Kubernetes 管理员认证(CKA)考试笔记

Posted 2021-11-12 山河已无恙

tags:

篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了Kubernetes 管理员认证(CKA)考试笔记相关的知识，希望对你有一定的参考价值。

写在前面

嗯，准备考 cka证书，报了个班，花了一个月工资，好心疼呀，一定要考过去。
这篇博客是报班听课后整理的笔记，适合温习。
博文内容涉及 docker ,k8s；
写的有点多了，因为粘贴了代码，所以只能分开发布
本部分内容涉及k8s多集群切换，k8s版本升级、etcd，pod相关
博文设计镜像小伙伴有需要可以留言

生活的意义就是学着真实的活下去，生命的意义就是寻找生活的意义 -----山河已无恙

k8s多集群切换

创建一个新的集群,配置ssh免密,修改主机清单，然后使用之前的配置文件修改下

┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$cat inventory
[node]
192.168.26.82
192.168.26.83
[master]
192.168.26.81
[temp]
192.168.26.91
192.168.26.92
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$cat init_c2_playbook.yml
- name: init k8s
  hosts: temp
  tasks:
    # 关闭防火墙
    - shell: firewall-cmd --set-default-zone=trusted
    # 关闭selinux
    - shell: getenforce
      register: out
    - debug: msg="{{out}}"
    - shell: setenforce 0
      when: out.stdout != "Disabled"
    - replace:
        path: /etc/selinux/config
        regexp: "SELINUX=enforcing"
        replace: "SELINUX=disabled"
    - shell: cat /etc/selinux/config
      register: out
    - debug: msg="{{out}}"
    - copy:
        src: ./hosts_c2
        dest: /etc/hosts
        force: yes
   # 关闭交换分区
    - shell: swapoff -a
    - shell: sed -i '/swap/d' /etc/fstab
    - shell: cat /etc/fstab
      register: out
    - debug: msg="{{out}}"
    # 配置yum源
    - shell: tar -cvf /etc/yum.tar /etc/yum.repos.d/
    - shell: rm -rf /etc/yum.repos.d/*
    - shell: wget ftp://ftp.rhce.cc/k8s/* -P  /etc/yum.repos.d/
    # 安装docker-ce
    - yum:
        name: docker-ce
        state: present
    # 配置docker加速
    - shell: mkdir /etc/docker
    - copy:
        src: ./daemon.json
        dest: /etc/docker/daemon.json
    - shell: systemctl daemon-reload
    - shell: systemctl restart docker
    # 配置属性，安装k8s相关包
    - copy:
        src: ./k8s.conf
        dest: /etc/sysctl.d/k8s.conf
    - shell: yum install -y kubelet-1.21.1-0 kubeadm-1.21.1-0 kubectl-1.21.1-0 --disableexcludes=kubernetes
    # 缺少镜像导入
    - copy:
        src: ./coredns-1.21.tar
        dest: /root/coredns-1.21.tar
    - shell: docker load -i /root/coredns-1.21.tar
    # 启动服务
    - shell: systemctl restart kubelet
    - shell: systemctl enable kubelet
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$

第二个集群，一个node节点，一个master节点

[root@vms91 ~]# kubectl get nodes
NAME                         STATUS   ROLES                  AGE    VERSION
vms91.liruilongs.github.io   Ready    control-plane,master   139m   v1.21.1
vms92.liruilongs.github.io   Ready    <none>                 131m   v1.21.1
[root@vms91 ~]# kubectl config view
apiVersion: v1
clusters:
- cluster:
    certificate-authority-data: DATA+OMITTED
    server: https://192.168.26.91:6443
  name: kubernetes
contexts:
- context:
    cluster: kubernetes
    user: kubernetes-admin
  name: kubernetes-admin@kubernetes
current-context: kubernetes-admin@kubernetes
kind: Config
preferences: {}
users:
- name: kubernetes-admin
  user:
    client-certificate-data: REDACTED
    client-key-data: REDACTED
[root@vms91 ~]#

一个控制台管理多个集群，多集群切换：
一个控制台管理多个集群
对于一个 kubeconfig文件来说，有3个部分：
cluster：集群信息
context：属性–默认的命名空间
user：用户密匙

