In todays article we will install MariaDB Galera cluster with HAproxy for load balanced MariaDB and wordpress. Galera is active-active clustering technology, meaning that it can support writes on all nodes which are then replicated across cluster. There is also active-passive clustering, where only node is writable. We will also install HAproxy for load balancing on our cluster. Install is going to be done on 5 CentOS 7 servers, three for MariaDB 10.1 Galera, one for Haproxy and one for wordpress. HAproxy works in such a way that it routes requests to each node in round robin mode, while presenting itself as a front end. Here we are using tradional way of clustering by having database servers sitting in private network and only webserver is facing to public ip address.
Setting up the Galera cluster
On all servers we need to install mysql. First we will add repository
echo '[mariadb] name = MariaDB
baseurl = http://yum.mariadb.org/10.1/centos7-amd64
gpgkey=https://yum.mariadb.org/RPM-GPG-KEY-MariaDB
gpgcheck=1' >> /etc/yum.repos.d/MariaDB.repo
Then we install mariadb, rsync and xinetd
sudo yum install mariadb-server rsync xinetd
We need to edit /etc/hosts, any editor will do but I will use nano
nano /etc/hosts
Out there ip and names of your hosts, for example
192.168.207.241 mariadb01
192.168.209.91 mariadb02
192.168.129.168 mariadb03
Make sure you use private ip of your hosts, if you use public ones you will need to encrypt traffic between them to secure your cluster.
After install MariaDB, edit
nano /etc/my.cnf.d/server.cnf
On all servers, you need to find [galera] section in file and make it look like this, save for ip addresses which are bold and should be changed
[galera] # Mandatory settings
wsrep_on=ON
wsrep_provider=/usr/lib64/galera/libgalera_smm.so#add your node ips here
wsrep_cluster_address="gcomm://192.168.207.241,192.168.209.91,192.168.129.168"
binlog_format=row
default_storage_engine=InnoDB
innodb_autoinc_lock_mode=2
#Cluster name
wsrep_cluster_name="linoxide_cluster"
# Allow server to accept connections on all interfaces.bind-address=0.0.0.0# this server ip, change for each server
wsrep_node_address="192.168.207.241"
# this server name, change for each server
wsrep_node_name="mariadb01"wsrep_sst_method=rsync
Staring the Galera Cluster
After this have been configured you need to start the cluster
First on the mariadb01 node which is the master with this command
galera_new_cluster
Then on other two nodes with normal systemctl command:
systemctl start mariadb
Next we can verify that cluster is running:
mysql -u root -p -e "SHOW STATUS LIKE 'wsrep_cluster_size'"
Next thing would be to run the mysql_secure_installation script
mysql_secure_installation
Setting up the firewalld
Now when all three nodes are connected we can bring up firewalld and configure it.
systemctl start firewalld
Open the mariadb client and galera replication ports:
firewall-cmd --permanent --add-port=3306/tcp
firewall-cmd --permanent --add-port=4567/tcp
Open rsync port that we use for replication
firewall-cmd --permanent --add-port=873/tcp
Other important ports
firewall-cmd --permanent --add-port=4444/tcp
firewall-cmd --permanent --add-port=9200/tcp
Lastly reload the firewall
firewall-cmd --reload
Using xinetd and clustercheck
Clustercheck is useful script for monitoring the cluster. Lets install it by following commands
wget https://raw.githubusercontent.com/olafz/percona-clustercheck/master/clustercheck
chmod +x clustercheck
mv clustercheck /usr/bin/
Next we need to add mysqlchk to the services list. For that we edit services file:
nano /etc/services
Since it is long file, in nano type Ctrl-W and search for 9200. All services using that port needs to be commented, and new service needs to be added, so that part needs to look like this:
mysqlchk 9200/tcp # mysqlchk
#wap-wsp 9200/tcp # WAP connectionless session service
#wap-wsp 9200/udp # WAP connectionless session service
When this is savaed and done we can start xinetd
systemctl start xinetd
All this need to be done on all nodes, and now only on master we need to add user for clustercheck.
