Ubuntu Manpage: ovn-nb - OVN_Northbound database schema

Provided by: ovn-central_2.5.9-0ubuntu0.16.04.3_amd64

NAME

       ovn-nb - OVN_Northbound database schema

       This  database  is  the  interface  between OVN and the cloud management system (CMS), such as OpenStack,
       running above it.  The CMS produces almost all of the contents of the database.  The  ovn-northd  program
       monitors the database contents, transforms it, and stores it into the OVN_Southbound database.

       We generally speak of ``the’’ CMS, but one can imagine scenarios in which multiple CMSes manage different
       parts of an OVN deployment.

   External IDs
       Each  of  the tables in this database contains a special column, named external_ids.  This column has the
       same form and purpose each place it appears.

              external_ids: map of string-string pairs
                     Key-value pairs for use by the CMS.  The CMS might  use  certain  pairs,  for  example,  to
                     identify entities in its own configuration that correspond to those in this database.

TABLE SUMMARY

       The  following  list  summarizes  the purpose of each of the tables in the OVN_Northbound database.  Each
       table is described in more detail on a later page.

       Table     Purpose
       Logical_Switch
                 L2 logical switch
       Logical_Port
                 L2 logical switch port
       ACL       Access Control List (ACL) rule
       Logical_Router
                 L3 logical router
       Logical_Router_Port
                 L3 logical router port

Logical_Switch TABLE

       Each row represents one L2 logical switch.

   Summary:
       name                          string
       ports                         set of Logical_Ports
       acls                          set of ACLs
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       name: string
              A name for the logical switch.  This name has no special meaning or purpose other than to  provide
              convenience  for human interaction with the ovn-nb database.  There is no requirement for the name
              to be unique.  The logical switch’s UUID should be used as the unique identifier.

       ports: set of Logical_Ports
              The logical ports connected to the logical switch.

              It is an error for multiple logical switches to include the same logical port.

       acls: set of ACLs
              Access control rules that apply to packets within the logical switch.

     Common Columns:

       external_ids: map of string-string pairs
              See External IDs at the beginning of this document.

Logical_Port TABLE

A port within an L2 logical switch.

Summary:
Core Features:
name string (must be unique within table)
type string
Options:
options map of string-string pairs
Options for router ports:
options : router-port optional string
Options for localnet ports:
options : network_name optional string
Options for vtep ports:
options : vtep-physical-switch
optional string
options : vtep-logical-switch
optional string
Containers:
parent_name optional string
tag optional integer, in range 1 to 4,095
Port State:
up optional boolean
enabled optional boolean
Addressing:
addresses set of strings
port_security set of strings
Common Columns:
external_ids map of string-string pairs

Details:
Core Features:

name: string (must be unique within table)
The logical port name.

For entities (VMs or containers) that are spawned in the hypervisor, the name used here must match
those used in the external_ids:iface-id in the Open_vSwitch database’s Interface table, because
hypervisors use external_ids:iface-id as a lookup key to identify the network interface of that
entity.

For containers that share a VIF within a VM, the name can be any unique identifier. See
Containers, below, for more information.

type: string
Specify a type for this logical port. Logical ports can be used to model other types of
connectivity into an OVN logical switch. The following types are defined:

(empty string)
A VM (or VIF) interface.

router A connection to a logical router.

localnet
A connection to a locally accessible network from each ovn-controller instance. A logical
switch can only have a single localnet port attached and at most one regular logical port.
This is used to model direct connectivity to an existing network.

vtep A port to a logical switch on a VTEP gateway.

Options:

options: map of string-string pairs
This column provides key/value settings specific to the logical port type. The type-specific
options are described individually below.

Options for router ports:
These options apply when type is router.

If a given logical switch has multiple router ports, the Logical_Router_Port rows that they reference
must be all on the same Logical_Router (for different subnets).

options : router-port: optional string
Required. The name of the Logical_Router_Port to which this logical switch port is connected.

