k8s kubeadm 群集部署
一.环境说明Kubernetes高可用一般建议大于等于3台的奇数台,我使用3台master来做高可用,如果是虚机的话不最好不要克隆192.168.31.105:6443 #为VIPkube-apiserver #三台节点kube-schedulet #三台节点kube-controller-manager #三台节点ETCD #三台节点需要注意的是在master节点需要将CPU设置为2,kubea
一.环境说明
Kubernetes高可用一般建议大于等于3台的奇数台,我使用3台master来做高可用,如果是虚机的话不最好不要克隆
- 192.168.31.105:6443 #为VIP
- kube-apiserver #三台节点
- kube-schedulet #三台节点
- kube-controller-manager #三台节点
- ETCD #三台节点
需要注意的是在master节点需要将CPU设置为2,kubeadm安装cpu需要为2
二.初始化环境
1.批量修改主机名,以及免密
hostnamectl set-hostname k8s01 #所有机器按照要求修改
bash #刷新主机名
#配置host
cat >> /etc/hosts <<EOF
192.168.31.100 k8s-01
192.168.31.101 k8s-02
192.168.31.102 k8s-03
192.168.31.103 k8s-04
192.168.31.104 k8s-05
EOF
#设置k8s-01为分发机 (只需要在k8s-01服务器操作即可)
wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo
curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
yum install -y expect
#分发公钥
ssh-keygen -t rsa -P "" -f /root/.ssh/id_rsa
for i in k8s-01 k8s-02 k8s-03 k8s-04 k8s-05;do
expect -c "
spawn ssh-copy-id -i /root/.ssh/id_rsa.pub root@$i
expect {
\"*yes/no*\" {send \"yes\r\"; exp_continue}
\"*password*\" {send \"123456\r\"; exp_continue}
\"*Password*\" {send \"123456\r\";}
} "
done
所有节点关闭Selinux、iptables、swap分区
systemctl stop firewalld
systemctl disable firewalld
iptables -F && iptables -X && iptables -F -t nat && iptables -X -t nat
iptables -P FORWARD ACCEPT
swapoff -a
sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab
setenforce 0
sed -i 's/^SELINUX=.*/SELINUX=disabled/' /etc/selinux/config
2.升级内核 (可选方案)
目前官方推荐内核版本大于3.10,因为kubernetes 1.18版本还是属于较新版本,如果不用最新的内核,个人会担心出现一些故障问题等。
rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-3.el7.elrepo.noarch.rpm
#默认安装为最新内核
yum --enablerepo=elrepo-kernel install kernel-ml
#修改内核顺序
grub2-set-default 0 && grub2-mkconfig -o /etc/grub2.cfg
#使用下面命令看看确认下是否启动默认内核指向上面安装的内核
grubby --default-kernel
#这里的输出结果应该为我们升级后的内核信息
reboot
#可以等所有初始化步骤结束进行reboot操作
在Kubernetes 1.18版本出现DNS解析异常,原因是最新Kubernetes使用IPVS模块比较新,需要内核系统版本支持,所以希望大家都升级为最新内核issues
3.所有节点配置yum源
curl -o /etc/yum.repos.d/CentOS-Base.repo https://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
新安装的服务器可以安装下面的软件包,可以解决99%的依赖问题
yum -y install gcc gcc-c++ make autoconf libtool-ltdl-devel gd-devel freetype-devel libxml2-devel libjpeg-devel libpng-devel openssh-clients openssl-devel curl-devel bison patch libmcrypt-devel libmhash-devel ncurses-devel binutils compat-libstdc++-33 elfutils-libelf elfutils-libelf-devel glibc glibc-common glibc-devel libgcj libtiff pam-devel libicu libicu-devel gettext-devel libaio-devel libaio libgcc libstdc++ libstdc++-devel unixODBC unixODBC-devel numactl-devel glibc-headers sudo bzip2 mlocate flex lrzsz sysstat lsof setuptool system-config-network-tui system-config-firewall-tui ntsysv ntp pv lz4 dos2unix unix2dos rsync dstat iotop innotop mytop telnet iftop expect cmake nc gnuplot screen xorg-x11-utils xorg-x11-xinit rdate bc expat-devel compat-expat1 tcpdump sysstat man nmap curl lrzsz elinks finger bind-utils traceroute mtr ntpdate zip unzip vim wget net-tools
4.由于开启内核 ipv4 转发需要加载 br_netfilter 模块,所以加载下该模块,每台节点:
modprobe br_netfilter
modprobe ip_conntrack
5.优化内核参数
cat > kubernetes.conf <<EOF
net.bridge.bridge-nf-call-iptables=1
net.bridge.bridge-nf-call-ip6tables=1
net.ipv4.ip_forward=1
vm.swappiness=0 # 禁止使用 swap 空间,只有当系统 OOM 时才允许使用它
