Cloud Operating System Unit 12 Cloud System Management I M. C. Chiang Department of Computer Science and Engineering National Sun Yat-sen University Kaohsiung, Taiwan, ROC Cloud Operating System

Outline  Out of the Machine  IDC Management  Based on the Machine  Service Availability  Virtual Machine Management The Management Tool: libvirt Snapshot and Checkpoint Live Migration Virtual Machine Security Rootkit  Summary 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-2

Out of the Machine  Cloud is not only the Cloud on the network.  Plenty of elements support the Cloud.  Server  Power Supplies  Air Conditioner  Staff Members  etc.  Virtual is built on reality. 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-3

IDC Management  Comfortable environment for machines.  Temperature, humidity level.  Prevents from natural disasters.  Flood, earthquake.  Prevents from power failure.  UPS.  Prevents from microwaves.  Well-planned escape.  Guarded entrance.  Limited use of data storage media.  Circumstance in movie “Transformers”. 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-4

Based on the Machine  Eventually, what customers concern is the services provided.  Here are some important issues.  Customers think what Cloud should be.  Maintainers think what help Cloud to be. 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-5

Service Availability (1)  Very important for all services  Amazon EC2 guarantees at least 99.95% availability in agreement (about minutes down time at most in a year)  Google App Engine guarantees same service level agreement  Both provide refund if the requirements are not met 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-6

Service Availability (2)  Possibly methods of increasing availability  Providing virtual machine instance snapshots Can backup VM’s state  Providing virtual machine live migration Can move the virtual machine to another physical machine on the fly  Redundant storage data In different physical storages and different place. 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-7

Virtual Machine Management  Most IaaS solutions aren’t bound with hypervisors  Can use different hypervisors in clouds  Manage instances will be an issue  A cloud is composited with many hosts, increasing even more complexity  A common layer for managing all hypervisors with one controlling point  Reduce the complexity greatly 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-8

libvirt - Introductions (1)  Initial release: Dec 19, 2005  Most recent stable release: Feb 13, 2012  An open source API, daemon and management tools are included  Aiming for “being a building block for higher level management tools” 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-9

libvirt - Introductions (2)  Supported by Red Hat  Writing in C  Binding with C#, Python, Perl, OCaml, Ruby, Java, PHP  Support hypervisor:  KVM, Xen, VMWare, MS Hyper-V, etc. 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-10

libvirt - Introductions (3) 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-11

libvirt - Features (1)  VM Management  Including provision, create, modify, monitor, control, migrate, and stop instances  Instance resources management  Network interfaces and firewall setup  Storage management  Overall instances’ states monitoring  Local physical host resource consumption monitoring. 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-12

libvirt - Features (2)  Remote management  Using TLS encryption and x509 certificates  Authenticating with Kerberos and SASL  Provides secure remote control  Portable client API for multiple OSs  Including Linux, Solaris, and Windows 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-13

libvirt – Operation Modes  libvirt has two operation modes.  Local use libvirt API directly  Remote executes extra libvirtd allows user to access hypervisors on remote machine through authenticated connections 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-14

libvirt – Tools Based on It  virsh  An interactive CLI including in libvirt  Virtual Machine Manager  An GUI developed by Red Hat  oVirt  Web application for virtual machines management. Developed by Red Hat as well  And more than 20 projects base or use libvirt 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-15

libvirt – Supported by Xen (1) 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-16

libvirt – Supported by Xen (2)  Programs using libvirt execute in Dom0.  libvirt can be initialized in two ways, each has their methods to connect to the Xen infrastructure.  With root access, use virConnectOpen(). Connect to the Xen Daemon through an HTTP RPC layer. A read/write ocnnection to the XenStore. Use Xen Hypervisor calls.  Without root access, use virConnectOpenReadOnly(). Fork a libvirt_proxy program (running as root) to provide read_only access to the API. Be useful for reporting and monitoring. 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-17

Snapshot and Checkpoint (1)  Not only the disk image  File-based representation of the state, data and hardware configuration of whole VM  Can “freeze” the virtual machine in some particular states, then resume the execution  Useful for system forensics, or restore the whole system back after failed upgrade/patch 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-18

Snapshot and Checkpoint (2)  Difference between “snapshot” and “checkpoint”  Different definitions in different hypervisors Xen Only “checkpoint” Microsoft Hyper-V “snapshot” for long-term backup “checkpoint” for short term recovery VMWare Only “snapshot” 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-19

Snapshot - Creation  With the CLI command, making snapshots can be scheduled and executed automatically  Different command for different hypervisor of course Xen xl save [OPTIONS] VMWare Workstation vmrun snapshot [OPTIONS]  With help of libvirt: All can be done with “virsh snapshot-create [OPTIONS]” 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-20

Live Migration (1)  Snapshot can make backups for disaster recovery  If host needs maintenance, we have to move virtual machine from host to host on the fly for minimizing downtime  Live migration can be seamless from end-users  Two ways of migration  Pre-copy memory  Post-copy memory 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-21

