CentOS7启动MySQL报错,解决Failed to start mariadb-service.service: Unit not found

CentOS7启动MySQL报错,解决Failed to start mysqld.service: Unit not found

当输入命令

[root@localhost ~]# systemctl start mysql.service

要启动MySQL数据库是却是这样的提示

Failed to start mariadb-service.service: Unit not found

解决方法如下:

　　首先需要安装mariadb-server

[root@localhost ~]# yum install -y mariadb-server

　　启动服务

[root@localhost ~]# systemctl start mariadb.service

　　添加到开机启动

[root@localhost ~]# systemctl enable mariadb.service

[root@localhost ~]# systemctl start mariadb-service
Failed to start mariadb-service.service: Unit not found.
[root@localhost ~]# systemctl start mariadb-service
Failed to start mariadb-service.service: Unit not found.
[root@localhost ~]# yum install mariadb-server
已加载插件：fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirrors.163.com
 * elrepo: ftp.ne.jp
 * extras: mirrors.163.com
 * updates: mirrors.163.com
软件包 1:mariadb-server-5.5.65-1.el7.x86_64 已安装并且是最新版本
无须任何处理
[root@localhost ~]# systemctl start mariadb-service
Failed to start mariadb-service.service: Unit not found.
[root@localhost ~]# yum install -y mariadb mariadb-server
已加载插件：fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirrors.163.com
 * elrepo: ftp.ne.jp
 * extras: mirrors.163.com
 * updates: mirrors.163.com
软件包 1:mariadb-5.5.65-1.el7.x86_64 已安装并且是最新版本
软件包 1:mariadb-server-5.5.65-1.el7.x86_64 已安装并且是最新版本
无须任何处理
[root@localhost ~]# systemctl status mariadb-service
Unit mariadb-service.service could not be found.
[root@localhost ~]# ps -ef | grep mariadb
root      63544  60579  0 20:42 pts/0    00:00:00 grep --color=auto mariadb
[root@localhost ~]# yum remove mariadb-libs.x86_64 
已加载插件：fastestmirror
正在解决依赖关系
--> 正在检查事务
---> 软件包 mariadb-libs.x86_64.1.5.5.65-1.el7 将被 删除
--> 正在处理依赖关系 libmysqlclient.so.18()(64bit)，它被软件包 perl-DBD-MySQL-4.023-6.el7.x86_64 需要
--> 正在处理依赖关系 libmysqlclient.so.18()(64bit)，它被软件包 2:postfix-2.10.1-9.el7.x86_64 需要
--> 正在处理依赖关系 libmysqlclient.so.18(libmysqlclient_18)(64bit)，它被软件包 perl-DBD-MySQL-4.023-6.el7.x86_64 需要
--> 正在处理依赖关系 libmysqlclient.so.18(libmysqlclient_18)(64bit)，它被软件包 2:postfix-2.10.1-9.el7.x86_64 需要
--> 正在处理依赖关系 mariadb-libs(x86-64) = 1:5.5.65-1.el7，它被软件包 1:mariadb-server-5.5.65-1.el7.x86_64 需要
--> 正在处理依赖关系 mariadb-libs(x86-64) = 1:5.5.65-1.el7，它被软件包 1:mariadb-5.5.65-1.el7.x86_64 需要
--> 正在检查事务
---> 软件包 mariadb.x86_64.1.5.5.65-1.el7 将被 删除
---> 软件包 mariadb-server.x86_64.1.5.5.65-1.el7 将被 删除
---> 软件包 perl-DBD-MySQL.x86_64.0.4.023-6.el7 将被 删除
---> 软件包 postfix.x86_64.2.2.10.1-9.el7 将被 删除
--> 解决依赖关系完成

依赖关系解决

================================================================================
 Package              架构         版本                   源               大小
================================================================================
正在删除:
 mariadb-libs         x86_64       1:5.5.65-1.el7         @anaconda       4.4 M
为依赖而移除:
 mariadb              x86_64       1:5.5.65-1.el7         @base            49 M
 mariadb-server       x86_64       1:5.5.65-1.el7         @base            58 M
 perl-DBD-MySQL       x86_64       4.023-6.el7            @base           323 k
 postfix              x86_64       2:2.10.1-9.el7         @anaconda        12 M

