Supercharged PlanetLab Platform, Control Overview

1
Supercharged PlanetLab Platform, Control Overview

• Fred Kuhns
• fredk_at_arl.wustl.edu
• Applied Research Laboratory
• Washington University in St. Louis

2
Prototype Organization

• One NP blade (with RTM) implements Line Card
• separate ingress/egress pipelines
• Second NP hosts multiple slice fast-paths
• multiple static code options for diverse slices
• configurable filters and queues
• GPEs run standard Planetlab OS with vServers

3
Connecting an SPP
East Coast
Local/Regional
West Coast
Host
plab/SPP
ARP endstations and intermediate routers
plab/SPP
plab/SPP
Ethernet SW
point-to-point
point-to-point
SPP
sw
Host
4
System Block Diagram
Substrate Control Daemon (SCD) Boot and
Configuration Manager (BCM)
External Interfaces
RTM
RTM
SPP Node
10 x 1GbE
NPE
NPE
NPE
GPE
LC
GPE
ARP Table FIB
NAT Tunnel filters (in/out)
PCI
PCI
pl_netflow
user slivers
flow stats (netflow)
xscale
xscale
xscale
xscale




NPU-A
NPU-B
NPU-A
NPU-B
TCAM
TCAM
GE
GE
vnet
SPI
SPI
interfaces
Hub
Fabric Ethernet Switch (10Gbps, data path)
Base Ethernet Switch (1Gbps, control)
I2C (IPMI)
Control Processor (CP)
Standalone GPEs
tftp, dhcpd
sshd
httpd
routed
Resource DB
nodeconf.xml
Shelf manager
route DB
boot files
Slivers DB
user info
flow stats
5
Software Components

• Utilities parts of BCM to generate config and
  distribution files
• Node configuration and management generate
  config files, dhcp, tftp, ramdisk
• Boot CD and distribution file management (images,
  RPM and tar files) for GPEs and CP.
• Control processor
• Boot and Configuration Manager (BCM)
• System Resource Manager (SRM)
• System Node Manager (SNM)
• user authentication and ssh forwarding daemon
• http daemon providing a node specific interface
  to netflow data (planetflow)
• Routing protocol daemon (BGP/OSPF/RIP) for
  maintaining FIB in Line Card
• General Purpose Element (GPE)
• Local Boot Manager (LBM) Modified BootManager
  running on the GPEs
• Local Resource Manager (LRM)
• Local Node Manager (LNM), that is the required
  changes to existing Node Manager software.
• Network Processor Element (NPE)
• Substrate Control Daemon (SCD, formally known as
  wuserv)
• kernel module to read/write memory locations
  (wumod)
• Command interpreter for configuring NPU memory
  (wucmd)
• Modified Radisys and Intel source ramdisk Linux
  kernel

6
Boot and Configuration management

• Read config file and allocate IP subnets and
  addresses for substrate
• Initialize Hub (delegate to SRM)
• base and fabric switches
• Initialize any switches not within the chassis
• Create dhcp configuration file and start daemon
• assigns control IP subnets and addresses
• assigns internal substrate IP subnet on fabric
  Ethernet
• Initialize Line Card to forward all traffic to CP
• Use the control interface, base or front panel
  (Base only connected to NPUA).
• All ingress traffic sent to CP
• What about Egress traffic when we are
  multi-homed, either through different physical
  ports or one port with more than one next hop?
• We could assume only one physical port and one
  next hop.
• This is a general issue, the general solution is
  to run routing protocols on the CP and keep the
  line cards TCAM up to date.
• Start remaining system level services (i.e.
  daemons)
• wuarl daemons
• system daemons sshd, httpd, routed
• System Node Manager maintains user login
  information for ssh forwarding

7
Boot and Configuration management

• Assist GPE in booting
• Download from PLC SPP specific version of the
  BootManager and NodeManager tar/rpm
  distributions.
• Downloads/maintains Planetlab bootstrap
  distribution
• Updated BootCD
• The boot CD contains SPP config file with CP
  address, spp_config.
• No modifications to initial boot scripts, they
  contact the BCM over the fabric interface (using
  the substrate IP subnet) and download the next
  stage.
• GPEs obtain distribution files from the BCM on
  the CP
• SPP changes are confined to the BootManager and
  NodeManage sources (that is the plan)
• PLC Database updated to place all SPP nodes in
  the SPP Node Group, we use this to trigger
  additional special processing.
• Modified BootManager scripts configure control
  interfaces (Base) and 2 Fabric interfaces (2 per
  Hub).
• Creates/Updates spp_config file on GPE node
• Installs BootStrap source then overwrites the
  NodeManager with our modified version.

