High Availability and Xen

Highly available infrastructures based on Xen Björn Brundert

2

Disclaimer

- All statements given in this presentation do not represent

the opinion of the speakers company but only the

personal opinion and experience of the speaker himself

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Introduction, overview and scope

1) Virtualization and high availability

2) Hardware requirements and planning

3) Available solutions today

4) Future prospect

5) Summary

6) Q&A

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1) Virtualization and high availability

- Standalone server does not meet HA-SLAs

- HA means redundancy clustering

- Cluster means higher complexity: building and operating

- Dedicated hardware per HA-service becomes more and

more expensive

- Hardware, infrastructure components, ETH/FC ports,

rackspace, power, cooling

- Active/passive cluster unused ressources

- How to achieve HA

1) Virtualization and high availability

ApplicationApplication

Operating SystemOperating System

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HardwareHardwareXen-HypervisorXen-Hypervisor Xen-HypervisorXen-Hypervisor

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1) Virtualization and high availability

- Virtualization offers enourmous benefits

- Consolidation: multiple services on one hardware

- Higher flexibility through VM encapsulation and hardware

independence

- Application does not require to be „cluster-ready“

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2) Hardware requirements and planning

- Key rules when thinking about HA

- Be as paranoid as you want

- There is never enough redundancy

- Murphy is with you

- Identify single points-of-failure

- Consolidation means also higher impact in case of an

outage

- Server:

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2) Hardware requirements and planning

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2) Hardware requirements and planning

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2) Hardware requirements and planning

- I/O Cards:

NC340TFC1143 NC340TFC1143

FC NIC

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2) Hardware requirements and planning

- Server

- Harddisk: RAID-configuration, spare

- Redundant I/O cards

- Redundant power supplies, redundant power cabeling and

redundant power circuits

- Redundant heartbeat-interconnect between nodes

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2) Hardware requirements and planning

- Network components

- Redundant cabeling to server NICs- Active/passive bonding needs to be set up in OS

- Redundant switch or redundant switch modules

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2) Hardware requirements and planning

- Storage components:

- RAID configuration with hot-spare harddrives

- Redundant controllers

- Redundant cabeling to every node

- Terminating on different HBAs

- Storage based replication

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3) Available solutions today

- Several implementations of Xen in the wild

- XenServer by Citrix- Bundeled Hypervisor, out-of-the-box solution, including HA-

mechanism- Version 5.5 released on June 16- Free since Feburary 2009

- Xen in Linux-Distributions- different implementations of HA-mechanisms like Red Hat

Cluster Suite

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4) Future prospect

- HA was only the first step

- Encapsulation is the key to more flexibility

- Fault-Tolerance is entering the market

- Xen Summit 2008: Demonstration of Kemari

- Marathon everRun VM: Available

- VMworld 2009 Europe: Announcement of VMware FT

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4) Future prospect

- What is meant by FT?

- Virtual machine is running on two nodes simultaneously

- Primary machine is visible to the outside world

- Secondary machine is running as a shadow instance that

can take over any time no need for restarting the VM

HardwareHardware HardwareHardware

Xen-HypervisorXen-Hypervisor Xen-HypervisorXen-Hypervisor

VM 1VM 1 VM 2VM 2 VM 1VM 1 VM 2VM 2

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4) Future prospect

- FT-mechanisms are on the roadmap for Xen 4.0

- Kemari (NTT, Japan): Unsupported version available

- Remus (UBC, Canada): Initial port to Xen unstable (3.4.0)

completed

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5) Summary

- Virtualization brings more complexity to the infrastructure

- But: virtualization also brings more flexibility to the

infrastructure

- Obligatory redundant infrastructure for traditional cluster

systems can be „recycled“ and used for multiple OS

- High availability through encapsulation and hardware-

independence of OS as a virtual machine

- Fault-tolerance mechanisms are going to revolutionize

availability of stand-alone-servers

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6) Q&A

- Any questions?

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Thank you for your attention

For further questions feel free to contact me at

[email protected]