Fix: safe_to_bootstrap: 1

# search for node with "safe_to_bootstrap: 1"
cat /var/lib/mysql/grastate.dat

killall mysqld
service mysql bootstrap-pxc
#/etc/init.d/mysql bootstrap-pxc
service mysql start

killall -9 mysqld
cat /var/lib/mysql/grastate.dat
mysqld_safe --wsrep-recover
service mysql status

service mysql start --wsrep-new-cluster
tail -f /var/log/mysqld.log

# n-th hosts
service mysql start



sed -i "/safe_to_bootstrap/s/0/1/" /var/lib/mysql/grastate.dat

https://www.percona.com/doc/percona-xtradb-cluster/LATEST/howtos/crash-recovery.html
# https://severalnines.com/blog/updated-how-bootstrap-mysql-or-mariadb-galera-cluster
killall -9 mysqld
cat /var/lib/mysql/grastate.dat
mysqld_safe --wsrep-new-cluster
service mysql restart

# restart start on remaining nodes

cat /var/lib/mysql/gvwstate.dat

Get cluster status

watch -d -n1 -x mysql -B -e "SHOW STATUS WHERE variable_name ='wsrep_local_state_comment' OR variable_name ='wsrep_cluster_size' OR variable_name ='wsrep_incoming_addresses' OR variable_name ='wsrep_cluster_status' OR variable_name ='wsrep_connected' OR variable_name ='wsrep_ready' OR variable_name ='wsrep_local_state_uuid' OR variable_name ='wsrep_cluster_state_uuid';"

Links
https://www.percona.com/doc/percona-xtradb-cluster/8.0/index.html
https://www.percona.com/blog/2014/09/01/galera-replication-how-to-recover-a-pxc-cluster/
https://pandorafms.com/docs/index.php?title=Pandora:Documentation_en:Percona_Cluster
https://www.claudiokuenzler.com/blog/494/galera-cluster-mysql-not-starting-failed-to-open-channel-reach-primary
https://www.clevernetsystems.com/troubleshooting-a-clustercontrol-mysql-pxc-cluster/

Login

mysql -u root -p

Optimize all databases

mysqlcheck --optimize --all-databases --host=localhost --user=${DB_USER} --password=${DB_PASS}

Links
phpMyAdmin - phpMyAdmin downloads

GUI

apt-get install -y mysql-admin

Allow access from outsice

sed -i 's|bind-address|#bind-address|g' /etc/mysql/my.cnf 
/etc/init.d/mysql restart

Allow access to database magento for user dbo_magento from any host

GRANT ALL PRIVILEGES ON magento.* TO  dbo_magento@'%' IDENTIFIED BY 'your_pass' 

# dont LOCK TABLE on export / import
mysqldump  --single-transaction --quick --skip-trigger ...

Export structure from a single table

mysqldump --no-data ${DB_NAME} ${TABLE_NAME} > ${DB_NAME}.${TABLE_NAME}.$(hostname).$(date -I).sql

Drop all tables from typo3_cms schema

DB_USER=foo
DB_PASS=bar
DB_NAME=db1
mysqldump -u ${DB_USER} -p${DB_PASS} --add-drop-table --no-data ${DB_NAME} | grep ^DROP | mysql -u ${DB_USER} -p${DB_PASS} ${DB_NAME}

DROP DATABASE db1;
CREATE DATABASE db1 CHARACTER SET utf8 COLLATE utf8_general_ci;

SSL
http://mysqlserverteam.com/ssltls-and-rsa-improvements-for-openssl-linked-mysql-5-7-binaries/

SSH tunnel

ssh -C -L 3306:db.example.com:3306 foo@gw.example.com -N
echo "show databases;" | mysql --host=127.0.0.1 --port=3306 --user='user' --password='pass'

Report / Tuning
http://www.mysqlcalculator.com/
http://www.cyberciti.biz/faq/mysql-server-status-with-mysqlreport-report-script/
https://github.com/major/mysqltuner-perl