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  • To create secure overlays where each overlay connects application and hub clusters together.
  • To allow application connectivity with external entities and entities of other clusters.

System Architecture

SDEWAN central controller The system includes the following components micro-services as showed in below diagram::

  • SDEWAN Central Controller:
    • API Router: provides REST API router for SDEWAN Central Controller
    • OverlayObjectManager: overlay registration, generate overlay root cert
    • HubObjectManager: hub registration and setup hub connection mesh
    • DeviceObjectManager: device/cluster registration and setup device connection mesh (if device has public IP)
    • HubDeviceObjectManager: setup connection between hub and device
    • IPRangeObjectManager: ip range registration and allocate/free overlay ip for device
    • ProposalObjectManager: proposal registration
    • DeviceConnManager: only support GET, query connection status of device
    • HubConnObjectManager: only support GET, query connection status of hub
    • Observability framework: system status monitoring, including connection status, CNF status etc.
  • Rsync
  • Web UI: a HTML5 based web UI to provide configuration of Application Cluster Registration, Hub Registration, Overlay, Application/Service Registration and Status tracking.
  • API Server: Exports Restful API for Application Cluster management, Hub management, Overlay management, Status monitoring management, logging.
  • Scheduler Manager: a daemon service which accepts request from API server from SDEWAN Central Controller (through RPC) then generates deploy relevant K8s CRs of SD-EWAN CNFs of various hubs and edges to establish the tunnels.
  • SDEWAN Management Mongo DB: a database to store information such as edge clusters, hubs, overlays, ip addresses, application/services etc.
  • Etcd: a metadata database to exchange configuration information between SDEWAN Central Controller and Rsync

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System Design

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Assumption

IP

  • Central Cloud has public IP as CIP
  • Traffic Hub has public IP as HIP1 HIP2, ...
  • Edge Location (Device) may have public IP in one edge node as EIP1, ... or don't have public IP (behind a gateway as EGIP1, ...)\

Connection for control plane (e.g. central cloud to k8s API server): 

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  • Edge to Edge: Host to host
  • Edge to Hub: Host (edge) to Site (Hub, using edge's subnet as rightsubnet)
  • Hub to Hub: Host to Host

Opens:

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Environment Setup (Pre-condition)

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  • K8s cluster is setup (by Kud)
  • Web UI (Optional), API Server, SDEWAN controllerRsync backend, DB service are deployed (manually or through EMCO)
  • Central SDEWAN Config Agent and CNF are deployed (through EMCO) with initial configuration (e.g. as Responder for Edge location without public IP, left: CIP, leftsubnet: from IP Address manager?, rightsourceip: from IP Address manager?)

Traffic Hub:

  • K8s cluster is setup (by Kud)
  • Hub SDEWAN Config Agent CRD Controller and CNF are deployed (through EMCO) with initial configuration (e.g. as Responder for Edge location without public IP, left: HIP, leftsubnet: from IP Address manager?, rightsourceip: from IP Address manager?NAT: enable DNAT for k8s API service and Istio Ingress service).

Edge Location (With Public IP):

  • K8s cluster is setup (by Kud)
  • Edge SDEWAN Config Agent SDEWAN CRD Controller and CNF are deployed (through EMCO) with initial configuration (e.g. NAT: enable DNAT for k8s API service and Istio Ingress service).

Edge Location (With Private IP):

  • K8s cluster is setup (by Kud)
  • Edge SDEWAN Config Agent SDEWAN CRD Controller and CNF are deployed (through EMCO) with initial configuration (e.g. As NAT: enable DNAT for k8s API service and Istio Ingress service; IPSec: as Initiator for Control plane - left: %any, leftsourceip:%config, right: CIPOwned Hub's HIP, rightsubnet:0.0.0.0/0). Note: at this stage, an OIP is assigned to the CNF and the Hub-Edge tunnel is set up (to be confirmed)

Opens:

  1. During current test, IPsec tunnel for Initiator to Responder requires Responder to be run before Initiatior, that means the SDEWAN CNF in Hub need to be run as Responder before a edge location (with private IP) setup, and the OIP Address range need to be configured first (read from IP address manager?) and can not be updated at run time, does this be expected behavior?
  2. Need to check how to get the assigned OIP after the tunnel between Hub and Edge Location (with private ip) setup (through strongswan command?), this is required for Ip address manager and cluster register process.
    1. Solution: Central Hub controller's IP address manager assign one OIP, then set Hub's responder's IPsec configuration with IP range to include only 1 IP (OIP) - Does this make sense?
  3. The registration of edge location information should be done by Admin manually or triggled automatically by EMCO's edge location registration process (assume similiar information shared)?
  4. Suppose edge location's OIP is assigned after setup and all following operation (e.g. overlay configuration) will reuse this OIP, right?  
    1. Suppose the answer is "No", and multiple OIP maybe assigned with edge location for different Hubs during overlay configuration, right?