8
Default Traffic Configurations
Control messages sent over an isolated base
Ethernet switch. For isolation and security
PE
NPE
GPE
LNM

Line card performs NAT like function for traffic
from vservers.
LRM
MP
root context
planetlab OS
4
3
2
1
x
x
x
x
10GbE (fabric, data)
5
6
1GbE (base, control)
x
x
Substrate
CP
LC
user login info
Resource DB
Default traffic forwarded to CP over 10Gbps
Ethernet switch (aka fabric)
PLC
sliver tbl
9
Logging Into a Slice
PE
NPE
GPE
LNM
Host (located within node)

LRM
MP
root context
planetlab OS
Once authenticated, session forwarded to
appropriate GPE and vserver.
4
3
2
1
x
x
x
x
10GbE (fabric, data)
5
6
1GbE (base, control)
x
x
Substrate
CP
LC
ssh fwder
user login info
Resource DB
ssh connection directed to CP for user
authentication
PLC
sliver tbl
10
System Node Manager

• Logically the top-half of the PlanetLab Node
  Manager
• PLC API method GetSlivers()
• periodically call PLC for current list of slices
  assigned to this node
• assign system slivers to each GPE, then split
  application slivers across available GPEs
• keep persistent tables to handle daemon crashes
  or local device reboots
• Local GetSlivers() (xmlrpc interface) to GPEs
• Local node managers (per GPE) list of allocated
  slivers along with other node specific
  datatimestamp, list of configuration files,
  node id, node groups, network addresses, assigned
  slivers
• Resource management across GPEs
• Manage Pool and VM RSpec assiSNMent for each GPE
• opportunity to extend RSpecs to account for
  distributed resources.
• Perform top-half processing of the per GPE LNM
  api (exported to sliver on this only). Calls on
  one GPE may impact resource assiSNMents or sliver
  status on a different GPE
• Ticket(), GetXIDs(), GetSSHKeys(), Create(),
  Destroy(), Start(), Stop(), GetEffectiveRSpec(),
  GetRSpec(), GetLoans(), validate_loans(),
  SetLoans()
• Currently the node manager uses CA Certs and SSH
  keys when communicating with PLC, we will need to
  do the same. But we can relax security between
  SNM and the LNMs.
• Tightly coupled with the System Resource Manager
• Maintain a globally unique (to the node) Sliver
  ID which corresponds to what we call the
  meta-router ID and make available to SRM when
  enabling fast path processing (VLANs, UDP Port
  numbers etc).
• must request/maintain list of available GPEs and
  resource availability on each. Used for
  allocating slivers to GPEs and handling RSpecs.
• SRM may delegate GPE management to SNM.

11
SNM Questions

• Robustness -- not contemplating for this version
• If a GPE goes down do we migrate slivers to
  remaining GPEs?
• If a GPE is added do we migrate some slivers to
  new GPE to load balance?
• Do we need to intercept any of the API calls made
  against the PLC?
• What about the boot manager api calls and the
  uploading of boot log files (alpina boot logs)?
• implementation of the remote reboot command and
  console logging.

12
Local Node Manager

• Bottom-Half of existing Node Manager
• modify GetSliver() to call the System Node
  Manager.
• use base interface and different security
  (currently they wrap xmlrpc calls with a curl
  command which includethe PLCs certified public
  key).
• Forward GPE oriented sliver resource operations
  to SNM see API list in SNM description

13
Update Local Slice Definitions
PE
NPE
GPE
LNM
Host (located within node)

LRM
MP
root context
planetlab OS
4
3
2
1
x
x
x
x
10GbE (fabric, data)
5
6
1GbE (base, control)
x
x
Substrate
update local database, allocate slice instances
(slivers) to GPE nodes
CP
LC
user login info
Resource DB
retrieve/update slice descriptions
PLC
sliver tbl
14
Creating Local Slice Instance
create new slice
retrieve/update slice descriptions
PE
NPE
GPE
LNM
Host (located within node)

LRM
MP
root context
planetlab OS
4
3
2
1
x
x
x
x
10GbE (fabric, data)
5
6
1GbE (base, control)
x
x
Substrate
CP
LC
user login info
Resource DB
PLC
sliver tbl
15
System Resource Manager
LC
GPE
LNM
LRM
root context
Resource DB
planetlab OS
NPE
SCD
FPk
FPk
FPk
16
System Resource Manager

• Maintains table describing system hardware
  components and their attributes
• NPEs and code-option
• GPEs and HW attributes
• Sliver attributes corresponding to internal
  representations and control mechanisms
• unique Sliver ID (aka meta-router ID)
• global port space across assigned IP addresses
• fast path VLAN assignment and corresponding IP
  Subnets
• Manage fabric Ethernet switches (including any
  used external to the Chassis or in a
  multi-chassis scenario)
• Manage line card table entries

17
System Resource management

• Allocate Global port space
• input Slice ID, Global IP address0, protoUDP,
  Port0
• actions allocate port
• output IP Address, Port, Proto or 0 cant
  allocate
• Allocate Sliver ID
• input Slice name
• actions
• Allocate unique Sliver ID and assign to slice
• allocate VLAN ID (1-to-1 map of sliver ID to
  VLAN)
• output Sliver ID, VLAN ID
• Allocate NPE code option (internal)
• input Sliver ID, code option id
• action Assign NPE slot to slice
• Allocate code option instance from an eligible
  NPE NPE, instance ID
• Allocate memory block for instance (the instance
  ID is just an index into an array of preallocated
  memory blocks).
• output NPE Instance NPE ID, Slot Number
• Allocate Stats Index

