Install Kubernetes

KubernetesAn overview of the

Kubernetes(hereinafter referred to as K8S) is a complete distributed system support platform. Security protection, load balancing, and multi-granularity resource quota management capabilities.

The following describes the components of K8S

Service

  • ServiceIs the core of the distributed cluster architecture, aServiceThe object has the following key characteristics.
    • Have a uniquely specified name (such as Redis-server).
    • Has a virtual IP(Cluster IP or VIP) and a port number.
    • Can provide some kind of remote service capability.
    • Can be mapped to a set of container applications that provide this service capability.

Pod

  • PodIs the smallest administrative element of K8S.
    • It is a combination of one or more containers. Do these containers share storage, networks, and namespaces, as well as specifications for how to operate
    • aPodThe shared context ofLinuxNamespace,cgroupsAnd other potentially quarantined content
    • In differentPodContainers in, have differentIPAddress, and therefore cannot communicate directly between processes. Commonly used between containersPod IPAddress to communicate.
    • PodRunning on nodesNodeOn the environment.
    • eachPodRun a special containerPause. Others are business containers.
    • These business containers sharePauseThe container’s network stack andVolumeMount the volume.

Node

  • Node is the host on which the Pod actually runs. It can be a physical machine or a virtual machine.
    • To manage pods, each Node must run at least the Container Runtime (such as Docker or RKT), Kubelet, and Kube-Proxy services.
    • These processes are responsible forPodCreate, start, monitor, restart, destroy, and implement software mode load balancer.
    • The node status information contains
      • Addresses. Describes network Addresses
      • Condition. Describe allRunningNode status
      • Capacity. Describes the hardware resources available on the node:CPU.RAM.DISKThe biggestPodNumber, etc.
      • Info. Description Basic node information. For example, the kernel version and OS name.

Set upKubernetes

System to prepare

* OS: CentOS Linux Release 7 + * USER: root 1+ (if CPUNumber is less than 2, 'kubeadm init' needs to add '--ignore-preflight-errors=NumCPU' option * RAM: 2Gib+Copy the code

The machine to prepare

OS CPU RAM LocaoIP NOTE
CentOS Linux release 7.3 1 2Gib 172.17.50.23 master
CentOS Linux release 7.3 1 2Gib 172.17.50.24 node1
CentOS Linux release 7.3 1 2Gib 172.17.50.25 node2

Deployment steps

Disabling the Firewall
sudo systemctl stop firewalld
sudo systemctl disable firewalld
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Shut downSELINUX
## Temporary shutdown
sudo setenforce 0
## Permanently closed
sudo sed "s/SELINUX=*/SELINUX=disabled/g" -i /etc/selinux/config
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Shut downswap
sudo swapoff -a
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Set iptables not to process bridge data
sudo cat <<EOF >  /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sudo sysctl --system
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The installationDocker(v18.06.3)
sudo yum install -y yum-utils device-mapper-persistent-data lvm2

## Change to Ali Yunyuansudo yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo sudo yum makecache Fast sudo yum-y --setopt= Obsoletes =0 Install Docker-ce-18.06.3. Ce 3.el7 \ Docker-ce-selinux-18.06.3. Ce 3.el7## Now enable and set boot auto
sudo systemctl enable docker && systemctl start docker
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addK8SThe source
## The default source is Google
sudo 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
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The installationkubelet kubeadm kubectl
sudo yum install -y kubelet kubeadm kubectl

## Set boot
sudo systemctl enable kubelet && systemctl start kubelet
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checkKubernetesversion

# kubectl version

Client Version: version.Info{Major:"1", Minor:"17", GitVersion:"v1.17.0", GitCommit:"70132b0f130acc0bed193d9ba59dd186f0e634cf", GitTreeState:"clean", BuildDate:"2019-12-07T21:20:10Z", GoVersion:"go1.13.4", Compiler:"gc", Platform:"linux/amd64"}
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At this point, Kubernetes is installed on the master, leaving the rest of the Node machines to follow the steps

Or use the one-click install command below to deploy

One-click install command

curl -sSL https://raw.githubusercontent.com/charSLee013/Kubernetes-learn/master/chapter01/kubernetes-centos-install.sh | bash
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Matters needing attention

  • The one-click install command will putyumThe source toAliyun
  • According to thePod NetworkDepending on the selection, some components may need to be enablediptablesForwarding function (please refer to the component’s official website for details)

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