Install and Configure MySQL for Cloudera Software

1. 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 http://repo.mysql.com/mysql-community-release-el7-5.noarch.rpm sudo rpm -ivh mysql-community-release-el7-5.noarch.rpm sudo yum update sudo yum install mysql-server sudo systemctl start mysqld

1. Stop the MySQL server if it is running.

   OS	Command
   RHEL 7 Compatible	sudo systemctl stop mysqld

2. 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.
3. Determine the location of the option file, my.cnf (/etc/my.cnf by default).
4. 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. Cloudera Manager will not start if its tables are configured with the MyISAM engine. (Typically, tables revert to MyISAM if the InnoDB engine is misconfigured.) To check which engine your tables are using, run the following command from the MySQL shell:

     mysql> show table status;

   • 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 Activity Monitor and Service Monitor) 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 five databases on one host (the databases for Cloudera Manager Server, Activity Monitor, Reports Manager, and Hive metastore), set the maximum connections to 550.
     • 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
   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

5. 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.
6. Ensure the MySQL server starts at boot:

   OS	Command
   RHEL 7 compatible	sudo systemctl enable mysqld

7. Start the MySQL server:

   OS	Command
   RHEL 7 Compatible	sudo systemctl start mysqld

8. 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!

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

• If you plan to use Apache Ranger, see the following topic for instructions on creating and configuring the Ranger database. See Configuring a Ranger 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 PostgreSQL databases for Cloudera software, continue to Step 5: Set up the Cloudera Manager Database to configure a database for Cloudera Manager.