需要配置config,多个集群配置文件合并为一个

┌──[root@vms81.liruilongs.github.io]-[~/.kube]
└─$pwd;ls
/root/.kube
cache  config

config

apiVersion: v1
clusters:
- cluster:
    certificate-authority-data: LS0.........0tCg==
    server: https://192.168.26.81:6443
  name: cluster1
- cluster:
    certificate-authority-data: LS0.........0tCg==
    server: https://192.168.26.91:6443
  name: cluster2
contexts:
- context:
    cluster: cluster1
    namespace: kube-public
    user: kubernetes-admin1
  name: context1
- context:
    cluster: cluster2
    namespace: kube-system
    user: kubernetes-admin2
  name: context2
current-context: context2
kind: Config
preferences: {}
users:
- name: kubernetes-admin1
  user:
    client-certificate-data: LS0.......0tCg==
    client-key-data: LS0......LQo=
- name: kubernetes-admin2
  user:
    client-certificate-data: LS0.......0tCg==
    client-key-data: LS0......0tCg==

多集群切换：kubectl config use-context context2

┌──[root@vms81.liruilongs.github.io]-[~/.kube]
└─$kubectl config get-contexts
CURRENT   NAME       CLUSTER    AUTHINFO            NAMESPACE
*         context1   cluster1   kubernetes-admin1   kube-public
          context2   cluster2   kubernetes-admin2   kube-system
┌──[root@vms81.liruilongs.github.io]-[~/.kube]
└─$kubectl get nodes
NAME                         STATUS   ROLES                  AGE   VERSION
vms81.liruilongs.github.io   Ready    control-plane,master   23h   v1.21.1
vms82.liruilongs.github.io   Ready    <none>                 23h   v1.21.1
vms83.liruilongs.github.io   Ready    <none>                 23h   v1.21.1
┌──[root@vms81.liruilongs.github.io]-[~/.kube]
└─$kubectl config use-context  context2
Switched to context "context2".
┌──[root@vms81.liruilongs.github.io]-[~/.kube]
└─$kubectl config get-contexts
CURRENT   NAME       CLUSTER    AUTHINFO            NAMESPACE
          context1   cluster1   kubernetes-admin1   kube-public
*         context2   cluster2   kubernetes-admin2   kube-system
┌──[root@vms81.liruilongs.github.io]-[~/.kube]
└─$kubectl get nodes
NAME                         STATUS   ROLES                  AGE   VERSION
vms91.liruilongs.github.io   Ready    control-plane,master   8h    v1.21.1
vms92.liruilongs.github.io   Ready    <none>                 8h    v1.21.1
┌──[root@vms81.liruilongs.github.io]-[~/.kube]
└─$

三、ETCD

单节点ETCD

┌──[root@liruilongs.github.io]-[~]
└─$ yum -y install etcd
┌──[root@liruilongs.github.io]-[~]
└─$ rpm -qc etcd
/etc/etcd/etcd.conf
┌──[root@liruilongs.github.io]-[~]
└─$ vim $(rpm -qc etcd)
┌──[root@liruilongs.github.io]-[~]
└─$
#[Member]
# 数据位置
ETCD_DATA_DIR="/var/lib/etcd/default.etcd" 
# 数据同步端口
ETCD_LISTEN_PEER_URLS="http://192.168.26.91:2380,http://localhost:2380" 
# 读写端口
ETCD_LISTEN_CLIENT_URLS="http://192.168.26.91:2379,http://localhost:2379" 
ETCD_NAME="default" 
#[Clustering]
ETCD_ADVERTISE_CLIENT_URLS="http://localhost:2379"

┌──[root@liruilongs.github.io]-[~]
└─$ systemctl enable etcd --now
┌──[root@liruilongs.github.io]-[~]
└─$ etcdctl member list
8e9e05c52164694d: name=default peerURLs=http://localhost:2380 clientURLs=http://localhost:2379 isLeader=true
┌──[root@liruilongs.github.io]-[~]
└─$ etcdctl cluster-health
member 8e9e05c52164694d is healthy: got healthy result from http://localhost:2379
cluster is healthy
┌──[root@liruilongs.github.io]-[~]
└─$ etcdctl ls /
┌──[root@liruilongs.github.io]-[~]
└─$ etcdctl mkdir cka
┌──[root@liruilongs.github.io]-[~]
└─$ etcdctl ls /
/cka
┌──[root@liruilongs.github.io]-[~]
└─$ etcdctl rmdir /cka
┌──[root@liruilongs.github.io]-[~]
└─$ etcdctl ls /
┌──[root@liruilongs.github.io]-[~]
└─$

