oracle linux 7 yum报错解决：COULD NOT RESOLVE HOST: YUM.ORACLE.COM

虚拟机中yum报错

[root@localhost ~]# yum -y install oracle-rdbms-server-11gR2-preinstall
Loaded plugins: langpacks, ulninfo
Resolving Dependencies
--> Running transaction check
---> Package oracle-rdbms-server-11gR2-preinstall.x86_64 0:1.0-6.el7 will be installed
--> Processing Dependency: gcc for package: oracle-rdbms-server-11gR2-preinstall-1.0-6.el7.x86_64
--> Processing Dependency: gcc-c++ for package: oracle-rdbms-server-11gR2-preinstall-1.0-6.el7.x86_64

( many more lines suppressed )

compat-libstdc++-33-3.2.3-72.e FAILED
https://yum.oracle.com/repo/OracleLinux/OL7/latest/x86_64/getPackage/compat-libstdc%2B%2B-33-3.2.3-72.el7.x86_64.rpm: [Errno 14] curl#6 - "Could not resolve host: yum.oracle.com; Unknown error"
Trying other mirror.
compat-libcap1-1.10-7.el7.x86_ FAILED
https://yum.oracle.com/repo/OracleLinux/OL7/latest/x86_64/getPackage/compat-libcap1-1.10-7.el7.x86_64.rpm: [Errno 14] curl#6 - "Could not resolve host: yum.oracle.com; Unknown error"
Trying other mirror.
cpp-4.8.5-36.0.1.el7.x86_64.rp FAILED
https://yum.oracle.com/repo/OracleLinux/OL7/latest/x86_64/getPackage/cpp-4.8.5-36.0.1.el7.x86_64.rpm: [Errno 14] curl#6 - "Could not resolve host: yum.oracle.com; Unknown error"ETA
Trying other mirror.
warning: /var/cache/yum/x86_64/7Server/ol7_latest/packages/gcc-4.8.5-36.0.1.el7.x86_64.rpm: Header V3 RSA/SHA256 Signature, key ID ec551f03: NOKEY ] 1.1 MB/s |  16 MB  00:00:36 ETA
Public key for gcc-4.8.5-36.0.1.el7.x86_64.rpm is not installed
(1/14): gcc-4.8.5-36.0.1.el7.x86_64.rpm                                                                                                                       |  16 MB  00:00:26
(2/14): gcc-c++-4.8.5-36.0.1.el7.x86_64.rpm                                                                                                                   | 7.2 MB  00:00:06
(3/14): glibc-2.17-260.0.15.el7_6.3.x86_64.rpm                                                                                                                | 3.7 MB  00:00:03
(4/14): glibc-common-2.17-260.0.15.el7_6.3.x86_64.rpm                                                                                                         |  12 MB  00:00:10
(5/14): glibc-devel-2.17-260.0.15.el7_6.3.x86_64.rpm                                                                                                          | 1.1 MB  00:00:01
(6/14): glibc-headers-2.17-260.0.15.el7_6.3.x86_64.rpm                                                                                                        | 685 kB  00:00:00
(7/14): kernel-headers-3.10.0-957.5.1.el7.x86_64.rpm                                                                                                          | 8.0 MB  00:00:06
(8/14): ksh-20120801-139.0.1.el7.x86_64.rpm                                                                                                                   | 883 kB  00:00:00
(9/14): libaio-devel-0.3.109-13.el7.x86_64.rpm                                                                                                                |  12 kB  00:00:00
(10/14): libstdc++-devel-4.8.5-36.0.1.el7.x86_64.rpm                                                                                                          | 1.5 MB  00:00:01
(11/14): oracle-rdbms-server-11gR2-preinstall-1.0-6.el7.x86_64.rpm                                                                                            |  22 kB  00:00:00     

Error downloading packages:
  cpp-4.8.5-36.0.1.el7.x86_64: [Errno 256] No more mirrors to try.
  compat-libcap1-1.10-7.el7.x86_64: [Errno 256] No more mirrors to try.
  compat-libstdc++-33-3.2.3-72.el7.x86_64: [Errno 256] No more mirrors to try.

[root@localhost ~]#

出现这个的原因是虚拟机中的主机网关不能dns到，加8.8.8.8作为dns即可

[root@localhost ~]# vim /etc/resolv.conf
# Generated by NetworkManager
nameserver 192.0.1.2
nameserver 8.8.8.8