Install and Configure MySQL for Cloudera Software

To use a MySQL database, follow these procedures. For information on compatible versions of the MySQL database, see Database Requirements.

Before you begin

Ensure that the MySQL DB is configured with the InnoDB engine by running the following command from the MySQL shell:

mysql> show table status;

Installing the MySQL Server

Install the MySQL database:


OS	Command
RHEL	MySQL is no longer included with RHEL. You must download the repository from the MySQL site and install it directly. You can use the following commands to install MySQL. For more information, visit the MySQL website. `wget <URL to MySQL RPM>` `sudo rpm -ivh <filename>.rpm` `sudo yum update` `sudo yum install mysql-server` `sudo systemctl start mysqld`
SLES	`sudo zypper install mysql libmysqlclient_r17`
Ubuntu	`sudo apt-get install mysql-server`

Configuring and Starting the MySQL Server

Stop the MySQL server if it is running.


OS	Command
RHEL 7 compatible, SLES, and Ubuntu	`sudo systemctl stop mysqld`

Move old InnoDB log files /var/lib/mysql/ib_logfile0 and /var/lib/mysql/ib_logfile1 out of /var/lib/mysql/ to a backup location.
Determine the location of the option file, my.cnf (/etc/my.cnf by default).
Update my.cnf so that it conforms to the following requirements:
- To prevent deadlocks, set the isolation level to READ-COMMITTED.
- Configure the InnoDB engine.
  important
  Cloudera Manager does not start if its tables are configured with the MyISAM engine. (Typically, tables revert to MyISAM if the InnoDB engine is misconfigured.)
- The default settings in the MySQL installations in most distributions use conservative buffer sizes and memory usage. Cloudera Management Service roles need high write throughput because they might insert many records in the database. Cloudera recommends that you set the innodb_flush_method property to O_DIRECT.
- Set the max_connections property according to the size of your cluster:
  - Fewer than 50 hosts - You can store more than one database (for example, both the Cloudera Manager Server and Reports Manager) on the same host. If you do this, you should:
    - Put each database on its own physical disk for best performance. You can do this by manually setting up symbolic links or running multiple database instances (each instance uses a different data directory path).
    - Allow 100 maximum connections for each database and then add 50 extra connections. For example, for two databases, set the maximum connections to 250. If you store four databases on one host (the databases for Cloudera Manager Server, Hue, Reports Manager, and Hive metastore), set the maximum connections to 450.
  - More than 50 hosts - Do not store more than one database on the same host. Use a separate host for each database/host pair. The hosts do not need to be reserved exclusively for databases, but each database should be on a separate host.
- If the cluster has more than 1000 hosts, set the max_allowed_packet property to 16M. Without this setting, the cluster may fail to start due to the following exception: com.mysql.jdbc.PacketTooBigException.
- Binary logging is not a requirement for Cloudera Manager installations. Binary logging provides benefits such as MySQL replication or point-in-time incremental recovery after database restore. Examples of this configuration follow. For more information, see The Binary Log.
Here is an option file with Cloudera recommended settings:
```
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
transaction-isolation = READ-COMMITTED
# Disabling symbolic-links is recommended to prevent assorted security risks;
# to do so, uncomment this line:
symbolic-links = 0

key_buffer_size = 32M
max_allowed_packet = 16M
thread_stack = 256K
thread_cache_size = 64

# The following 3 parameters only apply to MySQL version 5.7 and lower:
query_cache_limit = 8M
query_cache_size = 64M
query_cache_type = 1

max_connections = 550
#expire_logs_days = 10
#max_binlog_size = 100M

#log_bin should be on a disk with enough free space.
#Replace '/var/lib/mysql/mysql_binary_log' with an appropriate path for your
#system and chown the specified folder to the mysql user.
log_bin=/var/lib/mysql/mysql_binary_log

#In later versions of MySQL, if you enable the binary log and do not set
#a server_id, MySQL will not start. The server_id must be unique within
#the replicating group.
server_id=1

binlog_format = mixed

read_buffer_size = 2M
read_rnd_buffer_size = 16M
sort_buffer_size = 8M
join_buffer_size = 8M

# InnoDB settings
innodb_file_per_table = 1
innodb_flush_log_at_trx_commit  = 2
innodb_log_buffer_size = 64M
innodb_buffer_pool_size = 4G
innodb_thread_concurrency = 8
innodb_flush_method = O_DIRECT
innodb_log_file_size = 512M

[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

sql_mode=STRICT_ALL_TABLES
```
If you are using MySQL version 8, remove the following three parameters from the options file:
```
query_cache_limit = 8M
query_cache_size = 64M
query_cache_type = 1
```
If AppArmor is running on the host where MySQL is installed, you might need to configure AppArmor to allow MySQL to write to the binary.

