Getting mysqld_multi to work with upstart

Question

I used this guide to get started and this wiki page as a reference for the upstart script.

My problem is that when I do a service mysql start I get six processes instead of two, as if upstart ran three times. Here are the processes copied from ps:

/usr/sbin/mysqld --user=root --pid-file=/var/run/mysqld/mysqld1.pid --socket=/var/run/mysqld/mysqld1.sock --port=3301 --basedir=/usr --datadir=/var/lib/mysql1 --tmpdir=/tmp --lc-messages-dir=/usr/share/mysql --skip-external-locking --key_buffer=16M --max_allowed_packet=16M --thread_stack=192K --thread_cache_size=8 --myisam-recover=BACKUP --query_cache_limit=1M --query_cache_size=16M --general_log_file=/var/log/mysql/mysql1-general.log --log_error=/var/log/mysql/error.log --server-id=201 --log_bin=/var/log/mysql/mysql1-bin.log --expire_logs_days=10 --max_binlog_size=100M
/usr/sbin/mysqld --user=root --pid-file=/var/run/mysqld/mysqld2.pid --socket=/var/run/mysqld/mysqld2.sock --port=3302 --basedir=/usr --datadir=/var/lib/mysql2 --tmpdir=/tmp --lc-messages-dir=/usr/share/mysql --skip-external-locking --key_buffer=16M --max_allowed_packet=16M --thread_stack=192K --thread_cache_size=8 --myisam-recover=BACKUP --query_cache_limit=1M --query_cache_size=16M --general_log_file=/var/log/mysql/mysql2-general.log --log_error=/var/log/mysql/error.log --server-id=202 --log_bin=/var/log/mysql/mysql2-bin.log --expire_logs_days=10 --max_binlog_size=100M --innodb_file_per_table --innodb_flush_method=O_DIRECT --innodb_log_file_size=1G --innodb_buffer_pool_size=4G
/usr/sbin/mysqld --user=root --pid-file=/var/run/mysqld/mysqld1.pid --socket=/var/run/mysqld/mysqld1.sock --port=3301 --basedir=/usr --datadir=/var/lib/mysql1 --tmpdir=/tmp --lc-messages-dir=/usr/share/mysql --skip-external-locking --key_buffer=16M --max_allowed_packet=16M --thread_stack=192K --thread_cache_size=8 --myisam-recover=BACKUP --query_cache_limit=1M --query_cache_size=16M --general_log_file=/var/log/mysql/mysql1-general.log --log_error=/var/log/mysql/error.log --server-id=201 --log_bin=/var/log/mysql/mysql1-bin.log --expire_logs_days=10 --max_binlog_size=100M
/usr/sbin/mysqld --user=root --pid-file=/var/run/mysqld/mysqld2.pid --socket=/var/run/mysqld/mysqld2.sock --port=3302 --basedir=/usr --datadir=/var/lib/mysql2 --tmpdir=/tmp --lc-messages-dir=/usr/share/mysql --skip-external-locking --key_buffer=16M --max_allowed_packet=16M --thread_stack=192K --thread_cache_size=8 --myisam-recover=BACKUP --query_cache_limit=1M --query_cache_size=16M --general_log_file=/var/log/mysql/mysql2-general.log --log_error=/var/log/mysql/error.log --server-id=202 --log_bin=/var/log/mysql/mysql2-bin.log --expire_logs_days=10 --max_binlog_size=100M --innodb_file_per_table --innodb_flush_method=O_DIRECT --innodb_log_file_size=1G --innodb_buffer_pool_size=4G
/usr/sbin/mysqld --user=root --pid-file=/var/run/mysqld/mysqld1.pid --socket=/var/run/mysqld/mysqld1.sock --port=3301 --basedir=/usr --datadir=/var/lib/mysql1 --tmpdir=/tmp --lc-messages-dir=/usr/share/mysql --skip-external-locking --key_buffer=16M --max_allowed_packet=16M --thread_stack=192K --thread_cache_size=8 --myisam-recover=BACKUP --query_cache_limit=1M --query_cache_size=16M --general_log_file=/var/log/mysql/mysql1-general.log --log_error=/var/log/mysql/error.log --server-id=201 --log_bin=/var/log/mysql/mysql1-bin.log --expire_logs_days=10 --max_binlog_size=100M
/usr/sbin/mysqld --user=root --pid-file=/var/run/mysqld/mysqld2.pid --socket=/var/run/mysqld/mysqld2.sock --port=3302 --basedir=/usr --datadir=/var/lib/mysql2 --tmpdir=/tmp --lc-messages-dir=/usr/share/mysql --skip-external-locking --key_buffer=16M --max_allowed_packet=16M --thread_stack=192K --thread_cache_size=8 --myisam-recover=BACKUP --query_cache_limit=1M --query_cache_size=16M --general_log_file=/var/log/mysql/mysql2-general.log --log_error=/var/log/mysql/error.log --server-id=202 --log_bin=/var/log/mysql/mysql2-bin.log --expire_logs_days=10 --max_binlog_size=100M --innodb_file_per_table --innodb_flush_method=O_DIRECT --innodb_log_file_size=1G --innodb_buffer_pool_size=4G

This causes the following lines to appear in MySQL's error.log:

InnoDB: Unable to lock ./ibdata1, error: 11

It behaves this way even on reboot. My upstart script for MySQL is standard (as described in the wiki page linked above) except for the "script...end script" section:

script
exec /etc/init.d/mysql start
end script

I have modified the apparmor profile for MySQL and running /etc/init.d/mysql start works correctly.

How can I get upstart to run it's mysql.conf script only once?

Trying `expect fork` or `expect daemon` (as suggested [here](http://askubuntu.com/questions/89518/upstart-script-and-start-stop-daemon)) causes the `service mysql start` to hang and the error lines still appear in MySQL's `error.log` file. — jason, Mar 19 '13 at 15:12
Removing the "post-start script...end script" section of the upstart script causes 11 pairs of mysqld instances to be started. — jason, Mar 19 '13 at 19:35

score 0 · Accepted Answer · answered Mar 21 '13 at 12:41

Note: This answer assumes you have read the guide I used to setup mysqld_multi

The answer is to remove the upstart script (/etc/init/mysql.conf in my case). This will allow service mysql [start|stop] to function properly.

You will encounter a problem on reboot, however. When I rebooted the machine Ubuntu was removing the directory where my .sock files were placed (/var/run/mysqld/). Adding the following line to the /etc/init.d/mysql script solved the problem.

[ -d /var/run/mysqld ] || install -m 755 -o mysql -g root -d /var/run/mysqld

I placed the above line between the if..else and the case statements.

Despite adding this line the removal of the upstart script will cause MySQL to not even attempt to start on boot anymore. MySQL must be started manually by issuing the following command once the system is up:

$ sudo service mysql start

However, that seems like a separate question as the above information was able to get mysqld_multi to start two MySQL processes using the service command.

Getting mysqld_multi to work with upstart

1 Answers1