This document discusses high availability (HA) features in SUSE Linux Enterprise Server 12 SP2, including: - A policy-driven HA cluster with continuous data replication across nodes and simple setup/installation. - Key HA concepts like resources, constraints, and STONITH (shoot the other node in the head) fencing mechanisms. - The new Hawk2 web console for managing HA clusters. - Support for geo-clustering across data centers with concepts like tickets, boothd, and arbitrators. - Options for maintenance and standby modes, new Cluster-MD software RAID, DRBD replication, OCFS2 and GFS2 cluster filesystems, and easy HA

1. High Availability + GEO
SLE12 SP2
Antoine Giniès
Project Manager / Release Manager
SUSE / aginies@suse.com
Expert Days Paris
Feb 2017

2. 2
SUSE Entreprise Server
HA SLE12 SP2
Main Features
• Policy Driven Cluster
• Cluster Aware FS
• Continuous Data Replication
• Setup and Installation bootstrap
• Simple

3. 3
HA Cluster Stack Architecture

4. 4
Cluster Scenarios
Main Features
• A / A
• A / P
• Hybrid (Phy / virt)
• Geo Cluster

5. 5
Key Concept
Terminology
• Primitive
• RA ( React )
• Group ( other Node, order )
• Clone ( multiple Node, ie: FS )
• Constraint ( condition )

6. 6
STONITH / FENCING
Shoot The Other Node In The Head
• UPS (Uninterruptible Power Supply)
• PDU (Power Distribution Unit)
• Blade Power Control
• Light-out devices (iLo, Darc etc...)
• SBD Devices (>1)
• Crm configure ra list/info stonith:XXX

7. 7
HAWK2 (new)
High Availability Web Konsole
• Status
• Dashboard
• History
• Resources
• Constraint
• Wizard ( resources,
• Configuration ( constraints, cluster etc...)
• Logs ( debug )
• Access Control (Target = users / Role = access to CIB)
• Batch mode ( staging / simulate )

8. 8
GEO Concept
• Ticket ~= service
• Boothd ~= manage ticket
• Arbitrator ~= take decision
• Dead Man Dep ~= Fence?

9. 9
HA features by Difference

10. 10
Maintenance / Standby
How to Update
• Standby
– still a R
– Elligible as a R
• Maintenance
– Un-managed
– No more a R
– monitor

11. 11
Cluster-MD (new)
Cluster Multi-device
• Software based raid storage
• Improve performance compare to CLVM mirroring
• RAID1 (redundancy)
• Replace at Runtime
• Requires: corosync / DLM
• On top of 2 SAN storage → no more SPOF

12. 12
DRBD
Distributed Replicated Block Device
• Replication DATA
• Mirror of 2 block Devices
• Stacked DRBD
• 8 → 9 ! (meta data)

13. 13
DRBD VS Cluster-MD
• DRBD
– SAN storage
– 2 nodes only
– Possible Regular FS
– Primary / Primary with cluster aware FS
• Cluster-MD
– Classical or SAN storage
– > 2 nodes
– Cluster Aware FS

14. 14
OCFS2 VS GFS2
• OCFS2
– Fast: small/large data files on different nodes
– No quota support
– No online-resize (no mounted)
• GFS2
– Fast: Large data files
– Perf issue accessing small files on different nodes
– Quota support
– Online-resize (mounted)

15. 15
Testing HA easily
Get everything on github
• HA cluster testing using VM
• Fully automatic
• Testing scenarios
• https://github.com/krig/Deploy_HA_SLE_cluster