High-Availability Linux Services And Newtork Administration Bourbita Mahdi 2016

 Reliability  Availability  Serviceability

 What are HA clusters?  High-availability clusters are groups of computers that support sever applications that can be reliably utilized with a minimum of down-time.  Utilizes redundant computers in clusters that provide service when any system components fail.  Load balancing is a computer networking method to distribute workload across multiple computers or a computer cluster, network links, central processing units, disk drives, or other resources, to achieve optimal resource utilization, maximize throughput, minimize response time, and avoid overload

 Failover – A process by which HA clusters detect hardware or software faults and restart the application on another system without requiring administrative intervention  Emphasis on a layered approach to redundancies

 Primary software of Linux-HA is called Heartbeat  No fixed limit on nodes, allowing use with clusters of any size  Parallel resource monitoring – as with normal computing, but can shift resources from one node to another if the initial node fails  Automatically removes failed nodes from the cluster

 Integrates with many popular software packages, including: Apache, DB2, Oracle, PostgreSQL  GUI included for easier controlling and monitoring of the clusters and relevant resources

 Originally capable of only handling two nodes at a time  Did not include resource monitoring  Would later switch to a layered design implementing n-node clusters

 Project was split into various separate packages  Pacemaker – Cluster resource manager component that handles resource management and node failure  Heartbeat – Now only refers to the layer used for communication between clusters and the individual nodes of the cluster.

 Provide a high-availability (clustering) solution for linux which promotes reliability, availability, and serviceability  The support for high availability and scaling services under Linux continues to grow  In the long term, emerging technologies will help Linux to fulfill all the requirements for a highly available, scaled service