vm.overcommit_memory=1 # 不检查物理内存是否够用
vm.panic_on_oom=0 # 开启 OOM
fs.inotify.max_user_instances=8192
fs.inotify.max_user_watches=1048576
fs.file-max=52706963
fs.nr_open=52706963
net.ipv6.conf.all.disable_ipv6=1
net.netfilter.nf_conntrack_max=2310720
EOF
cp kubernetes.conf /etc/sysctl.d/kubernetes.conf
sysctl -p /etc/sysctl.d/kubernetes.conf
#分发到所有节点
for i in k8s-02 k8s-03 k8s-04 k8s-05
do
scp kubernetes.conf root@$i:/etc/sysctl.d/
ssh root@$i sysctl -p /etc/sysctl.d/kubernetes.conf
done
bridge-nf 使得netfilter可以对Linux网桥上的 IPv4/ARP/IPv6 包过滤。比如,设置net.bridge.bridge-nf-call-iptables=1后,二层的网桥在转发包时也会被 iptables的 FORWARD 规则所过滤。常用的选项包括:
net.bridge.bridge-nf-call-arptables:是否在 arptables 的 FORWARD 中过滤网桥的 ARP 包
net.bridge.bridge-nf-call-ip6tables:是否在 ip6tables 链中过滤 IPv6 包
net.bridge.bridge-nf-call-iptables:是否在 iptables 链中过滤 IPv4 包
net.bridge.bridge-nf-filter-vlan-tagged:是否在 iptables/arptables 中过滤打了 vlan 标签的包。
6.所有节点安装ipvs
为什么要使用IPVS,从k8s的1.8版本开始,kube-proxy引入了IPVS模式,IPVS模式与iptables同样基于Netfilter,但是采用的hash表,因此当service数量达到一定规模时,hash查表的速度优势就会显现出来,从而提高service的服务性能。
ipvs依赖于nf_conntrack_ipv4内核模块,4.19包括之后内核里改名为nf_conntrack,1.13.1之前的kube-proxy的代码里没有加判断一直用的nf_conntrack_ipv4,好像是1.13.1后的kube-proxy代码里增加了判断,我测试了是会去load nf_conntrack使用ipvs正常
cat > /etc/sysconfig/modules/ipvs.modules <<EOF
#!/bin/bash
modprobe -- ip_vs
modprobe -- ip_vs_rr
modprobe -- ip_vs_wrr
modprobe -- ip_vs_sh
modprobe -- nf_conntrack
EOF
chmod 755 /etc/sysconfig/modules/ipvs.modules && bash /etc/sysconfig/modules/ipvs.modules && lsmod | grep -e ip_vs -e nf_conntrack
#查看是否已经正确加载所需的内核模块
7.所有节点安装ipset
yum install ipset -y
iptables是Linux服务器上进行网络隔离的核心技术,内核在处理网络请求时会对iptables中的策略进行逐条解析,因此当策略较多时效率较低;而是用IPSet技术可以将策略中的五元组(协议,源地址,源端口,目的地址,目的端口)合并到有限的集合中,可以大大减少iptables策略条目从而提高效率。测试结果显示IPSet方式效率将比iptables提高100倍
为了方面ipvs管理,这里安装一下ipvsadm
yum install ipvsadm -y
8.所有节点设置系统时区
#将当前的 UTC 时间写入硬件时钟
timedatectl set-timezone Asia/Shanghai
timedatectl set-local-rtc 0
#重启依赖于系统时间的服务
systemctl restart rsyslog
systemctl restart crond
9/最后一步最好update一下 (可选操作)
yum update -y
三.安装各模块
安装配置Docker
1.docker安装配置需要在所有节点上操作
export VERSION=19.03
curl -fsSL "https://get.docker.com/" | bash -s -- --mirror Aliyun
所有机器配置加速源并配置docker的启动参数使用systemd,使用systemd是官方的建议
mkdir -p /etc/docker/
cat>/etc/docker/daemon.json<<EOF
{
"exec-opts": ["native.cgroupdriver=systemd"],
"registry-mirrors": [
"https://fz5yth0r.mirror.aliyuncs.com",
"https://dockerhub.mirrors.nwafu.edu.cn/",
"https://mirror.ccs.tencentyun.com",
"https://docker.mirrors.ustc.edu.cn/",
"https://reg-mirror.qiniu.com",
"http://hub-mirror.c.163.com/",
"https://registry.docker-cn.com"
],
"storage-driver": "overlay2",
"storage-opts": [
"overlay2.override_kernel_check=true"
],
"log-driver": "json-file",
"log-opts": {
"max-size": "100m",
"max-file": "3"
}
}
EOF
2.启动docker,检查状态是否正常
systemctl enable --now docker
3.查看docker info
[root@k8s-02 sysctl.d]# docker info
Client:
Debug Mode: false
Server:
Containers: 0
Running: 0
Paused: 0
Stopped: 0
Images: 0
Server Version: 19.03.10
Storage Driver: overlay2
Backing Filesystem: xfs
Supports d_type: true
Native Overlay Diff: true
Logging Driver: json-file
Cgroup Driver: systemd
Plugins:
Volume: local
Network: bridge host ipvlan macvlan null overlay
Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
Swarm: inactive
