容器编排系统k8s之基础入门

  一、kubernetes简介

  1、什么是kubernetes?它是干什么用的?

  kubernetes是google公司用go语言开发的一套容器编排系统,简称k8s;它主要用于容器编排;所谓容器编排简单的我们可以理解为管理容器;这个有点类似openstack,不同的是openstack是用来管理虚拟机,而k8s中是管理的pod(所谓pod就是容器的一个外壳,里面可以跑一个或多个容器,可以理解为pod就是将一个或多个容器逻辑的组织在一起);k8s除了可以全生命周期的管理pod,它还可以实现pod的自动化部署,自动修复以及动态的扩缩容等功能;

  2、k8s架构

容器编排系统k8s之基础入门

  提示:k8s是master/node模型,master是整个k8s的管理端,其上主要运行etcd,api server ,scheduler,controllermanager以及网络相关插件;其中etcd是一个kv键值存储数据库,主要存放k8s中所有配置信息以及pod状态信息,一旦etcd宕机,k8s整个系统将不可用;apiserver主要用来接收客户端请求,也是k8s中唯一的入口;用户的所有管理操作都是将请求发送给apiserver;scheduler主要用来调度用户请求,比如用户要在k8s系统上运行一个pod,至于这个pod该运行在那个node节点,这个就需要scheduler的调度;controllermanager主要用来管理以及监控pod状态;对于scheduler调度的结果,controlmanager就负责让对应节点上的对应pod精准处于调度的状态;node的节点是k8s的工作节点,主要用于运行pod;node节点主要运行的应用有docker,kubelet,kube-proxy;其中docker是用来运行容器的,kubelet主要负责执行master端controllermanager下发的任务;kube-proxy主要用来生成pod网络相关iptables或ipvs规则的;

  3、k8s工作过程

容器编排系统k8s之基础入门

  提示:k8s工作过程如上图所示,首先用户将请求通过https发送给apiserver,apiserver收到请求后,首先要验证客户端证书,如果通过验证,然后再检查用户请求的资源是否满足对应api请求的语法,满足则就把对应的请求资源以及资源状态信息存放在etcd中;scheduler和controllermanager以及kubelet这三个组件会一直监视着apiserver上的资源变动,一旦发现有合法的请求进来,首先scheduler会根据用户请求的资源,来评判该资源该在那个节点上创建,然后scheduler把对应的调度信息发送给apiserver,然后controllermanager结合scheduler的调度信息,把对应创建资源的方法也发送给apiserver;最后是各节点上的kubelet通过scheduler的调度信息来判断对应资源是否在本地执行,如果是,它就把controllermanager发送给apiserver的创建资源的方法在本地执行,把对应的资源在本地跑起来;后续controllermanager会一直监视着对应的资源是否健康,如果对应资源不健康,它会尝试重启资源,或者重建资源,让对应资源处于我们定义的状态;

  二、k8s集群搭建

  部署说明

  部署k8s集群的方式有两种,一种是在各节点上把对应的组件运行为容器的形式;第二种是将各组件运行为守护进程的方式;对于不同的环境我们部署的方式也有不同,对于测试环境,我们可以使用单master节点,单etcd实例,node节点按需而定;生产环境首先是etcd要高可用,我们要创建etcd高可用集群,一般创建3个或5个或7个节点;其次master也要高可用,高可用master我们需要注意apiserver是无状态的可多实例,前端使用nginx或haproxy做调度即可;对于scheduler和controller这两个组件各自只能有一个活动实例,如果是多个实例,其余的只能是备用;

  测试环境部署k8s,将各组件运行为容器

  环境说明

主机名 IP地址 角色
master01.k8s.org 192.168.0.41 master
node01.k8s.org 192.168.0.44 node01
node02.k8s.org 192.168.0.45 node02
node03.k8s.org 192.168.0.46 node03

 

 

 

 

 

 

 

