Kubernetes 環境搭建 之 FAQ for master

1.錯誤描述

[root@k8s centos]# kubeadm init
I1205 06:44:01.459391   12097 version.go:94] could not fetch a Kubernetes version from the internet: unable to get URL "https://dl.k8s.io/release/stable-1.txt": Get https://dl.k8s.io/release/stable-1.txt: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)
I1205 06:44:01.459549   12097 version.go:95] falling back to the local client version: v1.13.0
[init] Using Kubernetes version: v1.13.0
[preflight] Running pre-flight checks
        [WARNING Service-Docker]: docker service is not enabled, please run 'systemctl enable docker.service'
        [WARNING Hostname]: hostname "k8s.novalocal" could not be reached
        [WARNING Hostname]: hostname "k8s.novalocal": lookup k8s.novalocal on 10.32.148.99:53: no such host
        [WARNING Service-Kubelet]: kubelet service is not enabled, please run 'systemctl enable kubelet.service'
error execution phase preflight: [preflight] Some fatal errors occurred:
        [ERROR FileContent--proc-sys-net-bridge-bridge-nf-call-iptables]: /proc/sys/net/bridge/bridge-nf-call-iptables contents are not set to 1
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`

2. 錯誤

a. 概述，

這裏面有很多錯誤信息, 有的可以按照提示信息進行更改, 有的需要特殊解決

b. 網絡設置

• 錯誤內容
  /proc/sys/net/bridge/bridge-nf-call-iptables contents are not set to 1
• 解決方法：

echo 1 > /proc/sys/net/bridge/bridge-nf-call-iptables

c. Enable docker

• 告警內容：
  [WARNING Service-Docker]: docker service is not enabled, please run 'systemctl enable docker.service'
• 解決方法
  按照提示， 運行 systemctl enable docker.service
  

d. hostname的問題

• 告警內容

[WARNING Hostname]: hostname "k8s.novalocal" could not be reached
[WARNING Hostname]: hostname "k8s.novalocal": lookup k8s.novalocal on 10.32.148.99:53: no such host

• 解決方法

• • 命令更改主機名

hostnamectl set-hostname k8s

• • 更改/etc/hostname

echo k8s > /etc/hostname

– 更改/etc/hosts, 在後面追加主機名

e. Enable kubelet

• 告警內容：
  [WARNING Service-Kubelet]: kubelet service is not enabled, please run 'systemctl enable kubelet.service'
• Solution
  按照提示，運行 systemctl enable kubelet.service

f. 禁用SELinux, 用於啓動docker服務.

• i. 報錯信息
  在通過systemctl start docker.service進行啓動docker服務的時候, 發現無法啓動成功, 然後通過journalctl -xe進行查看, 如果發現下面的內容,則需要禁用SELinux配置.
  Error starting daemon: SELinux is not supported with the overlay2 graph driver on this kernel. Either boot into a newer kernel or disable selinux in docker (--selinux-enabled=false)
  
• ii. Solution
  更改/etc/selinux/config文件, 將SELINUX的值更改爲disabled. 然後reboot後再試.
  

3. 再次配置master