Red Hat Cluster Suite

Transcription

1 Red Hat Cluster Suite HP User Society / DECUS 17. Mai 2006 Joachim Schröder Red Hat GmbH

2 Two Key Industry Trends Clustering (scale-out) is happening 20% of all servers shipped will be clustered by Gartner Linux clusters are growing at a cagr of 44% per year. - IDC 30%+ of Red Hat inquiries are about implementing clusters. Clustering software is a $500m+ market today. Storage capacity and complexity are growing Storage (capacity) will continue to grow at 40-60% annually. - Aberdeen. SAN management software use grew by 36% year over year driven "primarily by customer need to support larger and more complex storage networks. - IDC Storage management software is a $5B+ market today.

3 What if you could...

4 Clustering motivation Reduce TCO by: Consolidate services to fewer systems Simplify management tasks Increase service uptime Approaches: Scale up: few very powerful systems running multiple services Scale out: many small systems collaborate on several services Requirements: Data sharing Monitoring infrastructure Service management layer

5 Clustering buzzwords Application Failover Detect service failures and failover to standby systems Load Balancing Distribute service load over multiple systems Common for network based systems Active/Passive Active node owns service, passive node is idle Failover requires hand-over of resources to passive node Advantage: generally any application Active/Active Multiple nodes are owning the service Requires typically data sharing Application needs active/active-support

6 Red Hat Clustering Architecture Red Hat Cluster Suite provides Application failover Improves application availability Included with GFS Core services for enterprise cluster configurations* Red Hat Global File System (GFS) Cluster-wide concurrent read-write file system Improves cluster availability, scalability and performance Includes Cluster Logical Volume Manager (CLVM)* Cluster File System HA Services (Failover) Core services*: DLM Connection Manager Service Manager I/O Fencing Heartbeats Management GUI Red Hat Cluster Suite Single node LVM2 Cluster Logical Volume Manager* Red Hat Global File System (GFS) IP Load Balancing Red Hat Enterprise Linux * These features will be available with launch of Cluster Suite v4 and GFS 6.1 availability concurrent with RHEL4 Update 1

7 Red Hat Cluster Suite: Core Cluster Services Core functionality for both Clustering and GFS is delivered in Red Hat Cluster Suite Membership management I/O fencing Lock management Heartbeats Management GUI Support for up to 300 nodes Two selectable lock management models Client-server with SLM/RLM (single/redundant lock manager) Was in prior version Distributed Lock Manager (DLM) New with Red Hat Cluster Suite v.4 Open, stable API consistent with VMS DLM

8 Red Hat Cluster Suite Overview Provides two major technologies High Availability failover suitable for unmodified applications IP Load Balancing enables network server farms to load share IP load New with Cluster Suite v4 Elimination of requirement for shared storage Significantly reduces the cost of high availability clustering Shared Quorum partition is no longer required Service state, previously stored in Quorum partition, is now distributed across cluster Online resource management modification Allows services to be updated without shutting down (where possible) Additional fencing agents

9 Red Hat Cluster Manager Architecture Clients Node 0 Node 1 Oracle Network Power Switch NFS bind Heartbeat SAN

10 Handling Failures Software Failures Monitoring provided by resource agents handles restarting If a resource fails and is correctly restarted, no other action is taken In the event that the resource fails to restart, RHCM will stop and relocate the entire service to another node Hardware, cluster failures If the cluster infrastructure evicts a node or nodes from the cluster; RHCM selects new nodes for the services it was running based on the failover domain if one exists If a NIC fails or a cable is pulled (but the node is still a member of the cluster), the service will be relocated Double Faults Usually difficult or impossible to choose a universally correct course of action when one occurs. Ex: Node with ilo losing all power vs. pulling all of its network cables.

11 After a node failure... Clients Node 0 Node 1 Network Power Switch Heartbeat NFS Oracle bind SAN

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14 Data Sharing Purpose: parallel access to data resources Files and Directories Needed identical or single data Data Sharing technologies SAN block based sharing NAS file based sharing Data Replication on cluster nodes File or block based, typically not symmetric

15 Red Hat Global File System v6.1 New version for Red Hat Enterprise Linux v.4 Uses new common cluster infrastructure in Red Hat Cluster Suite (included) Provides two major technologies GFS cluster file system concurrent file system access for database, web serving, NFS file serving, HPC, etc. environments CLVM cluster logical volume manager Fully POSIX compliant Much faster fsck Ported to GFS 6.0 on RHEL 3 Update 5 Data and meta-data journaling (per-node journals, clusterwide recovery) Maximum filesize & file system size: 16TB with 32-bit systems, 8EB with 64-bit systems Supports file system expansion Supports SAN, iscsi, GNBD Default use of new Distributed Lock Manager (DLM) Client-server locking optional

