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 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.
Northbound configuration for an OVN system. This table must have exactly
one row.
These columns allow a client to track the overall configuration state of
the system.
Sequence number for client to increment. When a client modifies any
part of the northbound database configuration and wishes to wait for
ovn-northd
and possibly all of the hypervisors to finish
applying the changes, it may increment this sequence number.
Sequence number that ovn-northd
sets to the value of after it finishes applying the corresponding
configuration changes to the database.
Sequence number that ovn-northd
sets to the smallest
sequence number of all the chassis in the system, as reported in the
Chassis
table in the southbound database. Thus, equals if all chassis are
caught up with the northbound configuration (which may never happen, if
any chassis is down). This value can regress, if a chassis was removed
from the system and rejoins before catching up.
See External IDs at the beginning of this document.
Each row represents one L2 logical switch.
There are two kinds of logical switches, that is, ones that fully
virtualize the network (overlay logical switches) and ones that provide
simple connectivity to a physical network (bridged logical switches).
They work in the same way when providing connectivity between logical
ports on same chasis, but differently when connecting remote logical
ports. Overlay logical switches connect remote logical ports by tunnels,
while bridged logical switches provide connectivity to remote ports by
bridging the packets to directly connected physical L2 segment with the
help of localnet
ports. Each bridged logical switch has
one and only one localnet
port, which has only one special
address unknown
.
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.
The logical ports connected to the logical switch.
It is an error for multiple logical switches to include the same
logical port.
Load balance a virtual ipv4 address to a set of logical port endpoint
ipv4 addresses.
Access control rules that apply to packets within the logical switch.
Additional configuration options for the logical switch.
Set this to an IPv4 subnet, e.g. 192.168.0.0/24
, to enable
ovn-northd
to automatically assign IP addresses within
that subnet. Use the dynamic
keyword in the table's column to request dynamic address assignment for a
particular port.
See External IDs at the beginning of this document.
A port within an L2 logical switch.
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 in the
database's table, because hypervisors use 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.
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. This is used
to model direct connectivity to an existing network.
l2gateway
-
A connection to a physical network.
vtep
-
A port to a logical switch on a VTEP gateway.
This column provides key/value settings specific to the logical port
. The type-specific options are described
individually below.
These options apply when is router
.
Required. The of the to which this logical switch port is
connected.
MAC address of the router-port
followed by a list of
SNAT and DNAT IP addresses. This is used to send gratuitous ARPs for
SNAT and DNAT IP addresses via localnet
and is valid for
only L3 gateway ports. Example: 80:fa:5b:06:72:b7 158.36.44.22
158.36.44.24
. This would result in generation of gratuitous
ARPs for IP addresses 158.36.44.22 and 158.36.44.24 with a MAC
address of 80:fa:5b:06:72:b7.
These options apply when is
localnet
.
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.
These options apply when is
l2gateway
.
Required. The name of the network to which the l2gateway
port is connected. The L2 gateway, via ovn-controller
,
uses its local configuration to determine exactly how to connect to
this network.
Required. The chassis on which the l2gateway
logical
port should be bound to. ovn-controller
running on the
defined chassis will connect this logical port to the physical network.
These options apply when is vtep
.
Required. The name of the VTEP gateway.
Required. A logical switch name connected by the VTEP gateway.
These options apply to logical ports with having
(empty string)
If set, indicates the maximum rate for data sent from this interface,
in kbps. Data exceeding this rate is dropped.
If set, indicates the maximum burst size for data sent from this
interface, in kb.
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.
The VM interface through which the nested container sends its network
traffic. This must match the column for some
other .
The VLAN tag in the network traffic associated with a container's
network interface. The client can request ovn-northd
to allocate a tag that is unique within the scope of a specific
parent (specified in ) by setting a value
of 0
in this column. The allocated value is written
by ovn-northd
in the column.
(Note that these tags are allocated and managed locally in
ovn-northd
, so they cannot be reconstructed in the event
that the database is lost.) The client can also request a specific
non-zero tag and ovn-northd
will honor it and copy that
value to the column.
