Xen Virtualization 2008


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A presentation on Xen and Virtualization in general.

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Xen Virtualization 2008

  1. 1. Michael Lang Xen Virtualization mwlang@cybrains.net November 2008
  2. 2. The Main Players
  3. 3. Virtualization Awareness Fully-virtualized  All hardware fully emulated.  Kernel is unaware it is virtualized. Para-virtualized  Kernel modified to be “aware”  Direct access to some hardware devices, so less emulation overhead.
  4. 4. CPU Technology: Intel-VT and AMD-V What is it Good for?  Efficient Hypervisor by eliminating need to “trap and emulate” End Result:  Running an unmodified version of an OS as a Guest.
  5. 5. When is Intel-VT and AMD-V Needed? VMWare Xen 32-bit 64-bit 32-bit 64-bit 32-bit 64-bit 32-bit 64-bit Intel-VT No Yes No Yes Yes Yes No No AMD-V No No No No Yes Yes No No Unmodified Kernel Fully virtualized Modified Kernel Para-virtualized
  6. 6. What am I getting into? Why Use Virtual Technologies?
  7. 7. Implement High Availability VM Guest stays up and running even if the physical Host machine goes down. Requires:  SAN  Three or More Physical Hosts  Clustered, Shared Filesystem
  8. 8. Increase Hardware Utilization  Run More on Less.  Boost CPU and RAM Utilization dramatically.  Take full advantage of RAM and Multi-core CPU’s.
  9. 9. Separate Service from Hardware  Liberate Windows Systems.  Backup and Restore a Fully configured system cheaply.  Upgrade hardware painlessly.
  10. 10. Business Continuity  Set up Once, distribute to multiple Data Centers.  Offsite Disaster Recovery through simple backup/restore process.  Load balance across Data Centers.
  11. 11. Try New Things  Provision New Servers within an Hour.  Teardown/Rebuild of Servers is highly efficient.  Clone and perform “dry-runs” before attempting on Production.
  12. 12. Getting Started… Order of Importance:  Sufficient RAM  Fast Front-Side Bus (FSB)  Fast Hard Drives and Controllers  Multi-core CPU’s  Cache memory  CPU speed  Network Bandwidth
  13. 13. Start Small…  Take a Desktop, install 2gb of RAM.  Install VMWare Server Free.  Install Windows and Linux as guest OS’s.  Get to know the terminology.
  14. 14. Try it in the Data Center…  Install Free versions of Xen or VMWare Server on an underutilized Server.  Bring up your new Service on VM Guests.  Get comfortable managing.  Learn to backup efficiently.
  15. 15. Make your Business Case…  Show your boss, make your case, get the equipment.  Convert oldest, slowest or most unstable servers first.  Save critical resources and high I/O systems (databases, file servers) for last.  Get used to diagnosing issues, pinpointing bottlenecks or stability issues.
  16. 16. Watch Your Performance Closely Know when you’re saturating:  Hard drive I/O throughput  Network bandwidth  CPU utilization Commercial/Enterprise Licenses make this easier to monitor and manage.
  17. 17. For High Availability  Dedicated iSCSI VLAN w/dedicated NICs.  Line-speed, non-blocking switches  Host Bus Adaptors with TCP/IP offload Engines (TOE).  Wide-striped LUN’s.  Load-balancing Storage Processors on your SAN
  18. 18. What I’m Using Hardware Software 3 x Dell 2950’s Linux: 2 x quad-core Xeon 2.33ghz Oracle VM for Host 16-gb RAM 4x250gb RAID 5 SCSI Fedora Core 8, CentOS 4, CentOS Dual port iSCSI HBA 5 Xen kernels for guests. 1 x Dell 2950 Red Hat’s Kickstart for 2 x quad-core Xeon 3.2ghz provisioning new VM guests. 16gb RAM 5x250gb RAID 5 SAS CentOS repositories to maintain Dual port iSCSI HBA patches on Oracle VM Host and CentOS guests. 1 x Dell AX150i 2 storage processors Fedora Core repositories for FC8 12x500gb SATA II drives 2 x Dell 6248 GbE Switches
  19. 19. Baphst01: xm list
  20. 20. Baphst01: xm top
  21. 21. What’s Running in our Environment? Apache Servers Host Guests Rails Application Servers Baphst01 18 Continuous Build Servers Baphst02 10 DNS Servers Baphst03 19 Email Servers Baphst04 15 MySQL Servers Total 62 PostgreSQL Servers Subversion Server Trac Wiki Servers Repositories Nagios
  22. 22. Maintenance Plan  Whenever Guest Images are provisioned or patched, Guest is downed and image backed up to SAN.  We use automated deployment tools and strict adherence to conventions to configure guest VMs and deploy our systems (Ruby on Rails).  Stress Rebuild over Restore.
  23. 23. Maintenance Plan  All config files kept in Subversion, which is hot copied to SAN via SAMBA shared resources.  Mysql, Postgresql and SQL Server 2005 backed up to SAN via SAMBA shared resources.  SAN backed up to portable 500gb USB drives via rsync.
  24. 24. Questions and Answers