在centos中运行yum install的时候发生了什么？

Question

[root@iZ2zed9zgziqo9et9ezfsjZ /]# yum install mariadb-server -y;
Loaded plugins: fastestmirror
Determining fastest mirrors
base | 3.6 kB 00:00:00
epel | 5.3 kB 00:00:00
extras | 3.4 kB 00:00:00
updates | 3.4 kB 00:00:00
(1/7): base/7/x86_64/group_gz | 166 kB 00:00:00
(2/7): epel/x86_64/group_gz | 88 kB 00:00:00
(3/7): epel/x86_64/updateinfo | 998 kB 00:00:00
(4/7): extras/7/x86_64/primary_db | 215 kB 00:00:00
(5/7): base/7/x86_64/primary_db | 6.0 MB 00:00:00
(6/7): epel/x86_64/primary_db | 6.8 MB 00:00:00
(7/7): updates/7/x86_64/primary_db | 7.4 MB 00:00:00
Resolving Dependencies
--> Running transaction check
---> Package mariadb-server.x86_64 1:5.5.60-1.el7_5 will be installed
--> Processing Dependency: mariadb(x86-64) = 1:5.5.60-1.el7_5 for package: 1:mariadb-server-5.5.60-1.el7_5.x86_64
--> Processing Dependency: perl-DBI for package: 1:mariadb-server-5.5.60-1.el7_5.x86_64
--> Processing Dependency: perl-DBD-MySQL for package: 1:mariadb-server-5.5.60-1.el7_5.x86_64
--> Processing Dependency: perl(Data::Dumper) for package: 1:mariadb-server-5.5.60-1.el7_5.x86_64
--> Processing Dependency: perl(DBI) for package: 1:mariadb-server-5.5.60-1.el7_5.x86_64
--> Processing Dependency: libaio.so.1(LIBAIO_0.4)(64bit) for package: 1:mariadb-server-5.5.60-1.el7_5.x86_64
--> Processing Dependency: libaio.so.1(LIBAIO_0.1)(64bit) for package: 1:mariadb-server-5.5.60-1.el7_5.x86_64
--> Processing Dependency: libaio.so.1()(64bit) for package: 1:mariadb-server-5.5.60-1.el7_5.x86_64
--> Running transaction check
---> Package libaio.x86_64 0:0.3.109-13.el7 will be installed
---> Package mariadb.x86_64 1:5.5.60-1.el7_5 will be installed
---> Package perl-DBD-MySQL.x86_64 0:4.023-6.el7 will be installed
---> Package perl-DBI.x86_64 0:1.627-4.el7 will be installed
--> Processing Dependency: perl(RPC::PlServer) >= 0.2001 for package: perl-DBI-1.627-4.el7.x86_64
--> Processing Dependency: perl(RPC::PlClient) >= 0.2000 for package: perl-DBI-1.627-4.el7.x86_64
---> Package perl-Data-Dumper.x86_64 0:2.145-3.el7 will be installed
--> Running transaction check
---> Package perl-PlRPC.noarch 0:0.2020-14.el7 will be installed
--> Processing Dependency: perl(Net::Daemon) >= 0.13 for package: perl-PlRPC-0.2020-14.el7.noarch
--> Processing Dependency: perl(Net::Daemon::Test) for package: perl-PlRPC-0.2020-14.el7.noarch
--> Processing Dependency: perl(Net::Daemon::Log) for package: perl-PlRPC-0.2020-14.el7.noarch
--> Processing Dependency: perl(Compress::Zlib) for package: perl-PlRPC-0.2020-14.el7.noarch
--> Running transaction check
---> Package perl-IO-Compress.noarch 0:2.061-2.el7 will be installed
--> Processing Dependency: perl(Compress::Raw::Zlib) >= 2.061 for package: perl-IO-Compress-2.061-2.el7.noarch
--> Processing Dependency: perl(Compress::Raw::Bzip2) >= 2.061 for package: perl-IO-Compress-2.061-2.el7.noarch
---> Package perl-Net-Daemon.noarch 0:0.48-5.el7 will be installed
--> Running transaction check
---> Package perl-Compress-Raw-Bzip2.x86_64 0:2.061-3.el7 will be installed
---> Package perl-Compress-Raw-Zlib.x86_64 1:2.061-4.el7 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

============================================================================================================================

Package Arch Version Repository Size

Installing:
mariadb-server x86_64 1:5.5.60-1.el7_5 base 11 M
Installing for dependencies:
libaio x86_64 0.3.109-13.el7 base 24 k
mariadb x86_64 1:5.5.60-1.el7_5 base 8.9 M
perl-Compress-Raw-Bzip2 x86_64 2.061-3.el7 base 32 k
perl-Compress-Raw-Zlib x86_64 1:2.061-4.el7 base 57 k
perl-DBD-MySQL x86_64 4.023-6.el7 base 140 k
perl-DBI x86_64 1.627-4.el7 base 802 k
perl-Data-Dumper x86_64 2.145-3.el7 base 47 k
perl-IO-Compress noarch 2.061-2.el7 base 260 k
perl-Net-Daemon noarch 0.48-5.el7 base 51 k
perl-PlRPC noarch 0.2020-14.el7 base 36 k

