Tim Mackey – XenServer Community Evangelist
Hypervisor Selection in Cloud Understanding the choices available
CloudStack Collaboration Conference Europe 2013
Building a successful cloud What are we trying to accomplish?
© Citrix 2013. More information at xenserver.org and follow me on twitter @XenServerArmy
Service Offerings
• Clearly define what you want to offer ᵒ What types of applications
ᵒ Who has access, and who owns them
ᵒ What type of access
• Define how templates need to be managed ᵒ Operating system support
ᵒ Patching requirements
• Define expectations around compliance and availability ᵒ Who owns backup and monitoring
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Define Tenancy Requirements
• Department data local to department ᵒ Where is the application data stored
• Data and service isolation ᵒ VM migration and host HA
ᵒ Network services
• Encryption of PII/PCI ᵒ Where do keys live when data location unknown
ᵒ Need encryption designed for the cloud
• Showback to stakeholders ᵒ More than just usage, compliance and audits
© Citrix 2013. More information at xenserver.org and follow me on twitter @XenServerArmy
Virtualization Infrastructure
• Hypervisor defined by service offerings ᵒ Don’t select hypervisor based on “standards”
ᵒ Understand true costs of virtualization
ᵒ Multiple hypervisors are “OK”
ᵒ Bare metal can be a hypervisor
• To “Pool” resources or not ᵒ Is there a real requirement for pooled resources
ᵒ Can the cloud management solution do better?
ᵒ Real cost of shared storage
• Primary storage defined by hypervisor
• Template storage defined by solution ᵒ Typically low cost options like NFS
The primary choices ….
© Citrix 2013. More information at xenserver.org and follow me on twitter @XenServerArmy
Networking Storage Compute
XenServer
Xen Project Hypervisor
Standard Linux Distribution (dom0)
qemu drivers
xapi
Guest
Driver front
Driver back
Guest
Driver front
patches
© Citrix 2013. More information at xenserver.org and follow me on twitter @XenServerArmy
KVM (Linux + KVM only)
Standard Linux Distribution
qemu drivers
Guest
Virtual driver
virtio
Guest
Virtual driver
KVM Module
libvir
t
agent
Networking Storage Compute
© Citrix 2013. More information at xenserver.org and follow me on twitter @XenServerArmy
vSphere 5.1 Managed by vCenter
vmkernel
Guest
Virtual driver
vSCSI
Guest
Virtual driver
Task
Scheduler
Service
Console
vmklinux vC
ente
r
drivers
vNIC
Networking Storage Compute
© Citrix 2013. More information at xenserver.org and follow me on twitter @XenServerArmy
Linux Containers
Standard Linux Distribution
Namespace
Container
Namespace
Container
KVM Module
libvir
t
agent Cgroups
Cgroup Cgroup
Namesspaces
Networking Storage Compute
Defining the network
© Citrix 2013. More information at xenserver.org and follow me on twitter @XenServerArmy
Flat Network – Basic Layer 3 Network
Feature XenServer vSphere KVM LXC
Security Groups Yes- bridge No Yes Yes
IPv6 No No Yes Yes
Multiple IPs per NIC
Yes Yes Yes Yes
Nicira NVP Yes No Yes No
BigSwitch VNS Yes No Yes No
65.11.1.2
65.11.1.3
65.11.1.4
65.11.1.5
Public Network 65.11.0.0/16
Guest VM 1
Guest VM 2
Guest VM 3
Guest VM 4
DHCP, DNS
CloudStack Virtual Router
Security Group 1
Security Group 2
© Citrix 2013. More information at xenserver.org and follow me on twitter @XenServerArmy
VLANs for Private Cloud
10.1.1.1
10.1.1.3
10.1.1.4
10.1.1.5
Public Network/Internet
