Generate distrobuilder LXD Ubuntu image with mysql-server package fails

Distrobuilder
1

Hi all,

I am trying to build an Ubuntu based image with distrobuilder and mysqld/php/apache2 on the image.
I grabbed the current Ubuntu image.yaml from the lxc-ci and stripped down for my needs, and built it with distrobuilder build-lxd mysqld.yaml .

The error message I get when running with distrobuilder is that dpkg cannot shut down the running MySQL process and fails the package installation.

    Setting up mysql-server-8.0 (8.0.22-0ubuntu0.20.04.3) ...
    invoke-rc.d: could not determine current runlevel
    invoke-rc.d: policy-rc.d denied execution of stop.
    update-alternatives: using /etc/mysql/mysql.cnf to provide /etc/mysql/my.cnf (my.cnf) in auto mode
    Renaming removed key_buffer and myisam-recover options (if present)
    Error: Unable to shut down server with process id 1723
    dpkg: error processing package mysql-server-8.0 (--configure):
     installed mysql-server-8.0 package post-installation script subprocess returned error exit status 1

A little bit of googling brought me to this workaround for lxc, but as I am building for LXD this doesn’t work.
Is there anyway to enable the same when using distrobuilder to build the images?
Any other workaround necessary for this to happen?

2

I don’t think the link you’re referring to applies here.
distrobuilder doesn’t operate in a container so isn’t restricted by apparmor.

It seems like this could be a packaging bug. We can clearly see distrobuilder’s policy-rc.d change at work which prevents any service from being started or stopped, yet mysql somehow still thinks it’s running and should be stopped?

3

Hum, seems that the package is not discovering properly the pid of the mysqld process.
If I check the processlist, the process is running:

tss      2218 34.1 16.2 1070252 164004 pts/0  Sl+  21:29   0:02 mysqld --initialize-insecure --user=mysql --init-file=/var/lib/mysql-files/tmp.pvEzRsUZrw

but dpkg reports:

Setting up mysql-server-8.0 (8.0.22-0ubuntu0.20.04.3) ...
invoke-rc.d: could not determine current runlevel
invoke-rc.d: policy-rc.d denied execution of stop.
update-alternatives: using /etc/mysql/mysql.cnf to provide /etc/mysql/my.cnf (my.cnf) in auto mode
Renaming removed key_buffer and myisam-recover options (if present)
mysqld will log errors to /var/log/mysql/error.log
mysqld is running as pid 1377
Error: Unable to shut down server with process id 1377

could not find anything running with PID 1377 on the host though.
I don’t know how the image itself s built by distrobuilder, is it within a chroot? Maybe I need to mount /proc “inside” the chroot?

4

FWIW, not sure if it is relevant, I get a couple of Z processes when its at the MySQL configuring step:

root      751  0.0  0.0  20144   284 pts/0    S+   22:07   0:00  |   \_ /snap/distrobuilder/314/bin/distrobuilder build-lxd ubuntu.yaml .
root      768  0.0  0.8 1165072 15420 pts/0   Sl+  22:07   0:00  |       \_ /snap/distrobuilder/314/bin/distrobuilder build-lxd ubuntu.yaml .
root      776  0.0  0.0      0     0 ?        Z    22:07   0:00  |           \_ [dirmngr] <defunct>
root      777  0.0  0.0      0     0 ?        Zs   22:07   0:00  |           \_ [dirmngr] <defunct>
root      780  0.0  0.0      0     0 ?        Z    22:07   0:00  |           \_ [gpg-agent] <defunct>
root      781  0.0  0.0      0     0 ?        Zs   22:07   0:00  |           \_ [gpg-agent] <defunct>
root      563  1.3  3.1  68012 59020 pts/0    S+   22:10   0:01  |           \_ apt-get -y install apt-transport-https fuse language-pack-en openssh-client openssh-server mysql-server vim cloud-init
root     2467  0.5  0.2   9108  4712 pts/0    S+   22:10   0:00  |           |   \_ /usr/bin/dpkg --status-fd 34 --configure --pending
root     3254  0.1  0.8  21048 16948 pts/0    S+   22:11   0:00  |           |       \_ /usr/bin/perl -w /usr/share/debconf/frontend /var/lib/dpkg/info/mysql-server-8.0.postinst configure
root     3259  0.1  0.2   5912  3868 pts/0    S+   22:11   0:00  |           |           \_ /bin/bash /var/lib/dpkg/info/mysql-server-8.0.postinst configure
root     3606  0.0  0.0   4260   592 pts/0    S+   22:12   0:00  |           |               \_ sleep 1
tss      3384  1.1  0.0      0     0 ?        Z    22:11   0:00  |           \_ [mysqld] <defunct>
5

It’s a chroot with its own PID namespace. It does have /proc mounted inside it.

6

In the end, the only option is to either download only the packages, or install mysql-server-core-8.0 and run the configuration steps at a later stage, since the configuration steps of the packages fail. For me, it is fine since one has to secure the MySQL installation anyway post image deployment.