Options for localnet ports:
These options apply when type is localnet.

options : network_name: optional string
Required. The name of the network to which the localnet port is connected. Each hypervisor, via
ovn-controller, uses its local configuration to determine exactly how to connect to this locally
accessible network.

Options for vtep ports:
These options apply when type is vtep.

options : vtep-physical-switch: optional string
Required. The name of the VTEP gateway.

options : vtep-logical-switch: optional string
Required. A logical switch name connected by the VTEP gateway.

Containers:
When a large number of containers are nested within a VM, it may be too expensive to dedicate a VIF to
each container. OVN can use VLAN tags to support such cases. Each container is assigned a VLAN ID and
each packet that passes between the hypervisor and the VM is tagged with the appropriate ID for the
container. Such VLAN IDs never appear on a physical wire, even inside a tunnel, so they need not be
unique except relative to a single VM on a hypervisor.

These columns are used for VIFs that represent nested containers using shared VIFs. For VMs and for
containers that have dedicated VIFs, they are empty.

parent_name: optional string
The VM interface through which the nested container sends its network traffic. This must match
the name column for some other Logical_Port.

tag: optional integer, in range 1 to 4,095
The VLAN tag in the network traffic associated with a container’s network interface.

When type is set to localnet, this can be set to indicate that the port represents a connection to
a specific VLAN on a locally accessible network. The VLAN ID is used to match incoming traffic and
is also added to outgoing traffic.

Port State:

up: optional boolean
This column is populated by ovn-northd, rather than by the CMS plugin as is most of this database.
When a logical port is bound to a physical location in the OVN Southbound database Binding table,
ovn-northd sets this column to true; otherwise, or if the port becomes unbound later, it sets it
to false. This allows the CMS to wait for a VM’s (or container’s) networking to become active
before it allows the VM (or container) to start.

enabled: optional boolean
This column is used to administratively set port state. If this column is empty or is set to
true, the port is enabled. If this column is set to false, the port is disabled. A disabled port
has all ingress and egress traffic dropped.

Addressing:

addresses: set of strings
Addresses owned by the logical port.

Each element in the set must take one of the following forms:

xx:xx:xx:xx:xx:xx
An Ethernet address owned by the logical port. Like a physical Ethernet NIC, a logical
port ordinarily has a single fixed Ethernet address.

When a OVN logical switch processes a unicast Ethernet frame whose destination MAC address
is in a logical port’s addresses column, it delivers it only to that port, as if a MAC
learning process had learned that MAC address on the port.

xx:xx:xx:xx:xx:xx a.b.c.d
This form has all the effects of the previous form. It also indicates that the logical
port owns the given IPv4 address.

The OVN logical switch uses this information to synthesize responses to ARP requests
without traversing the physical network. The OVN logical router connected to the logical
switch, if any, uses this information to avoid issuing ARP requests for logical switch
ports.

Note that the order here is important. The Ethernet address must be listed before the IP
address.

unknown
This indicates that the logical port has an unknown set of Ethernet addresses. When an OVN
logical switch processes a unicast Ethernet frame whose destination MAC address is not in
any logical port’s addresses column, it delivers it to the port (or ports) whose addresses
columns include unknown.

port_security: set of strings
A set of L2 (Ethernet) addresses from which the logical port is allowed to send packets and to
which it is allowed to receive packets. If this column is empty, all addresses are permitted.
Logical ports are always allowed to receive packets addressed to multicast and broadcast
addresses.

Each member of the set is an Ethernet address in the form xx:xx:xx:xx:xx:xx.

This specification will be extended to support L3 port security.

Common Columns:

external_ids: map of string-string pairs
See External IDs at the beginning of this document.

ACL TABLE

Each row in this table represents one ACL rule for a logical switch that points to it through its acls
column. The action column for the highest-priority matching row in this table determines a packet’s
treatment. If no row matches, packets are allowed by default. (Default-deny treatment is possible: add
a rule with priority 0, 0 as match, and deny as action.)