  各节点主机名解析

[root@master01 ~]# cat /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
192.168.0.99 time.test.org time-node
192.168.0.41  master01 master01.k8s.org
192.168.0.42  master02 master02.k8s.org
192.168.0.43  master03 master03.k8s.org
192.168.0.44  node01 node01.k8s.org
192.168.0.45  node02 node02.k8s.org
192.168.0.46  node03 node03.k8s.org
[root@master01 ~]#

  各节点时间同步

[root@master01 ~]# grep server /etc/chrony.conf
# Use public servers from the pool.ntp.org project.
server time.test.org iburst
# Serve time even if not synchronized to any NTP server.
[root@master01 ~]# chronyc sources             
210 Number of sources = 1
MS Name/IP address         Stratum Poll Reach LastRx Last sample               
===============================================================================
^~ time.test.org                 3   6   377    56   -6275m[ -6275m] +/-   20ms
[root@master01 ~]# ssh node01 'chronyc sources'
210 Number of sources = 1
MS Name/IP address         Stratum Poll Reach LastRx Last sample               
===============================================================================
^~ time.test.org                 3   6   377     6   -6275m[ -6275m] +/-   20ms
[root@master01 ~]# ssh node02 'chronyc sources' 
210 Number of sources = 1
MS Name/IP address         Stratum Poll Reach LastRx Last sample               
===============================================================================
^~ time.test.org                 3   6   377    41   -6275m[ -6275m] +/-   20ms
[root@master01 ~]# ssh node03 'chronyc sources' 
210 Number of sources = 1
MS Name/IP address         Stratum Poll Reach LastRx Last sample               
===============================================================================
^~ time.test.org                 3   6   377    35   -6275m[ -6275m] +/-   20ms
[root@master01 ~]# 

  提示:有关时间同步服务器的搭建请参考https://www.cnblogs.com/qiuhom-1874/p/12079927.html;ssh互信请参考https://www.cnblogs.com/qiuhom-1874/p/11783371.html

  各节点关闭selinux

[root@master01 ~]# cat /etc/selinux/config 

# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
#     enforcing - SELinux security policy is enforced.
#     permissive - SELinux prints warnings instead of enforcing.
#     disabled - No SELinux policy is loaded.
SELINUX=disabled
# SELINUXTYPE= can take one of three two values:
#     targeted - Targeted processes are protected,
#     minimum - Modification of targeted policy. Only selected processes are protected. 
#     mls - Multi Level Security protection.
SELINUXTYPE=targeted 


[root@master01 ~]# getenforce 
Disabled
[root@master01 ~]# 

  提示:将/etc/selinux/config中的SELINUX=enforcing修改成SELINUX=disabled,然后重启主机或者执行setenforce 0;

  关闭iptabels服务或firewalld服务

[root@master01 ~]# systemctl status firewalld
● firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled)
   Active: inactive (dead)
     Docs: man:firewalld(1)
[root@master01 ~]# iptables -nvL
Chain INPUT (policy ACCEPT 650 packets, 59783 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain OUTPUT (policy ACCEPT 503 packets, 65293 bytes)
 pkts bytes target     prot opt in     out     source               destination         
[root@master01 ~]# ssh node01 'systemctl status firewalld'
● firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled)
   Active: inactive (dead)
     Docs: man:firewalld(1)
[root@master01 ~]# ssh node02 'systemctl status firewalld' 
● firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled)
   Active: inactive (dead)
     Docs: man:firewalld(1)
[root@master01 ~]# ssh node03 'systemctl status firewalld' 
● firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled)
   Active: inactive (dead)
     Docs: man:firewalld(1)
[root@master01 ~]# 

  提示:将firewalld服务停掉并设置为开机禁用;并确保iptables规则表中没有任何规则;

