Linux Cluster Concepts
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This document discusses Linux clustering concepts and administration on Red Hat Enterprise Linux 5. It covers cluster types including storage, high availability, load balancing, and performance clusters. It also describes the components of the Red Hat Cluster Suite including the cluster infrastructure, HA service management, Global File System, Cluster Logical Volume Manager, and Linux Virtual Server for load balancing. Administration tools like Conga, System-config-cluster, and command line tools are also summarized.
Linux Cluster Concepts
- 1. Linux Cluster Administration RHEL 5 1Linux Clustering Document www.expertslogin.com
- 2. 2Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Cluster Basics What is cluster Cluster types Storage High Availability Load balancing High performance
- 3. 3Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Storage Clusters Provide consistent file system image across nodes Simplify storage administration Simplify backup & disaster recovery RHCS provides storage clustering through Red Hat GFS
- 4. 4Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 High Availability Clusters Provide continuous availability of services Maintain data integrity Node failures in a high-availability cluster are not vis- ible from outside the cluster RHCS provides high-availability clustering through its High availability Service Management component
- 5. 5Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Load balancing clusters Dispatch network service requests to multiple cluster nodes Provide cost-effective scalability Failures in a load-balancing cluster are not visible from outside the cluster RHCS provides load-balancing through LVS
- 6. 6Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Performance Clusters Use cluster nodes to perform concurrent calculations Allow applications to work in parallel Referred to as computational clusters or grid computing
- 7. 7Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Red Hat Cluster Suite RHCS RHCS major components: RHCS optional components Cluster infrastructure HA Service Management Cluster Administration tools Linux Virtual Server ( LVS) Global File System (GFS) Cluster Logical Volume Manager (CLVM) Global Network Block Device (GNBD)
- 8. 8Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Red Hat Cluster Suite RHCS
- 9. 9Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Cluster Management Lock Management Fencing Cluster Configuration Management Cluster Infrastructure
- 10. 10Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Cluster Infrastructure Cluster Management (CMAN) Distributed across all nodes CMAN track cluster quorum Prevents split-brain CMAN tracks membership
- 11. 11Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Service provides mechanism for other cluster components to synchronize their access to shared resources Distributed Lock Manager (DLM) GFS & CLVM use locks from DLM Cluster Infrastructure Lock Management
- 12. 12Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Cluster Infrastructure Fencing Disconnection of a node from the cluster’s shared storage fenced daemon performs fencing DLM & GFS recover after fenced Fencing methods
- 13. 13Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Fencing methods: SCSI3 Persistent Reservation Fencing Fiber Channel switch fencing GNBD fencing Cluster Infrastructure Fencing Power fencing External Integrated
- 14. 14Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Cluster Infrastructure Cluster ConfigurationSystem (CCS) CCS manage cluster configuration CCS provide information to other cluster components CCS ensures configuration file is up-to-date in all nodes
- 15. 15Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Configuration file /etc/cluster/cluster.conf Cluster characteristics Cluster Infrastructure Cluster ConfigurationSystem (CCS) Cluster name Cluster Fence Device Managed Resources
- 16. 16Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 HA Service Management Create & manage HA cluster services rgmanager implements cold failover HA service must be configured in cluster. conf Associate service to failover domain Failover priority in a failover domain
- 17. 17Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Failover Domains
- 18. 18Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Failover Domains Failover characteristics Unrestricted Restricted Unordered Ordered Failback
- 19. 19Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 GFS/GFS2 is a native file system GFS/GFS2 provides data sharing among nodes with single, consistent view of the file system name space GFS/GFS2 file system must be created on an LVM logical volume (linear or mirror) Red Hat Global File System
- 20. 20Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Cluster Logical Volume (CLVM) CLVM provides the same capabilities as LVM2 on a single node CLVM makes volume available to all nodes clvmd daemon provides clustering exten- sions to LVM2
- 21. 21Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Provides block-device access to GFS over TCP/IP Useful when FC or single initiator SCSI are not necessary or are cost prohibitive GNBD client , GNBD server Global Network Block Device (GNBD)
- 22. 22Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Global Network Block Device (GNBD)
- 23. 23Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Set of integrated s/w for load balancing Runs on equally configured computers LVS roles: Linux Virtual Server (LVS) Active LVS router Backup LVS router Load balancing Integrity of services check
- 24. 24Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Linux Virtual Server (LVS)
- 25. 25Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Two tiers : LVS routers & real servers Active LVS router uses NAT to direct from public network to real servers Service requests arrive to LVS to a virtual IP (VIP) Only one LVS is active at a time LVS distributes requests based on load balancing algorithms Linux Virtual Server (LVS)
- 26. 26Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Linux Virtual Server (LVS) Load-balancing algorithms: Round-Robin Scheduling Weighted Round-Robin Scheduling Least-Connection Weighted Least-Connections (default)
- 27. NAT Routing Direct Routing 27Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Routing Methods: Linux Virtual Server (LVS)
- 28. 28Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Cluster Administration tools Conga Cluster Administration GUI Command line administration tools
- 29. 29Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 s/w provides centralized configuration & management Conga primary components luci server runs on one computer & commu- nicates with multiple clusters & computers via ricci ricci agent that runs on each computer Cluster Administration tools Conga luci ricci
- 30. 30Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 System-config-cluster Cluster status tool Cluster Administration GUI
- 31. - ccs_tool → cluster configuration - cman_tool → cluster management - fence_tool → fence tool - clustat → cluster status - clusvcadm → cluster user service administration 31Linux Clustering Document www.expertslogin.com Linux Cluster Concepts And Administration on RHEL 5 Command Line Administration Tools Cluster Administration tools