Transaction Summary

Install 1 Package (+10 Dependent packages)

Total download size: 21 M
Installed size: 110 M
Downloading packages:
(1/11): libaio-0.3.109-13.el7.x86_64.rpm | 24 kB 00:00:00
(2/11): mariadb-server-5.5.60-1.el7_5.x86_64.rpm | 11 MB 00:00:00
(3/11): mariadb-5.5.60-1.el7_5.x86_64.rpm | 8.9 MB 00:00:00
(4/11): perl-Compress-Raw-Bzip2-2.061-3.el7.x86_64.rpm | 32 kB 00:00:00
(5/11): perl-Compress-Raw-Zlib-2.061-4.el7.x86_64.rpm | 57 kB 00:00:00
(6/11): perl-DBD-MySQL-4.023-6.el7.x86_64.rpm | 140 kB 00:00:00
(7/11): perl-DBI-1.627-4.el7.x86_64.rpm | 802 kB 00:00:00
(8/11): perl-IO-Compress-2.061-2.el7.noarch.rpm | 260 kB 00:00:00
(9/11): perl-Net-Daemon-0.48-5.el7.noarch.rpm | 51 kB 00:00:00
(10/11): perl-PlRPC-0.2020-14.el7.noarch.rpm | 36 kB 00:00:00

(11/11): perl-Data-Dumper-2.145-3.el7.x86_64.rpm | 47 kB 00:00:00

Total 18 MB/s | 21 MB 00:00:01
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
Warning: RPMDB altered outside of yum.
Installing : perl-Data-Dumper-2.145-3.el7.x86_64 1/11
Installing : libaio-0.3.109-13.el7.x86_64 2/11
Installing : 1:mariadb-5.5.60-1.el7_5.x86_64 3/11
Installing : 1:perl-Compress-Raw-Zlib-2.061-4.el7.x86_64 4/11
Installing : perl-Net-Daemon-0.48-5.el7.noarch 5/11
Installing : perl-Compress-Raw-Bzip2-2.061-3.el7.x86_64 6/11
Installing : perl-IO-Compress-2.061-2.el7.noarch 7/11
Installing : perl-PlRPC-0.2020-14.el7.noarch 8/11
Installing : perl-DBI-1.627-4.el7.x86_64 9/11
Installing : perl-DBD-MySQL-4.023-6.el7.x86_64 10/11
Installing : 1:mariadb-server-5.5.60-1.el7_5.x86_64 11/11
Verifying : 1:mariadb-server-5.5.60-1.el7_5.x86_64 1/11
Verifying : perl-Compress-Raw-Bzip2-2.061-3.el7.x86_64 2/11
Verifying : perl-Net-Daemon-0.48-5.el7.noarch 3/11
Verifying : perl-Data-Dumper-2.145-3.el7.x86_64 4/11
Verifying : perl-DBD-MySQL-4.023-6.el7.x86_64 5/11
Verifying : perl-IO-Compress-2.061-2.el7.noarch 6/11
Verifying : 1:perl-Compress-Raw-Zlib-2.061-4.el7.x86_64 7/11
Verifying : 1:mariadb-5.5.60-1.el7_5.x86_64 8/11
Verifying : perl-DBI-1.627-4.el7.x86_64 9/11
Verifying : libaio-0.3.109-13.el7.x86_64 10/11
Verifying : perl-PlRPC-0.2020-14.el7.noarch 11/11

Installed:
mariadb-server.x86_64 1:5.5.60-1.el7_5

Dependency Installed:
libaio.x86_64 0:0.3.109-13.el7 mariadb.x86_64 1:5.5.60-1.el7_5
perl-Compress-Raw-Bzip2.x86_64 0:2.061-3.el7 perl-Compress-Raw-Zlib.x86_64 1:2.061-4.el7
perl-DBD-MySQL.x86_64 0:4.023-6.el7 perl-DBI.x86_64 0:1.627-4.el7
perl-Data-Dumper.x86_64 0:2.145-3.el7 perl-IO-Compress.noarch 0:2.061-2.el7
perl-Net-Daemon.noarch 0:0.48-5.el7 perl-PlRPC.noarch 0:0.2020-14.el7

Complete!### 问题描述

问题出现的平台版本及自己尝试过哪些方法

相关代码

// 请把代码文本粘贴到下方（请勿用图片代替代码）

你期待的结果是什么？实际看到的错误信息又是什么？

Answer 1

yum安装的本质其实是RPM安装，也就是你执行yum install的时候，服务器先去yum源中查找你需要安装的包，再检查这个包是否依赖其他的包，如果有依赖就先下载并安装依赖包，再安装你所需要的包。这个步骤跟你自己下载RPM包，然后安装的时候会报依赖其他的RPM包，你再安装其他的RPM依赖包是一样的。。只不过它自动给你解决了包依赖（即包的安装顺序）的问题。。