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kubeadm 搭建 K8s - AskaJohnny
source link: https://www.cnblogs.com/askajohnny/p/16156755.html
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kubeadm 搭建 K8s
本篇主要记录一下 使用 kubeadm 搭建 k8s 详细过程 ，环境使用 VirtualBox 构建的3台虚拟机
1.环境准备
- 操作系统：Centos7 （CentOS Linux release 7.9.2009）
- Master 主节点： 1台 虚拟机
- Node 计算节点： 2台 虚拟机
- K8s version：v1.23.5 （选的较新的版本）
- Docker version：20.10.14
虚拟机创建我就不详细展开了
2.虚拟机网络配置(保证能访问外网)
虚拟机网卡 选择的是 1.网络地址转换NAT （主要用来访问外网的） 2.仅主机网络 （主要用来宿主机访问虚拟机的）
把对应的 ip 设置如下
kube-master 192.168.56.20
kube-node-1 192.168.56.21
kube-node-2 192.168.56.22
2.1 3台虚拟机 静态ip配置
cat /etc/sysconfig/network-scripts/ifcfg-enp0s3
TYPE="Ethernet"
PROXY_METHOD="none"
BROWSER_ONLY="no"
BOOTPROTO="none" #关闭
DEFROUTE="yes"
IPV4_FAILURE_FATAL="no"
IPV6INIT="yes"
IPV6_AUTOCONF="yes"
IPV6_DEFROUTE="yes"
IPV6_FAILURE_FATAL="no"
IPV6_ADDR_GEN_MODE="stable-privacy"
NAME="enp0s3"
UUID="35eac2d4-234d-4859-848e-ed2a30a64a81"
DEVICE="enp0s3"
#添加部分
IPADDR="10.0.2.20"
PREFIX="24"
GATEWAY="10.0.2.2"
DNS1="10.0.2.3"
DNS2="114.114.114.114"
ONBOOT="yes"
cat /etc/sysconfig/network-scripts/ifcfg-enp0s8
TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=static #修改为 static 静态ip
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=enp0s8
UUID=d06bac6d-294f-4bfe-bf08-5cb65c0a431f
DEVICE=enp0s8
#新增部分
IPADDR=192.168.56.20
PREFIX=24
ONBOOT=yes
2.2 虚拟机hosts 配置
在 3台虚拟机 /etc/hosts 中配置 如下
192.168.56.20 kube-master
192.168.56.21 kube-node-1
192.168.56.22 kube-node-2
3.k8s 基础环境设置
3.1 yum 换源(可选)
yum -y install wget
cd /etc/yum.repos.d
mv CentOS-Base.repo CentOS-Base.repo.bak
wget -O CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo
yum clean all
yum makecache #重新生成缓存
3.2 关闭 selinux
setenforce 0 #临时关闭
sed -i "s/SELINUX=enforcing/SELINUX=disabled/g" /etc/selinux/config #永久关闭
3.3 关闭swap分区或禁用swap文件
swapoff -a
# 注释掉关于swap分区的行
yes | cp /etc/fstab /etc/fstab_bak
cat /etc/fstab_bak |grep -v swap > /etc/fstab
3.4 允许iptables 检查桥接流量
cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
br_netfilter
EOF
cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sudo sysctl --system
3.5 关闭防火墙
systemctl stop firewalld
systemctl disable firewalld
3.6 /proc/sys/net/ipv4/ip_forward
echo 1 > /proc/sys/net/ipv4/ip_forward
4.kubectl、kubeadm、kubelet的安装
注意 先换源 https://developer.aliyun.com/mirror/kubernetes?spm=a2c6h.13651102.0.0.64be1b11iddYWH 阿里换源文档
4.1 添加Kubernetes的alibaba 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
yum install -y kubelet kubeadm kubectl
4.2 安装 kubelet kubeadm kubectl
yum install -y kubelet kubeadm kubectl
systemctl enable kubelet && systemctl start kubelet
由于官网未开放同步方式, 可能会有索引gpg检查失败的情况, 这时请用 yum install -y --nogpgcheck kubelet kubeadm kubectl 安装
4.3 启动kubelet 服务
