failed to stop MySQL server

[Zheng Xu]

This is a random error which does not happen always.

Reproduce steps :
  echo "===== Install mysql-server" \
  && apt-get -y install mysql-server \
  \
  && echo "===== Enable remote access for mysql-server" \
  && sed -i 's/bind-address/# bind-address/' /etc/mysql/mysql.conf.d/mysqld.cnf \
  \
  && echo "===== Start mysql service" \
  && service mysql start \
  \
  && echo "===== Set default root password for remote access" \
  && echo "GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'root' WITH GRANT OPTION;" | mysql -u root \
  \
  && echo "===== Create user : 'ent-user'" \
  && echo "CREATE USER 'ent-user'@'%' IDENTIFIED BY 'ent-user';" | mysql -u root \
  && echo "GRANT USAGE ON *.* TO 'ent-user'@'%';" | mysql -u root \
  && echo "CREATE DATABASE IF NOT EXISTS \`ent-user\`;" | mysql -u root \
  && echo "GRANT ALL PRIVILEGES ON \`ent-user\`.* TO 'ent-user'@'%';" | mysql -u root \
  \
  && echo "===== Stop mysql service" \
  && echo "===== Note : a false error will be reported randomly. Stop twice to get the right return code." \
  && (service mysql stop ; sleep 5s ; service mysql stop)

log :
===== Install mysql-server
blablabla ...
===== Enable remote access for mysql-server
===== Start mysql service
 * Starting MySQL database server mysqld
   ...done.
===== Set default root password for remote access
===== Create user : 'ent-user'
===== Stop mysql service
===== Note : a false error will be reported randomly. Stop twice to get the right return code.
 * Stopping MySQL database server mysqld
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)
 ...fail!
 * Stopping MySQL database server mysqld
   ...done.