一、主机安装
# 安装wget
[root@master ~]# yum install wget
[root@master ~]# yum install -y net-tools
二、环境初始化
1)检查操作系统的版本
# 此方式下安装kubernetes集群要求Centos版本要在7.5或以上
[root@master ~]# cat /etc/redhat-release
CentOS Linux release 7.9.2009 (Core)
2) 主机名解析
为了方便后面集群节点间的直接调用,在这配置一下主机解析,企业中推荐使用内部DNS服务器
[root@master ~]# cat /etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
# 主机名解析,编辑三台服务器的/etc/hosts文件,添加下面内容
192.168.56.100 master
192.168.56.101 node1
192.168.56.102 node2
3)时间同步
kubernetes要求集群中的节点时间必须精确一致,这里直接使用chronyd服务从网络同步时间。企业中建议配置内部的时间同步服务器
# 启动chronyd服务
[root@master ~]# systemctl start chronyd
[root@master ~]# systemctl enable chronyd
# chronyd服务启动稍等几秒钟,就可以使用date命令验证时间了
[root@master ~]# date
4)禁用iptables和firewalld服务
kubenetes和docker在运行中会产生大量的iptables规则,为了不让系统规则跟它们混淆,直接关闭系统的规则
[root@master ~]# systemctl stop firewalld
[root@master ~]# systemctl disable firewalld
5) 禁用selinux
selinux是linux系统下的一个安全服务,如果不关闭它,在安装集群中会产生各种各样的奇葩问题
# 编辑/etc/selinux/config 文件,修改SELINUX值为disabled
SELINUX=disabled
6)禁用swap分区
swap分区指的是虚拟内存分区,它的作用是在物理内存使用完之后,将磁盘空间虚拟成内存来使用,启用swap设备会对系统的性能产生非常负面的影响 ,因此kubernetes要求每个节点都要禁用 swap设备,但是如果因为某些原因确实不能关闭swap分区,就需要在集群安装过程中通过明确的参数进行配置说明
# 编辑分区文件/etc/fstab,注释掉swap分区一行
# 注意修改完毕之后需要重启linux
/dev/mapper/centos-root / xfs defaults 0 0
UUID=33791eac-1535-4957-92f2-c7364a6968a2 /boot xfs defaults 0 0
# /dev/mapper/centos-swap swap swap defaults 0 0
7)修改linux内核参数
# 修改linux的内核参数,添加网桥过滤和地址转换功能
# 编辑/etc/sysctl.d/kubernetes.conf文件,添加如下配置:
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
# 重新加载配置
[root@master ~]# sysctl -p
# 加载网桥过滤模块
[root@master ~]# modprobe br_netfilter
# 查看网桥过滤模块是否加载成功
[root@master ~]# lsmod|grep br_netfilter
8) 配置ipvs功能
在kubernetes中service有两种代理模型,一种是基于iptables的,一种是基于ipvs的,两者比较的话,ipvs的性能明显要高一些,但是如果要使用它,需要手动载入ipvs模块
# 1 安装ipset和ipvsadm
[root@master ~]# yum install ipset ipvsadm -y
# 2 添加需要加载的模块写入脚本文件
[root@master ~]# cat <<EOF > /etc/sysconfig/modules/ipvs.modules
#!/bin/bash
modprobe -- ip_vs
modprobe -- ip_vs_rr
modprobe -- ip_vs_wrr
modprobe -- ip_vs_sh
modprobe -- nf_conntrack_ipv4
EOF
# 3 为脚本文件添加执行权限
[root@master ~]# chmod +x /etc/sysconfig/modules/ipvs.modules
# 4 执行脚本文件
[root@master ~]# /bin/bash /etc/sysconfig/modules/ipvs.modules
# 5 查看对应的模块是否加载成功
[root@master ~]# lsmod|grep -e ip_vs -e nf_conntrack_ipv4
nf_conntrack_ipv4 15053 0
nf_defrag_ipv4 12729 1 nf_conntrack_ipv4
ip_vs_sh 12688 0
ip_vs_wrr 12697 0
ip_vs_rr 12600 0
ip_vs 145458 6 ip_vs_rr,ip_vs_sh,ip_vs_wrr
nf_conntrack 139264 2 ip_vs,nf_conntrack_ipv4
libcrc32c 12644 3 xfs,ip_vs,nf_conntrack
9) 重启服务器
上面步骤完成之后,需要重新启动linux系统
[root@master ~]# reboot
三、安装docker
# 1 切换镜像源
[root@master ~]# wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo
# 2 查看当前镜像源中支持的docker版本
[root@master ~]# yum list docker-ce --showduplicates
# 3 安装指定版本的docker-ce
# 必须指定--setopt=obsoletes=0, 否则yum会自动安装更高版本
[root@master ~]# yum install --setopt=obsoletes=0 docker-ce-18.06.3.ce-3.el7 -y
# 4 添加一个配置文件
# Docker在默认情况下使用Cgroup Driver为cgroupfs,而kubernetes推荐使用systemd来代替cgroupfs
[root@master ~]# mkdir /etc/docker
