This document provides an overview of HA clustering on OpenSUSE. It discusses key aspects of HA clusters including eliminating single points of failure, reliable crossovers, failure detection, increased availability, improved performance, and scalability. It also describes the typical architecture of an HA cluster including messaging/infrastructure layers, resource allocation layers, resource agents, and more. Tips are provided around configuration, troubleshooting, and references for further information.

1. HA-Cluster on OpenSUSE
A workshop on OpenSUSE.asia Submit 2015
Presented by
netman<netman@study-area.org>

2. Netman
➢臺灣酷學園 (Study-Area) 創辦人之一兼終身苦力成員
➢自以推廣自由軟體及分享技術爲樂
➢長年致力於 Linux 技術傳播
工作經歷
➢住華科技 : 工程師
➢奇科電腦、巨匠電腦、聯成電腦 : 講師
➢網虎集團 : 工程師
➢洗碗工
證照
➢LPIC 、 RHCE 、 NCLP
About Me ...

3. High Availability
➢Elimination of single points of failure.(redundancy)
➢Reliable crossover. (multithreaded)
➢Detection of failures as they occur. (never see a
failure)
Ref: Wikipedia, the free encyclopedia
What is a HA Cluster?

4. Linux is NEVER down! ...
Why HA?

5. Who knows ...

6. Even like this?!

7. ➢ Increased availability
➢ Improved performance
➢ Low cost of operation
➢ Scalability
➢ Disaster recovery
➢ Data protection
➢ Server consolidation
➢ Storage consolidation
Reasons ...

8. So ...
HA is GOOOOOOOD for you!

9. ➢ Wide Range of Clustering Scenarios
A/A, A/S, Local, Metro, GEO, ...
➢ Flexibility
monitoring, management, automation
➢ Storage and Data Replication
iSCSI, SAN, OCFS2, cLVM, DRBD, CTDB
➢ Support for Virtualized Environments
Xen, KVM
➢ Resource Agents
OCF Agents (Apache, IPv4, IPv6...)
➢ User-friendly Administration Tools
Yast, Hawk, crm Shell
Key features ...

10. Shared Storage

11. ➢ Messaging and Infrastructure Layer
➢ Corosync / Heart-beat
➢ Resource Allocation Layer
➢ Cluster Resource Manager (CRM)
➢ Cluster Information Base (CIB)
➢ Designated Coordinator (DC)
➢ Policy Engine (PE)
➢ Local Resource Manager (LRM)
➢ Resource Layer
➢ Resource Agents (RA)
➢ Programs(Shell Scripts)
Architecture

12. Process Flow

13. ➢ Purpose
➢ to power off nodes to protect shared data or complete
resource recovery
➢ Classes
➢ Resource Level
➢ Node Level
➢ STONITH
➢ Shoot The Other Node In The Head
➢ H/W & S/W Solutions
➢ PDU, UPS, Blade Power, Lights-out Devices, etc.
➢ SBD, kdumpcheck, ssh, etc.
Fencing

14. ➢ Hawk
➢ Web interface
➢ Redundant
➢ Multi-Path
➢ Bounding
➢ Time Synchronization
➢ NTP
Notes ...

15. the LAB
gw
ha1 ha2

17. ➢ Use raw device.
➢ Use Disk ID(/dev/disk/by­id/xxxxxx)
➢ ISCSI IQN must be unique.
➢ Incoming Authentication should be enough.
➢ Load softdog module on boot.
➢ Run mkfs.ocfs2 with stack and cluster names
first. (mkfs.ocfs2 --cluster-stack=pcmk --cluster-name=hacluser
/dev/disk/by-id/XXXXXX ; mounted.ocfs2 -t)
➢ Run csync2 ­xv before service cluster setup.
➢ Use CIDR mask format in Hawk.
➢ Put resources into groups & clones.
Tips ...

18. ➢ Check iscsi target
fdisk ­l
➢ Check sbd list
sbd ­d /dev/XXX list
➢ Check ocfs2
mounted.ocfs2 ­f
➢ Check csync2
csync2 ­xv
➢ Start/Stop cluster
crm cluster <start|stop>
➢ Show/Edit crm configure
crm configure <show|edit>
Troubleshooting ...

19. References ...
➢ SUSE Linux Enterprise High Availability
Extension 12
➢ https://www.suse.com/documentation/sle-ha-12/
➢ SDB Wiki
➢ http://www.linux-ha.org/wiki/SBD_Fencing
➢ Hawk Wiki
➢ http://clusterlabs.org/wiki/Hawk