58 lines
1.8 KiB
ReStructuredText
58 lines
1.8 KiB
ReStructuredText
================
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Distributed DHCP
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================
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Current Neutron Reference Implementation
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========================================
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The DHCP server is implemented using the Dnsmasq server
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running in a namespace on the network-node per tenant subnet
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that is configured with DHCP enabled.
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Currently High availability is achieved by running multiple Dnsmasq
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servers on multiple Network nodes.
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There is a namespace with Dnsmasq server per tenant subnet
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Problems with current DHCP implementation:
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1) Management and Scalability
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- Need to configure and mange multiple Dnsmasq instances
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2) Centralize solution depended on the network node
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DHCP agent
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----------
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Same Concept as L3 agent and namespaces for virtual router.
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Using black boxes that implement functionality and using them as the IaaS
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backbone implementation
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Distributed DHCP In Dragonflow
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==============================
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Dragonflow distribute DHCP policy/configuration using the pluggable DB.
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Each local controller installs DHCP redirection Openflow rules, to be
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handle by the local controller.
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Those rules are installed only for local ports that are
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attached to a virtual network with DHCP enabled.
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The controller set the flow metadata in the redirection rules
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to the local port unique key as a hint to allow fast port info lookup
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for the reactive DHCP packets handle by the DHCP application.
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The local DHCP application handle the redirected DHCP packets and answer as a
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DHCP server. DHCP traffic is handled directly at the compute node and never
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goes on the network.
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The following diagrams demonstrate this process:
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.. image:: ../images/dhcp1.jpg
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:alt: Distributed DHCP 1
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:width: 600
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:height: 525
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:align: center
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.. image:: ../images/dhcp2.jpg
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:alt: Distributed DHCP 1
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:width: 600
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:height: 525
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:align: center
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