1、问题描述：

• 新建docker容器

  docker run -it --rm ubuntu:18.04
  

• 执行apt update，报错：

  bash: ping: command not found
  root@d087aa834821:/# apt update
  Ign:1 http://security.ubuntu.com/ubuntu bionic-security InRelease
  Ign:2 http://archive.ubuntu.com/ubuntu bionic InRelease
  Ign:3 http://archive.ubuntu.com/ubuntu bionic-updates InRelease
  Err:4 http://security.ubuntu.com/ubuntu bionic-security Release
    404   [IP: 91.189.91.38 80]
  Ign:5 http://archive.ubuntu.com/ubuntu bionic-backports InRelease
  Err:6 http://archive.ubuntu.com/ubuntu bionic Release
    404   [IP: 91.189.88.142 80]
  Err:7 http://archive.ubuntu.com/ubuntu bionic-updates Release
    404   [IP: 91.189.88.142 80]
  Err:8 http://archive.ubuntu.com/ubuntu bionic-backports Release
    404   [IP: 91.189.88.142 80]
  Reading package lists... Done
  E: The repository 'http://security.ubuntu.com/ubuntu bionic-security Release' does not have a Release file.
  N: Updating from such a repository can't be done securely, and is therefore disabled by default.
  N: See apt-secure(8) manpage for repository creation and user configuration details.
  E: The repository 'http://archive.ubuntu.com/ubuntu bionic Release' does not have a Release file.
  N: Updating from such a repository can't be done securely, and is therefore disabled by default.
  N: See apt-secure(8) manpage for repository creation and user configuration details.
  E: The repository 'http://archive.ubuntu.com/ubuntu bionic-updates Release' does not have a Release file.
  N: Updating from such a repository can't be done securely, and is therefore disabled by default.
  N: See apt-secure(8) manpage for repository creation and user configuration details.
  E: The repository 'http://archive.ubuntu.com/ubuntu bionic-backports Release' does not have a Release file.
  N: Updating from such a repository can't be done securely, and is therefore disabled by default.
  N: See apt-secure(8) manpage for repository creation and user configuration details.
  

2、解决方法：

方法1：新建docker时指定参数--network=host：

docker run -itd --rm --network=host ubuntu:18.04 /bin/bash

方法2：重置docker0（ docker0为docker的默认网桥）

# 杀死docker进程
pkill docker 
# 清空nat表的所有链
iptables -t nat -F
#停止docker默认网桥
ifconfig docker0 down
#删除docker默认网桥
brctl delbr docker0 
# 
docker -d 
#重启docker
systemctl restart docker

• 查看网络基本信息

  ifconfig
  

• 查看网桥

  brctl show
  

方法3：修改docker默认配置文件

• 查看文件/etc/default/docker

  vi /etc/default/docker
  

• 文件内容中的DOCKER_OPTS选项为：

  DOCKER_OPTS =“-dns 8.8.8.8 –dns 8.8.4.4”
  

• 查看本机dns

  cat /etc/resolv.conf
  

• 输出为：

  # This file is managed by man:systemd-resolved(8). Do not edit.
  #
  # This is a dynamic resolv.conf file for connecting local clients to the
  # internal DNS stub resolver of systemd-resolved. This file lists all
  # configured search domains.
  #
  # Run "systemd-resolve --status" to see details about the uplink DNS servers
  # currently in use.
  #
  # Third party programs must not access this file directly, but only through the
  # symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a different way,
  # replace this symlink by a static file or a different symlink.
  #
  # See man:systemd-resolved.service(8) for details about the supported modes of
  # operation for /etc/resolv.conf.
  
  nameserver 127.0.0.53
  options edns0
  

  很明显docker参数中的dns地址与本机实际地址不一致，此时只需要注释掉DOCKER_OPTS参数即可。

• 重启docker

  systemctl restart docker