CentOS: Configure Piranha as Load Balancer (Direct Routing Method) Rumi, April 19, 2013 I am currently working on a web cluster project using CentOS. In this project, I have 2 web servers running on Apache and mounted the same document root to serve the HTTP content. I also have 2 servers in front of it to become the load balancer and failover to increase high availability of the two-node web server cluster. The virtual IP will be hold by load balancer #1 with auto failover to load balancer #2. You may refer to diagram below to get clearer picture: I am using following variables: All servers’ OS: CentOS 6.2 64bit Web server #1: 192.168.0.221 Web server #2: 192.168.0.222 Load balancer #1: 192.168.0.231 Load balancer #2: 192.168.0.232 Virtual IP: 192.168.0.220 Load Balancer Server 1. All steps should be done in both servers unless specified. We will install Piranha and other required packages using yum: $ yum install piranha ipvsadm -y 2. Open firewall ports as below: Piranha: 3636 HTTP: 80 Hearbeat: 539 3. Start all required services and make sure they will auto start if server reboot: $ service piranha-gui start $ chkconfig piranha-gui on $ chkconfig pulse on 4. Run following command to set password for user piranha. This will be used when accessing the web-based configuration tools: $ piranha-passwd 5. Turn on IP forwarding. Open /etc/sysctl.conf and make sure following line has value 1: net.ipv4.ip_forward = 1 And run following command to activate it: $ sysctl -p Load Balancer #1 1. Open Piranha web-based configuration tools at http://192.168.0.231:3636 and login as piranha with respective password. We start with configuring Global Settings as below: 2. Then, go to the Redundancy tab and enter the secondary server IP. In this case, we will put load balancer #2 IP as the redundant server in case load balancer #1 is down: 3. Under Virtual Servers tab, click Add and enter required information as below: 4. Now we need to configure the virtual IP and virtual HTTP server to map into the real HTTP server. Go to Virtual Servers > Real Server and add into the list as below: Make sure you activate the real server once the adding completed by clicking the (DE)ACTIVATE button. 5. Now copy the configuration file to load balancer #2 to as below: $ scp /etc/sysconfig/ha/lvs.conf 192.168.0.232:/etc/sysconfig/ha/ 6. Restart Pulse service to apply the new configuration: $ service pulse restart You can monitor what is happening with Pulse by tailing the /var/log/message output as below: $ tail -f /var/log/message Load Balancer #2 No need to configure anything in this server. We just need to restart Pulse service to get affected with the new configuration changes which being copied over from LB1. $ service pulse restart If you see the /var/log/message, pulse in this server will report that it will run on BACKUP mode. Web Servers 1. Since we are using direct-routing method, regards to your Apache installation, we also need to install another package called arptables_jf. Here is some quote from RedHat documentation page: Using the arptables_jf method, applications may bind to each individual VIP or port that the real server is servicing. For example, the arptables_jf method allows multiple instances of Apache HTTP Server to be running bound explicitly to different VIPs on the system. There are also significant performance advantages to usingarptables_jf over the IPTables option. However, using the arptables_jf method, VIPs can not be configured to start on boot using standard Red Hat Enterprise Linux system configuration tools. We will instsall using yum: $ yum install arptables_jf -y 2. Configure arptables_jf by executing following command: In web server #1: $ arptables -A IN -d 192.168.0.220 -j DROP $ arptables -A OUT -d 192.168.0.220 -j mangle –mangle-ip-s 192.168.0.221 In web server #2: $ arptables -A IN -d 192.168.0.220 -j DROP $ arptables -A OUT -d 192.168.0.220 -j mangle –mangle-ip-s 192.168.0.222 3. Save the arptables rules and make sure the service is started on boot: $ service arptables_jf save $ chkconfig arptables_jf on 4. Add the virtual IP address in the servers: $ ip addr add 192.168.0.220 dev eth0 5. Since the IP cannot be started during sysinit (boot time), we can automatically start the IP after sysinit complete. Open /etc/rc.local using text editor: $ vim /etc/rc.local And add following line: /sbin/ip addr add 192.168.0.220 dev eth0 Warning: Every time you restart your network service, please make sure to run step #4 to bring up the virtual IP in real server. Done. You can now point your website to the virtual IP and you will see that the load balancer #1 will report as below: $ ipvsadm -L IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConn TCP 192.168.0.220:http lblc -> 192.168.0.221:http Route 1 0 34 -> 192.168.0.222:http Route 1 0 19 Related Administrations Configurations (Linux) CentOSHALoadBalancerPiranha
How to Upgrade Node.js via NPM August 23, 2017 Steps to Upgrade Node.Js Use the following steps to install or upgrade node.js to latest available version. Current NodeJs Version – First check current nodejs version on your system using following command. In my case it is v0.10.37.rahul@tecadmin:~$ node -v v0.10.37 Clean Cache Forcefully – Now clean all npm cache from your… Read More
Reinstalling MySQL on CentOS/Redhat 6 February 7, 2016 Some time we faces issues with MySQL installation on Linux machine. If we simply remove MySQL packages and re-install doesn’t fixes the issue, in that case old settings may still exists on server which again affects new install. In that case first uninstall MySQL completely from system and erase all… Read More
Destroy Linux operating system with fork bomb January 20, 2024 If you don’t want to completely destroy your Linux system but just neutralize it, you can go with a fork bomb using the following command: :(){ :|: & };: This will create a process which will duplicate it self infinitely until the system crash. If you are in a situation… Read More