  各节点下载docker仓库配置文件

[root@master01 ~]# wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo
--2020-12-08 14:04:29--  https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
Resolving mirrors.aliyun.com (mirrors.aliyun.com)... 182.140.140.242, 110.188.26.241, 125.64.1.228, ...
Connecting to mirrors.aliyun.com (mirrors.aliyun.com)|182.140.140.242|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 2640 (2.6K) [application/octet-stream]
Saving to: ‘/etc/yum.repos.d/docker-ce.repo’

100%[======================================================================>] 2,640       --.-K/s   in 0s      

2020-12-08 14:04:30 (265 MB/s) - ‘/etc/yum.repos.d/docker-ce.repo’ saved [2640/2640]

[root@master01 ~]# ssh node01 'wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo'
--2020-12-08 14:04:42--  https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
Resolving mirrors.aliyun.com (mirrors.aliyun.com)... 182.140.139.60, 125.64.1.228, 118.123.2.185, ...
Connecting to mirrors.aliyun.com (mirrors.aliyun.com)|182.140.139.60|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 2640 (2.6K) [application/octet-stream]
Saving to: ‘/etc/yum.repos.d/docker-ce.repo’

     0K ..                                                    100%  297M=0s

2020-12-08 14:04:42 (297 MB/s) - ‘/etc/yum.repos.d/docker-ce.repo’ saved [2640/2640]

[root@master01 ~]# ssh node02 'wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo'
--2020-12-08 14:04:38--  https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
Resolving mirrors.aliyun.com (mirrors.aliyun.com)... 182.140.139.59, 118.123.2.183, 182.140.140.238, ...
Connecting to mirrors.aliyun.com (mirrors.aliyun.com)|182.140.139.59|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 2640 (2.6K) [application/octet-stream]
Saving to: ‘/etc/yum.repos.d/docker-ce.repo’

     0K ..                                                    100%  363M=0s

2020-12-08 14:04:38 (363 MB/s) - ‘/etc/yum.repos.d/docker-ce.repo’ saved [2640/2640]

[root@master01 ~]# ssh node03 'wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo'
--2020-12-08 14:04:43--  https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
Resolving mirrors.aliyun.com (mirrors.aliyun.com)... 118.123.2.184, 182.140.140.240, 182.140.139.63, ...
Connecting to mirrors.aliyun.com (mirrors.aliyun.com)|118.123.2.184|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 2640 (2.6K) [application/octet-stream]
Saving to: ‘/etc/yum.repos.d/docker-ce.repo’

     0K ..                                                    100%  218M=0s

2020-12-08 14:04:43 (218 MB/s) - ‘/etc/yum.repos.d/docker-ce.repo’ saved [2640/2640]

[root@master01 ~]# 

  创建kubernetes仓库配置文件

[root@master01 yum.repos.d]# cat 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
[root@master01 yum.repos.d]# 

  复制kubernetes仓库配置文件到各node节点

[root@master01 yum.repos.d]# scp kubernetes.repo node01:/etc/yum.repos.d/
kubernetes.repo                                                               100%  276    87.7KB/s   00:00    
[root@master01 yum.repos.d]# scp kubernetes.repo node02:/etc/yum.repos.d/
kubernetes.repo                                                               100%  276    13.6KB/s   00:00    
[root@master01 yum.repos.d]# scp kubernetes.repo node03:/etc/yum.repos.d/
kubernetes.repo                                                               100%  276   104.6KB/s   00:00    
[root@master01 yum.repos.d]# 

  在各节点安装docker-ce,kubectl,kubelet,kubeadm

yum install -y docker-ce kubectl kubeadm kubelet

  编辑docker unitfile文件,加上启动docker后执行iptables -P FORWARD ACCEPT

容器编排系统k8s之基础入门

  复制docker.service到各节点

[root@master01 ~]# scp /usr/lib/systemd/system/docker.service node01:/usr/lib/systemd/system/docker.service
docker.service                                                                100% 1764   220.0KB/s   00:00    
[root@master01 ~]# scp /usr/lib/systemd/system/docker.service node02:/usr/lib/systemd/system/docker.service
docker.service                                                                100% 1764   359.1KB/s   00:00    
[root@master01 ~]# scp /usr/lib/systemd/system/docker.service node03:/usr/lib/systemd/system/docker.service
docker.service                                                                100% 1764   792.3KB/s   00:00    
[root@master01 ~]# 

