Anatomy of the libvirt virtualization library http://www.ibm.com/developerworks/library/l-libvirt/ libvirt http://libvirt.org/index.html Scheduling http://docs.openstack.org/icehouse/config-reference/content/section_compute-scheduler.html Openstack Zoning – Region/Availability Zone/Host Aggregate https://kimizhang.wordpress.com/2013/08/26/openstack-zoning-regionavailability-zonehost-aggregate/ Availability Zones and Host Aggregates in OpenStack Compute (Nova) http://blog.russellbryant.net/2013/05/21/availability-zones-and-host-aggregates-in-openstack-compute-nova/ An Introduction to Droplet Metadata https://www.digitalocean.com/community/tutorials/an-introduction-to-droplet-metadata HOW WE USE CLOUDINIT IN OPENSTACK HEAT http://sdake.io/2013/03/03/how-we-use-cloudinit-in-openstack-heat/ How to inject file/meta/ssh key/root password/userdata/config drive to a VM during nova boot https://kimizhang.wordpress.com/2014/03/18/how-to-inject-filemetassh-keyroot-passworduserdataconfig-drive-to-a-vm-during-nova-boot/ Cloud-init https://cloudinit.readthedocs.org/en/latest/

1. Nova
OpenStack Study 4th
클라우드개발팀 신진호

2. nova-scheduler
• FilterScheduler is a default scheduler
– Supports filtering and weighting

3. • Filtering
– RetryFilter
• Prevents the scheduler from selecting the host that fails
to respond.
– AvailablilityZoneFilter
• Filters hosts by availability zone.
– RamFilter
• Select hosts that have sufficient RAM.
• Can overcommitment by configuration.
– ComputeFilter
• Passes all hosts that are operational and enabled.
nova-scheduler > filter scheduler

4. – ComputeCapabilitiesFilter
• Satisfy the extra specs associated with the instance type.
– ImagePropertiesFilter
• Filters hosts based on properties defined on the
instance's image.
nova-scheduler > filter scheduler

5. • Weighting
– Each time the scheduler selects a host and
subsequent selections are adjusted accordingly.
– Virtually consumes resources.
nova-scheduler > filter scheduler

6. Host aggregates and Availability zone
• Host aggregates
– Be logically grouped.
– Node can be assigned to multiple host aggregates.
– Only visible to administrators.
– For operations.
• e.g. nodes with SSD or nodes with 10G NIC
• Availability Zone
– Be logically grouped.
– One availability zone.
– Visible to users.
– For HA, physical isolation, …
• e.g. by using separate power supplies for HA and
network gears for load balancing

7. Host aggregate and Availability zone

8. It Supports multiple hypervisors.
Because, it Has an abstraction layer, Driver.
Components > nova-compute
nova-compute
Compute Agent
(KVM)
libvirt
KVM
VM VM
nova-compute
Compute Agent
(Hyper-v)
Hyper-v
VM VM
nova-compute
Abstraction layer,
Driver
any hypervisor
VM VM

9. Hypervisor Types
• Type-1: bare metal hypervisor
• Type-2: hosted hypervisor
nova-compute > hypervisors

10. Hypervisors
• Hypervisor-V
– Microsoft
– Windows Server Virtualization.
– Linux available
– On x86-64
• XenServer
– Citrix
• VMWare Vcenter
– VMware
nova-compute > hypervisors

11. • Libvirt
– Linux API for Virtualization
– KVM, LXC(LinuX Container), QEMU, Xen, …
• driver-based architecture
nova-compute > hypervisors

12. • Libvirt
– Two means of control
• Local
• Remote
nova-compute > hypervisors
local remote

13. • Ironic
– OpenStack Component for managing and
provisioning Bare Metal servers.
– Not VMs.
– Makes physical servers as easy to provision as
VMs in cloud.
nova-compute > hypervisors

14. How do we select a hypervisor ?
See ‘Hypervisor support matrix’
And Compare!
nova-compute > hypervisors
http://docs.openstack.org/developer/nova/support-matrix.html

15. nova-compute > hypervisors
There are so many!