systemctl enable kubelet && systemctl start kubelet
此时执行systemctl status kubelet查看服务状态，此时肯定有错误（因为我们还未进行初始化操作），错误可使用journalctl -xe查看错误信息。
5.Docker 安装和配置
Docker centos 安装文档 地址 https://docs.docker.com/engine/install/centos/
5.1 Docker 安装
sudo yum install -y yum-utils
sudo yum-config-manager \
--add-repo \
https://download.docker.com/linux/centos/docker-ce.repo
sudo yum install docker-ce docker-ce-cli containerd.io
# 也可以安装其他版本 yum list docker-ce --showduplicates | sort -r
# sudo yum install docker-ce-<VERSION_STRING> docker-ce-cli-<VERSION_STRING> containerd.io
#启动docker
sudo systemctl enable docker && systemctl start docker
5.2 Docker 镜像源更换
sudo tee /etc/docker/daemon.json <<-'EOF'
{
"registry-mirrors": ["https://9xxxx1clo.mirror.aliyuncs.com"] #请更换自己的 阿里云镜像地址
}
EOF
5.3 Docker 配置cgroup-driver
由于 cgroup-driver ，默认docker 是 cgroupfs ，而k8s 默认是 systemd，所以需要设置 docker 的 cgroup 为 systemd
推荐使用方式二进行修改
#查看cgroup-driver
docker info | grep -i cgroup
# 方式一 追加 --exec-opt native.cgroupdriver=systemd 参数
sed -i "s#^ExecStart=/usr/bin/dockerd.*#ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock --exec-opt native.cgroupdriver=systemd#g" /usr/lib/systemd/system/docker.service
systemctl daemon-reload # 重新加载服务
systemctl enable docker # 启用docker服务(开机自起)
systemctl restart docker # 启动docker服务
# 方式二 修改docker配置文件
vim /etc/docker/daemon.json
{
"exec-opts": ["native.cgroupdriver=systemd"]
}
5.4 拉取k8s所需镜像
kubeadm config images list查看 所需的镜像
kubeadm config images list
k8s.gcr.io/kube-apiserver:v1.23.5
k8s.gcr.io/kube-controller-manager:v1.23.5
k8s.gcr.io/kube-scheduler:v1.23.5
k8s.gcr.io/kube-proxy:v1.23.5
k8s.gcr.io/pause:3.6
k8s.gcr.io/etcd:3.5.1-0
k8s.gcr.io/coredns/coredns:v1.8.6
如果拉取不到镜像 可以通过 去 docker hub 上查找对应的 镜像
docker pull k8simage/kube-apiserver:v1.23.5
docker tag k8simage/kube-apiserver:v1.23.5 k8s.gcr.io/kube-apiserver:v1.23.5 #重新tag改成上面所需的镜像即可， 其他的都按照这样来
Tips: 完成上面操作后 你可以通过 docker save 导出镜像,以后再用的时候 可以通过 docker image load < 进行离线加载镜像
#导出镜像 ，批量导出所有镜像
docker save $(docker images --format '{{.Repository}}:{{.Tag}}') -o k8s.images.tar
#导入镜像 ，注意 是 < 不是 > 。。 > 后会导致tar 无法使用需要重新上传
docker image load < ...tar/zip
6.kube-master 节点 初始化
我这里选的是 flannel 网络插件，先来看看 flannel 的配置文件
6.1 查看flannel 网络范围
flannel.yml https://raw.githubusercontent.com/flannel-io/flannel/master/Documentation/kube-flannel.yml
不同的 网络插件 网络范围不同
6.2 kubeadm init 初始化
kubeadm init --pod-network-cidr=10.244.0.0/16 \ #网卡插件的 网络范围 --apiserver-advertise-address=192.168.56.20 #master 的 ip 地址
等一会就会有如下结果
可以把 kubeadm join 命令记下来 便于后面使用 保存输出中的kubeadm join部分内容，用于添加node节点，或者使用kubeadm token list 和kubeadm token create --print-join-command查看
执行后续步骤，可以看到提示
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
6.3 网络插件flannel 配置
前面提到了flannel 把对应的flannel.yml文件下载到服务器中，可以使用wget