Flow: Hub

Register Hub:

  • Trigger: Admin add/update hub information in Web UI or Remote Client Call with below informations:
    • Name, Description
    • Public IP address list
    • Managed IP ( ? )
    • Shared flag (whether the hub can be shared cross overlays)
    • Overlay name
    • CertificateId
    • Kubeconfig
  • Steps:
    • Save in DB
    • Setup control plane host-host tunnel with Central Cloud (e.g. Add a new IPSec policy in Central Cloud CNF with: left: CIP, right: HIP, CertificateId)

Opens:

  1. In case multiple public IPs, needs to define which HIP (Managed IP?) should be used in connection with Central Cloud - Yes?

Flow: Edge Location

Register Edge Location:

  • Trigger: Admin add/update edge location information in Web UI or Remote Client Call with below informations:
    • Name, Description
    • External IP address (empty if no public IP)
    • Flag as force Hub connectivity (Valid if external public IP is not empty)
    • Flag as use Hub for internet connectivity
    • Flag as Dedicated SFC
    • Number of overlay IP addresses
    • CertificateId
    • Kubeconfig
    • Owned Hub id
    • Owned Hub port (optional, used as proxy for Edge location's k8s server) 
  • Steps:
    • Save in DB
    • if public ip is not empty, Setup host-host tunnel with Central Cloud (e.g. Add a new IPSec policy in Central Cloud CNF with: left: CIP, right: EIP, CertificateId)
    • if public ip is empty, no more actions (suppose the tunnel had been setup after edge location setup)
    • if Owned Hub port is none, auto assign a port, then Setup DNAT rule (if DesPort: Owned Hub Port then change Destination IP: EOIP, DesPort: 443) in SDEWAN CNF of Owned Hub
    • Verify connection to Edge location's k8s API server

Opens:

  1. the OIP for control plane (with Central Cloud) will be generated by Hub responder, shall this OIP be used for data plane (e.g. edge1↔hub↔edge2) in Add-edge-location flow in overlay, and the Number of overlay IP address will be used to block Add-edge-location flow if exceeded?

Flow: Overlay

Add-basic-information:

  • Trigger: Admin add/update edge location information in Web UI or Remote Client Call with below informations:
    • Name, Description
    • CertificateId
    • Overlay IP ranges
  • Steps:
    • Save in DB

Opens:

  1. Can overlay IP ranges be same for different overlay? (Suppose "yes" as supposing the edges belongs to different overlays will not communicate even share the same hub)
  2. How to avoid EMCO deploy different microservices of one application into different overlays?

Add-hub:

  • Trigger: Admin add/update hub overlay information in Web UI or Remote Client Call with below informations:
    • Overlay name
    • hub name
    • Hub ip (if hub has more than 1 public IPs)
    • Hub overlay ip ranges
  • Steps:
    • Save hub list information in DB
    • Setup hub-hub tunnel (data plane): e.g. left: HIP1, right: HIP2, overlay CertificateId
    • Setup hub as responder of edge-hub tunnel (data plane): e.g. left: HIP, leftsubnet: Hub overlay ip subnet, rightsourceip: Hub overlay ip ranges

Opens:

  1. Does it need define overlay ip ranges special for a hub or use overlay's ip range directly?
  2. Can 2 Hub setup 2 channels with different masks/interface ids (Need check)?

Add-edge-location:

  • Trigger: Admin add/update application cluster overlay information in Web UI or Remote Client Call with below information:
    • Overlay name
    • edge location name
    • connected Hub name(s)
  • Steps:
    • Save application cluster overlay information in DB
    • Setup edge-hub tunnel with first hub (data plane): e.g. as Initiator - left: %any, leftsourceip:%config, right: HIP, rightsubnet:0.0.0.0/0, overlay CertificateId
    • Get the assigned OIP, save to DB and broadcast to other hubs (add to exclude list of its responder - Need to check how to do it)
    • Setup edge-hub tunnel with all hubs (data plane): e.g. as host-host tunnel
      • Edge - left: EOIP, right: HIP, overlay's CertificateId
      • Hub - left: HIP, right: EOIP, overlay's CertificateId

Opens:

  1. Suppose a edge location can only belong to one overlay at the same time? - Yes and hub is only belong to one overlay, right?
  2. Can edge location connected to more than 1 hubs? if yes, Can it be assigned multiple OIPs from different hubs? - Yes
  3. For edge with public ip, does it need setup Initiator-responder tunnel or host-host tunnel with hub?
  4. Does it need configuration in Overlay to configure edge-edge tunnel (support one edge has public ip) and in which flow?

