1、事件描述：CentOS7下使用tree命令，发现该命令没有被安装，在安装的过程中发现yum报错
[root@openstack-01 ~]# tree -d bash: tree: 未找到命令... [root@openstack-01 ~]# yum -y install tree 已加载插件：fastestmirror, langpacks Repodata is over 2 weeks old. Install yum-cron? Or run: yum makecache fast
2、处理过程
a、直接执行yum makecache fast
[root@openstack-01 ~]# yum makecache fast
已加载插件：fastestmirror, langpacks
Repodata is over 2 weeks old. Install yum-cron? Or run: yum makecache fast
备注：根据它的提示信息执行操作，发现提示信息依旧
b、清除yum缓存
[root@openstack-01 ~]# yum clean all 已加载插件：fastestmirror, langpacks Repodata is over 2 weeks old. Install yum-cron? Or run: yum makecache fast 正在清理软件源： base centos-ceph-hammer centos-openstack-mitaka centos-qemu-ev extras updates Cleaning up everything Cleaning up list of fastest mirrors [5]- 已杀死 yum update [root@openstack-01 ~]# yum makecache 已加载插件：fastestmirror, langpacks Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=stock error was 14: curl#6 - "Could not resolve host: mirrorlist.centos.org; 未知的错误" One of the configured repositories failed (未知), and yum doesn‘t have enough cached data to continue. At this point the only safe thing yum can do is fail. There are a few ways to work "fix" this: 1. Contact the upstream for the repository and get them to fix the problem. 2. Reconfigure the baseurl/etc. for the repository, to point to a working upstream. This is most often useful if you are using a newer distribution release than is supported by the repository (and the packages for the previous distribution release still work). 3. Disable the repository, so yum won‘t use it by default. Yum will then just ignore the repository until you permanently enable it again or use --enablerepo for temporary usage: yum-config-manager --disable <repoid> 4. Configure the failing repository to be skipped, if it is unavailable. Note that yum will try to contact the repo. when it runs most commands, so will have to try and fail each time (and thus. yum will be be much slower). If it is a very temporary problem though, this is often a nice compromise: yum-config-manager --save --setopt=<repoid>.skip_if_unavailable=true Cannot find a valid baseurl for repo: base/7/x86_64
这时候我开始怀疑是不是我的yum所在的网络也存在问题
c、检测网络连通性状态，发现的确是网络存在问题
检查了网卡配置，发现DNS配置存在一些问题，手动修改并重置网卡信息，网络恢复正常 [root@openstack-01 ~]# yum clean all 已加载插件：fastestmirror, langpacks 正在清理软件源： base centos-ceph-hammer centos-openstack-mitaka centos-qemu-ev extras updates Cleaning up everything [root@openstack-01 ~]# yum -y install tree 已加载插件：fastestmirror, langpacks base | 3.6 kB 00:00:00 centos-ceph-hammer | 2.9 kB 00:00:00 centos-openstack-mitaka | 2.9 kB 00:00:00 centos-qemu-ev | 2.9 kB 00:00:00 extras | 3.4 kB 00:00:00 updates | 3.4 kB 00:00:00 (1/7): centos-ceph-hammer/7/x86_64/primary_db | 30 kB 00:00:01 (2/7): extras/7/x86_64/primary_db | 132 kB 00:00:00 (3/7): updates/7/x86_64/primary_db | 4.9 MB 00:00:01 (4/7): centos-openstack-mitaka/x86_64/primary_db | 452 kB 00:00:04 (5/7): base/7/x86_64/primary_db | 5.3 MB 00:00:07 (6/7): base/7/x86_64/group_gz | 155 kB 00:00:15 (7/7): centos-qemu-ev/7/x86_64/primary_db | 23 kB 00:00:16 Determining fastest mirrors * base: mirrors.zju.edu.cn * extras: mirrors.aliyun.com * updates: mirrors.aliyun.com 正在解决依赖关系 --> 正在检查事务 ---> 软件包 tree.x86_64.0.1.6.0-10.el7 将被 安装 --> 解决依赖关系完成 依赖关系解决 ==================================================================================================================================================== Package 架构 版本 源 大小 ==================================================================================================================================================== 正在安装: tree x86_64 1.6.0-10.el7 base 46 k 事务概要 ==================================================================================================================================================== 安装 1 软件包 总下载量：46 k 安装大小：87 k Downloading packages: tree-1.6.0-10.el7.x86_64.rpm | 46 kB 00:00:00 Running transaction check Running transaction test Transaction test succeeded Running transaction 正在安装 : tree-1.6.0-10.el7.x86_64 1/1 验证中 : tree-1.6.0-10.el7.x86_64 1/1 已安装: tree.x86_64 0:1.6.0-10.el7 完毕！ [root@openstack-01 ~]# tree . ├── anaconda-ks.cfg ├── keystonerc_admin ├── keystonerc_demo ├── packstack-answers-20160505-132946.txt ├── packstack-answers-20160505-134047.txt ├── packstack-answers-20160505-152256.txt ├── \345\205\254\345\205\261 ├── \346\250\241\346\235\277 ├── \350\247\206\351\242\221 ├── \345\233\276\347\211\207 ├── \346\226\207\346\241\243 ├── \344\270\213\350\275\275 ├── \351\237\263\344\271\220 └── \346\241\214\351\235\242 ├── \346\234\252\345\221\275\345\220\215\346\226\207\344\273\266\345\244\271 └── \346\234\252\345\221\275\345\220\215\346\226\207\344\273\266\345\244\271\ 2 10 directories, 6 files
3、小结
在分析报错信息的时候，不能片面的根据提示信息去做，要抓住核心，才能速度解决问题。
本文出自 “冰冻vs西瓜” 博客，请务必保留此出处http://molewan.blog.51cto.com/287340/1785975
Repodata is over 2 weeks old. Install yum-cron? Or run: yum makecache fast
原文地址：http://molewan.blog.51cto.com/287340/1785975