Guest Virtual Network 10.0.0.0/8 VLAN 100
DHCP, DNS NAT Load Balancing VPN
Public IP 65.37.14.1
Gateway 10.1.1.1
Guest VM 1
Guest VM 2
Guest VM 3
Guest VM 4
CloudStack Virtual Router
Feature XenServer vSphere KVM LXC
Max VLANs 800 254 1024 1024
IPv6 No No Yes Yes
Multiple IPs per NIC
Yes Yes Yes Yes
Nicira NVP Yes No Yes No
BigSwitch VNS Yes No Yes No
MidoKura No No Yes No
VPC Yes Yes Yes No
NetScaler Yes Yes Yes No
F5 BigIP Yes Yes Yes No
Juniper SRX No Yes Yes No
Cisco VNMC No Yes No No
© Citrix 2013. More information at xenserver.org and follow me on twitter @XenServerArmy
Beyond the VLAN – Network Virtualization
Feature XenServer vSphere KVM LXC
OVS GRE tunnels Yes No No No
Nicira STT tunnel Yes No Yes No
MidoNet No No Yes No
VXLAN No Yes No No
NVGRE No No No No
Nexus 1000v No Yes No No
© Citrix 2013. More information at xenserver.org and follow me on twitter @XenServerArmy
Virtual Private Cloud and nTier Applications
Web
App
DB
Router
DC1
DC2 DC3
DC4
DC5
DC6
VLAN 1
VLAN 2
VLAN 3
S2S VPN
Private
GW
Feature XenServer vSphere KVM LXC
PVLAN Yes - ovs Yes ovs No
© Citrix 2013. More information at xenserver.org and follow me on twitter @XenServerArmy
Delivering specific network services
• IPv6 KVM is your only virtualized option (basic or advanced)
• Maximum VLANs XenServer or KVM are your best options
• Security Groups XenServer or KVM are your options
• VXLAN requires vSphere Enterprise Plus
• Cisco Nexus 1000v and ASA 1000v require vSphere Enterprise Plus
Instances need a home Storage, Storage and more Storage
© Citrix 2013. More information at xenserver.org and follow me on twitter @XenServerArmy
Primary Storage Options
Feature XenServer vSphere KVM LXC
Local storage Yes Yes Yes Yes
NFS Yes Yes Yes Yes
Single path iSCSI Yes Yes Yes No
Multipath iSCSI PreSetup No No No
Direct array No VAAI No No
Shared Mount No No Yes Yes
Template format VHD OVA QCOW2 TAR
Cluster
Host
Host
Primary Storage
Core virtualization capabilities The limits and features which matter
© Citrix 2013. More information at xenserver.org and follow me on twitter @XenServerArmy
CloudStack Features
Feature XenServer vSphere KVM LXC
Disk IO Statistics Yes No Yes
Memory Overcommit Yes (4x) Yes No No
Dedicated resources Yes Not with HA/DRS Yes No
Disk IO throttling No No Yes Yes
Disk snapshot (running) Yes Yes No No
Disk snapshot (Stopped) Yes Yes Yes No
Memory snapshot Yes Yes Yes No
Zone wide primary storage No Yes Yes Yes
Resize disk Offline Online Grow Online No
High availability CloudStack Native CloudStack No
© Citrix 2013. More information at xenserver.org and follow me on twitter @XenServerArmy
XenServer 6.2
Feature
Source code model Open Source (GPLv2)
Maximum VM Density 650
CloudStack VM Density 150
CloudStack integration Direct XAPI calls
Maximum native cluster Size 16
Maximum pRAM 1 TB
Largest VM 16vCPU/128GB
Windows Operating System All Windows supported by Microsoft
Linux Operating Systems RHEL, CentOS, Debian, Ubuntu, SLES, OEL
Advanced features supported ovs, Storage XenMotion, DMC
© Citrix 2013. More information at xenserver.org and follow me on twitter @XenServerArmy
vSphere 5.1 (vSphere 5.5 not supported)
Feature
Source code model Proprietary
Maximum VM Density 512
CloudStack VM Density 128
CloudStack integration vCenter
Maximum native cluster Size 32
Maximum pRAM 2 TB
Largest VM 64 vCPU/1TB
Windows Operating Systems DOS, All Windows Server/Client
Linux Operating Systems Most