Summary:
priority integer, in range 0 to 32,767
direction string, either to-lport or from-lport
match string
action string, one of allow-related, drop, allow, or reject
log boolean
Common Columns:
external_ids map of string-string pairs

Details:
priority: integer, in range 0 to 32,767
The ACL rule’s priority. Rules with numerically higher priority take precedence over those with
lower. If two ACL rules with the same priority both match, then the one actually applied to a
packet is undefined.

Return traffic from an allow-related flow is always allowed and cannot be changed through an ACL.

direction: string, either to-lport or from-lport
Direction of the traffic to which this rule should apply:

• from-lport: Used to implement filters on traffic arriving from a logical port. These rules
are applied to the logical switch’s ingress pipeline.

• to-lport: Used to implement filters on traffic forwarded to a logical port. These rules
are applied to the logical switch’s egress pipeline.

match: string
The packets that the ACL should match, in the same expression language used for the match column
in the OVN Southbound database’s Logical_Flow table. The outport logical port is only available
in the to-lport direction (the inport is available in both directions).

By default all traffic is allowed. When writing a more restrictive policy, it is important to
remember to allow flows such as ARP and IPv6 neighbor discovery packets.

Note that you can not create an ACL matching on a port with type=router.

action: string, one of allow-related, drop, allow, or reject
The action to take when the ACL rule matches:

• allow: Forward the packet.

• allow-related: Forward the packet and related traffic (e.g. inbound replies to an outbound
connection).

• drop: Silently drop the packet.

• reject: Drop the packet, replying with a RST for TCP or ICMP unreachable message for other
IP-based protocols. Not implemented--currently treated as drop

log: boolean
If set to true, packets that match the ACL will trigger a log message on the transport node or
nodes that perform ACL processing. Logging may be combined with any action.

Logging is not yet implemented.

Common Columns:

external_ids: map of string-string pairs
See External IDs at the beginning of this document.

Logical_Router TABLE

       Each row represents one L3 logical router.

   Summary:
       name                          string
       ports                         set of Logical_Router_Ports
       default_gw                    optional string
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       name: string
              A  name for the logical router.  This name has no special meaning or purpose other than to provide
              convenience for human interaction with the ovn-nb database.  There is no requirement for the  name
              to be unique.  The logical router’s UUID should be used as the unique identifier.

       ports: set of Logical_Router_Ports
              The router’s ports.

       default_gw: optional string
              IP address to use as default gateway, if any.

     Common Columns:

       external_ids: map of string-string pairs
              See External IDs at the beginning of this document.

Logical_Router_Port TABLE

A port within an L3 logical router.

Exactly one Logical_Router row must reference a given logical router port.

Summary:
name string (must be unique within table)
network string
mac string
enabled optional boolean
Attachment:
peer optional Logical_Router_Port
Common Columns:
external_ids map of string-string pairs

Details:
name: string (must be unique within table)
A name for the logical router port.

In addition to provide convenience for human interaction with the ovn-nb database, this column is
used as reference by its patch port in Logical_Port or another logical router port in
Logical_Router_Port.

network: string
The IP address of the router and the netmask. For example, 192.168.0.1/24 indicates that the
router’s IP address is 192.168.0.1 and that packets destined to 192.168.0.x should be routed to
this port.

mac: string
The Ethernet address that belongs to this router port.

Attachment:
A given router port serves one of two purposes:

• To attach a logical switch to a logical router. A logical router port of this type is
referenced by exactly one Logical_Port of type router. The value of name is set as
router-port in column options of Logical_Port. In this case peer column is empty.

• To connect one logical router to another. This requires a pair of logical router ports,
each connected to a different router. Each router port in the pair specifies the other in
its peer column. No Logical_Switch refers to the router port.

peer: optional Logical_Router_Port
For a router port used to connect two logical routers, this identifies the other router port in
the pair by name.

For a router port attached to a logical switch, this column is empty.

Common Columns:

external_ids: map of string-string pairs
See External IDs at the beginning of this document.

Open vSwitch 2.5.9 DB Schema 2.0.1 ovn-nb(5)