Runtimes: runc
Default Runtime: runc
Init Binary: docker-init
containerd version: 7ad184331fa3e55e52b890ea95e65ba581ae3429
runc version: dc9208a3303feef5b3839f4323d9beb36df0a9dd
init version: fec3683
Security Options:
seccomp
Profile: default
Kernel Version: 5.6.4-1.el7.elrepo.x86_64
Operating System: CentOS Linux 7 (Core)
OSType: linux
Architecture: x86_64
CPUs: 1
Total Memory: 1.915GiB
Name: k8s-02
ID: NVAE:PBC5:5AE5:TEW5:FWUQ:H4RQ:J6TD:J5KP:ZZS3:QUJF:ZOS3:4QET
Docker Root Dir: /var/lib/docker
Debug Mode: false
Registry: https://index.docker.io/v1/
Labels:
Experimental: false
Insecure Registries:
127.0.0.0/8
Registry Mirrors:
https://fz5yth0r.mirror.aliyuncs.com/
https://dockerhub.mirrors.nwafu.edu.cn/
https://mirror.ccs.tencentyun.com/
https://docker.mirrors.ustc.edu.cn/
https://reg-mirror.qiniu.com/
http://hub-mirror.c.163.com/
https://registry.docker-cn.com/
Live Restore Enabled: false
4.查看docker版本
[root@k8s-01 ~]# docker version
Client: Docker Engine - Community
Version: 19.03.10
API version: 1.40
Go version: go1.13.10
Git commit: 9424aeaee9
Built: Thu May 28 22:18:06 2020
OS/Arch: linux/amd64
Experimental: false
Server: Docker Engine - Community
Engine:
Version: 19.03.10
API version: 1.40 (minimum version 1.12)
Go version: go1.13.10
Git commit: 9424aeaee9
Built: Thu May 28 22:16:43 2020
OS/Arch: linux/amd64
Experimental: false
containerd:
Version: 1.2.13
GitCommit: 7ad184331fa3e55e52b890ea95e65ba581ae3429
runc:
Version: 1.0.0-rc10
GitCommit: dc9208a3303feef5b3839f4323d9beb36df0a9dd
docker-init:
Version: 0.18.0
GitCommit: fec3683
安装kubeadm
1.默认yum源在国外,这里需要修改为国内阿里源
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=0
EOF
2.master节点安装
#这里我在k8s-01 k8s-02 k8s-03执行master节点操作
yum install -y \
kubeadm-1.18.3 \
kubectl-1.18.3 \
kubelet-1.18.3 \
--disableexcludes=kubernetes && \
systemctl enable kubelet
#kubeadm 安装集群
#kubectl 通过命令行访问apiserver
#kubelet 负责Pod对应容器的创建、停止等任务
#node节点不需要安装kubectl,kubectl是一个agent读取kubeconfig访问api-server来操作集群,node节点一般不需要
3.node节点安装
#node节点安装默认是在所有节点安装,但是k8s中的master节点已经安装过了,我们就只在k8s-04 k8s-05中安装
yum install -y \
kubeadm-1.18.3 \
kubelet-1.18.3 \
--disableexcludes=kubernetes && \
systemctl enable kubelet
api-server 高可用部署 (单master可跳过)
我这里的环境是虚拟机,如果是云环境可以直接用slb的方式,这一步可以跳过。 虚拟机这里使用nginx local proxy
1.需要在master节点安装
#首先我们在原有的基础上添加一个host,只需要在master节点上执行即可
cat >>/etc/hosts<< EOF
192.168.31.100 k8s-master-01
192.168.31.101 k8s-master-02
192.168.31.102 k8s-master-03
192.168.31.105 k8s-master
EOF
2.添加nginx配置文件
mkdir -p /etc/kubernetes
cat > /etc/kubernetes/nginx.conf << EOF
user nginx nginx;
worker_processes auto;
events {
worker_connections 20240;
use epoll;
}
error_log /var/log/nginx_error.log info;
stream {
upstream kube-servers {
hash $remote_addr consistent;
server k8s-master-01:6443 weight=5 max_fails=1 fail_timeout=3s; #这里可以写IP
server k8s-master-02:6443 weight=5 max_fails=1 fail_timeout=3s;
server k8s-master-03:6443 weight=5 max_fails=1 fail_timeout=3s;
}
server {
listen 8443 reuseport;
proxy_connect_timeout 3s;
# 加大timeout
proxy_timeout 3000s;
proxy_pass kube-servers;
}
}
EOF
3.在master节点启动nginx容器
#这里我使用容器运行nginx,当然自己也可以写成staticPod的yaml在init的阶段放入目录里,或者二进制安装nginx
docker run --restart=always \
-v /etc/kubernetes/nginx.conf:/etc/nginx/nginx.conf \
-v /etc/localtime:/etc/localtime:ro \