Ensure the MySQL server starts at boot:


OS	Command
RHEL 7 compatible, SLES, and Ubuntu	`sudo systemctl enable mysqld`

Start the MySQL server:


OS	Command
RHEL 7 compatible, SLES, and Ubuntu	`sudo systemctl start mysqld`

Run /usr/bin/mysql_secure_installation to set the MySQL root password and other security-related settings. In a new installation, the root password is blank. Press the Enter key when you're prompted for the root password. For the rest of the prompts, enter the responses listed below in bold:

sudo /usr/bin/mysql_secure_installation

[...]
Enter current password for root (enter for none):
OK, successfully used password, moving on...
[...]
Set root password? [Y/n] Y
New password:
Re-enter new password:
Remove anonymous users? [Y/n] Y
[...]
Disallow root login remotely? [Y/n] N
[...]
Remove test database and access to it [Y/n] Y
[...]
Reload privilege tables now? [Y/n] Y
All done!

Installing the MySQL JDBC Driver

Install the JDBC driver on the Cloudera Manager Server host, as well as any other hosts running services that require database access.

Cloudera recommends that you consolidate all roles that require databases on a limited number of hosts, and install the driver on those hosts. Locating all such roles on the same hosts is recommended but not required. Make sure to install the JDBC driver on each host running roles that access the database.


OS	Command
RHEL	important Using the `yum install` command to install the MySQL driver package before installing a JDK installs OpenJDK, and then uses the Linux `alternatives` command to set the system JDK to be OpenJDK. If you intend to use an Oracle JDK, make sure that it is installed before installing the MySQL driver using `yum install`. If you want to use OpenJDK, you can install the driver using `yum`. Alternatively, use the following procedure to manually install the driver. Download the MySQL JDBC driver from http://www.mysql.com/downloads/connector/j/5.1.html (in `.tar.gz` format). As of the time of writing, you can download version 5.1.48 using `wget` as follows: `wget https://dev.mysql.com/get/Downloads/Connector-J/mysql-connector-java-5.1.48.tar.gz` Extract the JDBC driver JAR file from the downloaded file. For example: `tar zxvf mysql-connector-java-5.1.48.tar.gz` Copy the JDBC driver, renamed, to `/usr/share/java/`. If the target directory does not yet exist, create it. For example: `sudo mkdir -p /usr/share/java/ cd mysql-connector-java-5.1.48 sudo cp mysql-connector-java-5.1.48-bin.jar /usr/share/java/mysql-connector-java.jar`
SLES	`sudo zypper install mysql-connector-java`
Ubuntu	`sudo apt-get install libmysql-java`

Creating Databases for Cloudera Software

Services that require databases

Create databases and service accounts for components that require databases:

Cloudera Manager Server
Cloudera Management Service roles:
- Reports Manager
Data Analytics Studio (DAS) Supported with PostgreSQL only.
Hue
Each Hive metastore
Oozie
Data Analytics Studio
Schema Registry
Streams Messaging Manager

Steps

Log in as the root user, or another user with privileges to create database and grant privileges:
```
mysql -u root -p
```
```
Enter password:
```

Create databases for each service deployed in the cluster using the following commands. You can use any value you want for the <database>, <user>, and <password> parameters. The Databases for Cloudera Software table, below lists the default names provided in the Cloudera Manager configuration settings, but you are not required to use them.

Configure all databases to use the utf8 character set.

Include the character set for each database when you run the CREATE DATABASE statements described below.

CREATE DATABASE <database> DEFAULT CHARACTER SET utf8 DEFAULT COLLATE utf8_general_ci;

Query OK, 1 row affected (0.00 sec)

Create USER by following the steps in this topic: CREATE USER Statement.

GRANT ALL ON <database>.* TO '<user>'@'%' IDENTIFIED BY '<password>';

Query OK, 0 rows affected (0.00 sec)

Table 1. Databases for Cloudera Software
Service	Database	User
Cloudera Manager Server	scm	scm
Reports Manager	rman	rman
Ranger RHEL/CentOS/Ubuntu	ranger	rangeradmin
Ranger KMS RHEL/CentOS	ranger	rangerkms
Hue	hue	hue
Hive Metastore Server	hive	hive
Oozie	oozie	oozie
Data Analytics Studio (DAS) Supported with PostgreSQL only.	das	das
Schema Registry	schemaregistry	schemaregistry
Streams Messaging Manager	smm	smm

Confirm that you have created all of the databases:
```
SHOW DATABASES;
```
You can also confirm the privilege grants for a given user by running:
```
SHOW GRANTS FOR '<user>'@'%';
```
Record the values you enter for database names, usernames, and passwords. The Cloudera Manager installation wizard requires this information to correctly connect to these databases.

Next Steps

If you plan to use Apache Ranger, see the following topic for instructions on creating and configuring the Ranger database. See Configuring a Ranger or Ranger KMS Database: MySQL/MariaDB.
If you plan to use Schema Registry or Streams Messaging Manager, see the following topic for instructions on configuring the database: Configuring the Database for Streaming Components
After you install and configure MySQL databases for Cloudera software, continue to Set up and configure the Cloudera Manager database to configure a database for Cloudera Manager.