2和3版本切换

┌──[root@liruilongs.github.io]-[~]
└─$ etcdctl -v
etcdctl version: 3.3.11
API version: 2
┌──[root@liruilongs.github.io]-[~]
└─$ export ETCDCTL_API=3
┌──[root@liruilongs.github.io]-[~]
└─$ etcdctl version
etcdctl version: 3.3.11
API version: 3.3
┌──[root@liruilongs.github.io]-[~]
└─$

etcd集群构建

ETCD集群是一个分布式系统,使用Raft协议来维护集群内各个节点状态的一致性。
主机状态 Leader, Follower, Candidate
当集群初始化时候，每个节点都是Follower角色，通过心跳与其他节点同步数据
当Follower在一定时间内没有收到来自主节点的心跳，会将自己角色改变为Candidate，并发起一次选主投票
配置etcd集群，建议尽可能是奇数个节点，而不要偶数个节点

创建集群

环境准备

┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$cat inventory
......
[etcd]
192.168.26.100
192.168.26.101
192.168.26.102
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible etcd -m ping
192.168.26.100 | SUCCESS => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python"
    },
    "changed": false,
    "ping": "pong"
}
192.168.26.102 | SUCCESS => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python"
    },
    "changed": false,
    "ping": "pong"
}
192.168.26.101 | SUCCESS => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python"
    },
    "changed": false,
    "ping": "pong"
}
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible etcd -m yum -a "name=etcd state=installed"

配置文件修改

这里用前两台(192.168.26.100,192.168.26.101)初始化集群，第三台(192.168.26.102 )以添加的方式加入集群

本机编写配置文件。

┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$cat etcd.conf
ETCD_DATA_DIR="/var/lib/etcd/cluster.etcd"

ETCD_LISTEN_PEER_URLS="http://192.168.26.100:2380,http://localhost:2380"
ETCD_LISTEN_CLIENT_URLS="http://192.168.26.100:2379,http://localhost:2379"

ETCD_NAME="etcd-100"
ETCD_INITIAL_ADVERTISE_PEER_URLS="http://192.168.26.100:2380"

ETCD_ADVERTISE_CLIENT_URLS="http://localhost:2379,http://192.168.26.100:2379"

ETCD_INITIAL_CLUSTER="etcd-100=http://192.168.26.100:2380,etcd-101=http://192.168.26.101:2380"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"

把配置文件拷贝到192.168.26.100,192.168.26.101

┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible 192.168.26.100,192.168.26.101 -m copy -a "src=./etcd.conf dest=/etc/etcd/etcd.conf force=yes"
192.168.26.101 | CHANGED => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python"
    },
    "changed": true,
    "checksum": "bae3b8bc6636bf7304cce647b7068aa45ced859b",
    "dest": "/etc/etcd/etcd.conf",
    "gid": 0,
    "group": "root",
    "md5sum": "5f2a3fbe27515f85b7f9ed42a206c2a6",
    "mode": "0644",
    "owner": "root",
    "size": 533,
    "src": "/root/.ansible/tmp/ansible-tmp-1633800905.88-59602-39965601417441/source",
    "state": "file",
    "uid": 0
}
192.168.26.100 | CHANGED => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python"
    },
    "changed": true,
    "checksum": "bae3b8bc6636bf7304cce647b7068aa45ced859b",
    "dest": "/etc/etcd/etcd.conf",
    "gid": 0,
    "group": "root",
    "md5sum": "5f2a3fbe27515f85b7f9ed42a206c2a6",
    "mode": "0644",
    "owner": "root",
    "size": 533,
    "src": "/root/.ansible/tmp/ansible-tmp-1633800905.9-59600-209338664801782/source",
    "state": "file",
    "uid": 0
}

检查配置文件

┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible 192.168.26.100,192.168.26.101 -m shell -a "cat /etc/etcd/etcd.conf"
192.168.26.101 | CHANGED | rc=0 >>
ETCD_DATA_DIR="/var/lib/etcd/cluster.etcd"

ETCD_LISTEN_PEER_URLS="http://192.168.26.100:2380,http://localhost:2380"
ETCD_LISTEN_CLIENT_URLS="http://192.168.26.100:2379,http://localhost:2379"

ETCD_NAME="etcd-100"
ETCD_INITIAL_ADVERTISE_PEER_URLS="http://192.168.26.100:2380"

ETCD_ADVERTISE_CLIENT_URLS="http://localhost:2379,http://192.168.26.100:2379"

ETCD_INITIAL_CLUSTER="etcd-100=http://192.168.26.100:2380,etcd-101=http://192.168.26.101:2380"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"
192.168.26.100 | CHANGED | rc=0 >>
ETCD_DATA_DIR="/var/lib/etcd/cluster.etcd"