--name k8s \
--net host \
-d \
nginx:alpine
4.启动完毕可以检查看一下
[root@k8s-01 ~]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
d8b3955bda68 nginx:alpine "nginx -g 'daemon of…" 2 minutes ago Up 2 minutes k8s
[root@k8s-01 ~]# lsof -i:8443
lsof: no pwd entry for UID 101
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
nginx 3360 root 5u IPv4 58860 0t0 TCP *:pcsync-https (LISTEN)
lsof: no pwd entry for UID 101
nginx 3374 101 5u IPv4 58860 0t0 TCP *:pcsync-https (LISTEN)
配置keeplive服务
1.高可用方案需要一个VIP,供集群内部访问,在所有master节点安装
yum install -y keepalived
2.配置keeplived服务
cat > /etc/keepalived/keepalived.conf <<EOF
! Configuration File for keepalived
global_defs {
router_id 192.168.31.100 #节点ip,master每个节点配置自己的IP
}
vrrp_script chk_nginx {
script "/etc/keepalived/check_port.sh 8443"
interval 2
weight -20
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 251
priority 100
advert_int 1
mcast_src_ip 192.168.31.100 #节点IP
nopreempt
authentication {
auth_type PASS
auth_pass 11111111
}
track_script {
chk_nginx
}
virtual_ipaddress {
192.168.31.105 #VIP
}
}
EOF
#编写健康检查脚本
vim /etc/keepalived/check_port.sh
CHK_PORT=$1
if [ -n "$CHK_PORT" ];then
PORT_PROCESS=`ss -lt|grep $CHK_PORT|wc -l`
if [ $PORT_PROCESS -eq 0 ];then
echo "Port $CHK_PORT Is Not Used,End."
exit 1
fi
else
echo "Check Port Cant Be Empty!"
fi
3.启动keepalived
systemctl enable --now keepalived
测试vip是否正常
ping vip
配置kubeadm
1.这里我们在k8s-01上配置打印init默认配置信息
kubeadm config print init-defaults >kubeadm-init.yaml
2.默认配置如下
[root@k8s-01 ~]# cat kubeadm-init.yaml
apiVersion: kubeadm.k8s.io/v1beta2
bootstrapTokens:
- groups:
- system:bootstrappers:kubeadm:default-node-token
token: abcdef.0123456789abcdef
ttl: 24h0m0s
usages:
- signing
- authentication
kind: InitConfiguration
localAPIEndpoint:
advertiseAddress: 1.2.3.4
bindPort: 6443
nodeRegistration:
criSocket: /var/run/dockershim.sock
name: k8s-01
taints:
- effect: NoSchedule
key: node-role.kubernetes.io/master
---
apiServer:
timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta2
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controllerManager: {}
dns:
type: CoreDNS
etcd:
local:
dataDir: /var/lib/etcd
imageRepository: k8s.gcr.io
kind: ClusterConfiguration
kubernetesVersion: v1.18.0
networking:
dnsDomain: cluster.local
serviceSubnet: 10.96.0.0/12
scheduler: {}
3.修改初始化文件
请对应我的IP进行配置,这里主要是master的IP.可以复制我的,但是主机名等要和我相同
apiVersion: kubeadm.k8s.io/v1beta2
kind: InitConfiguration
localAPIEndpoint:
advertiseAddress: 192.168.31.100 #master ip,这里不可以填写VIP和域名
bindPort: 6443
nodeRegistration:
criSocket: /var/run/dockershim.sock
name: k8s-01 #创建集群的节点
taints:
- effect: NoSchedule #标签,默认资源不调度到master上
key: node-role.kubernetes.io/master
---
apiServer:
timeoutForControlPlane: 4m0s
extraArgs:
authorization-mode: "Node,RBAC"
enable-admission-plugins: "NamespaceLifecycle,LimitRanger,ServiceAccount,PersistentVolumeClaimResize,DefaultStorageClass,DefaultTolerationSeconds,NodeRestriction,MutatingAdmissionWebhook,ValidatingAdmissionWebhook,ResourceQuota,Priority,PodPreset"
runtime-config: api/all=true,settings.k8s.io/v1alpha1=true
storage-backend: etcd3
etcd-servers: https://192.168.31.100:2379,https://192.168.31.101:2379,https://192.168.31.102:2379 #etcd集群节点ip
certSANs: #master节点信息
- 10.96.0.1
- 127.0.0.1
- localhost
- k8s-master
