Upgrading Fedora Core

There's an article [1] here. I thought I'd bookmark it, for easy reference.

Reference

[1] Fedora Magazine - Upgrading Fedora 31 to Fedora 32

https://fedoramagazine.org/upgrading-fedora-31-to-fedora-32/

Keyboard problems in Linux with IntelliJ

Numpad arrow keys

So the numpad arrow keys do not work in my IntelliJ editor under Fedora Core 31.

I read about similar issues on the Internet.

One of the solutions that worked for me, was to change the file /usr/share/X11/xkb/symbols/keypad.

First off copying the original file seems like a good idea, something like keypad.original.

Then replace all occurrences of KP_Up, KP_Down, KP_Left, KP_Right with Up, Down, Left, Right respectively.

Either rebooting or executing a setxkbmap should do the trick.

Ctrl-Alt-Left and Ctrl-Alt-Right

I use these to go to the next or previous call in Intellij. Linux just wants to switch Workspaces, when I do that.

The shortcuts could not be found using the standard Settings tool.

But I found a solution at [2].

gsettings set org.gnome.desktop.wm.keybindings switch-to-workspace-up []
gsettings set org.gnome.desktop.wm.keybindings switch-to-workspace-down []
gsettings set org.gnome.desktop.wm.keybindings switch-to-workspace-left []
gsettings set org.gnome.desktop.wm.keybindings switch-to-workspace-right []

With a reset if I decide to need it like:

gsettings reset org.gnome.desktop.wm.keybindings switch-to-workspace-up
gsettings reset org.gnome.desktop.wm.keybindings switch-to-workspace-down
gsettings reset org.gnome.desktop.wm.keybindings switch-to-workspace-left
gsettings reset org.gnome.desktop.wm.keybindings switch-to-workspace-right

References

Medium.com - A simple, humble but comprehensive guide to XKB for linux

https://medium.com/@damko/a-simple-humble-but-comprehensive-guide-to-xkb-for-linux-6f1ad5e13450

[2] Ubuntu - How to disable the keyboard shortcut to switch between workspaces

https://askubuntu.com/questions/744214/how-to-disable-the-keyboard-shortcut-to-switch-between-workspaces

Backup & Restore of Mariadb Server

Hello, again!

This is just a small blog post on how to backup and restore a MariaDB server, without using MysqlDump, but by directly copying the files in /var/lib/mysql.

Backing up

First of course we need to shutdown mariadb.

# systemctl status mariadb

# systemctl stop mariadb

Copying files:

tar zcvf database_backup_`date +%F`.tgz /var/lib/mysql

Restoring

When putting things back, things start to go wrong¹.

Copying the files to a new host, causes this:

2020-04-14 10:45:32 0 [ERROR] InnoDB: Operating system error number 13 in a file operation. 2020-04-14 10:45:32 0 [ERROR] InnoDB: The error means mysqld does not have the access rights to the directory. 2020-04-14 10:45:32 0 [ERROR] InnoDB: os_file_get_status() failed on './ibdata1'. Can't determine file permissions

So, if the below code works, than SELinux is causing the issue:

sudo semanage permissive -a mysqld_t

Now you added mysql_t to permissive, as shown by the below printout:

]# semanage permissive -l

Builtin Permissive Types


Customized Permissive Types

mysqld_t

Turning it back to enforcing, means running:

# semanage permissive -d mysqld_t
libsemanage.semanage_direct_remove_key: Removing last permissive_mysqld_t module (no other permissive_mysqld_t module exists at another priority).

We need to relabel the new /var/lib/mysql directory:

sudo semanage fcontext -a -t mysqld_db_t "/var/lib/mysql(/.*)?"
sudo restorecon -Rv /var/lib/mysql

Checking the current file contexts:

$ ls --directory --context /var/lib/mysql
unconfined_u:object_r:mysqld_db_t:s0 /var/lib/mysql

MariaBackup

I need to check out MariaBackup^{2 3}, as a better solution for creating backups compared to mysqldump.

References

[1] Security-Enhanced Linux with MariaDB

https://mariadb.com/kb/en/selinux/

[2] Backing up and restoring databases

https://mariadb.com/kb/en/backing-up-and-restoring-databases/

[3] MariaBackup

https://mariadb.com/kb/en/mariabackup/

[4] Full Backup and Restore with MariaBackup

https://mariadb.com/kb/en/full-backup-and-restore-with-mariabackup/