18
System Resource manager

• Add Tunnel (aka Meta-Interface) to NPE Instance
• input Sliver ID, NPE Instance, IP Address, UDP
  Port
• actions
• Add mapping to NPE demux table VLANIP AddrUDP
  Port lt-gt Instance ID
• Update instances attribute blocktunnel fields,
  exception/local delivery, QID, physical port,
  Ethernet addr for NPE/LC
• Update next hop table (result index map to next
  hop tunnel)
• Set default QM weights, number of queues,
  thresholds.
• Update Line Card Ingress and Egress lookup
  tables tunnel, NPE Ethernet address, physical
  port, QIDs etc.??
• Update LC ingress and egress queue attributes for
  tunnel??
• Create NPE Sliver instance
• Input Slice ID IP address, UDP Port
  Interface ID, Physical Port SRAM block
  filter table entries of queues queues of
  packet buffers code option amount of SRAM
  required total reserved bandwidth
• Actions
• Allocate NPE code option
• Add tunnel to NPE Instance
• enable Sliver VLAN on associated fabric interface
  ports
• delegate to LRM configure GPE vnet module (via
  LRM) to accept Slivers VLAN traffic. Open UDP
  Port for data and control in root context and
  pass back to client.
• output (NPE code option) Instance number

19
Local Resource manager

• Act as intermediary between client virtual
  machines and the node control infrastructure.
• all exported interfaces are implemented by the
  LRM
• managing the life cycle of an NPE code instance
• accessing instance data and memory locations
• read/write to code option instances memory block
• get/set queue attributes threshold, weight
• get/add/remove/update lookup table entries (i.e.
  TCAM filters)
• get/clear pre/post queue counters, for a given
  stats index
• one-time or periodic get
• get packet/byte counter for tunnel at Line card
• allocate/release local Port

20
Allocating NPE (Creating Meta-Router)
Open local socket for exception and local
delivery traffic return to client vserver
Allocate NPE sliver code option, SRAM,
Interfaces/Ports, etc
NPE
FP - fast path
PE
GPE
LNM
Host (located within node)
FPk

LRM
MP
root context
planetlab OS
Forward request to System resource manager
Returns status and assigned global Port number
4
3
2
1
VLANk
x
x
x
x
10GbE (fabric, data)
5
6
1GbE (base, control)
x
x
Substrate
CP
LC
MI1
user login info
Resource DB
Allocate shared NPE resources, associate with new
slice fast path SRAM block filter table
entries of queues queues of packet buffers
code option amount of SRAM required total
reserved bandwidth
Allocate global UDP port for requested
interface(s) configure Line card.
PLC
sliver tbl
Allocate and Enable VLAN to isolate internal
slice traffic, VLANk
21
Managing the Data Path

• Allocate or Delete NPE Slice instance
• Add, remove or alter filters
• each slice is allocated a portion of the NPEs
  TCAM
• Read or write to per slice memory blocks in SRAM
• each slice is allocated a block of SRAM
• Read counters
• one time or periodic
• Set Queue rate or threshold.
• Get queue lengths

NPE
GPE
LNM
DPl
DPl
FPk
LRM
SCD
root context
planetlab OS
2
1
x
x
10GbE (fabric, data)
6
1GbE (base, control)
x
CP
user login info
Resource DB
sliver tbl
FP - fast path
22
Other LC Functions

• Line Card Table maintenance
• multi-homed SPP node must be able to send packets
  to the correct next hop router/endsystem
• random traffic from/to the GPE must be handled
  correctly
• tunnels represent point-to-point connections so
  it may be alright to explicitly indicate which of
  possibly several interfaces and next (Ethernet)
  hop devices the tunnel should be bound
• alternatively if were are running the routing
  protocols we could provide the user with the
  output port as a utility program.
• But there are problems with running routing
  protocols we could forward all route updates to
  the CP. But standard implementations assume the
  interfaces are physically connected to the
  endsystem.
• We could play tricks as vini does.
• or we assume that there is only one interface
  connected to one Ethernet device.
• NAT Functions
• traffic originating from within SPP
• may also want to selective map global proto/port
  number to specific GPEs?
• ARP and FIB on Line card
• route daemon runs on CP and keeps FIB up to date
• ARP runs on xscale and maps FIB next hop entries
  to their corresponding Ethernet destination
  addresses.
• netflow
• flow-based statistics collection
• SRM collects periodically and posts via web

23
Other Functions

• vnet
• isolation based on VLAN IDs
• support port reservations
• ssh forwarding
• maintain user login information on CP
• modify ssh daemon (or have wrapper) to forward
  user logins to correct GPE
• rebooting Node (spp), even when line card fails??