- k8s-master-01
- k8s-master-02
- k8s-master-03
- 192.168.31.100
- 192.168.31.101
- 192.168.31.102
- master
- kubernetes
- kubernetes.default
- kubernetes.default.svc
- kubernetes.default.svc.cluster.local
extraVolumes:
- hostPath: /etc/localtime
mountPath: /etc/localtime
name: localtime
readOnly: true
apiVersion: kubeadm.k8s.io/v1beta2
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controllerManager:
extraArgs:
bind-address: "0.0.0.0"
experimental-cluster-signing-duration: 867000h
extraVolumes:
- hostPath: /etc/localtime
mountPath: /etc/localtime
name: localtime
readOnly: true
dns:
type: CoreDNS
imageRepository: coredns
imageTag: 1.6.7 #coredns版本
etcd:
local:
dataDir: /var/lib/etcd #etcd数据存储目录
imageRepository: quay.io/coreos
imageTag: v3.4.7 #etcd版本
serverCertSANs:
- master
- 192.168.31.100
- 192.168.31.101
- 192.168.31.102
- k8s-01
- k8s-02
- k8s-03
peerCertSANs:
- master
- 192.168.31.100
- 192.168.31.101
- 192.168.31.102
- k8s-01
- k8s-02
- k8s-03
extraArgs:
auto-compaction-retention: "1h"
max-request-bytes: "33554432"
quota-backend-bytes: "8589934592"
enable-v2: "false"
imageRepository: registry.aliyuncs.com/google_containers
kind: ClusterConfiguration
kubernetesVersion: v1.18.2 #k8s版本
networking:
dnsDomain: cluster.local
serviceSubnet: 10.96.0.0/12 #svc ip网段
podSubnet: 10.244.0.0/16 #pod 网段
controlPlaneEndpoint: k8s-master:8443 #vip域名或者ip
scheduler:
extraArgs:
bind-address: "0.0.0.0"
extraVolumes:
- hostPath: /etc/localtime #时间同步
mountPath: /etc/localtime
name: localtime
readOnly: true
---
apiVersion: kubeproxy.config.k8s.io/v1alpha1
kind: KubeProxyConfiguration # https://godoc.org/k8s.io/kube-proxy/config/v1alpha1#KubeProxyConfiguration
mode: ipvs # or iptables
---
apiVersion: kubelet.config.k8s.io/v1beta1
kind: KubeletConfiguration # https://godoc.org/k8s.io/kubelet/config/v1beta1#KubeletConfiguration
cgroupDriver: systemd
failSwapOn: true # 如果开启swap则设置为false
4.检查文件是否错误,忽略warning,错误的话会抛出error,没错则会输出到包含字符串kubeadm join xxx
kubeadm init --config init.yaml --dry-run
kubeadm init参数说明
--apiserver-advertise-address string 设置 apiserver 绑定的 IP.
--apiserver-bind-port int32 设置apiserver 监听的端口. (默认 6443)
--apiserver-cert-extra-sans strings api证书中指定额外的Subject Alternative Names (SANs) 可以是IP 也可以是DNS名称。 证书是和SAN绑定的。
--cert-dir string 证书存放的目录 (默认 "/etc/kubernetes/pki")
--certificate-key string kubeadm-cert secret 中 用于加密 control-plane 证书的key
--config string kubeadm 配置文件的路径.
--cri-socket string CRI socket 文件路径,如果为空 kubeadm 将自动发现相关的socket文件; 只有当机器中存在多个 CRI socket 或者 存在非标准 CRI socket 时才指定.
--dry-run 测试,并不真正执行;输出运行后的结果.
--feature-gates string 指定启用哪些额外的feature 使用 key=value 对的形式。
-h, --help 帮助文档
--ignore-preflight-errors strings 忽略前置检查错误,被忽略的错误将被显示为警告. 例子: 'IsPrivilegedUser,Swap'. Value 'all' ignores errors from all checks.
--image-repository string 选择拉取 control plane images 的镜像repo (default "k8s.gcr.io")
--kubernetes-version string 选择K8S版本. (default "stable-1")
--node-name string 指定node的名称,默认使用 node 的 hostname.
--pod-network-cidr string 指定 pod 的网络, control plane 会自动将 网络发布到其他节点的node,让其上启动的容器使用此网络
--service-cidr string 指定service 的IP 范围. (default "10.96.0.0/12")
--service-dns-domain string 指定 service 的 dns 后缀, e.g. "myorg.internal". (default "cluster.local")
--skip-certificate-key-print 不打印 control-plane 用于加密证书的key.
