Distributed Systems. 31. The Cloud: Infrastructure as a Service Paul Krzyzanowski. Rutgers University. Fall 2013

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1 Distributed Systems 31. The Cloud: Infrastructure as a Service Paul Krzyzanowski Rutgers University Fall 2013 December 12, Paul Krzyzanowski 1

2 Motivation for the Cloud Self-service configuration Provision the servers, storage, and network connectivity they need Hosting Don t worry about hosting and maintenance Elastic growth & metered service Users can add more to their environment as needed Pay for what you use CAPEX OPEX No capital purchases, depreciation December 12, Paul Krzyzanowski 2

XaaS Software as a Service (SaaS) Ability to use software in the cloud Users Web-based email, Google apps, Microsoft Office Online, Apple

network service; Google App Engine: Python, Java, PGP, Go Infrastructure as a Service (IaaS) Create a computing environment in the cloud

3 XaaS Software as a Service (SaaS) Ability to use software in the cloud Users Web-based , Google apps, Microsoft Office Online, Apple iwork for icloud Platform as a Service (PaaS) Ability to deploy apps in the cloud Programmers Java/Eclipse programming platform as a network service; Google App Engine: Python, Java, PGP, Go Infrastructure as a Service (IaaS) Create a computing environment in the cloud IT Create a web service with several load-balanced web servers, app servers, and a back-end database December 12, Paul Krzyzanowski 3

4 Public vs. Private Private cloud Dedicated to one organization; hosted on premises Public cloud Hosted Enterprise Cloud Set of infrastructure dedicated to one organization Hosted and operated by a third party (e.g., Rackspace) Multi-tenant Public Cloud Shared and dedicated resources Elastic scaling Services accessible by multiple customers over the Internet Hybrid Cloud Services provided with a combination of private and public cloud December 12, Paul Krzyzanowski 4

Vendors Many vendors: frameworks & providers Popular open efforts: CloudStack, Openstack, & Eucalyptus Share some of the same components Enable the use of a variety of VMs, network controllers,

5 Vendors Many vendors: frameworks & providers Popular open efforts: CloudStack, Openstack, & Eucalyptus Share some of the same components Enable the use of a variety of VMs, network controllers, and storage systems Also: Google Compute Engine (GCE) Amazon EC2 (Elastic Compute Cloud) + Amazon S3 (storage) + Amazon RDS (relational DB) + Microsoft Azure December 12, Paul Krzyzanowski 5

6 CloudStack [initially Citrix] Mostly written in Java >100 production clouds Up to 30K physical hosts Supports lots of hypervisors Multiple datacenters Amazon EC2 compatible OpenStack [initially Rackspace] Mostly written in Python Not widely used commercially Supports lots of hypervisors Network is a point of failure Partial support for Amazon EC2 Difficult to install Eucalyptus Mostly written in Java Focus on private cloud KVM & Xen hypervisor support Amazon EC2 and S3 compatible December 12, Paul Krzyzanowski 6

7 The following examples will focus on CloudStack December 12, Paul Krzyzanowski 7

8 Cloud infrastructure hierarchy Managed collection of hosts, networks, storage: may span data centers Server Farm Collection of hosts, networks, storage: one or more zones per data center Zone A rack Pod Secondary storage Rack Templates, snapshots, & ISO images Group of hosts & associated primary storage Cluster Hosts Primary storage VM storage VMs December 12, Paul Krzyzanowski 8

9 Core Components Dashboard Management Identity Compute Network Storage December 12, Paul Krzyzanowski 9

10 Compute December 12, Paul Krzyzanowski 10

11 Virtual Machines Each physical machines runs a hypervisor Allows running of multiple operating systems Provides virtual interfaces to hardware (storage, NIC, MMU, ) Management server interacts with hypervisor Setup: user actions Select OS Number of CPUs and RAM Disk size, number of volumes Network Provisioning Primary storage volume(s) allocated on a cluster VM configured from template & configuration data Instance of VM copied from secondary storage to primary storage December 12, Paul Krzyzanowski 11

12 Network December 12, Paul Krzyzanowski 12

13 The Network Administrator actions Define networks (local addresses) Attach VMs to networks Acquire public address(es) for NAT Configure firewall rules for access and load balancing December 12, Paul Krzyzanowski 13

14 The Network: keeping things separated Physical hosts share a physical network Virtual network (VLAN) Tag on ethernet frame identifies virtual network Traffic from multiple hosts multiplexed on the same physical network Management traffic is untagged Hypervisor involvement Traffic labels defined by management interface and configured on hypervisor Hypervisor provides virtual LAN interface Filters traffic to VM December 12, Paul Krzyzanowski 14

15 The Network: connecting networks Virtual router DHCP: assign internal addresses DNS: domain name lookup Load balancing: define a pool of internal servers VPN: secure channel between internal & remote networks/machines Virtual routers manage connectivity between Internal subnets Internal & external networks May deploy a combination of virtual and physical network hardware E.g., dedicated firewalls and load balancers, virtual router for DHCP & DNS December 12, Paul Krzyzanowski 15

16 Storage December 12, Paul Krzyzanowski 16

17 Storage Primary Storage The VM s disks Presented as a block device (looks like a raw disk) The VM writes a file system on it Accessible from on VM host or a cluster within a pod Uses local disk, iscsi, Fibre Channel, or NFS Secondary Storage Zone-level configuration Stores templates, snapshots, ISO images Uses NFS or OpenStack Swift object store Other (beyond IaaS) Access other storage servers Distributed file systems, Bigtable, Amazon S3, Databases December 12, Paul Krzyzanowski 17

Snapshots Backup images of a VM Allows restoring state of a machine to the latest snapshot Administrator configures frequency of snapshots Hypervisor writes them

18 Snapshots Backup images of a VM Allows restoring state of a machine to the latest snapshot Administrator configures frequency of snapshots Hypervisor writes them Initially written to primary storage (fast) Then moved to secondary storage Backup network traffic can be segregated to lower impact December 12, Paul Krzyzanowski 18

19 High Availability December 12, Paul Krzyzanowski 19

20 High Availability Poll VMs for liveness (heartbeats) Fencing Disallow dead/unknown VM from accessing storage Restart VM Use snapshots for restoring VM state Other mechanisms for HA (beyond IaaS) Active/active, active/passive redundancy Application-level heartbeats Paxos/Virtual synchrony December 12, Paul Krzyzanowski 20

21 The End December 12, Paul Krzyzanowski 21

Xen and CloudStack. Ewan Mellor. Director, Engineering, Open-source Cloud Platforms Citrix Systems

Xen and CloudStack. Ewan Mellor. Director, Engineering, Open-source Cloud Platforms Citrix Systems Xen and CloudStack Ewan Mellor Director, Engineering, Open-source Cloud Platforms Citrix Systems Agenda What is CloudStack? Move to the Apache Foundation CloudStack architecture on Xen The future for CloudStack