docker容器无法ping外网

http://mirrors.aliyun.com/centos/6.10/extras/x86_64/Packages/epel-release-6-8.noarch.rpm: [Errno 14] PYCURL ERROR 6 - "Couldn't resolve host 'mirrors.aliyun.com'"
Trying other mirror.
http://mirrors.neusoft.edu.cn/centos/6.10/extras/x86_64/Packages/epel-release-6-8.noarch.rpm: [Errno 14] PYCURL ERROR 6 - "Couldn't resolve host 'mirrors.neusoft.edu.cn'"
Trying other mirror.
http://mirrors.nwsuaf.edu.cn/centos/6.10/extras/x86_64/Packages/epel-release-6-8.noarch.rpm: [Errno 14] PYCURL ERROR 6 - "Couldn't resolve host 'mirrors.nwsuaf.edu.cn'"
Trying other mirror.
http://mirrors.shu.edu.cn/centos/6.10/extras/x86_64/Packages/epel-release-6-8.noarch.rpm: [Errno 14] PYCURL ERROR 6 - "Couldn't resolve host 'mirrors.shu.edu.cn'"
Trying other mirror.
http://mirrors.sohu.com/centos/6.10/extras/x86_64/Packages/epel-release-6-8.noarch.rpm: [Errno 14] PYCURL ERROR 6 - "Couldn't resolve host 'mirrors.sohu.com'"
Trying other mirror.
http://mirrors.tuna.tsinghua.edu.cn/centos/6.10/extras/x86_64/Packages/epel-release-6-8.noarch.rpm: [Errno 14] PYCURL ERROR 6 - "Couldn't resolve host 'mirrors.tuna.tsinghua.edu.cn'"
Trying other mirror.
http://mirrors.zju.edu.cn/centos/6.10/extras/x86_64/Packages/epel-release-6-8.noarch.rpm: [Errno 14] PYCURL ERROR 6 - "Couldn't resolve host 'mirrors.zju.edu.cn'"
Trying other mirror.

wget http://mirrors.163.com/.help/CentOS6-Base-163.repo

unknown host mirrors.163.com

在容器内部
ping www.baidu.com

ping: unknown host www.baidu.com

service docker restart