ETCD_LISTEN_PEER_URLS="http://192.168.26.100:2380,http://localhost:2380"
ETCD_LISTEN_CLIENT_URLS="http://192.168.26.100:2379,http://localhost:2379"

ETCD_NAME="etcd-100"
ETCD_INITIAL_ADVERTISE_PEER_URLS="http://192.168.26.100:2380"

ETCD_ADVERTISE_CLIENT_URLS="http://localhost:2379,http://192.168.26.100:2379"

ETCD_INITIAL_CLUSTER="etcd-100=http://192.168.26.100:2380,etcd-101=http://192.168.26.101:2380"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"

修改101的配置文件

┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible 192.168.26.101  -m shell -a "sed -i  '1,9s/100/101/g' /etc/etcd/etcd.conf"
192.168.26.101 | CHANGED | rc=0 >>

┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible 192.168.26.100,192.168.26.101 -m shell -a "cat -n /etc/etcd/etcd.conf"
192.168.26.100 | CHANGED | rc=0 >>
     1  ETCD_DATA_DIR="/var/lib/etcd/cluster.etcd"
     2
     3  ETCD_LISTEN_PEER_URLS="http://192.168.26.100:2380,http://localhost:2380"
     4  ETCD_LISTEN_CLIENT_URLS="http://192.168.26.100:2379,http://localhost:2379"
     5
     6  ETCD_NAME="etcd-100"
     7  ETCD_INITIAL_ADVERTISE_PEER_URLS="http://192.168.26.100:2380"
     8
     9  ETCD_ADVERTISE_CLIENT_URLS="http://localhost:2379,http://192.168.26.100:2379"
    10
    11  ETCD_INITIAL_CLUSTER="etcd-100=http://192.168.26.100:2380,etcd-101=http://192.168.26.101:2380"
    12  ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
    13  ETCD_INITIAL_CLUSTER_STATE="new"
192.168.26.101 | CHANGED | rc=0 >>
     1  ETCD_DATA_DIR="/var/lib/etcd/cluster.etcd"
     2
     3  ETCD_LISTEN_PEER_URLS="http://192.168.26.101:2380,http://localhost:2380"
     4  ETCD_LISTEN_CLIENT_URLS="http://192.168.26.101:2379,http://localhost:2379"
     5
     6  ETCD_NAME="etcd-101"
     7  ETCD_INITIAL_ADVERTISE_PEER_URLS="http://192.168.26.101:2380"
     8
     9  ETCD_ADVERTISE_CLIENT_URLS="http://localhost:2379,http://192.168.26.101:2379"
    10
    11  ETCD_INITIAL_CLUSTER="etcd-100=http://192.168.26.100:2380,etcd-101=http://192.168.26.101:2380"
    12  ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
    13  ETCD_INITIAL_CLUSTER_STATE="new"
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$

查看etcd集群

┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible 192.168.26.100,192.168.26.101 -m shell -a "etcdctl member list"
192.168.26.100 | CHANGED | rc=0 >>
6f2038a018db1103: name=etcd-100 peerURLs=http://192.168.26.100:2380 clientURLs=http://192.168.26.100:2379,http://localhost:2379 isLeader=false
bd330576bb637f25: name=etcd-101 peerURLs=http://192.168.26.101:2380 clientURLs=http://192.168.26.101:2379,http://localhost:2379 isLeader=true
192.168.26.101 | CHANGED | rc=0 >>
6f2038a018db1103: name=etcd-100 peerURLs=http://192.168.26.100:2380 clientURLs=http://192.168.26.100:2379,http://localhost:2379 isLeader=false
bd330576bb637f25: name=etcd-101 peerURLs=http://192.168.26.101:2380 clientURLs=http://192.168.26.101:2379,http://localhost:2379 isLeader=true
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$

添加etcd 192.168.26.102

┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible 192.168.26.100 -m shell -a "etcdctl member add etcd-102 http://192.168.26.102:2380"
192.168.26.100 | CHANGED | rc=0 >>
Added member named etcd-102 with ID 2fd4f9ba70a04579 to cluster

ETCD_NAME="etcd-102"
ETCD_INITIAL_CLUSTER="etcd-102=http://192.168.26.102:2380,etcd-100=http://192.168.26.100:2380,etcd-101=http://192.168.26.101:2380"
ETCD_INITIAL_CLUSTER_STATE="existing"
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$

