Kubernetes-3：k8s集群环境安装部署及常见报错解决方法

k8s集群安装

环境说明：

k8s-Master-Centos8 ip：192.168.152.53

k8s-Node1-Centos7 ip：192.168.152.253

k8s-Node2-Centos8 ip：192.168.152.252

注意：

Master与Node节点操作步骤基本一致

Node节点只需配置到本文的第6步即可

1、前期准备

#关闭防火墙
[root@Centos8 ~]# systemctl stop firewalld.service 

#关闭SElinux，永久关闭可修改/etc/selinux/config文件
[root@Centos8 ~]# setenforce 0    

#关闭Swap分区，防止将K8S安装至swap内存中
[root@Centos8 ~]# swapoff -a
[root@Centos8 ~]# sed -i '/swap/ s/^/#/g' /etc/fstab

#安装iptables并设置为空规则及开机自启
yum -y install iptables-services iptables
systemctl enable --now iptables.service
iptables -F  #清空规则
service iptables save  #保存
iptables -L  #检查是否为空规则

2、升级内核，建议 >= 4.4

#—————————————— Centos8 ————————————————#
#——————Centos8最好不要做升级，如果非要要建议也升级到4.4 ————————#
#——————以下只是演示升级过程，真实不要升级到5.6，貌似本身不支持nf_conntrack_ipv4 ————————#
#安装ELrepo仓库
rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
yum install https://www.elrepo.org/elrepo-release-8.0-2.el8.elrepo.noarch.rpm

#查看可用的系统内核包
yum --disablerepo="*" --enablerepo="elrepo-kernel" list available

#安装内核
yum --enablerepo=elrepo-kernel install kernel-ml

# 安装完毕后，查看现有所有内核
grubby --info=ALL

#设置启动内核
grubby --set-default /boot/vmlinuz-5.6.2-1.el8.elrepo.x86_64

#———————————————— Centos7 ————————————————#
#下载内核rpm包
rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-3.el7.elrepo.noarch.rpm

#指定包名安装新版kernel
yum --enablerepo=elrepo-kernel install -y kernel-lt

#设置默认启动的内核
grub2-set-default 'CentOS Linux (4.4.218-1.el7.elrepo.x86_64) 7 (Core)'

#———————————————— 以下相同 ————————————————#
#重启生效
systemctl reboot

#重新查看内核版本
[root@Centos8 ~]# uname -r
5.6.2-1.el8.elrepo.x86_64

3、设置kube-proxy开启ipvs的前置条件

modprobe br_netfilter

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_ipv4
EOF

chmod 755 /etc/sysconfig/modules/ipvs.modules && bash /etc/sysconfig/modules/ipvs.modules

# 查看是否加载成功ipvs模块
lsmod | grep -e ip_vs -e nf_conntrack_ipv4

　　nf_conntrack_ipv4 20480 4
　　nf_defrag_ipv4 16384 1 nf_conntrack_ipv4
　　ip_vs_sh 16384 0
　　ip_vs_wrr 16384 0
　　ip_vs_rr 16384 0
　　ip_vs 147456 6 ip_vs_rr,ip_vs_sh,ip_vs_wrr
　　nf_conntrack 114688 9 ip_vs,nf_nat,nf_nat_ipv4,nf_nat_ipv6,xt_conntrack,nf_nat_masquerade_ipv4,nf_conntrack_netlink,nf_conntrack_ipv4,nf_conntrack_ipv6
　　libcrc32c 16384 2 xfs,ip_vs

4、安装Docker

#安装环境
yum install -y yum-utils device-mapper-persistent-data lvm2

#添加docker仓库
yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

#安装dpcker
yum -y install docker-ce
报错：
   package docker-ce-3:19.03.8-3.el7.x86_64 requires containerd.io >= 1.2.2-3, but none of the providers can be installed

先安装containerd.io >= 1.2.2-3：
dnf install https://download.docker.com/linux/centos/7/x86_64/stable/Packages/containerd.io-1.2.6-3.3.el7.x86_64.rpm

