在一測試服務器（CentOS Linux release 7.2.1511）上安裝MySQL 5.6（5.6.19 MySQL Community Server）時遇到下面錯誤，這個是因為CentOS 7的默認數據庫已經不再是MySQL了，而是MariaDB. MySQL安裝時的mysql lib庫與mariadb的庫、包沖突了，如下詳情所示（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
檢查是否存在mariadb的相關組件,然後刪除mariadb相關組件。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
當然此處刪除mariadb-libs-5.5.50-1.el7_2.x86_64組件時遇到依賴錯誤，遂強制刪除該組件，最好使用yum刪除mariadb相關組件。然後重新安裝MySQL時遇到"error: MySQL-server-advanced-5.6.20-1.rhel5.x86_64: install failed"錯誤，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]#
對這個錯誤有點莫名其妙，卸載MySQL相關組件後，重新安裝MySQL，發現缺少Perl相關模組。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安裝了 perl perl-devel相關包（注意：此處安裝MySQL時，沒有輸出安裝相關Detail的信息，是因為Perl相關模組沒有安裝的緣故，此處還漏掉了安裝perl-Data-Dumper）
[root@azrlnx06 jirasetup]# yum install -y perl perl-devel
安裝完Perl相關組件後，重新安裝MySQL，如下所示，安裝成功，但是沒有輸出安裝相關Detail的信息（因為沒有安裝perl-Data-Dumper），啟動MySQL報錯
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的錯誤日志，然後檢查/var/lib/mysql/azrlnx06.err錯誤日志，發現如下錯誤信息：
[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
搜索了一些相關資料，應該是perl-Data-Dumper模組沒有安裝，導致安裝過程中，初始化數據庫失敗，所以啟動MySQL服務時，找不到相關系統表。具體參考官方文檔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
解決方法：
1：安裝perl-Data-Dumper模組。
[root@azrlnx06 mysql]# yum install -y perl-Data-Dumper
2：初始化數據庫
[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.
當然也可以卸載MySQL，然後重新安裝，就能看到安裝過程輸出的Detail信息輸出了。