修改之前写好的配置文件给102

┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$sed -i '1,8s/100/102/g' etcd.conf
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$sed -i '13s/new/existing/'  etcd.conf
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$sed -i 's#ETCD_INITIAL_CLUSTER="#ETCD_INITIAL_CLUSTER="etcd-102=http://192.168.26.102:2380,#' etcd.conf
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$cat -n etcd.conf
     1  ETCD_DATA_DIR="/var/lib/etcd/cluster.etcd"
     2
     3  ETCD_LISTEN_PEER_URLS="http://192.168.26.102:2380,http://localhost:2380"
     4  ETCD_LISTEN_CLIENT_URLS="http://192.168.26.102:2379,http://localhost:2379"
     5
     6  ETCD_NAME="etcd-102"
     7  ETCD_INITIAL_ADVERTISE_PEER_URLS="http://192.168.26.102:2380"
     8
     9  ETCD_ADVERTISE_CLIENT_URLS="http://localhost:2379,http://192.168.26.100:2379"
    10
    11  ETCD_INITIAL_CLUSTER="etcd-102=http://192.168.26.102:2380,etcd-100=http://192.168.26.100:2380,etcd-101=http://192.168.26.101:2380"
    12  ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
    13  ETCD_INITIAL_CLUSTER_STATE="existing"
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$

配置文件拷贝替换，启动etcd

┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible 192.168.26.102 -m copy -a "src=./etcd.conf dest=/etc/etcd/etcd.conf force=yes"
192.168.26.102 | CHANGED => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python"
    },
    "changed": true,
    "checksum": "2d8fa163150e32da563f5e591134b38cc356d237",
    "dest": "/etc/etcd/etcd.conf",
    "gid": 0,
    "group": "root",
    "md5sum": "389c2850d434478e2d4d57a7798196de",
    "mode": "0644",
    "owner": "root",
    "size": 574,
    "src": "/root/.ansible/tmp/ansible-tmp-1633803533.57-102177-227527368141930/source",
    "state": "file",
    "uid": 0
}
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible 192.168.26.102 -m shell -a "systemctl enable etcd --now"
192.168.26.102 | CHANGED | rc=0 >>
Created symlink from /etc/systemd/system/multi-user.target.wants/etcd.service to /usr/lib/systemd/system/etcd.service.
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$

检查集群是否添加成功

┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible etcd -m shell -a "etcdctl member list"
192.168.26.101 | CHANGED | rc=0 >>
2fd4f9ba70a04579: name=etcd-102 peerURLs=http://192.168.26.102:2380 clientURLs=http://192.168.26.100:2379,http://localhost:2379 isLeader=false
6f2038a018db1103: name=etcd-100 peerURLs=http://192.168.26.100:2380 clientURLs=http://192.168.26.100:2379,http://localhost:2379 isLeader=false
bd330576bb637f25: name=etcd-101 peerURLs=http://192.168.26.101:2380 clientURLs=http://192.168.26.101:2379,http://localhost:2379 isLeader=true
192.168.26.102 | CHANGED | rc=0 >>
2fd4f9ba70a04579: name=etcd-102 peerURLs=http://192.168.26.102:2380 clientURLs=http://192.168.26.100:2379,http://localhost:2379 isLeader=false
6f2038a018db1103: name=etcd-100 peerURLs=http://192.168.26.100:2380 clientURLs=http://192.168.26.100:2379,http://localhost:2379 isLeader=false
bd330576bb637f25: name=etcd-101 peerURLs=http://192.168.26.101:2380 clientURLs=http://192.168.26.101:2379,http://localhost:2379 isLeader=true
192.168.26.100 | CHANGED | rc=0 >>
2fd4f9ba70a04579: name=etcd-102 peerURLs=http://192.168.26.102:2380 clientURLs=http://192.168.26.100:2379,http://localhost:2379 isLeader=false
6f2038a018db1103: name=etcd-100 peerURLs=http://192.168.26.100:2380 clientURLs=http://1以上是关于Kubernetes 管理员认证(CKA)考试笔记的主要内容，如果未能解决你的问题，请参考以下文章 
 Kubernetes 管理员认证(CKA)考试笔记
 Kubernetes 管理员认证(CKA)考试笔记
 Kubernetes 管理员认证(CKA)考试笔记
 Kubernetes 管理员认证(CKA)考试笔记
 CKA 考试心得
 简单Kubernetes 认证管理员（CKA）-最少成本顺利考过指南