在一测试服务器（CentOS Linux release 7.2.1511）上安装MySQL 5.6（5.6.19 MySQL Community Server）时遇到下面错误，这个是因为CentOS 7的默认数据库已经不再是MySQL了，而是MariaDB. MySQL安装时的mysql lib库与mariadb的库、包冲突了，如下详情所示（省略了大量日志）
[root@azrlnx06 tmp]# rpm -ivh MySQL-server-advanced-5.6.20-1.rhel5.x86_64.rpm
Preparing... ################################# [100%]
file /usr/share/mysql/czech/errmsg.sys from install of MySQL-server-advanced-5.6.20-1.rhel5.x86_64 conflicts with file from package mariadb-libs-1:5.5.50-1.el7_2.x86_64
file /usr/share/mysql/danish/errmsg.sys from install of MySQL-server-advanced-5.6.20-1.rhel5.x86_64 conflicts with file from package mariadb-libs-1:5.5.50-1.el7_2.x86_64
file /usr/share/mysql/dutch/errmsg.sys from install of MySQL-server-advanced-5.6.20-1.rhel5.x86_64 conflicts with file from package mariadb-libs-1:5.5.50-1.el7_2.x86_64
file /usr/share/mysql/english/errmsg.sys from install of MySQL-server-advanced-5.6.20-1.rhel5.x86_64 conflicts with file from package mariadb-libs-1:5.5.50-1.el7_2.x86_64
file /usr/share/mysql/estonian/errmsg.sys from install of MySQL-server-advanced-5.6.20-1.rhel5.x86_64 conflicts with file from package mariadb-libs-1:5.5.50-1.el7_2.x86_64
file /usr/share/mysql/french/errmsg.sys from install of MySQL-server-advanced-5.6.20-1.rhel5.x86_64 conflicts with file from package mariadb-libs-1:5.5.50-1.el7_2.x86_64
file /usr/share/mysql/german/errmsg.sys from install of MySQL-server-advanced-5.6.20-1.rhel5.x86_64 conflicts with file from package mariadb-libs-1:5.5.50-1.el7_2.x86_64
file /usr/share/mysql/greek/errmsg.sys from install of MySQL-server-advanced-5.6.20-1.rhel5.x86_64 conflicts with file from package mariadb-libs-1:5.5.50-1.el7_2.x86_64
........................................................................................................................................................................
file /usr/share/mysql/charsets/macroman.xml from install of MySQL-server-advanced-5.6.20-1.rhel5.x86_64 conflicts with file from package mariadb-libs-1:5.5.50-1.el7_2.x86_64
file /usr/share/mysql/charsets/swe7.xml from install of MySQL-server-advanced-5.6.20-1.rhel5.x86_64 conflicts with file from package mariadb-libs-1:5.5.50-1.el7_2.x86_64
检查是否存在mariadb的相关组件,然后删除mariadb相关组件。如下所示：
[root@azrlnx06 mysql]# more /etc/redhat-release
CentOS Linux release 7.2.1511 (Core)
[root@azrlnx06 mysql]# rpm -qa |grep mariadb
mariadb-libs-5.5.50-1.el7_2.x86_64
[root@azrlnx06 mysql]# rpm -e mariadb-libs-5.5.50-1.el7_2.x86_64
error: Failed dependencies:
libmysqlclient.so.18()(64bit) is needed by (installed) postfix-2:2.10.1-6.el7.x86_64
libmysqlclient.so.18(libmysqlclient_18)(64bit) is needed by (installed) postfix-2:2.10.1-6.el7.x86_64
[root@azrlnx06 mysql]# rpm -e mariadb-libs-5.5.50-1.el7_2.x86_64 --nodeps
当然此处删除mariadb-libs-5.5.50-1.el7_2.x86_64组件时遇到依赖错误，遂强制删除该组件，最好使用yum删除mariadb相关组件。然后重新安装MySQL时遇到"error: MySQL-server-advanced-5.6.20-1.rhel5.x86_64: install failed"错误，如下所示：
[root@azrlnx06 mysql]# cd /tmp
[root@azrlnx06 tmp]# ls
hsperfdata_azrlnx06 jirasetup MySQL-server-advanced-5.6.20-1.rhel5.x86_64.rpm
[root@azrlnx06 tmp]# rpm -ivh MySQL-server-advanced-5.6.20-1.rhel5.x86_64.rpm
Preparing... ################################# [100%]
Updating / installing...