  配置docker加速器

[root@master01 ~]# mkdir /etc/docker
[root@master01 ~]# cd /etc/docker
[root@master01 docker]# cat >> daemon.json << EOF
> {
> "registry-mirrors": ["https://cyr1uljt.mirror.aliyuncs.com"]
> }
> EOF
[root@master01 docker]# cat daemon.json 
{
"registry-mirrors": ["https://cyr1uljt.mirror.aliyuncs.com"]
}
[root@master01 docker]# 

  在各节点上创建/etc/docker目录,并复制master端上daemon.json文件到各节点

[root@master01 docker]# ssh node01 'mkdir /etc/docker'
[root@master01 docker]# ssh node02 'mkdir /etc/docker' 
[root@master01 docker]# ssh node03 'mkdir /etc/docker' 
[root@master01 docker]# scp daemon.json node01:/etc/docker/
daemon.json                                                                   100%   65    30.6KB/s   00:00    
[root@master01 docker]# scp daemon.json node02:/etc/docker/
daemon.json                                                                   100%   65    52.2KB/s   00:00    
[root@master01 docker]# scp daemon.json node03:/etc/docker/
daemon.json                                                                   100%   65    17.8KB/s   00:00    
[root@master01 docker]# 

  各节点启动docker,并设置为开机启动

[root@master01 docker]# systemctl enable docker --now
Created symlink from /etc/systemd/system/multi-user.target.wants/docker.service to /usr/lib/systemd/system/docker.service.
[root@master01 docker]# ssh node01 'systemctl enable docker --now'
Created symlink from /etc/systemd/system/multi-user.target.wants/docker.service to /usr/lib/systemd/system/docker.service.
[root@master01 docker]# ssh node02 'systemctl enable docker --now' 
Created symlink from /etc/systemd/system/multi-user.target.wants/docker.service to /usr/lib/systemd/system/docker.service.
[root@master01 docker]# ssh node03 'systemctl enable docker --now' 
Created symlink from /etc/systemd/system/multi-user.target.wants/docker.service to /usr/lib/systemd/system/docker.service.
[root@master01 docker]# 

  验证各节点docker是加速器是否应用?

[root@master01 docker]# docker info |grep aliyun
  https://cyr1uljt.mirror.aliyuncs.com/
[root@master01 docker]# ssh node01 'docker info |grep aliyun'
  https://cyr1uljt.mirror.aliyuncs.com/
[root@master01 docker]# ssh node02 'docker info |grep aliyun' 
  https://cyr1uljt.mirror.aliyuncs.com/
[root@master01 docker]# ssh node03 'docker info |grep aliyun' 
  https://cyr1uljt.mirror.aliyuncs.com/
[root@master01 docker]# 

  提示:在对应节点执行docker info命令能够看到对应的加速器地址,说明加速器应用成功;

  验证所有节点iptables FORWARD链默认规则是否是ACCEPT

[root@master01 docker]# iptables -nvL|grep FORWARD
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
[root@master01 docker]# ssh node01 'iptables -nvL|grep FORWARD'
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
[root@master01 docker]# ssh node02 'iptables -nvL|grep FORWARD' 
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
[root@master01 docker]# ssh node03 'iptables -nvL|grep FORWARD' 
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
[root@master01 docker]# 

