Cluster computing is a type of computing in which group of independent computers (nodes) are linked together to perform a specific task and all the machines connected act like a single entity. The advantage of using cluster is that the computing system will be always available and it will not fail also called redundancy of systems.
You can understand it more clearly by taking an example of the web hosting sites. When the load on any one of the server increases, the cluster distributes the load of the visitors across an array of machines as to accumulate as many visitors at the same time. The same technique is used by gaming servers when there are a number of online players increases.
Hardware clustering on other hand is completely different as in this, component systems have reasonably identical hardware and operating systems which aim at providing similar performance levels when any single failed component is to be replaced by another. All the component devices which are connected in a cluster are kept in synchronization through high speed and dedicated communication channels.
What is Cluster in Cloud Computing?
A cluster can be defined as a group of all interconnected and independent IT resources that work as a single unit or a system. The advantage of connecting computers/nodes to each other makes resources more reliable and at the same time, the availability of resources increased. At the same time, redundancy and failover features are inherent to the cluster.
Also Read: What is utility computing?
In computer clusters, all loosely and tightly connected computers are connected to work together unlike grid computing in which computer clusters have each node to perform the same task in which each task is scheduled by software. Clusters are composed of commodity computers which are linked together through high-speed dedicated networks.
A computer cluster provides much efficient and faster processing speed along with better data integrity, large storage capacity, reliability and wider availability of resources. Computer clusters are more costly and hard to maintain but the result is much higher running overhead as compared to the single computer.
Clusters are mainly used for High Availability (HA) for greater reliability and also for High-Performance Computing so as to provide greater computational power which a single computer can never provide individually.
Transparency of Systems in Cluster Computing
The smallest cluster can be a connection of two computers (also called nodes) that work together to execute a particular set of tasks and the users who are accessing have an impression that only single system responds to them.
This creates an illusion that only you are accessing the resources and hardware at the same time but this generally not happens. Each user who is accessing the resources through nodes is unaware of the other user accessing the single resource (virtual machine). This concept is called transparency of the systems.
Advantages of Cluster Computing
Here are some of the advantages of using cluster computing and grid computing.
- High performance
- Fault tolerance
- Scalability of any system becomes simpler
- Resource consolidation
- Centralized management
- Disaster and data recovery is easier
- Parallel data processing
Types of Cluster Computing
By now you must be clear with the definition of cluster computing and what exactly clusters are? Let’s try to understand what are the different types of clusters and how they are categorized.
- High Availability (HA) clusters
- Grid Cluster
- Load balancing clusters
- High-performance (HPC) clusters
High Availability of Failover Clusters
You must be clear with the name itself as these types of clusters are highly available which are designed to provide uninterrupted availability of services or data to the end user community. An example of this type of clusters is web services. If any node fails all the services can be restored without affecting other nodes.
Also Read: What is distributed computing?
If any node fails all the services can be restored without affecting the availability of services which are provided by the cluster. The only problem is that performance will be affected if any node is missing but the application will be still available. High Availability clusters are mainly used for load balancing, backup, and failovers.
The purpose of these types of clusters is to ensure that if there is any failure in the system, the instance of the application must always be available and running on one cluster member at a time. If the cluster member is not available due to some technical issues, the application will failover to another cluster member.
In High Availability cluster computing, there is one primary load balancer and to support that there is a backup load balancer server in case the primary server is not available or fails. High Availability Clusters (HA) are best for those applications that are mission critical or databases, mail, web, or application servers.
Load Balancing Clusters
In some applications where grid computing is difficult to implement, load balancing clusters can be useful as this type of clusters distributes incoming requests for content and resources among multiple nodes which are running the same program.
High availability clusters and load balancing clusters technologies can be combined so as to increase the reliability of the system along with availability and scalability of data resources. Every node in the cluster is capable of handling requests for same content and application. The best example of load balancing clusters is a web hosting environment.
When a client makes a request for any resource or data, the request is first passed to the active load balancer which diverts the request to any server which is capable of handling request at that time.
Parallel/Distributed Processing Clusters
Parallel processing is performed mainly by multiple processes in specially designed parallel computers. All the multiple processes running on parallel clusters share a single memory and bus interface located within a single computer. These clusters are used to increase availability,
These clusters are used to increase availability, scalability, and performance of applications particularly used for data-intensive tasks.
High-Performance Clusters (HPC)
Some places where the application is on big projects which do not require high availability and load balancing clusters, high-performance cluster computing are used. In these, some components are extremely complex which also requires the use of multiple computers that can communicate with each other easily. If all the computers are not synchronized, there can be changes in the entire system.
Some applications of this type of clusters include test theories in meteorology which often run on computing clusters as there is much calculation work is to be done which is impossible to do without high-performance clusters.
Cluster Computing Architecture
What is a Beowulf Cluster?
Well, you must be using a personal computer today which is one of the most remarkable technological achievement of today. You must have seen that the computational performance of personal computers has been increased gradually over time along with the decrease in price.
The Beowulf cluster was developed in order to meet the growing need for high processing power in different scientific areas in order to build powerful and affordable cloud computing systems. The software used in Beowulf clusters are high performance and highly compatible with other tools such as GNU/Linux and FreeBSD OS.