系統配置

在安裝之前，需要先做如下準備。兩臺CentOS 7.4主機如下：

cat /etc/hosts
192.168.61.11 node1
192.168.61.12 node2

如果各個主機啟用了防火牆，需要開放Kubernetes各個元件所需要的埠，可以檢視Installing kubeadm中的"Check required ports"一節。 這裡簡單起見在各節點禁用防火牆：

systemctl stop firewalld
systemctl disable firewalld

禁用SELINUX：

setenforce 0
vi /etc/selinux/config
SELINUX
 
=disabled

建立/etc/sysctl.d/k8s.conf檔案，新增如下內容：

net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
modprobe br_netfilter
sysctl -p /etc/sysctl.d/k8s.conf

關閉系統的swap

swapoff -a

安裝外掛

yum install ipset ipvsadm conntrack-tools.x86_64 -y

載入模組

modprobe ip_vs_rr
modprobe ip_vs_wrr
modprobe ip_vs_sh
modprobe ip_vs
 

安裝docker

yum install -y yum-utils device-mapper-persistent-data lvm2
yum-config-manager \
    --add-repo \
    https://download.docker.com/linux/centos/docker-ce.repo

yum install -y --setopt=obsoletes=0 \
  docker-ce

systemctl start docker
systemctl enable docker

使用kubeadm部署kubernetes

下面在各個節點安裝kubeadm和kubelet

cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg
        https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
EOF
yum -y install kubelet kubeadm kubectl

systemctl enable kubelet.service

安裝所需映象

下面在各個節點安裝所需要的的映象

for i in `kubeadm config images list`; do   
    imageName=${i#k8s.gcr.io/}  
    docker pull registry.aliyuncs.com/google_containers/$imageName      
    docker tag registry.aliyuncs.com/google_containers/$imageName k8s.gcr.io/$imageName  
    docker rmi registry.aliyuncs.com/google_containers/$imageName
done

使用kubeadm init初始化叢集

在master節點操作

kubeadm init \ 
--kubernetes-version=v1.12.0 \ 
--pod-network-cidr=10.244.0.0/16 \ 
--apiserver-advertise-address=192.168.61.11 \
--ignore-preflight-errors=Swap

[init] using Kubernetes version: v1.12.0
[preflight] running pre-flight checks
        [WARNING Swap]: running with swap on is not supported. Please disable swap
[preflight/images] Pulling images required for setting up a Kubernetes cluster
[preflight/images] This might take a minute or two, depending on the speed of your internet connection
[preflight/images] You can also perform this action in beforehand using 'kubeadm config images pull'
[kubelet] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[preflight] Activating the kubelet service
[certificates] Generated etcd/ca certificate and key.
[certificates] Generated etcd/peer certificate and key.
[certificates] etcd/peer serving cert is signed for DNS names [node1 localhost] and IPs [192.168.61.11 127.0.0.1 ::1]
[certificates] Generated apiserver-etcd-client certificate and key.
[certificates] Generated etcd/server certificate and key.
[certificates] etcd/server serving cert is signed for DNS names [node1 localhost] and IPs [127.0.0.1 ::1]
[certificates] Generated etcd/healthcheck-client certificate and key.
[certificates] Generated ca certificate and key.
[certificates] Generated apiserver certificate and key.
[certificates] apiserver serving cert is signed for DNS names [node1 kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.168.61.11]
[certificates] Generated apiserver-kubelet-client certificate and key.
[certificates] Generated front-proxy-ca certificate and key.
[certificates] Generated front-proxy-client certificate and key.
[certificates] valid certificates and keys now exist in "/etc/kubernetes/pki"
[certificates] Generated sa key and public key.
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/admin.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/kubelet.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/controller-manager.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/scheduler.conf"
[controlplane] wrote Static Pod manifest for component kube-apiserver to "/etc/kubernetes/manifests/kube-apiserver.yaml"
[controlplane] wrote Static Pod manifest for component kube-controller-manager to "/etc/kubernetes/manifests/kube-controller-manager.yaml"
[controlplane] wrote Static Pod manifest for component kube-scheduler to "/etc/kubernetes/manifests/kube-scheduler.yaml"
[etcd] Wrote Static Pod manifest for a local etcd instance to "/etc/kubernetes/manifests/etcd.yaml"
[init] waiting for the kubelet to boot up the control plane as Static Pods from directory "/etc/kubernetes/manifests"
[init] this might take a minute or longer if the control plane images have to be pulled
[apiclient] All control plane components are healthy after 26.503672 seconds
[uploadconfig] storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.12" in namespace kube-system with the configuration for the kubelets in the cluster
[markmaster] Marking the node node1 as master by adding the label "node-role.kubernetes.io/master=''"
[markmaster] Marking the node node1 as master by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[patchnode] Uploading the CRI Socket information "/var/run/dockershim.sock" to the Node API object "node1" as an annotation
[bootstraptoken] using token: zalj3i.q831ehufqb98d1ic
[bootstraptoken] configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
[bootstraptoken] configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
[bootstraptoken] configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
[bootstraptoken] creating the "cluster-info" ConfigMap in the "kube-public" namespace
[addons] Applied essential addon: CoreDNS
[addons] Applied essential addon: kube-proxy

Your Kubernetes master 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/

You can now join any number of machines by running the following on each node
as root:

  kubeadm join 192.168.61.11:6443 --token zalj3i.q831ehufqb98d1ic --discovery-token-ca-cert-hash sha256:6ee48b19ba61a2dda77f6b60687c5fd11072ab898cfdfef32a68821d1dbe8efa

• [kubelet] 生成kubelet的配置檔案"/var/lib/kubelet/config.yaml"
• [certificates]生成相關的各種證書
• [kubeconfig]生成相關的kubeconfig檔案
• [bootstraptoken]生成token記錄下來，後邊使用kubeadm join往叢集中新增節點時會用到
• 下面的命令是配置常規使用者如何使用kubectl訪問叢集：

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

• 最後給出了將節點加入叢集的命令kubeadm join 192.168.61.11:6443 --token zalj3i.q831ehufqb98d1ic --discovery-token-ca-cert-hash sha256:6ee48b19ba61a2dda77f6b60687c5fd11072ab898cfdfef32a68821d1dbe8efa

在slave節點操作

kubeadm join 192.168.61.11:6443 \
--token zalj3i.q831ehufqb98d1ic \
--discovery-token-ca-cert-hash sha256:6ee48b19ba61a2dda77f6b60687c5fd11072ab898cfdfef32a68821d1dbe8efa \
--ignore-preflight-errors=Swap