再次安装docker：
yum -y install docker-ce

#启动docker，并设置开机自启
systemctl enable --now docker.service

#配置daemon.设置默认的cgroup组为systemd，并使docker的日志以json形式输出
cat > /etc/docker/daemon.json <<EOF
{
    "exec-opts": ["native.cgroupdriver=systemd"],
    "log-driver": "json-file",
    "log-opts": {
        "max-size": "100m"
    }
}
EOF

#创建配置文件目录
mkdir -p /etc/systemd/system/docker.service.d

#重新加载daemon 及 重启docker
systemctl daemon-reload && systemctl restart docker.service

5、安装Kubeadm（主从配置）

#配置yum仓库
cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=http://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=0
repo_gpgcheck=0
gpgkey=http://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
EOF

#安装kubeadm、kubectl、kubelet
yum -y install kubeadm-1.15.1 kubectl-1.15.1 kubelet-1.15.1

#设置开机自启
systemctl enable kubelet.service

6、拉取初始化镜像

vim initimage.sh
...
#!/usr/bin/env bash
K8S_VERSION=v1.15.1
ETCD_VERSION=3.3.10
DASHBOARD_VERSION=v1.8.3
FLANNEL_VERSION=v0.10.0-amd64
DNS_VERSION=1.3.1
PAUSE_VERSION=3.1
# 基本组件
docker pull mirrorgooglecontainers/kube-apiserver-amd64:$K8S_VERSION
docker pull mirrorgooglecontainers/kube-controller-manager-amd64:$K8S_VERSION
docker pull mirrorgooglecontainers/kube-scheduler-amd64:$K8S_VERSION
docker pull mirrorgooglecontainers/kube-proxy-amd64:$K8S_VERSION
docker pull mirrorgooglecontainers/etcd-amd64:$ETCD_VERSION
docker pull mirrorgooglecontainers/pause:$PAUSE_VERSION
docker pull coredns/coredns:$DNS_VERSION

# 修改tag
docker tag mirrorgooglecontainers/kube-apiserver-amd64:$K8S_VERSION k8s.gcr.io/kube-apiserver:$K8S_VERSION
docker tag mirrorgooglecontainers/kube-controller-manager-amd64:$K8S_VERSION k8s.gcr.io/kube-controller-manager:$K8S_VERSION
docker tag mirrorgooglecontainers/kube-scheduler-amd64:$K8S_VERSION k8s.gcr.io/kube-scheduler:$K8S_VERSION
docker tag mirrorgooglecontainers/kube-proxy-amd64:$K8S_VERSION k8s.gcr.io/kube-proxy:$K8S_VERSION
docker tag mirrorgooglecontainers/etcd-amd64:$ETCD_VERSION k8s.gcr.io/etcd:$ETCD_VERSION
docker tag mirrorgooglecontainers/pause:$PAUSE_VERSION k8s.gcr.io/pause:$PAUSE_VERSION
docker tag coredns/coredns:$DNS_VERSION k8s.gcr.io/coredns:$DNS_VERSION

#删除冗余的images
docker rmi mirrorgooglecontainers/kube-apiserver-amd64:$K8S_VERSION
docker rmi mirrorgooglecontainers/kube-controller-manager-amd64:$K8S_VERSION
docker rmi mirrorgooglecontainers/kube-scheduler-amd64:$K8S_VERSION
docker rmi mirrorgooglecontainers/kube-proxy-amd64:$K8S_VERSION
docker rmi mirrorgooglecontainers/etcd-amd64:$ETCD_VERSION
docker rmi mirrorgooglecontainers/pause:$PAUSE_VERSION
docker rmi coredns/coredns:$DNS_VERSION
...
chmod +x initimage.sh