  添加内核参数配置文件,并复制配置文件到其他节点

[root@master01 ~]# cat /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
[root@master01 ~]# scp /etc/sysctl.d/k8s.conf node01:/etc/sysctl.d/k8s.conf
k8s.conf                                                                      100%   79    25.5KB/s   00:00    
[root@master01 ~]# scp /etc/sysctl.d/k8s.conf node02:/etc/sysctl.d/k8s.conf
k8s.conf                                                                      100%   79    24.8KB/s   00:00    
[root@master01 ~]# scp /etc/sysctl.d/k8s.conf node03:/etc/sysctl.d/k8s.conf
k8s.conf                                                                      100%   79    20.9KB/s   00:00    
[root@master01 ~]#

  应用内核参数使其生效

[root@master01 ~]# sysctl -p /etc/sysctl.d/k8s.conf       
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
[root@master01 ~]# ssh node01 'sysctl -p /etc/sysctl.d/k8s.conf'    
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
[root@master01 ~]# ssh node02 'sysctl -p /etc/sysctl.d/k8s.conf' 
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
[root@master01 ~]# ssh node03 'sysctl -p /etc/sysctl.d/k8s.conf' 
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
[root@master01 ~]# 

  配置kubelet,让其忽略swap开启报错

[root@master01 ~]# cat /etc/sysconfig/kubelet
KUBELET_EXTRA_ARGS="--fail-swap-on=false"
[root@master01 ~]# scp /etc/sysconfig/kubelet node01:/etc/sysconfig/kubelet
kubelet                                                                       100%   42    12.2KB/s   00:00    
[root@master01 ~]# scp /etc/sysconfig/kubelet node02:/etc/sysconfig/kubelet
kubelet                                                                       100%   42    16.2KB/s   00:00    
[root@master01 ~]# scp /etc/sysconfig/kubelet node03:/etc/sysconfig/kubelet
kubelet                                                                       100%   42    11.2KB/s   00:00    
[root@master01 ~]# 

  查看kubelet版本

[root@master01 ~]# rpm -q kubelet 
kubelet-1.20.0-0.x86_64
[root@master01 ~]# 

  初始化master节点

[root@master01 ~]# kubeadm init --pod-network-cidr="10.244.0.0/16" \
> --kubernetes-version="v1.20.0" \
> --image-repository="registry.aliyuncs.com/google_containers" \
> --ignore-preflight-errors=Swap

  提示:初始化master需要注意,默认不指定镜像仓库地址它会到k8s.gcr.io这个仓库中下载对应组件的镜像;gcr.io这个地址是google的仓库,在国内一般是无法正常连接;

容器编排系统k8s之基础入门

  提示:一定要看到初始化成功的提示才表示master初始化没有问题;这里还需要将最后的kubeadm join 这条命令记录下来,后续加node节点需要用到这个命令;

  在当前用户家目录下创建.kube目录,并复制kubectl配置文件到.kube目录下命名为config

[root@master01 ~]# mkdir -p $HOME/.kube
[root@master01 ~]# cp -i /etc/kubernetes/admin.conf $HOME/.kube/config

  提示:复制配置文件的主要原因是我们要在master端用kubectl命令来管理集群,配置文件中包含证书信息以及对应master的地址,默认执行kubctl命令会在当前用户的家目录查找config配置文件,只有当kubectl验证成功后才可以正常管理集群;如果不是root用户,是其他普通用户,还需要将config文件的属主和属组修改成对应的用户;

  安装flannel插件

[root@master01 ~]# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
The connection to the server raw.githubusercontent.com was refused - did you specify the right host or port?
[root@master01 ~]#

  提示:这里提示raw.githubusercontent.com不能访问,解决办法在/etc/hosts文件中加入对应的解析记录

  添加raw.githubusercontent.com的解析

[root@master01 ~]# cat /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
192.168.0.99 time.test.org time-node
192.168.0.41  master01 master01.k8s.org
192.168.0.42  master02 master02.k8s.org
192.168.0.43  master03 master03.k8s.org
192.168.0.44  node01 node01.k8s.org
192.168.0.45  node02 node02.k8s.org
192.168.0.46  node03 node03.k8s.org
151.101.76.133 raw.githubusercontent.com
[root@master01 ~]# 