Live Migration (2)  Pre-copy memory migration implementation  Warm-up Copy the current memory pages to destination If pages change, re-copy them until the rate is less than given rate  Stop-and-copy Stop the source VM and copy the remaining dirty pages to target VM. Downtime happens here. Could be milliseconds to seconds, depends on memory size. 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-22

Live Migration (3)  Post-copy memory migration implementation  Suspending the source VM first, then copy the minimal execution state of the VM to the destination Including CPU, registers, and non-pageable memory  After copying the state the VM at destination start running  What about the memory? Each time the page that haven’t transferred it generates page-faults. The page-faults will be handled by hypervisor, and copy from the source through network. 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-23

Live Migration (4)  Pre-Copy  Need warm-up stage for copying most pagetable  Longer downtime depends on the VM’s workload From 60ms to 210ms*  Post-Copy  Even less downtime than pre-copy  Performance impact after migration Demand-paging mechanism reduce the performance impact 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-24

VM Security  Virtual machine monitor security is recently the most important issue for Cloud Computing.  All virtual machines controlled by VMM.  VMM is the bridge between virtual machines and the hardware. Hard disk Memory CPU, etc.  Theoretically, a virtual machine is a completely isolated guest operating system installation. 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-25

VM Security – Virtual Machine Escape  What is virtual machine escape?  The process of breaking out of a virtual machine and interacting with the host OS.  The first discovery of virtual machine escape.  2008, within VMWare  By Core Security Technologies  CVE Allows guest OS users to read and write arbitrary files on the host OS. 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-26

VM Security – VMWare (1)  The number of security vulnerabilities in record  154 due to 2012/04/02  The oldest record  CVE Miss Buffer overflow in VMWare for Linux. Method Uses a long HOME environmental variable. 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-27

VM Security – VMWare (2)  The newest record  CVE Miss VMWare ESX/ESXi 3.5, 4.0 and 4.1 do not implement port- based I/O operations properly. Effect Allows guest OS users to gain guest OS privileges. Method Overwrites memory locations in a read-only memory block associated with the Virtual DOS Machine. 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-28

VM Security – Xen (1)  The number of security vulnerabilities in record  9 due to 2012/04/02  The newest record  CVE Miss tools/libxc/xc_dom_bzimageloader.c in Xen 3.2, 3.3, 4.0 and 4.1 Effect Allows local users to cause a DoS Method Unspecified vectors related to “Lack of error checking in the decompression loop” 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-29

VM Security – Xen (2)  The oldest record  CVE Miss xend in Xen does not properly limit the contents of the /local/domain/xenstore directory tree restrict a guest VM’s write access within the directory tree Effect Allows guest OS users to cause a DoS 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-30

VM Security – Hyper-V  The number of security vulnerabilities in record  3 due to 2012/04/02  All allow users to cause a DoS  CVE  Host OS hang  Via a crafted application that executes a malformed series of machine instructions.  CVE  host OS hang  By sending a crafted encapsulated packet over the VMBus.  CVE  host OS infinite loop  Via malformed machine instructions in a VMBus packet. 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-31

VM Security - OpenStack  The number of security vulnerabilities in record  2 due to 2012/04/02  CVE  When enabling EC2 API and the S3/RegisterImage image-registration method, allow remote authenticated users to overwrite arbitrary files.  CVE  When using OpenStack API, allow remote authenticated uses to bypass access restrictions for tenants of other users. 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-32

VM Security – About Vulnerability  Top 3 of vulnerability types  Execute Code  Denial of Service  SQL Injection  Information resource  supplies the records above   9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-33

VM Management – Rootkit  What is a rootkit?  A tool for getting root or cleaning the invade history.  A kind of malicious software.  In order to hide the existence of certain processes.  It is nice, before.  Sony BMG copy protection rootkit scandal.  Trojan can be seen as a rootkit. 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-34

Rootkit - Examples  We have already known that a rootkit is a software which intends to get the control of the computer  Here are two VMBRs (Virtual-Machine Based Rootkit).  SubVirt  Blue Pill 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-35

Rootkit– SubVirt (1)  Proposed by team of Microsoft Research and University of Michigan on  The procedure of infection.  We assume that SubVirt has the administrator authority.  After rebooting, SubVirt should be executed first.  SubVirt starts VMM and runs the original operating system as a virtual machine on VMM.  SubVirt can collects the wanted information. 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-36

Rootkit– SubVirt (2) 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-37

Rootkit– Blue Pill (1)  Designed by Joanna Rutkowska.  First demonstrated at the Black Hat Briefings on August 3,  Originally it required AMD-V support, but was ported to Intel VT-x as well.  It will start a thin hypervisor and virtualize the rest of the machine under it.  The machine doesn’t need to be restarted. 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-38

Rootkit– Blue Pill (2) 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-39

Summary  Cloud is not only what user see.  Snapshot and checkpoint can help to retain the service availability.  There are two ways for live migration:  Pre-copy memory  Post-copy memory  Services based on virtual machines, and virtual machines managed by hypervisors, so the security of hypervisors is important. 9/4/2015 Cloud Operating System - Unit 12: Cloud Management U12-40