#!/bin/bash
# forksand-mariadb-setup
#
# Script template for setting up MySQL compatible MariaDB Cluster
# on four nodes: sql1 sql2 sql3 sql4
#
# https://mariadb.com/kb/en/library/getting-started-with-mariadb-galera-cluster/
# 
# Get repo mirror:
# https://downloads.mariadb.org/mariadb/repositories

exit 0

# As root
apt-get install software-properties-common dirmngr
apt-key adv --recv-keys --keyserver keyserver.ubuntu.com 0xF1656F24C74CD1D8
add-apt-repository 'deb [arch=amd64] http://sfo1.mirrors.digitalocean.com/mariadb/repo/10.3/debian stretch main'
apt-get update
apt-get install mariadb-server
apt-get clean

# Set config like here:
# https://mariadb.org/installing-mariadb-galera-cluster-on-debian-ubuntu/
# /etc/mysql/my.cnf
# =================================================
[galera]
# Mandatory settings
wsrep_on=ON
wsrep_provider=/usr/lib/galera/libgalera_smm.so
wsrep_cluster_address="gcomm://10.42.1.171,10.42.1.172,10.42.1.173,10.42.1.174"
wsrep_cluster_name="XXX"
binlog_format=row
default_storage_engine=InnoDB
innodb_autoinc_lock_mode=2
wsrep_sst_method=rsync
query_cache_size=0
query_cache_type=0
#
# Allow server to accept connections on all interfaces.
#
bind-address=10.42.1.174
#
# Optional setting
#wsrep_slave_threads=1
#innodb_flush_log_at_trx_commit=0

# =================================================

service mysql stop
# on just sql1:
galera_new_cluster

# See if the cluster node comes up:
mysql -p -u root -e 'SELECT VARIABLE_VALUE as "cluster size" FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME="wsrep_cluster_size"'

# Start another node, sql2:
service mysql start

# See if it came up:
mysql -p -u root -e 'SELECT VARIABLE_VALUE as "cluster size" FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME="wsrep_cluster_size"'

# Then do sql3 sql4
service mysql start

# See if it came up:
mysql -p -u root -e 'SELECT VARIABLE_VALUE as "cluster size" FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME="wsrep_cluster_size"'

###############################################
# run this to lock down:
mysql_secure_installation


###########################################
# If all cluster nodes get shutdown at the same time, the cluster needs to be boot strapped again.
# On just one node, the most advanced, if known (e.g. sql1):
galera_new_cluster

# On other nodes sql2 sql3 sql4
service mysql start

# Maybe need on most advanced node:
# sed -i -e 's/safe_to_bootstrap: 0/safe_to_bootstrap: 1/g' /var/lib/mysql/grastate.dat


##########################
# haproxy

# for code.forksand.com, insert on sql1 (or any of them):
# http://galeracluster.com/documentation-webpages/haproxy.html
USE mysql;

# This fails. Not a good way to create users either.
CREATE USER 'haproxy'@'10.42.1.163' IDENTIFIED BY 'password';
FLUSH PRIVILEGES;
SHOW GRANTS FOR 'haproxy'@'10.42.1.163';


# pen proxy instead of haproxy
# To run manually:
pen -l pen.log -p pen.pid localhost:3306 10.42.1.171:3306 10.42.1.172:3306 10.42.1.173:3306 10.42.1.174:3306


useradd pen
echo "d /var/run/pen 0755 pen pen -" > /etc/tmpfiles.d/pen.conf
systemd-tmpfiles --create

mkdir -p /etc/pen
cat > /etc/pen/galera.cfg <<EOF
server 0 address 10.42.1.171 port 3306
server 2 address 10.42.1.172 port 3306
server 3 address 10.42.1.173 port 3306
server 4 address 10.42.1.174 port 3306
debug 1
EOF

cat > /lib/systemd/system/pen-galera.service <<EOF
[Unit]
Description=Pen load balancer (galera)
After=network.target

[Service]
User=pen
Type=forking
PIDFile=/var/run/pen/galera.pid
ExecStart=/usr/bin/pen -u pen -C /var/run/pen/galera.ctl -F /etc/pen/galera.cfg -p /var/run/pen/galera.pid 127.0.0.1:3306
Restart=on-failure

[Install]
WantedBy=multi-user.target
EOF

systemctl restart pen-galera
systemctl enable pen-galera.service


################
# XXX fix on sql1 sql2 sql3 sql4
# For firewall, need to open port 4444 for rsync when cluster node needs to sync up.

-A INPUT -p tcp --dport 4444 -j ACCEPT