mysql -u root -pGRANT PROCESS ON *.* TO 'clustercheckuser'@'localhost' IDENTIFIED BY 'clustercheckpassword!';exit;
Next we can try clustercheck script
clustercheck
Setting up HAproxy
Login to your designated haproxy server. We are now installing the load balancer
Edit your /etc/hosts file to be something like this (with your ips, of course)
192.168.207.241 mariadb01
192.168.209.91 mariadb02
192.168.129.168 mariadb03
192.168.210.252 haproxy01
Next we can install haproxy
yum install haproxy
Next we need to edit rsyslog.conf
nano /etc/rsyslog.conf
Uncomment those two lines
# Provides UDP syslog reception
$ModLoad imudp
$UDPServerRun 514
Save and exit
echo 'local2.=info /var/log/haproxy-access.log
local2.notice /var/log/haproxy-info.log
' >> /etc/rsyslog.d/haproxy.conf
lets backup default haproxy configuration
mv /etc/haproxy/haproxy.cfg /etc/haproxy/haproxy.cfg.bk
Next we make new file with with nano
nano /etc/haproxy/haproxy.cfg
Use this pastebin as configuration, but change the ip addresses.
It is time to setup firewall on haproxy node
systemctl start firewalld
firewall-cmd --permanent --add-port=9000/tcp
firewall-cmd --permanent --add-port=3030/tcp
Then reload the firewall
firewall-cmd --reload
Setting up access the MariaDB from HAproxy
On mariadb cluster type:
mysql -u root -pGRANT ALL PRIVILEGES ON *.* TO root@'%' IDENTIFIED BY "verystrongpassword";
Then we go to haproxy01 server and try to access the database.
You must have the MariaDB-client installed, so lets first do that:
echo '[mariadb] name = MariaDB
baseurl = http://yum.mariadb.org/10.1/centos7-amd64
gpgkey=https://yum.mariadb.org/RPM-GPG-KEY-MariaDB
gpgcheck=1' >> /etc/yum.repos.d/MariaDB.repo
That was for adding repository, this command installs it
yum install MariaDB-client
And then lets test if
mysql -u root -p -h 192.168.210.252 -P 3030 -e "select Host, User, Password from mysql.user"
Make sure you enter verystrongpassword as password and not your regular root password.
Installing Wordpress
Lastly we will setup wordpress to use on our cluster. There is work to be done on mariadb01 node, on haproxy01 and on wp01 node.
On mariadb01
mysql -u root -pCREATE DATABASE wordpress;CREATE USER wordpressuser@localhost IDENTIFIED BY 'password';GRANT ALL ON wordpress.* TO wordpressuser@'192.168.210.252' IDENTIFIED BY 'password';
On wp01 node set in /etc/hosts/
192.168.220.17 wp01
192.168.210.252 haproxy01
Also on haproxy01 add
192.168.220.17 wp01
Next we need to install required packages on wp01 node
yum install httpd php php-gd php-mysqlnd rsync
From here we need to use non-root account with sudo privileges. I don't have one, so I will create it:
useradd miki
usermod miki -aG wheelpasswd miki
Then log in as my user
su miki
Change dir to home
cd
And then download the latest version of wordpress and unpack it
wget http://wordpress.org/latest.tar.gz
tar xzvf latest.tar.gz
We will use rsync to copy the wordpress to apache dir
sudo rsync -avP ~/wordpress/ /var/www/html/
mkdir /var/www/html/wp-content/uploads
We also need to change ownership to apache user
sudo chown -R apache:apache /var/www/html/*
Configuring wordpress
WordPress is configured in wp-config.php file, there we need to set parameters like host address of database server, login credentials, database name. Lets backup the config file:
cd /var/www/htmlcp wp-config-sample.php wp-config.php
And then we do editing:
nano wp-config.php
Only change those lines
define('DB_NAME', 'wordpress');/** MySQL database username */
define('DB_USER', 'wordpressuser');/** MySQL database password */
define('DB_PASSWORD', 'password');/** MySQL hostname */
define('DB_HOST', '192.168.210.252:3030');
Lastly, we restart the apache webserver:
sudo systemctl restart httpd
Complete the install of the WordPress from the browser
We can go to public address of wordpress node like bellow to continue install process of word-press
Now we have the cluster set up with wordpress running
Conclusion
Here we have set up wordpress on top of Galera cluster loadbalanced by HAproxy. This is resilient solution for high load sites and although it takes a while to setup, it gives your site near complete insurance from downtime. All traffic between nodes is done by private ip addresses, and only one public address for the Worpress front end is used to access the site
As for the connection to Oracle database, I found 64-bit oracle data access components. It helped to connect with database directly.
ReplyDelete