可以看到 在没配置 flannel 的时候 coredns 一直是 pending 状态
wget https://raw.githubusercontent.com/flannel-io/flannel/master/Documentation/kube-flannel.yml #可能会下载不到，文章最后我会提供内容，直接copy过去即可
#Tips: 可能需要指定一下网卡 ，在kube-flannel.yml中 - /opt/bin/flanneld args: 后面添加
#- --iface=enp0s8 # 需要指定网卡，否则可能k8s会导致使用错误的网卡
kubectl apply -f kube-flannel.yml #应用该文件
kubectl get pods --all-namespaces -o wide #查看是否安装成功，它会在 master 和 node 节点上都会自动部署
最后通过 kubectl get nodes -o wide 查看 节点
7.kube-node 节点初始化
7.1 查看token
可以通过该命令进行查看 token
kubeadm token create --print-join-command
#kubeadm join kube-master:6443 --token ii5xyw.mywlktar1e8f60cu --discovery-token-ca-cert-hash sha256:358f92418178342f79aa7b049e6c18a423f0fb88186189142459016fe6efb8e7
7.2 node节点上 执行 kubeadmin join
kubeadm join kube-master:6443 --token ii5xyw.mywlktar1e8f60cu --discovery-token-ca-cert-hash sha256:358f92418178342f79aa7b049e6c18a423f0fb88186189142459016fe6efb8e7
7.3 在master 上查看结果
watch kubectl get nodes -o wide #可以通过watch 实时监听 加入情况
至此使用 kubeadm 已经成功搭建k8s 集群
本篇主要讲解了 如何使用 kubeadm 进行搭建 k8s 集群 ，搭建的是 k8s 较新版本 v1.23.5 版本，使用kubeadm 搭建相对来说还是比较简单的 。
k8s官网文档
https://kubernetes.io/zh/docs/setup/production-environment/tools/kubeadm/install-kubeadm/
阿里 k8s 更换镜像文档
https://developer.aliyun.com/mirror/kubernetes?spm=a2c6h.13651102.0.0.64be1b11iddYWH
Docker hub 地址
https://hub.docker.com/r/k8simage/
Docker 安装地址
https://docs.docker.com/engine/install/centos/
flannel.yml 文件
---
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-plugin
#image: flannelcni/flannel-cni-plugin:v1.0.1 for ppc64le and mips64le (dockerhub limitations may apply)
image: rancher/mirrored-flannelcni-flannel-cni-plugin:v1.0.1
command:
- cp
args:
- -f
- /flannel
- /opt/cni/bin/flannel
volumeMounts:
- name: cni-plugin
mountPath: /opt/cni/bin
- name: install-cni
#image: flannelcni/flannel:v0.17.0 for ppc64le and mips64le (dockerhub limitations may apply)
image: rancher/mirrored-flannelcni-flannel:v0.17.0
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: flannelcni/flannel:v0.17.0 for ppc64le and mips64le (dockerhub limitations may apply)
image: rancher/mirrored-flannelcni-flannel:v0.17.0
command:
- /opt/bin/flanneld
args:
#- --iface=enp0s8 # 需要指定网卡，否则可能会导致问题
- --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
- name: EVENT_QUEUE_DEPTH
value: "5000"
volumeMounts:
- name: run
mountPath: /run/flannel
- name: flannel-cfg
mountPath: /etc/kube-flannel/
- name: xtables-lock
mountPath: /run/xtables.lock
volumes:
- name: run
hostPath:
path: /run/flannel
- name: cni-plugin
hostPath:
path: /opt/cni/bin
- name: cni
hostPath:
path: /etc/cni/net.d
- name: flannel-cfg
configMap:
name: kube-flannel-cfg
- name: xtables-lock
hostPath:
path: /run/xtables.lock
type: FileOrCreate
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