[root@master ~]# cat <<EOF > /etc/docker/daemon.json
{
"exec-opts": ["native.cgroupdriver=systemd"],
"registry-mirrors": ["https://kn0t2bca.mirror.aliyuncs.com"]
}
EOF
# 5 启动docker
[root@master ~]# systemctl restart docker
[root@master ~]# systemctl enable docker
# 6 检查docker状态和版本
[root@master ~]# docker version
四、安装kubernetes组件
# 由于kubernetes的镜像源在国外,速度比较慢,这里切换成国内镜像源
# 编辑/etc/yum.repos.d/kubernetes.repo,添加下面的配置
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
enable=1
gpgcheck=0
repo_gpgcheck=0
gpgkey=http://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
http://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
# 安装kubeadm、kubelet和kubectl
[root@master ~]# yum install --setopt=obsoletes=0 kubeadm-1.17.4-0 kubelet-1.17.4-0 kubectl-1.17.4-0 -y
# 配置kubelet的cgroup
# 编辑/etc/sysconfig/kubelet,添加下面的配置
KUBELET_CGROUP_ARGS="--cgroup-driver=systemd"
KUBE_PROXY_MODE="ipvs"
# 4 设置kubelet开机自启
[root@master ~]# systemctl enable kubelet
五、准备集群镜像
# 在安装kubernetes集群之前,必须要提前准备好集群需要的镜像,所需镜像可以通过下面命令查看
[root@master ~]# kubeadm config images list
# 下载镜像
# 此镜像在kubernetes的仓库中,由于网络原因,无法连接,下面提供一种替代方案
images=(
kube-apiserver:v1.17.4
kube-controller-manager:v1.17.4
kube-scheduler:v1.17.4
kube-proxy:v1.17.4
pause:3.1
etcd:3.4.3-0
coredns:1.6.5
)
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
docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName
done
六、集群初始化
下面开始对集群进行初始化,并将 node节点加入到集群中
下面的操作只需要在master节点上执行即可
# 创建集群
[root@master ~]# kubeadm init \
--kubernetes-version=v1.17.4 \
--pod-network-cidr=10.244.0.0/16 \
--service-cidr=10.96.0.0/12 \
--apiserver-advertise-address=192.168.56.100
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 192.168.56.100:6443 --token imw8fh.sv7ir51jzini1c3a \
--discovery-token-ca-cert-hash sha256:6e6aa0b439b6c41f7e8ae42be989ea03041ef27e201f677b3f50224dc4458b2d
# 开始使用集群
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
kubeadm init
执行中如果提示cpu核数必须大于2时,可以在指定虚拟机的设置
/系统
里更改为2
七、安装网络插件
kubernetes支持多种网络插件,比如flannel、calico、canal等,任选一种使用即可,本次选择flannel
下面操作依旧只在master节点执行即可,插件使用的是DaemonSet的控制器,它会在每个节点上都运行
# 获取flannel的配置文件
wget https://raw.githubusercontent.com/flannel-io/flannel/release/v0.14.1/Documentation/kube-flannel.yml
[root@master tools]# 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 created
上面的网址在国内不太好访问,具体项目地址:https://github.com/flannel-io/flannel ,可以去
Documentation
目录下找到对应适合的版本
kube-flannel.yml文件,也可以在https://gitee.com/yooome/golang/raw/main/k8s%E8%AF%A6%E7%BB%86%E6%95%99%E7%A8%8B/kube-flannel.yml
下载
---
apiVersion: policy/v1beta1
kind: PodSecurityPolicy
metadata:
name: psp.flannel.unprivileged
annotations:
seccomp.security.alpha.kubernetes.io/allowedProfileNames: docker/default
seccomp.security.alpha.kubernetes.io/defaultProfileName: docker/default
apparmor.security.beta.kubernetes.io/allowedProfileNames: runtime/default
apparmor.security.beta.kubernetes.io/defaultProfileName: runtime/default
spec:
privileged: false
volumes:
- configMap
- secret
- emptyDir
- hostPath
allowedHostPaths:
- pathPrefix: "/etc/cni/net.d"
- pathPrefix: "/etc/kube-flannel"
