[root@CentOS ~]# wget http://repo.mysql.com/mysql-community-release-el7-5.noarch.rpm
[root@CentOS ~]# sudo rpm -ivh mysql-community-release-el7-5.noarch.rpm
[root@CentOS ~]# yum install -y mysql-server
[root@CentOS ~]# systemctl start mysqld
[root@CentOS ~]# systemctl enable mysqld

[root@CentOS ~]# mysql_secure_installation
NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MySQL
      SERVERS IN PRODUCTION USE!  PLEASE READ EACH STEP CAREFULLY!

In order to log into MySQL to secure it, we'll need the current
password for the root user.  If you've just installed MySQL, and
you haven't set the root password yet, the password will be blank,
so you should just press enter here.

Enter current password for root (enter for none):   # 默认是空密码，直接回车即可
OK, successfully used password, moving on...

Setting the root password ensures that nobody can log into the MySQL
root user without the proper authorisation.

Set root password? [Y/n] y
New password: 
Re-enter new password: 
Password updated successfully!
Reloading privilege tables..
 ... Success!

By default, a MySQL installation has an anonymous user, allowing anyone
to log into MySQL without having to have a user account created for
them.  This is intended only for testing, and to make the installation
go a bit smoother.  You should remove them before moving into a
production environment.

Remove anonymous users? [Y/n] y
 ... Success!

Normally, root should only be allowed to connect from 'localhost'.  This
ensures that someone cannot guess at the root password from the network.

Disallow root login remotely? [Y/n] y
 ... Success!

By default, MySQL comes with a database named 'test' that anyone can
access.  This is also intended only for testing, and should be removed
before moving into a production environment.

Remove test database and access to it? [Y/n] y
 - Dropping test database...
ERROR 1008 (HY000) at line 1: Can't drop database 'test'; database doesn't exist
 ... Failed!  Not critical, keep moving...
 - Removing privileges on test database...
 ... Success!

Reloading the privilege tables will ensure that all changes made so far
will take effect immediately.

Reload privilege tables now? [Y/n] y
 ... Success!

All done!  If you've completed all of the above steps, your MySQL
installation should now be secure.

Thanks for using MySQL!

Cleaning up...

[root@CentOS ~]# mysql -u root -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 15
Server version: 5.6.43 MySQL Community Server (GPL)

Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> 

mysql> create database madblog character set utf8 collate utf8_general_ci;
Query OK, 1 row affected (0.00 sec)

mysql> grant all on madblog.* to 'testuser' identified by 'password';
Query OK, 0 rows affected (0.00 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)

mysql> quit;
Bye

[root@CentOS ~]# yum install -y epel-release
[root@CentOS ~]# yum install -y redis
[root@CentOS ~]# systemctl start redis
[root@CentOS ~]# systemctl enable redis

# 0. Need Java 8++
[root@CentOS ~]# yum -y install java-1.8.0-openjdk

# 1. Download and install the public signing key
[root@CentOS ~]# rpm --import https://artifacts.elastic.co/GPG-KEY-elasticsearch

# 2. Create yum repository
[root@CentOS ~]# vim /etc/yum.repos.d/elasticsearch.repo
内容如下：

[elasticsearch-7.x]
name=Elasticsearch repository for 7.x packages
baseurl=https://artifacts.elastic.co/packages/7.x/yum
gpgcheck=1
gpgkey=https://artifacts.elastic.co/GPG-KEY-elasticsearch
enabled=1
autorefresh=1
type=rpm-md

# 3. Install Elasticsearch
[root@CentOS ~]# yum -y install elasticsearch
[root@CentOS ~]# systemctl start elasticsearch.service
[root@CentOS ~]# systemctl enable elasticsearch.service