16. • More summary
– Mandatory
• Get instance status
• Launch instance
• Shutdown instance
• Image storage support
– Choice
• Flat networking or VLAN networking
– Provide network connectivity to guests
– Optional
• Attach/Detach block volume to instance
– hotplug additional block storage to a running instance.
nova-compute > hypervisors

17. • Consideration about optional features
– Are your instances a pet or a cattle?
• Pet
– A unique instance. It is only one.
» Attach/Detach block volume to/from instance.
» Live migrate instance across hosts.
» Suspend instance
» Swap block volumes
• Cattle
– Replaceable. Remove and Re-Create.
– Enough mandatory features.
nova-compute > hypervisors

18. initialization of a cloud instance
• File Injection
• Metadata Service
– Instance-specific data.
• Metadata, user data, ssh key
– At http://169.254.169.254.
– Supports an OpenStack metadat API and an EC2-
compatible API.
# nova boot –flavor 1 –image cirros –nic net-id=d58bbcac-1908-4cda-a9da-
a13cfbbf4e77 –file /fileinject=/root/keystonerc vm-file-inject

19. initialization of a cloud instance
• Cloud-init
– Defacto multi-distribution package
– Setting a default local
– Setting a instance hostname
– Generating instance ssh private keys
– Adding ssh keys to users, so they can log in.
– Setting up ephemeral mount point
– be configured via user-data

20. initialization of a cloud instance
– User-data
• Arbitary data that a user can supply to a instance during
its creation time
• ‘—user-data’
– The base64-encoded MIME user data for the instances.
• ‘—user-data-file’
– The file name of the user data for the instances.

21. initialization of a cloud instance
– be configured via user-data
• Format
– User-Data Script (shell script)
» ‘#!’ or ‘Content-Type: text/x-shellscript’
– Include File
» ‘#include’ or ‘Content-Type: text/x-include-url’
– Cloud Config Data (YAML)
» ‘#cloud-config’ or ‘Content-Type: text/cloud-config’
– Upstart Job
» ‘#upstart-job’ or ‘Content-Type: text/upstart-job’
– Cloud Boothook
» ‘#cloud-boothook’ or ‘Content-Type: text/cloud-boothook’
– Part Handler
» ‘#part-handler’ or ‘Content-Type: text/part-handler’

22. initialization of a cloud instance
#!/bin/sh echo
"Hello World. The time is now $(date -R)!" | tee /root/output.txt
$ euca-run-instances --key mykey --user-data-file myscript.sh ami-a07d95c9
#cloud-config
# vim: syntax=yaml
#
# Add yum repository configuration to the system
#
# The following example adds the file /etc/yum.repos.d/epel_testing.repo
# which can then subsequently be used by yum for later operations.
yum_repos:
# The name of the repository
epel-testing:
# Any repository configuration options
# See: man yum.conf
#
# This one is required!
baseurl: http://download.fedoraproject.org/pub/epel/testing/5/$basearch
enabled: false
failovermethod: priority
gpgcheck: true
gpgkey: file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL
name: Extra Packages for Enterprise Linux 5 - Testing

23. initialization of a cloud instance
• Two ways to initialization
– Injection by hypervisor
– By Metadata Service and Cloud-init
1. Boots an instance.
2. Executes Cloud-init.
3. Cloud-init gets metadata from a metadata service.
4. Bootstrap the instance with desired configurations.
# nova boot –flavor 1 –image cirros –nic net-id=d58bbcac-1908-4cda-a9da-
a13cfbbf4e77 –file /fileinject=/root/keystonerc vm-file-inject

24. Links
• Anatomy of the libvirt virtualization library
– http://www.ibm.com/developerworks/library/l-libvirt/
• libvirt
– http://libvirt.org/index.html
• Scheduling
– http://docs.openstack.org/icehouse/config-reference/content/section_compute-scheduler.html
• Openstack Zoning – Region/Availability Zone/Host Aggregate
– https://kimizhang.wordpress.com/2013/08/26/openstack-zoning-regionavailability-zonehost-aggregate/
• Availability Zones and Host Aggregates in OpenStack Compute (Nova)
– http://blog.russellbryant.net/2013/05/21/availability-zones-and-host-aggregates-in-openstack-compute-
nova/
• An Introduction to Droplet Metadata
– https://www.digitalocean.com/community/tutorials/an-introduction-to-droplet-metadata
• HOW WE USE CLOUDINIT IN OPENSTACK HEAT
– http://sdake.io/2013/03/03/how-we-use-cloudinit-in-openstack-heat/
• How to inject file/meta/ssh key/root password/userdata/config drive to a VM during nova boot
– https://kimizhang.wordpress.com/2014/03/18/how-to-inject-filemetassh-keyroot-passworduserdataconfig-
drive-to-a-vm-during-nova-boot/
• Cloud-init
– https://cloudinit.readthedocs.org/en/latest/

25. EOF