的get_helm.sh。

[root@k8s-node1 k8s]# ll
total 68
-rw-r--r-- 1 root root  7149 Feb 27 01:58 get_helm.sh
-rw-r--r-- 1 root root  6310 Feb 28 05:16 ingress-controller.yaml
-rw-r--r-- 1 root root   209 Feb 28 13:18 ingress-demo.yml
-rw-r--r-- 1 root root   236 May  4 05:09 ingress-tomcat6.yaml
-rwxr--r-- 1 root root 15016 Feb 26 15:05 kube-flannel.yml
-rw-r--r-- 1 root root  4737 Feb 26 15:38 kubernetes-dashboard.yaml
-rw-r--r-- 1 root root  3841 Feb 27 01:09 kubesphere-complete-setup.yaml
-rw-r--r-- 1 root root   392 Feb 28 11:33 master_images.sh
-rw-r--r-- 1 root root   283 Feb 28 11:34 node_images.sh
-rw-r--r-- 1 root root  1053 Feb 28 03:53 product.yaml
-rw-r--r-- 1 root root   931 May  3 10:08 Vagrantfile
[root@k8s-node1 k8s]# sh get_helm.sh 
Downloading https://get.helm.sh/helm-v2.16.6-linux-amd64.tar.gz
Preparing to install helm and tiller into /usr/local/bin
helm installed into /usr/local/bin/helm
tiller installed into /usr/local/bin/tiller
Run 'helm init' to configure helm.
[root@k8s-node1 k8s]#

2）验证版本

helm version

3）创建权限（master执行）

创建helm-rbac.yaml，写入如下内容

apiVersion: v1
kind: ServiceAccount
metadata:
  name: tiller
  namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: tiller
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
  - kind: ServiceAccount
    name: kubernetes-dashboard
    namespace: kube-system

应用配置：

[root@k8s-node1 k8s]#  kubectl apply -f helm-rbac.yaml
serviceaccount/tiller created
clusterrolebinding.rbac.authorization.k8s.io/tiller created
[root@k8s-node1 k8s]#

2、安装Tilller（Master执行）

1、初始化

[root@k8s-node1 k8s]# helm init --service-account=tiller --tiller-image=sapcc/tiller:v2.16.3 --history-max 300 
Creating /root/.helm 
Creating /root/.helm/repository 
Creating /root/.helm/repository/cache 
Creating /root/.helm/repository/local 
Creating /root/.helm/plugins 
Creating /root/.helm/starters 
Creating /root/.helm/cache/archive 
Creating /root/.helm/repository/repositories.yaml 
Adding stable repo with URL: https://kubernetes-charts.storage.googleapis.com 
Adding local repo with URL: http://127.0.0.1:8879/charts 
$HELM_HOME has been configured at /root/.helm.

Tiller (the Helm server-side component) has been installed into your Kubernetes Cluster.

Please note: by default, Tiller is deployed with an insecure 'allow unauthenticated users' policy.
To prevent this, run `helm init` with the --tiller-tls-verify flag.
For more information on securing your installation see: https://v2.helm.sh/docs/securing_installation/
[root@k8s-node1 k8s]#

–tiller-image 指定镜像，否则会被墙，等待节点上部署的tiller完成即可。

[root@k8s-node1 k8s]#  kubectl get pods -n kube-system
NAME                                   READY   STATUS             RESTARTS   AGE
coredns-546565776c-9sbmk               1/1     Running            3          23h
coredns-546565776c-t68mr               1/1     Running            3          23h
etcd-k8s-node1                         1/1     Running            3          23h
kube-apiserver-k8s-node1               1/1     Running            3          23h
kube-controller-manager-k8s-node1      1/1     Running            3          23h
kube-flannel-ds-amd64-5xs5j            1/1     Running            4          22h
kube-flannel-ds-amd64-6xwth            1/1     Running            5          23h
kube-flannel-ds-amd64-fvnvx            1/1     Running            4          22h
kube-proxy-7tkvl                       1/1     Running            3          22h
kube-proxy-mvlnk                       1/1     Running            4          22h
kube-proxy-sz2vz                       1/1     Running            3          23h
kube-scheduler-k8s-node1               1/1     Running            3          23h
kubernetes-dashboard-975499656-jxczv   0/1     ImagePullBackOff   0          7h45m
tiller-deploy-8cc566858-67bxb          1/1     Running            0          31s
[root@k8s-node1 k8s]#

查看集群的所有节点信息：

 kubectl get node -o wide

[root@k8s-node1 k8s]#  kubectl get node -o wide
NAME        STATUS   ROLES    AGE   VERSION   INTERNAL-IP   EXTERNAL-IP   OS-IMAGE                KERNEL-VERSION               CONTAINER-RUNTIME
k8s-node1   Ready    master   23h   v1.17.3   10.0.2.15     <none>        CentOS Linux 7 (Core)   3.10.0-957.12.2.el7.x86_64   docker://19.3.8
k8s-node2   Ready    <none>   22h   v1.17.3   10.0.2.4      <none>        CentOS Linux 7 (Core)   3.10.0-957.12.2.el7.x86_64   docker://19.3.8
k8s-node3   Ready    <none>   22h   v1.17.3   10.0.2.5      <none>        CentOS Linux 7 (Core)   3.10.0-957.12.2.el7.x86_64   docker://19.3.8
[root@k8s-node1 k8s]#

2、测试

helm install stable/nginx-ingress --name nginx-ingress

最小化安装 KubeSphere

若集群可用 CPU > 1 Core 且可用内存 > 2 G，可以使用以下命令最小化安装 KubeSphere：

kubectl apply -f https://raw.githubusercontent.com/kubesphere/ks-installer/master/kubesphere-minimal.yaml

提示：若您的服务器提示无法访问 GitHub，可将 kubesphere-minimal.yaml 或 kubesphere-complete-setup.yaml 文件保存到本地作为本地的静态文件，再参考上述命令进行安装。

  1. 查看滚动刷新的安装日志，请耐心等待安装成功。
$ kubectl logs -n kubesphere-system $(kubectl get pod -n kubesphere-system -l app=ks-install -o jsonpath='{.items[0].metadata.name}') -f

说明：安装过程中若遇到问题，也可以通过以上日志命令来排查问题

标签：kubectl,kube,tomcat6,集群,谷粒,node1,k8s,root
来源： https://blog.csdn.net/wangzhipeng47/article/details/117664186