16 Distributed Lock Manager Red Hat Cluster Suite v.4 includes a Distributed Lock Manager (DLM) Primarily used by Red Hat Global File System Available for general purpose use by any application Closely mirrors the original Digital VMS DLM A DLM is a highly functional, distributed (cluster-wide), application synchronization subsystem Processes use the DLM to synchronize access to a shared resource (e.g. a file, program, or device) by establishing locks on named resources Permits the creation of distributed applications e.g Oracle RAC (which uses a private DLM) Provides a collection of services Multiple lock spaces and concurrency (lock) modes Lock hierarchies/domains (resources & subresources) Range locking Lock conversions & value blocks Blocking notifications Asynchronous completions

17 Cluster Logical Volume Manager (CLVM) CLVM builds upon LVM 2.0 and the kernel device mapper component included in 2.5 and 2.6 Linux distributions Essentially a cluster-aware version of LVM 2.x Commands, features, functions all work just fine in a cluster, any Linux server may mount any volume Provides Cluster safe volume operations Cluster-wide concatenation and stripping of volumes Dynamic Volume resizing Cluster-wide snapshots (mid '06) Cluster-wide mirroring (mid '06) Other RAID levels (mid '06)

18 Use Case: High availability with local data Red Hat Enterprise Linux (ext3) + Red Hat Cluster Suite v4 Requires NO ADDITIONAL HARDWARE No physically shared storage Prior to RHEL4, physically shared storage was required Ensures that an application stays running Monitors all cluster nodes Fails-over applications/services from stopped nodes Simple management GUI Service definitions are automatically propagated and synchronized, cluster-wide Topology: - 2 or mode nodes - NIC card - NO shared storage Applications: - Read-only data - Small web serving - NFS/FTP serving - Edge of network Local storage only Application failover H/A Cluster Data model: - Unshared, static data - Replication w/ rsync - ext3 file system

19 Use Case: Shared file datastore, NAS Red Hat Enterprise Linux (NFS) Uses an external NFS file server Shared storage file based (NFS) Cluster nodes are NFS clients Addnl. Cluster features: - Increased storage capacity - Applications can failover and access the same data as before - NFS sharing model Applications: - Small/medium web serving - NFS/FTP serving - Read/write data - File level access HA Cluster HPC Cluster NetApp, etc. Data model: - Physically shared data - File based (NFS) NetApp, etc.

20 Use Case: Shared block datastore, SAN Red Hat Enterprise Linux (ext3, integrated HBA drivers) Offers higher, SAN-based, performance Addnl. Cluster features: - SAN access provides: -- improved performance -- heterogeneous access by other systems Applications: - Medium/large web serving - Medium database - Read/write data - Block level access Shared storage block based (SAN) Partitions accessed on a per node basis SAN Data models: - Storage Area Network - Physically shared storage - Block based - ext3 file system

21 Use Case: Concurrent file system access Red Hat Enterprise Linux + Red Hat Global File System Includes Red Hat Cluster Suite Shared file system access Scalable performance Same hardware as previous configurations Common software infrastructure with previous configuration Shared storage block based (SAN) Partitions concurrently accessed by all nodes SAN Applications: - Large web serving - Large database - Read/write data - Block level access - Concurrent access Data models: - Storage Area Network - Shared file system access - Block based - GFS file system Addnl. Cluster features: - SAN access provides: -- improved performance -- heterogeneous access by other systems

22 About Piranha & IPVS Piranha Front-end to IPVS (or LVS) which enables IPVS director failover Provides a web-based configuration GUI IPVS does the heavy lifting Layer-4 (application) switching/routing Multiple scheduling algorithms: round-robin, weighted round-robin, leastconnections, weighted-least-connections, and more... Several routing topologies: NAT, Direct Routing, IP Tunneling DR and TUN are tricky to set up, and require configuration on the Real Servers

23 Piranha Architecture Appears as one mega-machine to clients: SSI at the IP level One or two nodes acting as IPVS directors Stand-alone cluster: Not dependent on CMAN, GULM, etc. IPVS routing table is replicated between the primary and backup directors for hot-standby operation No dependencies on shared storage (no shared data to protect) Real servers can use GFS, NFS, or manual replication (using rsync, for example)for static content Provides high availability for applications via redundant Real Servers and (optionally) a redundant director

24 Piranha Architecture Director Internet Real Server Virtual IP Primary Heartbeat Backup RS0 RS1 RS2

25 Piranha Real Server Failure Director Internet Real Server Virtual IP Primary Heartbeat Backup RS0 RS1 RS2

26 Piranha Director Failure Director Internet Real Server Virtual IP Primary Heartbeat Backup RS0 RS1 RS2

27 New! Red Hat and GFS Joint Linux Clustering Solution HP Serviceguard for Linux creates a cluster of Linux servers that make application services available despite hardware or software failures or planned downtime. Red Hat Global File System (GFS) is a cluster file system that enables multiple servers to simultaneously read and write to a single shared file system on a Storage Area Network. Recently tested. Working together, now provide best of breed clustering technologies for Linux. The combination offers greater availability of applications and data using a cluster of low cost Linux servers. White Paper Solution Brief Joint marketing

28 Questions?

29 Vielen Dank! Joachim Schröder, Solution Architect