--skip-phases strings 跳过指定的阶段(phase)
--skip-token-print 不打印 kubeadm init 生成的 default bootstrap token
--token string 指定 node 和control plane 之间,简历双向认证的token ,格式为 [a-z0-9]{6}\.[a-z0-9]{16} - e.g. abcdef.0123456789abcdef
--token-ttl duration token 自动删除的时间间隔。 (e.g. 1s, 2m, 3h). 如果设置为 '0', token 永不过期 (default 24h0m0s)
--upload-certs 上传 control-plane 证书到 kubeadm-certs Secret.
4.检查镜像是否正确,版本号不正确就把yaml里的kubernetesVersion取消注释写上自己对应的版本号
kubeadm config images list --config init.yaml
5.预拉取镜像
kubeadm config images pull --config init.yaml
6.在k8s-01上初始化
kubeadm init --config init.yaml --upload-certs
请保留结束后的2行输出!
7.init大致流程如下
preflight 预置检查
kubelet-start 生成 kubelet 配置,并重启kubelet
certs 生成认证
/etcd-ca 生成自签名CA以为etcd配置标识
/apiserver-etcd-client 生成apiserver用于访问etcd的证书
/etcd-healthcheck-client 生成liveness探针使用的证书,用于检查etcd 的 healtcheck 状态
/etcd-server 生成 etcd 服务使用的的证书
/etcd-peer 为etcd节点生成证书以相互通信
/ca 生成自签名的 Kubernetes CA,为其他 Kubernetes 组件预配标识
/apiserver 生成用于提供 Kubernetes API 的证书 api server端证书
/apiserver-kubelet-client 为 API 服务器生成证书以连接到 kubelet
/front-proxy-ca 生成自签名 CA 以预配front proxy 标识
/front-proxy-client 为前端代理客户端生成证书
/sa 生成用于对服务帐户令牌及其公钥进行签名的私钥
kubeconfig 生成 control plane 和 admin 管理员相关的kubeconfig 文件
/admin 生成admin 管理员和kubeadm 自身使用的kubeconfig文件
/kubelet 生成kebelet使用的,仅用于引导集群(bootstrap)的kubeconfig 文件
/controller-manager 生成 controller manager 使用的kubeconfig文件
/scheduler 生成 scheduler 使用的kubeconfig文件
kubelet-start 生成kubelet的环境变量文件/var/lib/kubelet/kubeadm-flags.env 和 配置信息文件 /var/lib/kubelet/config.yaml,然后 启动/重启 kubelet(systemd 模式)
control-plane 生成拉起 control plane(master)static Pod 的 manifest 文件
/apiserver 生成拉起 kube-apiserver 的 static Pod manifest
/controller-manager 生成拉起 kube-controller-manager 的static Pod manifest
/scheduler 生成拉起 kube-scheduler 的 static Pod manifest
etcd 生成本地 ETCD的 static Pod manifest 文件
/local 生成单节点本地 ETCD static Pod manifest 文件
upload-config 上传kubeadm和kubelet配置为 ConfigMap
/kubeadm 上传 kubeadm ClusterConfiguration 为 ConfigMap
/kubelet 上传 kubelet component config 为 ConfigMap
upload-certs 上传证书到 kubeadm-certs
mark-control-plane 标识节点为 control-plane
bootstrap-token 生成 bootstrap tokens 用于其他节点加入集群
addon 安装所需的插件以通过一致性测试
/coredns 安装 CoreDNS 插件
/kube-proxy 安装 kube-proxy 插件
8.记住init后打印的token,复制kubectl的kubeconfig,kubectl的kubeconfig路径默认是~/.kube/config
mkdir -p $HOME/.kube
cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
chown $(id -u):$(id -g) $HOME/.kube/config
9.初始化的配置文件为保存在configmap里面
kubectl -n kube-system get cm kubeadm-config -o yaml
10.手动拷贝(某些低版本不支持上传证书的时候操作) 我们1.18这个版本可以不执行(可选)
在前面我们已经添加了–upload-certs参数,这个参数是将我们的证书文件提交到secret中,所以可以不用在拷贝证书。低版本可能需要有拷贝证书的步骤
for node in k8s-02 k8s-03;do
ssh $node 'mkdir -p /etc/kubernetes/pki/etcd'
scp -r /etc/kubernetes/pki/ca.* $node:/etc/kubernetes/pki/
scp -r /etc/kubernetes/pki/sa.* $node:/etc/kubernetes/pki/
scp -r /etc/kubernetes/pki/front-proxy-ca.* $node:/etc/kubernetes/pki/
scp -r /etc/kubernetes/pki/etcd/ca.* $node:/etc/kubernetes/pki/etcd/
done
11.在其他master节点上执行join
#token如果忘记可以通过kubeadm token list查看
kubeadm join k8s-master:8443 --token 58msro.ou3s6067slh6orw7 \
--discovery-token-ca-cert-hash sha256:b2ffc7bd4b8c5d4cd6f5f016f7a19d49dba3090c5cb018827b712fa1138961b5 \