- pathPrefix: "/run/flannel"
readOnlyRootFilesystem: false
# Users and groups
runAsUser:
rule: RunAsAny
supplementalGroups:
rule: RunAsAny
fsGroup:
rule: RunAsAny
# Privilege Escalation
allowPrivilegeEscalation: false
defaultAllowPrivilegeEscalation: false
# Capabilities
allowedCapabilities: ['NET_ADMIN', 'NET_RAW']
defaultAddCapabilities: []
requiredDropCapabilities: []
# Host namespaces
hostPID: false
hostIPC: false
hostNetwork: true
hostPorts:
- min: 0
max: 65535
# SELinux
seLinux:
# SELinux is unused in CaaSP
rule: 'RunAsAny'
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: flannel
rules:
- apiGroups: ['extensions']
resources: ['podsecuritypolicies']
verbs: ['use']
resourceNames: ['psp.flannel.unprivileged']
- apiGroups:
- ""
resources:
- pods
verbs:
- get
- apiGroups:
- ""
resources:
- nodes
verbs:
- list
- watch
- apiGroups:
- ""
resources:
- nodes/status
verbs:
- patch
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: flannel
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: flannel
subjects:
- kind: ServiceAccount
name: flannel
namespace: kube-system
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: flannel
namespace: kube-system
---
kind: ConfigMap
apiVersion: v1
metadata:
name: kube-flannel-cfg
namespace: kube-system
labels:
tier: node
app: flannel
data:
cni-conf.json: |
{
"name": "cbr0",
"cniVersion": "0.3.1",
"plugins": [
{
"type": "flannel",
"delegate": {
"hairpinMode": true,
"isDefaultGateway": true
}
},
{
"type": "portmap",
"capabilities": {
"portMappings": true
}
}
]
}
net-conf.json: |
{
"Network": "10.244.0.0/16",
"Backend": {
"Type": "vxlan"
}
}
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: kube-flannel-ds
namespace: kube-system
labels:
tier: node
app: flannel
spec:
selector:
matchLabels:
app: flannel
template:
metadata:
labels:
tier: node
app: flannel
spec:
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: kubernetes.io/os
operator: In
values:
- linux
hostNetwork: true
priorityClassName: system-node-critical
tolerations:
- operator: Exists
effect: NoSchedule
serviceAccountName: flannel
initContainers:
- name: install-cni
image: quay.io/coreos/flannel:v0.14.0
command:
- cp
args:
- -f
- /etc/kube-flannel/cni-conf.json
- /etc/cni/net.d/10-flannel.conflist
volumeMounts:
- name: cni
mountPath: /etc/cni/net.d
- name: flannel-cfg
mountPath: /etc/kube-flannel/
containers:
- name: kube-flannel
image: quay.io/coreos/flannel:v0.14.0
command:
- /opt/bin/flanneld
args:
- --ip-masq
- --kube-subnet-mgr
resources:
requests:
cpu: "100m"
memory: "50Mi"
limits:
cpu: "100m"
memory: "50Mi"
securityContext:
privileged: false
capabilities:
add: ["NET_ADMIN", "NET_RAW"]
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
volumeMounts:
- name: run
mountPath: /run/flannel
- name: flannel-cfg
mountPath: /etc/kube-flannel/
volumes:
- name: run
hostPath:
path: /run/flannel
- name: cni
hostPath:
path: /etc/cni/net.d
- name: flannel-cfg
configMap:
name: kube-flannel-cfg
执行后,docker images
可以看到新增一个flannel镜像,如图:
再执行kubectl get nodes
查看状态