MySQL Bugs: #98953: update-rc.d: error: insserv rejected the header

Bug #98953	update-rc.d: error: insserv rejected the header
Submitted:	15 Mar 2020 9:11	Modified:	16 Mar 2020 8:24
Reporter:	Helious wu	Email Updates:
Status:	Not a Bug	Impact on me:	None
Category:	MySQL Server: Installing	Severity:	S3 (Non-critical)
Version:	5.7.29	OS:	Ubuntu (16.04)
Assigned to:	MySQL Verification Team	CPU Architecture:	Any
Tags:	dpkg: error processing package mysql-server (--configure)

Description:
I'm a newer to Linux.I'd like to install mysql-server with following commands 'sudo apt-get install mysql-server'on ubuntu16.04.I found following errors which i couldn't solve.
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'''Errors'''
root@Helious:/tmp# sudo apt-get install mysql-server
Reading package lists... Done
Building dependency tree
Reading state information... Done
mysql-server is already the newest version (5.7.29-0ubuntu0.16.04.1).
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
2 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n] y
Setting up mysql-server-5.7 (5.7.29-0ubuntu0.16.04.1) ...
Renaming removed key_buffer and myisam-recover options (if present)
insserv: script mysql: service mysql already provided!
insserv: exiting now!
update-rc.d: error: insserv rejected the script header
dpkg: error processing package mysql-server-5.7 (--configure):
subprocess installed post-installation script returned error exit status 1
dpkg: dependency problems prevent configuration of mysql-server:
mysql-server depends on mysql-server-5.7; however:
Package mysql-server-5.7 is not configured yet.

dpkg: error processing package mysql-server (--configure):
dependency problems - leaving unconfigured
Errors were encountered while processing:
mysql-server-5.7
mysql-server
E: Sub-process /usr/bin/dpkg returned an error code (1)

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So,I tried to use command 'sudo apt-get install -f",which shows the same error.
I check error which says
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"insserv: script mysql: service mysql already provided!"
###############################
I try the command of "ps -ef | grep "mysql",which says
"root 30540 11086 0 17:00 pts/0 00:00:00 grep --color=auto mysqld"
which means no process of mysql running at background.
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dpkg -l |grep mysql
ii mysql-client 5.7.29-0ubuntu0.16.04.1 all MySQL database client (metapackage depending on the latest version)
ii mysql-client-5.7 5.7.29-0ubuntu0.16.04.1 amd64 MySQL database client binaries
ii mysql-client-core-5.7 5.7.29-0ubuntu0.16.04.1 amd64 MySQL database core client binaries
ii mysql-common 5.7.29-0ubuntu0.16.04.1 all MySQL database common files, e.g. /etc/mysql/my.cnf
iU mysql-server 5.7.29-0ubuntu0.16.04.1 all MySQL database server (metapackage depending on the latest version)
iF mysql-server-5.7 5.7.29-0ubuntu0.16.04.1 amd64 MySQL database server binaries and system database setup
ii mysql-server-core-5.7 5.7.29-0ubuntu0.16.04.1
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How to repeat:
Every time I tried to "apt-get install mysql-server".
Also, I tried to resintall the mysql-server,but the same problem break out again.

Suggested fix:
Sorry,I really don't know how to fix it.
And i googled for the question.None of them suits me.
Thank you for your help.

This is mysqld status
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root@Helious:/tmp# service mysqld status
● mysqld.service - LSB: start and stop MySQL
   Loaded: loaded (/etc/init.d/mysqld; bad; vendor preset: enabled)
   Active: active (exited) since Sun 2020-03-15 16:04:48 CST; 1h 9min ago
     Docs: man:systemd-sysv-generator(8)

Mar 15 16:04:48 Helious systemd[1]: Stopped LSB: start and stop MySQL.
Mar 15 16:04:48 Helious systemd[1]: Starting LSB: start and stop MySQL...
Mar 15 16:04:48 Helious mysqld[17032]: Starting MySQL
Mar 15 16:04:48 Helious mysqld[17032]:  *
Mar 15 16:04:48 Helious systemd[1]: Started LSB: start and stop MySQL.
Mar 15 16:04:49 Helious mysqld_safe[18509]: Logging to '/var/log/mysql/error.log'.
Mar 15 16:04:49 Helious mysqld[17032]: 2020-03-15T08:04:49.603047Z mysqld_safe A mysqld process already exists
Mar 15 16:04:49 Helious mysqld_safe[18533]: A mysqld process already exists
##################################

Hi,

This is not a bug. MySQL Server is already installed, that's what your system is telling you.

kind regards
Bogdan