#执行此脚本，开始导入镜像...
./initimage.sh

[root@Centos8 ]# docker images 
REPOSITORY                           TAG                 IMAGE ID            CREATED             SIZE
quay.io/coreos/flannel               v0.12.0-amd64       4e9f801d2217        4 weeks ago         52.8MB
k8s.gcr.io/kube-scheduler            v1.15.1             b0b3c4c404da        8 months ago        81.1MB
k8s.gcr.io/kube-controller-manager   v1.15.1             d75082f1d121        8 months ago        159MB
k8s.gcr.io/kube-proxy                v1.15.1             89a062da739d        8 months ago        82.4MB
k8s.gcr.io/kube-apiserver            v1.15.1             68c3eb07bfc3        8 months ago        207MB
k8s.gcr.io/coredns                   1.3.1               eb516548c180        15 months ago       40.3MB
k8s.gcr.io/etcd                      3.3.10              2c4adeb21b4f        16 months ago       258MB
k8s.gcr.io/pause                     3.1                 da86e6ba6ca1        2 years ago         742kB

7、初始化主节点

#打印k8s默认的初始化配置文件至kubeadm-conf.yaml中
kubeadm config print init-defaults > kubeadm-conf.yaml

#修改kubeadm-conf.yaml
vim kubeadm-conf.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: 192.168.152.53    #此处需要修改为你的真实ip
  bindPort: 6443
nodeRegistration:
  criSocket: /var/run/dockershim.sock
  name: centos8
  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: v1.15.1   #版本信息修改一致
networking:
  dnsDomain: cluster.local
  podSubnet: "10.244.0.0/16"  #添加此配置，用于指定flannel的默认PodNet网段
  serviceSubnet: 10.96.0.0/12
scheduler: {}
---    #以下为新增配置，将默认的调度方式改为ipvs
apiVersion: kubeproxy.config.k8s.io/v1alpha1
kind: KubeProxyConfiguration
featureGates:
  SupportIPVSProxyMode: true
mode: ipvs
...

#开始初始化
kubeadm init --config=kubeadm-config.yaml --experimental-upload-certs | tee kubeadm-init.log
报错：
    [ERROR NumCPU]: the number of available CPUs 1 is less than the required 2
    很明显，cpu数目小于所需的2，重新设置一个虚拟机CPU个数就ok

初始化成功回显：
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

kubeadm join 192.168.152.53:6443 --token abcdef.0123456789abcdef 
    --discovery-token-ca-cert-hash sha256:50ca5375950abfa05cd4bd37dfb60e9ccd078083aeca49fa8bb6275c13d2a2cd 

#根据回显创建文件及目录
#目的为保存 kubectl 与 api server 交互时的缓存，交互过程为https协议
mkdir -p $HOME/.kube
cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
chown $(id -u):$(id -g) $HOME/.kube/config

#查看当前拥有节点，可见状态为NotReady，是因为没有添加网络
[root@Centos8 .kube]# kubectl get node 
NAME      STATUS     ROLES    AGE    VERSION
centos8   NotReady   master   4m1s   v1.15.1

#添加flannel网络
mkdir -p install-k8s/plugin/flannel
mkdir -p install-k8s/core
cd install-k8s/core
mv /etc/kubernetes/kubeadm-init.log /etc/kubernetes/kubeadm-config.yaml ./
cd ../plugin/flannel
#下载flannel.yml
wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
#执行yaml文件
kubectl create -f kube-flannel.yml

#构建完成，查看当前名称空间为kube-system的pod状态，-n 指定名称空间
[root@Centos8 core]# kubectl get pod -n kube-system
NAME                              READY   STATUS             RESTARTS   AGE
coredns-5c98db65d4-5gwmj          0/1     CrashLoopBackOff   22         91m
coredns-5c98db65d4-c277w          0/1     CrashLoopBackOff   22         91m
etcd-centos8                      1/1     Running            0          90m
kube-apiserver-centos8            1/1     Running            0          90m
kube-controller-manager-centos8   1/1     Running            0          90m
kube-flannel-ds-amd64-ggghn       1/1     Running            0          8m45s
kube-proxy-gslw2                  1/1     Running            0          91m
kube-scheduler-centos8            1/1     Running            0          90m