  再次执行kubectl apply -f  https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml命令

[root@master01 ~]# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
Unable to connect to the server: read tcp 192.168.0.41:46838->151.101.76.133:443: read: connection reset by peer
[root@master01 ~]#

  提示:这里还是提示我们不能连接;解决办法,用浏览器打开 https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml,将其内容复制出来,然后在当前目录下创建flannel.yml文件

  flannel.yml文件内容

容器编排系统k8s之基础入门

[root@master01 ~]# cat flannel.yml
---
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:v0.13.1-rc1
        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:v0.13.1-rc1
        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

[root@master01 ~]# 

View Code

  使用 flannel.yml文件来安装flannel插件

[root@master01 ~]# kubectl apply -f 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
[root@master01 ~]# 

  查看master端运行的pod情况

[root@master01 ~]# kubectl get pods -n kube-system
NAME                                       READY   STATUS     RESTARTS   AGE
coredns-7f89b7bc75-k9gdt                   0/1     Pending    0          30m
coredns-7f89b7bc75-kp855                   0/1     Pending    0          30m
etcd-master01.k8s.org                      1/1     Running    0          30m
kube-apiserver-master01.k8s.org            1/1     Running    0          30m
kube-controller-manager-master01.k8s.org   1/1     Running    0          30m
kube-flannel-ds-zgq92                      0/1     Init:0/1   0          9m45s
kube-proxy-pjv9s                           1/1     Running    0          30m
kube-scheduler-master01.k8s.org            1/1     Running    0          30m
[root@master01 ~]# 

  提示:这里可以看到kube-flannel一直在初始化,原因是在flannel.yml资源清单中使用的是quay.io/coreos/flannel:v0.13.1-rc1这个镜像,这个镜像仓库在国内访问速度非常慢,有时候几乎就下载不到对应的镜像;解决办法,翻墙出去把对应镜像打包,然后再导入镜像;

  导入 quay.io/coreos/flannel:v0.13.1-rc镜像

[root@master01 ~]# ll
total 64060
-rw------- 1 root root 65586688 Dec  8 15:16 flannel-v0.13.1-rc1.tar
-rw-r--r-- 1 root root     4822 Dec  8 14:57 flannel.yml
[root@master01 ~]# docker load -i flannel-v0.13.1-rc1.tar 
70351a035194: Loading layer [==================================================>]  45.68MB/45.68MB
cd38981c5610: Loading layer [==================================================>]   5.12kB/5.12kB
dce2fcdf3a87: Loading layer [==================================================>]  9.216kB/9.216kB
be155d1c86b7: Loading layer [==================================================>]   7.68kB/7.68kB
Loaded image: quay.io/coreos/flannel:v0.13.1-rc1
[root@master01 ~]# 

  复制flannel镜像打包文件到其他节点,并导入镜像

[root@master01 ~]# scp flannel-v0.13.1-rc1.tar node01:/root/
flannel-v0.13.1-rc1.tar                                                       100%   63MB  62.5MB/s   00:01    
[root@master01 ~]# scp flannel-v0.13.1-rc1.tar node02:/root/
flannel-v0.13.1-rc1.tar                                                       100%   63MB  62.4MB/s   00:01    
[root@master01 ~]# scp flannel-v0.13.1-rc1.tar node03:/root/
flannel-v0.13.1-rc1.tar                                                       100%   63MB  62.5MB/s   00:01    
[root@master01 ~]# ssh node01 'docker load -i /root/flannel-v0.13.1-rc1.tar'
Loaded image: quay.io/coreos/flannel:v0.13.1-rc1
[root@master01 ~]# ssh node02 'docker load -i /root/flannel-v0.13.1-rc1.tar' 
Loaded image: quay.io/coreos/flannel:v0.13.1-rc1
[root@master01 ~]# ssh node03 'docker load -i /root/flannel-v0.13.1-rc1.tar' 
Loaded image: quay.io/coreos/flannel:v0.13.1-rc1
[root@master01 ~]# 