--control-plane --certificate-key d8272e844a395ad81d1cced7a6de6ebb52dd9be6ea93897fd608bd54aebdc45f
12.所有master创建kubeconfig
mkdir -p $HOME/.kube
cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
chown $(id -u):$(id -g) $HOME/.kube/config
配置etcdctl
1.最好在所有的master节点上执行
docker cp
docker ps -a | awk ‘/k8s_etcd/{print $1}’:/usr/local/bin/etcdctl /usr/local/bin/etcdctl
2.配置etcd参数
#注意修改ETCD节点ip
cat >/etc/profile.d/etcd.sh<<'EOF'
ETCD_CERET_DIR=/etc/kubernetes/pki/etcd/
ETCD_CA_FILE=ca.crt
ETCD_KEY_FILE=healthcheck-client.key
ETCD_CERT_FILE=healthcheck-client.crt
ETCD_EP=https://192.168.31.100:2379,https://192.168.31.101:2379,https://192.168.31.102:2379
alias etcd_v2="etcdctl --cert-file ${ETCD_CERET_DIR}/${ETCD_CERT_FILE} \
--key-file ${ETCD_CERET_DIR}/${ETCD_KEY_FILE} \
--ca-file ${ETCD_CERET_DIR}/${ETCD_CA_FILE} \
--endpoints $ETCD_EP"
alias etcd_v3="ETCDCTL_API=3 \
etcdctl \
--cert ${ETCD_CERET_DIR}/${ETCD_CERT_FILE} \
--key ${ETCD_CERET_DIR}/${ETCD_KEY_FILE} \
--cacert ${ETCD_CERET_DIR}/${ETCD_CA_FILE} \
--endpoints $ETCD_EP"
EOF
3.手动加载一下环境变量,如果需要多个master查看,那么将脚本分发到多个节点即可
[root@k8s-01 ~]# . /etc/profile.d/etcd.sh
[root@k8s-01 ~]# etcd_v3 endpoint status --write-out=table #下面是输出
+-----------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+
| ENDPOINT | ID | VERSION | DB SIZE | IS LEADER | IS LEARNER | RAFT TERM | RAFT INDEX | RAFT APPLIED INDEX | ERRORS |
+-----------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+
| https://192.168.31.100:2379 | c95fd6fdbb91a5 | 3.4.7 | 2.4 MB | false | false | 6 | 5656 | 5656 | |
| https://192.168.31.101:2379 | cfee13793e1cc392 | 3.4.7 | 2.3 MB | true | false | 6 | 5656 | 5656 | |
| https://192.168.31.102:2379 | c9662d268621483c | 3.4.7 | 2.3 MB | false | false | 6 | 5656 | 5656 | |
+-----------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+
Node 节点配置
- 初始化步骤
- 安装docker
- 安装nginx
- 安装kubeadm kubelet
1.添加node节点只需要执行下面的join就可以
#这个结果在我们初始化master的时候下面给的,一共2个配置,一个针对master节点,一个针对于node节点,请不要直接复制我的。根据自己的输出的结果复制
kubeadm join k8s-master:8443 --token 58msro.ou3s6067slh6orw7 \
--discovery-token-ca-cert-hash sha256:b2ffc7bd4b8c5d4cd6f5f016f7a19d49dba3090c5cb018827b712fa1138961b5
2.在node节点添加完毕可以在get node中查看到对应的节点
[root@k8s-01 ~]# kubectl get node
NAME STATUS ROLES AGE VERSION
k8s-01 NotReady master 44m v1.18.3
k8s-02 NotReady master 26m v1.18.3
k8s-03 NotReady master 25m v1.18.3
k8s-04 NotReady 68s v1.18.3
k8s-05 NotReady 63s v1.18.3
[root@k8s-01 ~]# kubectl get cs
NAME STATUS MESSAGE ERROR
scheduler Healthy ok
controller-manager Healthy ok
etcd-1 Healthy {"health":"true"}
etcd-0 Healthy {"health":"true"}
etcd-2 Healthy {"health":"true"}
3.默认情况下master节点不会进行调度,但是可能机器存在资源不够的情况下,如果想要放开节点。可以执行下面的命令
kubectl taint nodes k8s-01 node-role.kubernetes.io/master-
kubectl taint nodes k8s-02 node-role.kubernetes.io/master-
kubectl taint nodes k8s-03 node-role.kubernetes.io/master-
部署flannel
1.由于容器的网络暂时还没有,coredns无法分配的ip会处于pending状态,这里需要手动部署flannel插件
[root@k8s-01 ~]# kubectl -n kube-system get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
coredns-78c7b4d59d-c4dcl 0/1 Pending 0 45m
coredns-78c7b4d59d-d6rrv 0/1 Pending 0 45m
etcd-k8s-01 1/1 Running 0 46m 192.168.31.100 k8s-01
etcd-k8s-02 1/1 Running 0 28m 192.168.31.101 k8s-02