Advanced features supported HA, DRS, DVS, Storage vMotion
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KVM (RHEL/CentOS 6.3 and Ubuntu 12.04)
Feature
Source code model Open Source (GPLv2)
Maximum VM Density 10 times the number of pCores
CloudStack VM Density 50
CloudStack integration CloudStack Agent (libvirt)
Maximum native cluster size No native cluster support
Maximum pRAM 2 TB
Largest VM
Windows Operating Systems
Linux Operating Systems
Advanced features supported None
© Citrix 2013. More information at xenserver.org and follow me on twitter @XenServerArmy
Linux Containers
Feature
Source code model Open Source (GPLv2)
Maximum container Density 6000 (theoretical)
CloudStack container Density 50
CloudStack integration CloudStack Agent (libvirt), requires KVM for SVMs
Maximum native cluster size N/A
Maximum pRAM 2 TB
Largest container 2TB
Windows Operating Systems N/A
Linux Operating Systems Kernel compatible distros
Picking the “best one” When to use which hypervisor…
© Citrix 2013. More information at xenserver.org and follow me on twitter @XenServerArmy
KVM
• Primary value proposition: ᵒ Low cost with available vendor support
ᵒ Familiar administration model
ᵒ Broad CloudStack feature set with active development
• Cloud use cases: ᵒ Linux centric workloads
ᵒ Dev/test clouds
ᵒ Web hosting
ᵒ Tenant density which dictates SDN options
• Weaknesses: ᵒ Requires use of an installed CloudStack libvirt agent
ᵒ Limited native storage options
ᵒ No use of advanced native features
© Citrix 2013. More information at xenserver.org and follow me on twitter @XenServerArmy
Linux Containers
• Primary value proposition: ᵒ Low cost with available vendor support
ᵒ Familiar administration model
• Cloud use cases: ᵒ Dev/test clouds
ᵒ Web hosting
• Weaknesses: ᵒ Requires use of an installed CloudStack libvirt agent
ᵒ Requires KVM for system VMs
ᵒ No use of advanced native features
© Citrix 2013. More information at xenserver.org and follow me on twitter @XenServerArmy
vSphere
• Primary value proposition: ᵒ Broad application and operating system support
ᵒ Readily available pool of vSphere administration talent
ᵒ Large eco-system of vendor partners
ᵒ Many CloudStack features are native implementations
ᵒ Direct feature integration via vCenter
• Cloud use cases: ᵒ Private enterprise clouds
ᵒ Dev/test clouds
• Weaknesses: ᵒ vSphere up-front license and ongoing support costs
ᵒ vCenter integration requires redundant designs
ᵒ Single data center per zone model
© Citrix 2013. More information at xenserver.org and follow me on twitter @XenServerArmy
XenServer
• Primary value proposition: ᵒ Low cost with available vendor support
ᵒ Broad CloudStack feature set with active development
ᵒ Large CloudStack install base
ᵒ Direct integration via XAPI toolstack
• Cloud use cases: ᵒ Linux centric workloads
ᵒ Dev/test clouds
ᵒ Web hosting
ᵒ Desktop as a Service clouds
ᵒ Large VM and tenant
• Weaknesses: ᵒ Minimal use of advanced native features
© Citrix 2013. More information at xenserver.org and follow me on twitter @XenServerArmy
What About Multiple Hypervisor Support?
• vSphere Datacenter must be contained within a single zone
• Force system VMs to a specific hypervisor type
• HA won’t migrate between hypervisors
• Zone wide primary storage doesn’t support multiple hypervisors
• Capacity planning at the cluster/pod level more difficult
Work better. Live better.