1:MySQL-server-advanced-5.6.20-1.rh################################# [100%]
error: unpacking of archive failed on file /usr/bin/innochecksum;582535c8: cpio: read failed - No such file or directory
error: MySQL-server-advanced-5.6.20-1.rhel5.x86_64: install failed
[root@azrlnx06 tmp]#
对这个错误有点莫名其妙，卸载MySQL相关组件后，重新安装MySQL，发现缺少Perl相关模组。如下所示：
[root@azrlnx06 jirasetup]# rpm -ivh MySQL-server-advanced-5.6.20-1.rhel5.x86_64.rpm
Preparing... ################################# [100%]
Updating / installing...
1:MySQL-server-advanced-5.6.20-1.rh################################# [100%]
FATAL ERROR: please install the following Perl modules before executing /usr/bin/mysql_install_db:
Data::Dumper
[root@azrlnx06 jirasetup]#
使用yum安装了 perl perl-devel相关包（注意：此处安装MySQL时，没有输出安装相关Detail的信息，是因为Perl相关模组没有安装的缘故，此处还漏掉了安装perl-Data-Dumper）
[root@azrlnx06 jirasetup]# yum install -y perl perl-devel
安装完Perl相关组件后，重新安装MySQL，如下所示，安装成功，但是没有输出安装相关Detail的信息（因为没有安装perl-Data-Dumper），启动MySQL报错
root@azrlnx06 jirasetup]# rpm -ivh MySQL-server-advanced-5.6.20-1.rhel5.x86_64.rpm
Preparing... ################################# [100%]
Updating / installing...
1:MySQL-server-advanced-5.6.20-1.rh################################# [100%]
[root@azrlnx06 jirasetup]# rpm -ivh MySQL-client-advanced-5.6.20-1.rhel5.x86_64.rpm
Preparing... ################################# [100%]
Updating / installing...
1:MySQL-client-advanced-5.6.20-1.rh################################# [100%]
[root@azrlnx06 ~]# service mysql start
Starting MySQL............. ERROR! The server quit without updating PID file (/var/lib/mysql/azrlnx06.pid).
[root@azrlnx06 ~]#
找到MySQL的错误日志，然后检查/var/lib/mysql/azrlnx06.err错误日志，发现如下错误信息：
[root@azrlnx06 mysql]# find / -name *.err
/var/lib/mysql/azrlnx06.err
/var/log/azure/Microsoft.OSTCExtensions.LinuxDiagnostic/2.3.9011/mdsd.err
/var/log/azure/Microsoft.OSTCExtensions.LinuxDiagnostic/2.3.9013/mdsd.err
/var/log/mdsd/mdsd.err
[root@azrlnx06 mysql]# more /var/lib/mysql/azrlnx06.err
161111 03:28:25 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
2016-11-11 03:28:25 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2016-11-11 03:28:25 2144 [Note] Plugin 'FEDERATED' is disabled.
/usr/sbin/mysqld: Table 'mysql.plugin' doesn't exist
2016-11-11 03:28:25 2144 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it.
2016-11-11 03:28:25 2144 [Note] InnoDB: Using atomics to ref count buffer pool pages
2016-11-11 03:28:25 2144 [Note] InnoDB: The InnoDB memory heap is disabled
2016-11-11 03:28:25 2144 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2016-11-11 03:28:25 2144 [Note] InnoDB: Memory barrier is not used
2016-11-11 03:28:25 2144 [Note] InnoDB: Compressed tables use zlib 1.2.3
2016-11-11 03:28:25 2144 [Note] InnoDB: Using Linux native AIO
2016-11-11 03:28:25 2144 [Note] InnoDB: Using CPU crc32 instructions
2016-11-11 03:28:25 2144 [Note] InnoDB: Initializing buffer pool, size = 128.0M
2016-11-11 03:28:25 2144 [Note] InnoDB: Completed initialization of buffer pool
2016-11-11 03:28:25 2144 [Note] InnoDB: The first specified data file ./ibdata1 did not exist: a new database to be created!