etcd-k8s-03 1/1 Running 0 27m 192.168.31.102 k8s-03
kube-apiserver-k8s-01 1/1 Running 0 46m 192.168.31.100 k8s-01
kube-apiserver-k8s-02 1/1 Running 0 28m 192.168.31.101 k8s-02
kube-apiserver-k8s-03 1/1 Running 0 27m 192.168.31.102 k8s-03
kube-controller-manager-k8s-01 1/1 Running 1 46m 192.168.31.100 k8s-01
kube-controller-manager-k8s-02 1/1 Running 0 28m 192.168.31.101 k8s-02
kube-controller-manager-k8s-03 1/1 Running 0 27m 192.168.31.102 k8s-03
kube-proxy-7rlb4 1/1 Running 0 27m 192.168.31.102 k8s-03
kube-proxy-c8kbl 1/1 Running 0 45m 192.168.31.100 k8s-01
kube-proxy-f87b8 1/1 Running 0 28m 192.168.31.101 k8s-02
kube-proxy-pcx6p 1/1 Running 1 2m59s 192.168.31.104 k8s-05
kube-proxy-zscwf 1/1 Running 1 3m4s 192.168.31.103 k8s-04
kube-scheduler-k8s-01 1/1 Running 1 46m 192.168.31.100 k8s-01
kube-scheduler-k8s-02 1/1 Running 0 28m 192.168.31.101 k8s-02
kube-scheduler-k8s-03 1/1 Running 0 27m 192.168.31.102 k8s-03
2.安装flannel
#手动打patch,后续扩的node也记得打下
nodes=`kubectl get node --no-headers | awk '{print $1}'`
for node in $nodes;do
cidr=`kubectl get node "$node" -o jsonpath='{.spec.podCIDRs[0]}'`
[ -z "$(kubectl get node $node -o jsonpath='{.spec.podCIDR}')" ] && {
kubectl patch node "$node" -p '{"spec":{"podCIDR":"'"$cidr"'"}}'
}
done
wget http://down.i4t.com/k8s1.18/kube-flannel.yml
kubectl apply -f kube-flannel.yml
3.flannel如果存在多网卡,需要在kube-flannel.yml中指定网卡
containers:
- name: kube-flannel
image: quay.io/coreos/flannel:v0.12.0-amd64
command:
- /opt/bin/flanneld
args:
- --ip-masq
- --kube-subnet-mgr
- --iface=eth0 # 如果是多网卡的话,指定内网网卡的名称
温馨提示: 在kubeadm.yaml文件中设置了podSubnet网段,同时在flannel中网段也要设置相同的。 (我这里默认就是相同的配置)
四.验证集群
1.验证
kubectl -n kube-system get pod -o wide
2.等kube-system命名空间下的Pod都为Running,这里先测试一下dns是否正常
cat<<EOF | kubectl apply -f -
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx
spec:
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- image: nginx:alpine
name: nginx
ports:
- containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
name: nginx
spec:
selector:
app: nginx
type: NodePort
ports:
- protocol: TCP
port: 80
targetPort: 80
nodePort: 30001
---
apiVersion: v1
kind: Pod
metadata:
name: busybox
namespace: default
spec:
containers:
- name: busybox
image: abcdocker9/centos:v1
command:
- sleep
- "3600"
imagePullPolicy: IfNotPresent
restartPolicy: Always
EOF
3.创建后Pod我们进行检查
[root@k8s-01 ~]# kubectl get pod,svc
NAME READY STATUS RESTARTS AGE
pod/busybox 1/1 Running 0 4m21s
pod/nginx-97499b967-lfvcq 1/1 Running 0 4m21s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.96.0.1 443/TCP 16h
service/nginx NodePort 10.96.21.46 80:30001/TCP 15h
4.使用nslookup查看是否能返回地址
[root@k8s-01 ~]# kubectl exec -ti busybox -- nslookup kubernetes
Server: 10.96.0.10
Address: 10.96.0.10#53
Name: kubernetes.default.svc.cluster.local
Address: 10.96.0.1
5.测试nginx svc以及Pod内部网络通信是否正常
for i in k8s-01 k8s-02 k8s-03 k8s-04 k8s-05
do
ssh root@$i curl -s 10.96.21.46 #nginx svc ip
ssh root@$i curl -s 10.244.3.4 #pod ip
done
6.端口我这里使用了nodeport,在集群任意节点访问节点IP:30001检查是否正常
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初始化集群(如果过程中出现问题,我们可以直接执行下面的命令进行初始化集群)
kubeadm reset
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