Flow: Application Connection

Add-application-rule:

  • Trigger: Admin add/update application crule in Web UI or Remote Client (ONAP4K8s connectivity orchestrator?) Call with below informations:
    • Application name
    • Deployed edge location name
    • Firewall/SNAT/DNAT
  • Steps:
    • Save application rule information in DB
    • Setup openwrt rules in SDEWAN CNF of edge location

Add-application2application-rule:

  • Trigger: Admin add/update application crule in Web UI or Remote Client (ONAP4K8s connectivity orchestrator?) Call with below informations:
    • Application1 name
    • Application2 name, port
    • Edge location1 names for application1
    • Edge location2 names for application2
  • Steps:
    • Save application2application rule information in DB
    • Setup openwrt SNAT rule of SDEWAN CNF for edge location1
    • Setup openwrt DNAT rule of SDEWAN CNF for edge location2
    • Setup ip route rule in hubs between edge location1 and edge location2

Opens:

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Restful API definition and Back-End flow

ResourceDescriptionURLFieldsBack-End flow
OverlayDefine a group of edge location clusters (devices) and hubs, a overlay is usually owned by one customer and full mesh connections are setup automacally between hub-hub and device-device (with public IPs)/scc/v1/overlays
  • name
  • description
  • caid

Registration:

  • SCC requests a CA from cert-manager, the CA is used as root CA for this overlay
  • SCC save the caid in DB
ProposalDefine proposals which can be used for IPsec tunnel in this overlay/scc/v1/overlays/{overlay-name}/proposals
  • name
  • description
  • encryption
  • hash
  • dhgroup

Registration:

  • SCC saves the proposals information in DB
HubDefine a traffic Hub in an overlay/scc/v1/overlays/{overlay-name)/hubs
  • name
  • description
  • publicIps
  • certificateId
  • kubeConfig

Registration:

  • SCC checks hub's k8s API server access with kubeConfig for each ip in publicIps
  • For each registered hub in this overlay
    • SCC requests cert-manager to generate a public/private key pair based on overlay CA
    • SCC generates the IPsec CR for new hub and registered hub then call rsync to deploy CR to setup route based host-host IPsec tunnel (with BGP/OSPF enabled):
      • All proposals in this Overlay will be used as candidate proposals for IPsec configuration
      • Use the public/privite key pair generated in previous step as IPsec cert
  • SCC saves hub information in DB
IPRangeDefine the overlay IPrange which will be used as OIP of devices/scc/v1/overlays/{overlay-name}/ipranges
  • name
  • description
  • subnet
  • minIp
  • maxIp

Registration:

  • SCC save ip range information in DB
DeviceDefine a edge location device information which may be a CNF, VNF or PNF/scc/v1/overlays/{overlay-name}/devices
  • name
  • description
  • publicIps
  • forceHubConnectivity
  • proxyHub
  • proxyHubPort
  • useHub4Internet
  • dedidatedSFC
  • certicatedId
  • kubeConfig

Registration:

  • If has publicIps and forceHubConnection==false:

    • SCC checks device's k8s API server access with kubeConfig for each ip in publicIps
    • For each registered device of this overlay:

      • SCC requests cert-manager to generate a public/private key pair based on overlay CA
      • SCC generates the IPsec CR for new device and registered device then call rsync to deploy CR to setup host-host IPsec tunnel:
        • All proposals in this Overlay will be used as candidate proposals for IPsec configuration
        • Use the public/privite key pair generated in previous step as IPsec cert
  • else
    • (Assumption) Kud configures device as Initiator to proxyHub
    • SCC find 1 available OIP from overlay's IPRange, configure then deploy (through rsync) IPsec CR for proxyHub as Responder with OIP as the only 1 candidate ip for Initiator
      • Expectation: the IPsec tunnel between proxyHub and device should setup up and the device will get the assigned OIP
    • SCC creates DNAT CR (dst: HIP, dst_port: proxyHubPort change to dst: OIP, dst_port: 6443) then deploy to proxyHub (SCC will auto geterate a proxyHubPort if not provided)
    • SCC checks device's k8s API server access with kubeConfig for proxyHub:proxyHubPort
    • For each registered device with public ip and forceHubConnection==false:

      • SCC requests cert-manager to generate a public/private key pair based on overlay CA
      • SCC generates the IPsec CR for new device and registered device (with public IP) then call rsync to deploy CR to setup host-host IPsec tunnel:
        • All proposals in this Overlay will be used as candidate proposals for IPsec configuration
        • Use the public/privite key pair generated in previous step as IPsec cert
  • SCC saves device information in DB
Hub-device connectionDefine a connection between hub and device/scc/v1/overlays/{overlay-name}/hubs/{hub-name}/devices/{device-name}
  • N/A

Create:

  • SCC find 1 available OIP from overlay's IPRange, configure then deploy (through rsync) IPsec CR for hub as Responder with OIP as the only 1 candidate ip for Initiator
  • SCC configure the deploy IPsec CR as Initiator to Hub for device
    • Expectation: the IPsec tunnel between hub and device should setup up and the device will get the assigned OIP

Todo: Confirm "ip route" rule for OIP in this hub and all other hub are setup automatically or need new CR to execute linux shell in host

Error handling

DB Schema

Module Design

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