Virtual Networks: Host Perspective IETF-77 Anaheim, CA Virtual Network Research Group March 23rd, 2010 Sunay Tripathi Sunay.Tripathi@Oracle.Com 1
Evolving Virtualization Landscape Physical OS Hypervisor Server Server Server Virtual Virtual Virtual Server Server Server NIC NIC NIC VNIC VNIC VNIC Physical Virtual Switch Switch Evolving Domain Physical Router Switch Network Router Network ● New Challenges – Defining the Virtual Network and its scope – Identifying the Virtual Machines on the network and policy enforcement – Added complexity with new layers 2
Components of a Virtual Network • Assigning MAC address to virtual NICs (VNIC) and VSwitches > A randomly created MAC address is preferred to aid virtual machine migration > L2 networks are becoming bigger in data centers (1000s of hosts) and the hosts and becoming more powerful capable of hosting 100s of VM so MAC addresses can collide fairly often > For a Vswitch to be managed and be a identifyiable entity, it needs to have a MAC address too • Identifying Virtual Machine on the network > Need mechanisms to find current physical location • Policies associated with VNICs and VM migration > MAC address, B/W limits, ACLs, host resources (CPUs, MIBs, stats, etc) need to be transferred to destination hypervisor during Virtual Machine migration > A centralized Port Profile Manager is not preferable since it creates another point of failure 3
Scope of a Virtual Network • Naming and Identifying a Virtual Network • Do they span just a layer 2 network or they span multiple IP networks that can be geographically separated > Perhaps we can classify them into two three types including a simple network that just spans a L2 • Migrating, snapshotting a Virtual Network 4
Security in a Virtualized Network • L2 network open to new attacks > With SR-IOV virtualized NICs, a VM has ability to send bridge PDU, OSPF packets, etc and attack the L2 networks in new ways > Some OSes along with NICs can protect themselves but others can't > Some switch can deal with per VM security while others can't > Who does the protection can be a business decision so both modes need to be supported • Performance and Security > Doing security checks twice doesn't improve performance > Clear protocols needed to negotiate who is doing the enforcement so we don't end up doing it twice (EVB group has some drafts) > At the same time, need to guarantee that it has been done atleast once • Challenges > The environment gets very dynamic in terms of Number of Virtual Machines and migration > The policy enforcement, negotiation needs to scale in this environment 5
Isolation and B/W sharing • For some people, Virtual Network means VLANs > VLANs do provide functional separation of the broadcast domains but have no resources attached to them > The hypervisors have QoS mechanisms that can be set on per VNIC basis > Some switches can do QoS per VM basis • Challenges > Too many VMs and VNICs make up a Virtual Network > Configuring them individually is too challenging and error prone > Need a way to tie a group of VMs to a VLAN or extended VLAN and a mechanism for hypervisor and switch to negotiate B/W sharing mode 6
Diagnostics and Observability • Statistics in a Virtualized Network > Need per VNIC statistics – some OSes (like OpenSolaris) do it while others don't > Need per Virtual Network aggregated statistics 7
OpenSolaris Network Virtualization • Implemented via project Crossbow > Supports VNICs and Vswitches with NIC H/W assist > Per VNIC MIBs > Supports configurable link speeds (QoS) between VMs > Works with link aggregation and IPMP > VNICs can have VLAN tags assigned to them > VNICs have dedicated NIC, CPU, kernel threads and queues and are fully isolated from each other within the system 8
Crossbow: Virtual Network in a Box Physical Wire w/Physical Machines Router Host 1 Host 2 Client Port 6 Port 9 Port 3 Port 1 Port 2 20.0.03 20.0.01 10.0.03 10.0.01 10.0.02 1 Gbps 1 Gbps 1 Gbps 100 Mbps 1 Gbps Switch 3 Switch 1 Virtual Wire w/Virtual Machines Router Host 1 Host 2 (Virtual Client Router) VNIC6 VNIC9 VNIC3 VNIC1 VNIC2 20.0.03 20.0.01 10.0.03 10.0.01 10.0.02 1 Gbps 1 Gbps 1 Gbps 100 Mbps 1 Gbps Vswitch 3 Vswitch 1 9
More details • Related Links > CrossBow: http://opensolaris.org/os/project/crossbow > VNM: http://opensolaris.org/os/project/vnm > Networking: http://opensolaris.org/os/community/networking • Research Papers > Sigcomm VISA 2009 - “Crossbow: From H/W Virtualized NICs to Virtualized Networks” > Sigcomm WREN 2009 - “Crossbow: A vertically integrated QoS stack” > Usenix LISA 2009 - “Crossbow Virtual Wire: Network in a Box” • All the papers can be accessed via http://blogs.sun.com/sunay 10
BACKUP 11
Crossbow ' Hardware Lanes ' Ground Up Design for multi-core and multi-10GigE > Linear Scalability by using ' Hardware Lanes ' with dedicated resources > Network Virtualization and QoS designed in the stack > More Efficiency due to ' Dynamic Polling and Packet Chaining ' Physical Machine Physical NIC Hardware Kernel Threads Virtual C Virtual and Queues NIC Rings/DMA Machine/Zone L A Hardware Lane Hardware Kernel Threads Virtual Virtual S Rings/DMA and Queues NIC Machine/Zone S Switch I VLAN F Separated I E Hardware Kernel Threads R Squeue Application Rings/DMA and Queues 12
Virtual Network Containers Virtualization Solaris Zone Zone xb1-z1 xb1-z2 Global Flows • Zone Virtual NICs & Virtual Switches • Virtual Virtual Virtual Wire • SQUEUE SQUEUE Resource Control Exclusive IP Exclusive IP Instance Instance Bandwidth Partitioning • NIC H/W Partitioning • VNIC1 VNIC2 bge0 (100Mbps) (200Mbps) CPUs/pri assignment • Observability Real time usage for each Link/flow • Rx/Tx Rx/Tx Rx/Tx DMA DMA DMA Finer grained stats per Link/flow • History at no cost • Flow Classifier NIC Client Client xb2 xb3 13
Virtual NIC (VNIC) & Virtual Switches Virtual NICs > Functionally physical NICs: > IP address assigned statically or via DHCP and snooped individually > Appear in MIB as separate ' if ' with configured link speed shown as ' ifspeed ' > VNICs can be created over Link Aggregation on can be assigned to IPMP groups for load balancing and failover support > VNICs Can have multiple hardware lanes assigned to them > Can be created over physical NIC (without needing a Vswitch) to provide external connectivity with switching done in NIC H/W > VNICs have configurable link speed, CPU and priority assignment > Standards based End to End Network Virtualization > VLAN tags and Priority Flow Control (PFC) assigned to VNIC extend Hardware Lanes to Switch > No configuration changes needed on switch to support virtualization Virtual Switches > Can be created to provide private connectivity between Virtual Machines 14
Virtual Machines Solaris Guest OS 2 Solaris Guest OS 1 Solaris Host OS NIC Virtualization Engine NIC Virtualization Engine NIC Virtualization Engine Guest OS 2 Guest OS 1 Host OS VIRTUAL SQUEUE VIRTUAL SQUEUE All Traffic VIRTUAL SQUEUE All Traffic HTTP HTTPS DEFAULT SQUEUE SQUEUE SQUEUE Guest OS 2 VNIC Virtual Virtual Virtual Host OS VNIC NIC NIC NIC Guest Guest Guest Guest Host OS OS 1 OS 1 OS 1 OS 2 All traffic HTTP HTTPS DEFAULT All Traffic H/W Flow Classifier NIC 15
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