2016-11-11 03:28:25 2144 [Note] InnoDB: Setting file ./ibdata1 size to 12 MB
2016-11-11 03:28:25 2144 [Note] InnoDB: Database physically writes the file full: wait...
2016-11-11 03:28:26 2144 [Note] InnoDB: Setting log file ./ib_logfile101 size to 48 MB
2016-11-11 03:28:31 2144 [Note] InnoDB: Setting log file ./ib_logfile1 size to 48 MB
2016-11-11 03:28:37 2144 [Note] InnoDB: Renaming log file ./ib_logfile101 to ./ib_logfile0
2016-11-11 03:28:37 2144 [Warning] InnoDB: New log files created, LSN=45781
2016-11-11 03:28:37 2144 [Note] InnoDB: Doublewrite buffer not found: creating new
2016-11-11 03:28:37 2144 [Note] InnoDB: Doublewrite buffer created
2016-11-11 03:28:37 2144 [Note] InnoDB: 128 rollback segment(s) are active.
2016-11-11 03:28:37 2144 [Warning] InnoDB: Creating foreign key constraint system tables.
2016-11-11 03:28:37 2144 [Note] InnoDB: Foreign key constraint system tables created
2016-11-11 03:28:37 2144 [Note] InnoDB: Creating tablespace and datafile system tables.
2016-11-11 03:28:38 2144 [Note] InnoDB: Tablespace and datafile system tables created.
2016-11-11 03:28:38 2144 [Note] InnoDB: Waiting for purge to start
2016-11-11 03:28:38 2144 [Note] InnoDB: 5.6.20 started; log sequence number 0
2016-11-11 03:28:38 2144 [Warning] No existing UUID has been found, so we assume that this is the first time that this server has been started. Generating a new UUID: ef3b0cd5-a7be-11e6-98b3-000d3a8062fe.
2016-11-11 03:28:38 2144 [Note] RSA private key file not found: /var/lib/mysql//private_key.pem. Some authentication plugins will not work.
2016-11-11 03:28:38 2144 [Note] RSA public key file not found: /var/lib/mysql//public_key.pem. Some authentication plugins will not work.
2016-11-11 03:28:38 2144 [Note] Server hostname (bind-address): '*'; port: 3306
2016-11-11 03:28:38 2144 [Note] IPv6 is available.
2016-11-11 03:28:38 2144 [Note] - '::' resolves to '::';
2016-11-11 03:28:38 2144 [Note] Server socket created on IP: '::'.
2016-11-11 03:28:38 2144 [ERROR] Fatal error: Can't open and lock privilege tables: Table 'mysql.user' doesn't exist
161111 03:28:38 mysqld_safe mysqld from pid file /var/lib/mysql/azrlnx06.pid ended
搜索了一些相关资料，应该是perl-Data-Dumper模组没有安装，导致安装过程中，初始化数据库失败，所以启动MySQL服务时，找不到相关系统表。具体参考官方文档MySQL-server RPM does not install perl-Data-Dumper as a dependency
Description:
MySQL-server requires perl-Data-Dumper to function. However, perl-Data-Dumper is not listed by the MySQL-server RPM as a dependency. So if a linux server does not have perl-Data-Dumper installed, the install-mysql-db will fail. And because of missing the initial database, the mysql service could not be started.
How to repeat:
On a linux server, make sure there is no perl-Data-Dumper installed. Install MySQL-server using yum. There should be error message complaining database could not be created.
Suggested fix:
Add perl-Data-Dumper as a dependency of the RPM package
解决方法：
1：安装perl-Data-Dumper模组。
[root@azrlnx06 mysql]# yum install -y perl-Data-Dumper
2：初始化数据库
[root@azrlnx06 mysql]# sudo mysql_install_db --user=mysql --basedir=/usr/ --ldata=/var/lib/mysql/
[root@azrlnx06 mysql]# service mysql start
Starting MySQL. SUCCESS!
[root@azrlnx06 mysql]# /usr//bin/mysqladmin -u root password 'Qwe!23'
Warning: Using a password on the command line interface can be insecure.
当然也可以卸载MySQL，然后重新安装，就能看到安装过程输出的Detail信息输出了。
