Luckily it was just Kanboard, but unfortunately I lost mountains of tasks and data. This forced me to look into backups more seriously. Below is my backup script and crontab configuration.
Script to backup kanboard configuration:
docker exec kanboard-db-1 /usr/bin/mysqldump -u kb --password=kb-secret kanboard > /srv/data/opt/kanboard/backups/backup-$(date '+%Y-%m-%d').sql
# Backup
#docker exec CONTAINER /usr/bin/mysqldump -u root --password=root DATABASE > backup.sql
# Restore
#cat backup.sql | docker exec -i CONTAINER /usr/bin/mysql -u root --password=root DATABASE
#cat backup-2023-05-26.sql | docker exec -i kanboard-db-1 /usr/bin/mysql -u root --password=secret kanboard
Crontab:
0 4 * * * /srv/data/opt/kanboard/kb-mysqldump.sh