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]# clip_image001
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 clip_image002
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/ clip_image003
[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。