#构建完成后，网卡界面会显示flannel信息
[root@Centos8 core]# ifconfig
flannel.1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1450
        inet 10.244.0.0  netmask 255.255.255.255  broadcast 0.0.0.0
        inet6 fe80::4019:beff:fe7c:5582  prefixlen 64  scopeid 0x20<link>
        ether 42:19:be:7c:55:82  txqueuelen 0  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 13 overruns 0  carrier 0  collisions 0

　#网络加载成功，状态变为Ready

　[root@Centos8 ~]# kubectl get node
　NAME 　 STATUS ROLES AGE VERSION
　centos8 Ready master 53d v1.15.1

8、配置从节点与主节点关联

# 直接将kubeadm-init.log的最后一句回显在node节点运行即可
[root@kube-node2 ~]# kubeadm join 192.168.152.53:6443 --token abcdef.0123456789abcdef 
>     --discovery-token-ca-cert-hash sha256:c291b4fc646b5925299f8cdf7fafe33ad9c0505a1609041d8c8214d104eb08da

[root@kube-node2 ~]# kubeadm join 192.168.152.53:6443 --token abcdef.0123456789abcdef 
>     --discovery-token-ca-cert-hash sha256:c291b4fc646b5925299f8cdf7fafe33ad9c0505a1609041d8c8214d104eb08da

补充：

node节点为了方便以后的部署和扩展，我采用Ansible自动化安装docker及k8s。

ansible服务端为k8s的MASTER端：192.168.152.53

客户端根据node节点需求来控制

#### 注意：所有的操作及文件都在192.168.152.53中 ####
[root@Centos8 ansible]# pwd
/root/ansible

*** 先编辑好导入导出images的脚本 ***
[root@Centos8 ansible]# cat saveImages.sh  #导出镜像脚本
#!/usr/bin/env bash

IMAGESNAME=(`docker images | awk '/ago/{print $1}'`)
IMAGESTAG=(`docker images | awk '/ago/{print $2}'`)
IPADDR1='192.168.152.253'
IPADDR2='192.168.152.252'

if [[ -d /root/images ]];then
  for i in `seq 0 6`;do
    docker save > /root/images/${i}.tar.gz ${IMAGESNAME[$i]}:${IMAGESTAG[$i]}
    scp /root/images/${i}.tar.gz ${IPADDR1}:/root/
    scp /root/images/${i}.tar.gz ${IPADDR2}:/root/
  done
else
  mkdir -p /root/images
  for i in `seq 0 6`;do
    docker save > /root/images/${IMAGESNAME[$i]}.tar.gz ${IMAGESNAME[$i]}:${IMAGESTAG[$i]}
    scp /root/images/${i}.tar.gz ${IPADDR1}:/root/
    scp /root/images/${i}.tar.gz ${IPADDR2}:/root/
  done
fi

[root@Centos8 ansible]# cat loadImages.sh  #导入镜像脚本
#!/usr/bin/env bash

for i in `seq 0 6`;do
  docker load < /root/${i}.tar.gz && rm -f /root/${i}.tar.gz
done

*** 在本地执行saveImages.sh ***
./saveImages.sh

*** 创建PlayBook ***
[root@Centos8 ansible]# vim kuber.yaml
...
---
- name: Install docker and k8s
  hosts: all
  tasks:
  - block:
    - name: Add repository
      shell: yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
    - name: install docker-ass
      yum:
        name:
          - yum-utils
          - device-mapper-persistent-data
          - lvm2
          - https://download.docker.com/linux/centos/7/x86_64/stable/Packages/containerd.io-1.2.6-3.3.el7.x86_64.rpm
          - docker-ce
        state: latest
    - name: mkdir docker.service.d
      file:
        path: '{{ item }}'
        state: directory
      loop:
      - /etc/docker
      - /etc/systemd/system/docker.service.d
    - name: Copy daemon.json
      copy:
        src: /etc/docker/daemon.json
        dest: /etc/docker/daemon.json
    - name: daemon-reload
      shell: systemctl daemon-reload
    - name: Start docker
      service:
        name: docker
        state: restarted
        enabled: yes
    rescue:
    - debug:
        msg: 'docker Installation failed!'
  - name: Copy using inline content
    copy:
      content: 
        '[kubernetes]
        