  再次查看pod运行情况

[root@master01 ~]# kubectl get pods -n kube-system
NAME                                       READY   STATUS    RESTARTS   AGE
coredns-7f89b7bc75-k9gdt                   1/1     Running   0          39m
coredns-7f89b7bc75-kp855                   1/1     Running   0          39m
etcd-master01.k8s.org                      1/1     Running   0          40m
kube-apiserver-master01.k8s.org            1/1     Running   0          40m
kube-controller-manager-master01.k8s.org   1/1     Running   0          40m
kube-flannel-ds-zgq92                      1/1     Running   0          19m
kube-proxy-pjv9s                           1/1     Running   0          39m
kube-scheduler-master01.k8s.org            1/1     Running   0          40m
[root@master01 ~]# 

  提示:可以看到kube-flannel已经正常running起来了;

  查看节点信息

[root@master01 ~]# kubectl get nodes
NAME               STATUS   ROLES                  AGE   VERSION
master01.k8s.org   Ready    control-plane,master   41m   v1.20.0
[root@master01 ~]# 

  提示:可以看到master节点已经处于ready状态,表示master端已经部署好了;

  将node01加入到k8s集群作为node节点

[root@node01 ~]# kubeadm join 192.168.0.41:6443 --token dz6bs3.ohitv535s1fmcuag \
> --discovery-token-ca-cert-hash sha256:330db1e5abff4d0e62150596f3e989cde40e61bdc73d6477170d786fcc1cfc67 \
> --ignore-preflight-errors=Swap
[preflight] Running pre-flight checks
        [WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
        [WARNING SystemVerification]: this Docker version is not on the list of validated versions: 20.10.0. Latest validated version: 19.03
        [WARNING Service-Kubelet]: kubelet service is not enabled, please run 'systemctl enable kubelet.service'
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Starting the kubelet
[kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap...

This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.

Run 'kubectl get nodes' on the control-plane to see this node join the cluster.

[root@node01 ~]# 

  提示:执行相同的命令将其他节点加入到k8s集群,作为node节点;

  在master节点上查看集群节点信息

[root@master01 ~]# kubectl get nodes
NAME               STATUS   ROLES                  AGE     VERSION
master01.k8s.org   Ready    control-plane,master   49m     v1.20.0
node01.k8s.org     Ready    <none>                 5m53s   v1.20.0
node02.k8s.org     Ready    <none>                 30s     v1.20.0
node03.k8s.org     Ready    <none>                 25s     v1.20.0
[root@master01 ~]# 

  提示:可以看到master和3个node节点都处于ready状态;

  测试:运行一个nginx 控制器,并指定使用nginx:1.14-alpine这个镜像,看看是否可以正常运行?

[root@master01 ~]# kubectl create deploy nginx-dep --image=nginx:1.14-alpine
deployment.apps/nginx-dep created
[root@master01 ~]# kubectl get pod
NAME                        READY   STATUS    RESTARTS   AGE
nginx-dep-8967df55d-j8zp7   1/1     Running   0          18s
[root@master01 ~]# kubectl get pod -o wide
NAME                        READY   STATUS    RESTARTS   AGE   IP           NODE             NOMINATED NODE   READINESS GATES
nginx-dep-8967df55d-j8zp7   1/1     Running   0          30s   10.244.2.2   node02.k8s.org   <none>           <none>
[root@master01 ~]#

  验证:访问podip看看对应nginx是否能够被访问到?

[root@master01 ~]# curl 10.244.2.2
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
    body {
        width: 35em;
        margin: 0 auto;
        font-family: Tahoma, Verdana, Arial, sans-serif;
    }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>
[root@master01 ~]# 

  提示:可以看到访问pod ip能够正常访问到对应nginx pod;到此一个单master节点,3个node节点的k8s集群就搭建好了;

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