事务概要
================================================================================
移除  1 软件包 (+4 依赖软件包)

安装大小：124 M
是否继续？[y/N]：y
Downloading packages:
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  正在删除    : 1:mariadb-server-5.5.65-1.el7.x86_64                        1/5 
  正在删除    : 1:mariadb-5.5.65-1.el7.x86_64                               2/5 
  正在删除    : perl-DBD-MySQL-4.023-6.el7.x86_64                           3/5 
  正在删除    : 2:postfix-2.10.1-9.el7.x86_64                               4/5 
  正在删除    : 1:mariadb-libs-5.5.65-1.el7.x86_64                          5/5 
  验证中      : 1:mariadb-server-5.5.65-1.el7.x86_64                        1/5 
  验证中      : 1:mariadb-libs-5.5.65-1.el7.x86_64                          2/5 
  验证中      : perl-DBD-MySQL-4.023-6.el7.x86_64                           3/5 
  验证中      : 1:mariadb-5.5.65-1.el7.x86_64                               4/5 
  验证中      : 2:postfix-2.10.1-9.el7.x86_64                               5/5 

删除:
  mariadb-libs.x86_64 1:5.5.65-1.el7                                            

作为依赖被删除:
  mariadb.x86_64 1:5.5.65-1.el7          mariadb-server.x86_64 1:5.5.65-1.el7   
  perl-DBD-MySQL.x86_64 0:4.023-6.el7    postfix.x86_64 2:2.10.1-9.el7          

完毕！
[root@localhost ~]# yum remove mariadb
已加载插件：fastestmirror
参数 mariadb 没有匹配
不删除任何软件包
[root@localhost ~]# yum install -y mariadb-server
已加载插件：fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirrors.163.com
 * elrepo: ftp.ne.jp
 * extras: mirrors.163.com
 * updates: mirrors.163.com
正在解决依赖关系
--> 正在检查事务
---> 软件包 mariadb-server.x86_64.1.5.5.65-1.el7 将被 安装
--> 正在处理依赖关系 mariadb-libs(x86-64) = 1:5.5.65-1.el7，它被软件包 1:mariadb-server-5.5.65-1.el7.x86_64 需要
--> 正在处理依赖关系 mariadb(x86-64) = 1:5.5.65-1.el7，它被软件包 1:mariadb-server-5.5.65-1.el7.x86_64 需要
--> 正在处理依赖关系 perl-DBD-MySQL，它被软件包 1:mariadb-server-5.5.65-1.el7.x86_64 需要
--> 正在检查事务
---> 软件包 mariadb.x86_64.1.5.5.65-1.el7 将被 安装
---> 软件包 mariadb-libs.x86_64.1.5.5.65-1.el7 将被 安装
---> 软件包 perl-DBD-MySQL.x86_64.0.4.023-6.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:
 mariadb-server        x86_64        1:5.5.65-1.el7           base         11 M
为依赖而安装:
 mariadb               x86_64        1:5.5.65-1.el7           base        8.7 M
 mariadb-libs          x86_64        1:5.5.65-1.el7           base        759 k
 perl-DBD-MySQL        x86_64        4.023-6.el7              base        140 k

事务概要
================================================================================
安装  1 软件包 (+3 依赖软件包)

总下载量：21 M
安装大小：112 M
Downloading packages:
(1/4): mariadb-libs-5.5.65-1.el7.x86_64.rpm                | 759 kB   00:00     
(2/4): perl-DBD-MySQL-4.023-6.el7.x86_64.rpm               | 140 kB   00:00     
(3/4): mariadb-5.5.65-1.el7.x86_64.rpm                     | 8.7 MB   00:01     
(4/4): mariadb-server-5.5.65-1.el7.x86_64.rpm              |  11 MB   00:02     
--------------------------------------------------------------------------------
总计                                               9.4 MB/s |  21 MB  00:02     
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  正在安装    : 1:mariadb-libs-5.5.65-1.el7.x86_64                          1/4 
  正在安装    : perl-DBD-MySQL-4.023-6.el7.x86_64                           2/4 
  正在安装    : 1:mariadb-5.5.65-1.el7.x86_64                               3/4 
  正在安装    : 1:mariadb-server-5.5.65-1.el7.x86_64                        4/4 
  验证中      : 1:mariadb-server-5.5.65-1.el7.x86_64                        1/4 
  验证中      : 1:mariadb-libs-5.5.65-1.el7.x86_64                          2/4 
  验证中      : perl-DBD-MySQL-4.023-6.el7.x86_64                           3/4 
  验证中      : 1:mariadb-5.5.65-1.el7.x86_64                               4/4 

