OpenSAF and Alternate HA Approaches

Murthy Esakonu

GoAhead Software

&

OpenSAF TLC

Agenda

Different HA approaches

Application level HA

Virtual Machine Level HA

Virtualization HA Architecture

Integration of OpenSAF in to Virtualization HA

Summary and Recommendations

Application HA – Using OpenSAF

Active - App

Standby - App

OpenSAF Node local infrastructure

OpenSAFClusterInfrastructure

OpenSAF Node local infrastructure

State Replication-SAF Ckpt

ActiveStandby

OS OS

Virtualization based HA

Physical Node

Hypervisor

Cluster Mgr

Virtual Machine

Physical Node

Hypervisor

Cluster Mgr

Virtual Machine

Lock-step

Data- sync

Active Standby

Virtualization HA architecture

The Active Virtual machine is replicated to the Standby Virtual machine (Live Migration, Non-live Migration)

Deterministic Replay can be achieved by recording non-deterministic inputs and then injecting them at the same execution point during the replay (Lock-step).

If Lock-step interval increases Hypervisor slows down the Active Virtual machine.

OpenSAF in Virtualization HA - 1

Physical Node

Hypervisor

PLMC

Virtual Machine

Physical Node

Hypervisor

PLMC

Virtual Machine

Lock-step

Data- sync

Active Standby

PLM->CLM->AMF PLM->CLM->AMF

Rolechange

Rolechange

OpenSAF in Virtualization HA - 1

The Hypervisors are configured as PLM Execution environments. Hypervisors integrates with AMF for determining the Active/Standby

Hypervisor indicates the fault to PLMC or PLMC checks the health of Hypervisor.

In Fault situation, PLMC sends the information to PLMS, CLM receives this information from PLMS and node is declared as out of the cluster. AMF subscribes to CLM notifications knows this node left the cluster, does the Active Role assignment to the currently Standby Hypervisor.

OpenSAF in Virtualization HA - 2

Physical Node

Hypervisor

PLMC

VM

Active

OpenSAF Controller (PLM->CLM->AMF)

Rolechange

App

OpenSAF Payload

Physical Node

Hypervisor

PLMC

VM

Standby

Rolechange

App

OpenSAF Payload

PLMCPLMC

SAF-CKPT

OpenSAF Controller (PLM->CLM->AMF)

OpenSAF in Virtualization HA - 2

In this approach Virtual machines run OpenSAF. Applications has access to OpenSAF services.

Virtual machines acts as OpenSAF payload nodes.

If the Virtual machine fails the problem gets reported to the OpenSAF controller and it takes appropriate recovery actions

If the Hypervisor indicates the fault to PLMC or PLMC checks the health of Hypervisor.

Based on the Hypervisor capabilities and based on PLM configuration in imm.xml either Hypervisor and all the VMs controlled by the Hypervisor are taken out of service or only Hypervisor is recovered.

OpenSAF in Virtualization HA - 3

OpenSAFVirtual Machine

ProxyComponent

Application

AMF

OpenSAF in Virtualization HA - 3

In this Modeling approach OpenSAF AMF plays significant role.

The virtual machine and Applications running within the Virtual machines are monitored through OpenSAF Proxy –Proxied approach.

The monitoring specifics for the applications and VM are hidden under Proxy framework.

OpenSAF capabilities are not available for applications running within VMs.

Summary and Recommendations Virtualization based HA

Live mirroring of VM data is expensive.

It doesn’t work on SMP and multicore environments well.

But this HA environment is non intrusive.

Generally Deployed in 2N redundancy model.

Very Suitable for Legacy application HA.

OpenSAF based HA

Gives lot of utilities and deployment flexibility with redundancy capabilities (2N, N+M, N-Way, N-Way active, etc).

Transparent to SMP and Uniprocessor environments.

It is intrusive HA and more suitable for new Applications HA.

As always System Designer is better judge

Questions?