# \[fixed\] Debconf \`percona-server-server/existing\_config\_file\` not taken into account when upgrade

**URL:** <https://forums.percona.com/t/fixed-debconf-percona-server-server-existing-config-file-not-taken-into-account-when-upgrade/40840>\
**Category:** MySQL & MariaDB\
**Tags:** percona\
**Created:** [May 26, 2026, 4:26pm UTC](https://forums.percona.com/t/fixed-debconf-percona-server-server-existing-config-file-not-taken-into-account-when-upgrade/40840 "2026-05-26T16:26:06Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![tchernomax](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/tchernomax/32/23223_2.png) [@tchernomax](https://forums.percona.com/u/tchernomax)\
**Post date:** [May 26, 2026, 4:26pm UTC](https://forums.percona.com/t/fixed-debconf-percona-server-server-existing-config-file-not-taken-into-account-when-upgrade/40840/1 "2026-05-26T16:26:06Z")

</div>

On debian /var/lib/dpkg/info/percona-server-server.postinst:

```auto
case "$1" in
        configure)

        if [-z "$2"];
        then
                …
        else
                # If the existing config file is a proper file, we back it up
                if [-f "/etc/mysql/my.cnf"] && [! -L "/etc/mysql/my.cnf"]; then
                        cp /etc/mysql/my.cnf /etc/mysql/my.cnf.bak
                        echo "WARNING: /etc/mysql/my.cnf moved to /etc/mysql/my.cnf.bak"
                        echo "Please use etc/mysql/mysql.conf.d for any custom configuration settings"
                fi
                update-alternatives --force --install /etc/mysql/my.cnf my.cnf "/etc/mysql/mysql.cnf" 300
                if [-f "/etc/apparmor.d/usr.sbin.mysqld"]; then
                        check_apparmor_files
                else
                        mv -f /etc/apparmor.d/usr.sbin.mysqld.in2 /etc/apparmor.d/usr.sbin.mysqld 2> /dev/null || true
                fi
                rm -f /etc/apparmor.d/old_apparmor
                if aa-status --enabled 2>/dev/null; then
                        apparmor_parser -r -T -W /etc/apparmor.d/usr.sbin.mysqld 2>/dev/null || true
                fi
        fi

```

Which means that debconf:

```auto
# Select which my.cnf should be used
# Choices: Use existent my.cnf (RECOMMENDED), Use NEW my.cnf
percona-server-server percona-server-server/existing_config_file select Use existent my.cnf (RECOMMENDED)

```

isn’t taken into account when doing percona upgrade.

IMHO it’s a bug.

What do you think ?

(I didn’t found the source to provide a PR)

---

<div class="post-metadata">

**Author:** ![Evgeniy\_Patlan](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/evgeniy_patlan/32/41_2.png) [@Evgeniy\_Patlan](https://forums.percona.com/u/Evgeniy_Patlan)\
**Post date:** [May 26, 2026, 6:19pm UTC](https://forums.percona.com/t/fixed-debconf-percona-server-server-existing-config-file-not-taken-into-account-when-upgrade/40840/2 "2026-05-26T18:19:13Z")

</div>

Hey @tchernomax.  
Could you please provide a bit more information about this case?  
What version you are using and what exact commands you execute so we can reproduce this issue

---

<div class="post-metadata">

**Author:** ![tchernomax](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/tchernomax/32/23223_2.png) [@tchernomax](https://forums.percona.com/u/tchernomax)\
**Post date:** [May 27, 2026, 7:57am UTC](https://forums.percona.com/t/fixed-debconf-percona-server-server-existing-config-file-not-taken-into-account-when-upgrade/40840/3 "2026-05-27T07:57:53Z")

</div>

My host : Debian 12 (but it should be reproducible on all debian)

```auto
# cat /etc/apt/sources.list.d/percona.list
deb http://repo.percona.com/ps-80/apt bookworm main
# dpkg -l percona-server-server
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-=====================-====================-============-=======================================
ii percona-server-server 8.0.40-31-1.bookworm amd64 Percona Server database server binaries
# debconf-get-selections | grep percona-server-server/existing_config_file
percona-server-server	percona-server-server/existing_config_file	select	Use existent my.cnf (RECOMMENDED)
# cat /etc/mysql/my.cnf
!includedir /etc/mysql/ansible.d/
# apt update
# apt install percona-server-server=8.0.45-36-1.bookworm

```

-\> `/etc/mysql/my.cnf` is replaced by the upgrade (postinst script) and `mysql.service` is restarted (without all the configuration from ansible)…

In my case, the `log_bin` was overwritten by ansible, so the upgrade broke my replication.

---

<div class="post-metadata">

**Author:** ![tchernomax](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/tchernomax/32/23223_2.png) [@tchernomax](https://forums.percona.com/u/tchernomax)\
**Post date:** [June 1, 2026, 2:46pm UTC](https://forums.percona.com/t/fixed-debconf-percona-server-server-existing-config-file-not-taken-into-account-when-upgrade/40840/4 "2026-06-01T14:46:48Z")

</div>

I found a solution.

create `/etc/mysql/ansible.cnf` and include it in update-alternatives:

```auto
update-alternatives --force --install /etc/mysql/my.cnf my.cnf /etc/mysql/ansible.cnf 999
update-alternatives --set my.cnf /etc/mysql/ansible.cnf

```

After that, the upgrade process will not touch our config.