systemd Service Management & Multi-version MySQL Deployment

01 - Organize the systemctl database Service files

Option 1: Standard production daemon configuration

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[Unit]
Description=MySQL Server
After=network.target

[Service]
User=mysql
Group=mysql
ExecStart=/usr/local/mysql/bin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
ExecReload=/bin/kill -HUP $MAINPID
PIDFile=/var/run/mysqld/mysqld.pid
PrivateTmp=true
RuntimeDirectory=mysqld

[Install]
WantedBy=multi-user.target

Option 2: With config file and file-handle limits

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[Unit]
Description=MySQL Server
After=network.target

[Service]
User=mysql
Group=mysql
ExecStart=/usr/local/mysql/bin/mysqld --defaults-file=/etc/my.cnf
RuntimeDirectory=mysqld
LimitNOFILE=65536
Restart=on-failure

[Install]
WantedBy=multi-user.target

After the modification

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[root@master local]#systemctl daemon-reload
[root@master local]#systemctl restart mysqld.service
[root@master local]#systemctl enable  mysqld.service

02 - Multi-version MySQL (5.6 / 5.7) install & upgrade-prep practice

Step 1: Download the software archives

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# MySQL 5.7.40 binary package
[root@master local]#wget https://downloads.mysql.com/archives/get/p/23/file/mysql-5.7.40-linux-glibc2.12-x86_64.tar.gz

# MySQL 5.6.48 binary package
[root@master local]#wget https://downloads.mysql.com/archives/get/p/23/file/mysql-5.6.48-linux-glibc2.12-x86_64.tar.gz

Step 2: Extract, install, and create symlinks

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# install version 5.7
[root@master local]#tar xf mysql-5.7.40-linux-glibc2.12-x86_64.tar.gz
[root@master local]#ln -s mysql-5.7.40-linux-glibc2.12-x86_64 mysql57
# Note: during multi-version coexistence debugging, do not set the global env var yet to avoid command-path conflicts

# install version 5.6
[root@master local]#tar xf mysql-5.6.48-linux-glibc2.12-x86_64.tar.gz
[root@master local]#ln -s mysql-5.6.48-linux-glibc2.12-x86_64 mysql56
# Note: do not configure the global env var for now

Step 3: Initialize the database software

MySQL 5.7 initialization (data directory 3357):

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[root@master local]#mkdir -p /data/3357/data
[root@master local]#chown -R mysql.mysql /data/3357/data
[root@master local]#/usr/local/mysql57/bin/mysqld --initialize-insecure --user=mysql --datadir=/data/3357/data --basedir=/usr/local/mysql57
[root@master local]#echo $?
0

MySQL 5.6 initialization (data directory 3356):

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[root@master local]#mkdir -p /data/3356/data
[root@master local]#chown -R mysql.mysql /data/3356/data
[root@master local]#/usr/local/mysql56/scripts/mysql_install_db --user=mysql --datadir=/data/3356/data --basedir=/usr/local/mysql56
FATAL ERROR: please install the following Perl modules before executing /usr/local/mysql56/scripts/mysql_install_db:
Data::Dumper
# missing Perl module
[root@master local]#yum install -y perl-Data-Dumper
[root@master local]#/usr/local/mysql56/scripts/mysql_install_db --user=mysql --datadir=/data/3356/data --basedir=/usr/local/mysql56
# check whether the output contains two OKs and confirm the exit code:
[root@master local]#echo $?
0

Step 4: Write the multi-instance dedicated config files

MySQL 5.7 (instance 3357) configuration:

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[root@master local]#vim /etc/my3357.cnf
[mysql]
socket=/tmp/mysql3357.sock

[mysqld]
user=mysql
basedir=/usr/local/mysql57
datadir=/data/3357/data
socket=/tmp/mysql3357.sock
port=3357
pid-file=/run/mysqld3357/mysqld.pid

[root@master local]#vim /usr/lib/systemd/system/mysqld3357.service
[Unit]
Description=MySQL 5.7 Server (3357)
After=network.target

[Service]
User=mysql
Group=mysql
ExecStart=/usr/local/mysql57/bin/mysqld --defaults-file=/etc/my3357.cnf
RuntimeDirectory=mysqld3357
LimitNOFILE=65536
Restart=on-failure

[Install]
WantedBy=multi-user.target

MySQL 5.6 (instance 3356) configuration:

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[root@master local]#vim /etc/my3356.cnf
[mysql]
socket=/tmp/mysql3356.sock

[mysqld]
user=mysql
basedir=/usr/local/mysql56
datadir=/data/3356/data
socket=/tmp/mysql3356.sock
port=3356
pid-file=/run/mysqld3356/mysqld.pid

[root@master local]#vim /usr/lib/systemd/system/mysqld3356.service
[Unit]
Description=MySQL 5.6 Server (3356)
After=network.target

[Service]
User=mysql
Group=mysql
ExecStart=/usr/local/mysql56/bin/mysqld --defaults-file=/etc/my3356.cnf
RuntimeDirectory=mysqld3356
LimitNOFILE=65536
Restart=on-failure

[Install]
WantedBy=multi-user.target

Step 5: Run, start, and verify management

Start/Stop the MySQL 5.7 service:

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# Method 1: start
[root@master local]#cp /usr/local/mysql57/support-files/mysql.server /etc/init.d/mysqld57
[root@master local]#chmod +x /etc/init.d/mysqld57
[root@master local]#/etc/init.d/mysqld57 start
[root@master local]#/etc/init.d/mysqld57 stop

# Method 2: start
[root@master local]#systemctl daemon-reload
[root@master local]#systemctl start mysqld3357.service
[root@master local]#systemctl enable mysqld3357.service
Created symlink from /etc/systemd/system/multi-user.target.wants/mysqld3357.service to /usr/lib/systemd/system/mysqld3357.service.

Start/Stop the MySQL 5.6 service:

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# Method 1: start
[root@master local]#cp /usr/local/mysql56/support-files/mysql.server /etc/init.d/mysqld56
[root@master local]#chmod +x /etc/init.d/mysqld56
[root@master local]#/etc/init.d/mysqld56 start
[root@master local]#/etc/init.d/mysqld56 stop

# Method 2: start
[root@master local]#systemctl daemon-reload
[root@master local]#systemctl start mysqld3356.service
[root@master local]#systemctl enable mysqld3356.service
Created symlink from /etc/systemd/system/multi-user.target.wants/mysqld3356.service to /usr/lib/systemd/system/mysqld3356.service.

Verify the status of the three services (all running)

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[root@master local]#for svc in mysqld mysqld3356 mysqld3357; do
>   a=$(systemctl show -p ActiveState "$svc" | cut -d= -f2)
>   s=$(systemctl show -p SubState   "$svc" | cut -d= -f2)
>   echo "$svc: $a ($s)"
> done
mysqld: active (running)
mysqld3356: active (running)
mysqld3357: active (running)

01 - Organize the systemctl database Service files#

Option 1: Standard production daemon configuration#

Option 2: With config file and file-handle limits#

02 - Multi-version MySQL (5.6 / 5.7) install & upgrade-prep practice#

Step 1: Download the software archives#

Step 2: Extract, install, and create symlinks#

Step 3: Initialize the database software#

Step 4: Write the multi-instance dedicated config files#

Step 5: Run, start, and verify management#