        name=Kubernetes
        
        baseurl=http://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
        
        enabled=1
        
        gpgcheck=0
        
        repo_gpgcheck=0
        
        gpgkey=http://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg'
      dest: /etc/yum.repos.d/kubernetes.repo
  - name: Install k8s
    yum:
      name:
        - kubeadm-1.15.1
        - kubectl-1.15.1
        - kubelet-1.15.1
      state: present
  - name: Start kubelet
    service:
      name: kubelet
      state: started
      enabled: yes
  - name: Run script load Images
    script: /root/ansible/loadImages.sh
...

ansible-playbook kuber.yaml  #执行，完成，最后在node节点再执行以上第8步即可

遇到的问题及启动服务报错：

1、W0412 04:57:19.803140     846 watcher.go:87] Error while processing event ("/sys/fs/cgroup/devices/libcontainer_30695_systemd_test_default.slice": 0x40000100 == IN_CREATE|IN_ISDIR): inotify_add_watch /sys/fs/cgroup/devices/libcontainer_30695_systemd_test_default.slice: no such file or directory

## 问题的原因是docker与kubelet的cgroup组不一致
## 查看kubeadm的配置文件位置
[root@Centos8 ~]# rpm -ql kubeadm
/usr/bin/kubeadm
/usr/lib/systemd/system/kubelet.service.d/10-kubeadm.conf

## 修改配置文件,将kubelet的cgroup改为systemd
vim /usr/lib/systemd/system/kubelet.service.d/10-kubeadm.conf
...
Environment="KUBELET_CONFIG_ARGS=--config=/var/lib/kubelet/config.yaml --cgroup-driver=systemd"
...

## 重新加载配置文件及重启服务
[root@Centos8 ~]# systemctl daemon-reload 
[root@Centos8 ~]# systemctl restart kubelet.service 

2、node2节点的flannel一直报错

## 还未找到根本原因，正在排错，如有大佬路过，希望指点
kube-flannel-ds-amd64-b47l9       0/1     Init:ErrImagePull   0          3m50s

3、如果需要重新安装master节点，执行：

# kubeadm reset
然后再进行重新安装

4、如果需要重新安装node节点，执行：

# kubectl drain <node name> --delete-local-data --force --ignore-daemonsets
# kubectl delete node <node name>
或
kubeadm reset #直接重新join

5、node节点加入master时报错：error execution phase preflight: couldn't validate the identity of the API Server: abort connecting to API servers after timeout of 5m0s

原因：master的token过期了，需要重新创建

解决：

Master：
[root@Centos8 ~]# kubeadm token create
blopur.fn8gtr06gsjlq7yi

Node：
kubeadm join 192.168.152.53:6443 --token blopur.fn8gtr06gsjlq7yi --discovery-token-ca-cert-hash sha256:c291b4fc646b5925299f8cdf7fafe33ad9c0505a1609041d8c8214d104eb08da

6、node2节点加入master后，systemctl status kubelet.service报错：Unable to update cni config: No networks found in /etc/cni/net.d

vim /usr/lib/systemd/system/kubelet.service.d/10-kubeadm.conf
...
添加：
Environment="KUBELET_NETWORK_ARGS=--network-plugin=cni --cni-conf-dir=/etc/cni/ --cni-bin-dir=/opt/cni/bin"
...

systemctl daemon-reload && systemctl restart kubelet.service

7、node2节点加入master后，systemctl status kubelet.service报错：open /run/flannel/subnet.env: no such file or directory

## 将master节点的/run/flannel/subnet.env文件拷贝到此处即可
[root@Centos8 flannel]# scp subnet.env kubenode2:/run/flannel/

## 重启
systemctl restart kubelet.service