CloudStack Silicon Valley Meetup September 2015

XenServer Virtualization in Cloud Environments

#whoami

Name: Tim Mackey

Current roles: XenServer Community Manager and Evangelist; occasional coder

Cool things I’ve done• Designed laser communication systems• Early designer of retail self-checkout machines• Embedded special relativity algorithms into industrial control system

Find me• Twitter: @XenServerArmy• SlideShare: slideshare.net/TimMackey• LinkedIn: www.linkedin.com/in/mackeytim• Github: github.com/xenserverarmy

What is XenServer?

What is a “XenServer”?

Packaged Linux distribution for virtualization• All software required in a single ISO

Designed to behave as an appliance• Managed via SDK, CLI, UI

Not intended to be a toolkit• Customization requires special attention

Open Source• Open source roots• Acquired by Citrix in 2007• Made open source in 2013 (xenserver.org)

XenServer market dynamic

Millions of Downloads

Over 1 million servers deployed

Optimized for XenDesktop

Powering NetScaler SDX

Supporting Hyper-Dense Clouds

Why XenServer?

Broad provisioning support• Apache CloudStack• Citrix CloudPlatform and XenDesktop• OpenStack• Microsoft System Center• VMware vCloud

Full type-1 hypervisor• Strong VM isolation• Supporting Intel TXT for secure boot

Designed for scale• 1000 VMs per host• Over 120 Gbps throughput in NetScaler SDX• Up to 96 shared hardware GPU instances per host

Understanding the architecture

Strong technical foundation with Xen Project

Core components

Xen Project hypervisor• XenServer 6.5: version 4.4

Customized and optimized CentOS control domain (dom0)• XenServer 6.5: 64 bit CentOS 5.10, 3.10+ kernel.org kernel, ovs 2.1.2

Xen Project XAPI toolstack

XenCenter UI

Networking StorageCompute

Simplified XenServer architecture diagram

Xen Project Hypervisor

Standard Linux Distribution (dom0)

qemu

drivers

xapi

Guest

Driver front

Driver back

Guest

Driver front

What is dom0?

Domain 0 is a compact specialized Linux VM that manages the network and storage I/O of all guest VMs (domU) … and isn’t the XenServer hypervisor

Deploying a Linux VM

Linux VMs include paravirtualized kernels and drivers, and Xen Project Hypervisor is part of Mainline Linux 3.0

Deploying a Windows VM

Windows VMs use paravirtualized drivers to access storage and network resources through dom0

Core capabilities

Management paradigm

“Single host mentality”

Traditional ManagementArchitecture

Single backend management server

XenServer

DistributedManagement Architecture

Clustered management layer

Role-based administration

Provide user roles with varying permissions• Pool Admin• Pool Operator• VM Power Admin• VM Admin• VM Operator• Read-only

Roles are defined within a Resource Pool

Assigned to Active Directory users, groups

XenMotion Live VM Migration

XenServerXenServerXenServer

Shared Storage

XenServer Pool

Migrates VM disks from any storage type to any other storage type• Local, DAS, iSCSI, FC

Supports cross pool migration• Requires compatible CPUs

Encrypted Migration model

Specify management interface for optimal performance

Live storage migration

XenServer Host

VDI(s)

Live Virtual

Machine

Heterogeneous resource pools

Safe Live Migrations

Feature 5

Virtual Machine

Older CPU

Feature 1

Feature 2

Feature 3

Feature 4

XenServer 1

Newer CPU

Feature 1

Feature 2

Feature 3

Feature 4

XenServer 2

Mixed Processor Pools

Memory over-commit

Feature: Dynamic Memory Control

Ability to over-commit RAM resources

VMs operate in a compressed or balanced mode within set range

Allow memory settings to be adjusted while VM is running

Can increase number of VMs per host

Live memory snapshot and rollback

Live VM snapshot and revert• Both memory and disk state are captured• Optional quiesce option via VSS provider

(Windows guests)• One-click revert

Snapshot branches• Support for parallel subsequent checkpoints

based on a previous common snapshot

GPU virtualization

Without GPU virtualization, each user requires their own Blade PC

With GPU virtualization, users share expensive GPU resources

GPU cards

XenServer Host

Taking advantage of GPUs

NVIDIA• vGPU with NVIDIA GRID providing 96 GPU instances• GPU pass-through• CUDA support on Linux• Uses NVIDIA drivers for capability

Intel• GVT-d support with Haswell and newer

• No extra hardware!!• Uses standard Intel drivers

AMD• GPU pass-through

Visibility into Docker containers

Containers• Great for application packaging• Extensive tools for deployment

Virtualization• Total process isolation• Complete control

Docker and XenServer• View container details• Manage container life span• Integrated in XenCenter

Distributed virtual networks for cloud

Virtual Switch• Open source: www.openvswitch.org• Provides a rich layer 2 feature set• Cross host private networks• Rich traffic monitoring options• ovs 2.1.2

OVS Controller• Basic controller from Citrix – DVSC• CloudStack GRE tunnel support• Production controllers from VMware (NSX),

Juniper and Nuage VSP

VM

VM

VM

VM

VM

Deployment Design

Typical deployment scenario

To pool or not to pool?• Shared storage• Network redundancy• Provisioning management

Hardware selection• Understanding the HCL

Support requirements• Commercial support limitations

Host requirements

VT-Enabled x86 processor• BIOS features enabled

Legacy BIOS support• EFI profiles won’t boot (in preview today)

Limits• Up to 1TB RAM• Up to 160 pCPUs• Up to 16 physical NICs• Up to 16 hosts per cluster

Network topologies

Management networks• Handle pool configuration and storage traffic• Require default VLAN configuration• IPv4 only

VM networks• Handle guest traffic• IPv4 and IPv6• Can assign VLAN and QoS• Can define ACL and mirroring policy• Should be separated from mgmt networks

All networks in pool must match

Storage topologies

Local storage• Yes: SAS, SATA, HW RAID, DAS• No: USB, Flash cards, SW RAID

Shared Storage• iSCSI, NFSv3 – CloudStack can auto-define single path• HBA – Check HCL• CloudStack HBA/Multipath requires “PreSetup”• CloudStack bonded NFS requires “PreSetup”

ISO storage – not used in CloudStack• CIFS/NFSv3

CloudStack view of templates

Template management

My first template• Existing VM or appliance in VHD format – compression optional• Need to have HTTP server

• Set secstorage.allowed.internal.sites if private cloud

Creation options• Register template in UI

• Templates Register Template• Upload using registerTemplate API

• http://cloudstack.apache.org/docs/api/apidocs-4.5/user/registerTemplate.html• Clone from CloudStack instance

• Stop instance View Volumes Create Template

Key template attributes

Obvious• Hypervisor• Operating system type• Zone

Not so obvious• IsDynamicallyScalable Hypervisor tools• PasswordEnabled CloudStack sets root pwd• SSHKeyEnabled Can post configure• RequiresHVM Defines virtualization mode

XenServer 6.5 in CloudStack

FeatureSource code model Open Source (GPLv2)Maximum VM Density 1000 CloudStack VM Density 500CloudStack integration Direct XAPI callsMaximum native cluster size 16Maximum pRAM 1 TBLargest supported VM 32 vCPU/256GBWindows Operating System All Windows supported by MicrosoftLinux Operating Systems RHEL, CentOS, Debian, Ubuntu, SLES, OELAdvanced features supported ovs, Storage XenMotion, DMC, Pool HA, GPU