已安装:
  mariadb-server.x86_64 1:5.5.65-1.el7                                          

作为依赖被安装:
  mariadb.x86_64 1:5.5.65-1.el7           mariadb-libs.x86_64 1:5.5.65-1.el7    
  perl-DBD-MySQL.x86_64 0:4.023-6.el7    

完毕！
[root@localhost ~]# systemctl start mariadb.service 
[root@localhost ~]# systemctl status mariadb.service 
● mariadb.service - MariaDB database server
   Loaded: loaded (/usr/lib/systemd/system/mariadb.service; disabled; vendor preset: disabled)
   Active: active (running) since 六 2020-07-11 20:44:47 CST; 8s ago
  Process: 64645 ExecStartPost=/usr/libexec/mariadb-wait-ready $MAINPID (code=exited, status=0/SUCCESS)
  Process: 64533 ExecStartPre=/usr/libexec/mariadb-prepare-db-dir %n (code=exited, status=0/SUCCESS)
 Main PID: 64644 (mysqld_safe)
    Tasks: 20
   Memory: 106.1M
   CGroup: /system.slice/mariadb.service
           ├─64644 /bin/sh /usr/bin/mysqld_safe --basedir=/usr
           └─64807 /usr/libexec/mysqld --basedir=/usr --datadir=/var/lib/mysq...

7月 11 20:44:44 localhost.localdomain systemd[1]: Starting MariaDB database ...
7月 11 20:44:44 localhost.localdomain mariadb-prepare-db-dir[64533]: Initial...
7月 11 20:44:45 localhost.localdomain mariadb-prepare-db-dir[64533]: 200711 ...
7月 11 20:44:45 localhost.localdomain mariadb-prepare-db-dir[64533]: 200711 ...
7月 11 20:44:45 localhost.localdomain mariadb-prepare-db-dir[64533]: PLEASE ...
7月 11 20:44:45 localhost.localdomain mysqld_safe[64644]: 200711 20:44:45 my...
7月 11 20:44:45 localhost.localdomain mysqld_safe[64644]: 200711 20:44:45 my...
7月 11 20:44:47 localhost.localdomain systemd[1]: Started MariaDB database s...
Hint: Some lines were ellipsized, use -l to show in full.
[root@localhost ~]# systemctl enable mariadb.service 
Created symlink from /etc/systemd/system/multi-user.target.wants/mariadb.service to /usr/lib/systemd/system/mariadb.service.
[root@localhost ~]# systemctl status mariadb.service 
● mariadb.service - MariaDB database server
   Loaded: loaded (/usr/lib/systemd/system/mariadb.service; enabled; vendor preset: disabled)
   Active: active (running) since 六 2020-07-11 20:44:47 CST; 54s ago
 Main PID: 64644 (mysqld_safe)
   CGroup: /system.slice/mariadb.service
           ├─64644 /bin/sh /usr/bin/mysqld_safe --basedir=/usr
           └─64807 /usr/libexec/mysqld --basedir=/usr --datadir=/var/lib/mysq...

7月 11 20:44:44 localhost.localdomain systemd[1]: Starting MariaDB database ...
7月 11 20:44:44 localhost.localdomain mariadb-prepare-db-dir[64533]: Initial...
7月 11 20:44:45 localhost.localdomain mariadb-prepare-db-dir[64533]: 200711 ...
7月 11 20:44:45 localhost.localdomain mariadb-prepare-db-dir[64533]: 200711 ...
7月 11 20:44:45 localhost.localdomain mariadb-prepare-db-dir[64533]: PLEASE ...
7月 11 20:44:45 localhost.localdomain mysqld_safe[64644]: 200711 20:44:45 my...
7月 11 20:44:45 localhost.localdomain mysqld_safe[64644]: 200711 20:44:45 my...
7月 11 20:44:47 localhost.localdomain systemd[1]: Started MariaDB database s...
Hint: Some lines were ellipsized, use -l to show in full.