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 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

1. Stop the MySQL server if it is running.

   OS	Command
   RHEL 7 Compatible	sudo systemctl stop mysqld
   RHEL 6 Compatible	sudo service mysqld stop
   SLES, Ubuntu	sudo service mysql stop

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. (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. CDH 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 storage volume.
       • 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, 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.
   • Although binary logging is not a requirement for CDH installations, it provides benefits such as MySQL replication or point-in-time incremental recovery after a database restore. The provided example configuration enables the binary log. 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 = 32M
   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
   RHEL 6 compatible	sudo chkconfig mysqld on
   SLES	sudo chkconfig --add mysql
   Ubuntu	sudo chkconfig mysql on

7. Start the MySQL server:

   OS	Command
   RHEL 7 Compatible	sudo systemctl start mysqld
   RHEL 6 Compatible	sudo service mysqld start
   SLES, Ubuntu	sudo service mysql start

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 any hosts running services that require database access. For more information on Cloudera software that uses databases, see Required Databases.

sudo zypper install mysql-connector-java

sudo apt-get install libmysql-java

After completing the above instructions to install and configure MySQL databases for Cloudera software, continue to Step 4: Install CDH Packages.