When is set to localnet
or
l2gateway
, 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.
The VLAN tag allocated by ovn-northd
based on the
contents of the column.
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 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.
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.
Addresses owned by the logical port.
Each element in the set must take one of the following forms:
Ethernet address followed by zero or more IPv4 or IPv6 addresses (or both)
-
An Ethernet address defined is 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 column, it delivers it only to that port, as
if a MAC learning process had learned that MAC address on the
port.
If IPv4 or IPv6 address(es) (or both) are defined, it indicates
that the logical port owns the given IP addresses.
If IPv4 address(es) are defined, 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(es) if defined.
Examples:
80:fa:5b:06:72:b7
-
This indicates that the logical port owns the above mac address.
80:fa:5b:06:72:b7 10.0.0.4 20.0.0.4
-
This indicates that the logical port owns the mac address and two
IPv4 addresses.
80:fa:5b:06:72:b7 fdaa:15f2:72cf:0:f816:3eff:fe20:3f41
-
This indicates that the logical port owns the mac address and
1 IPv6 address.
80:fa:5b:06:72:b7 10.0.0.4 fdaa:15f2:72cf:0:f816:3eff:fe20:3f41
-
This indicates that the logical port owns the mac address and
1 IPv4 address and 1 IPv6 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
column, it delivers it to the port (or
ports) whose columns include
unknown
.
dynamic
-
Use this keyword to make
ovn-northd
generate a
globally unique MAC address and choose an unused IPv4 address with
the logical port's subnet and store them in the port's column. ovn-northd
will
use the subnet specified in in the port's .
Ethernet address followed by keyword "dynamic"
-
The keyword dynamic
after the MAC address indicates
that ovn-northd
should choose an unused IPv4 address
from the logical port's subnet and store it with the specified
MAC in the port's column.
ovn-northd
will use the subnet specified in in
the port's table.
Examples:
80:fa:5b:06:72:b7 dynamic
-
This indicates that the logical port owns the specified
MAC address and
ovn-northd
should allocate an
unused IPv4 address for the logical port from the corresponding
logical switch subnet.
Addresses assigned to the logical port by ovn-northd
, if
dynamic
is specified in .
Addresses will be of the same format as those that populate the column. Note that dynamically assigned
addresses are constructed and managed locally in ovn-northd, so they
cannot be reconstructed in the event that the database is lost.
This column controls the addresses from which the host attached to the
logical port (``the host'') is allowed to send packets and to which it
is allowed to receive packets. If this column is empty, all addresses
are permitted.
Each element in the set must begin with one Ethernet address.
This would restrict the host to sending packets from and receiving
packets to the ethernet addresses defined in the logical port's
column. It also restricts the inner
source MAC addresses that the host may send in ARP and IPv6
Neighbor Discovery packets. The host is always allowed to receive packets
to multicast and broadcast Ethernet addresses.
Each element in the set may additionally contain one or more IPv4 or
IPv6 addresses (or both), with optional masks. If a mask is given, it
must be a CIDR mask. In addition to the restrictions described for
Ethernet addresses above, such an element restricts the IPv4 or IPv6
addresses from which the host may send and to which it may receive
packets to the specified addresses. A masked address, if the host part
is zero, indicates that the host is allowed to use any address in the
subnet; if the host part is nonzero, the mask simply indicates the size
of the subnet. In addition:
-
If any IPv4 address is given, the host is also allowed to receive
packets to the IPv4 local broadcast address 255.255.255.255 and to
IPv4 multicast addresses (224.0.0.0/4). If an IPv4 address with a
mask is given, the host is also allowed to receive packets to the
broadcast address in that specified subnet.
If any IPv4 address is given, the host is additionally restricted
to sending ARP packets with the specified source IPv4 address.
(RARP is not restricted.)
-
If any IPv6 address is given, the host is also allowed to receive
packets to IPv6 multicast addresses (ff00::/8).
If any IPv6 address is given, the host is additionally restricted
to sending IPv6 Neighbor Discovery Solicitation or Advertisement
packets with the specified source address or, for solicitations,
the unspecified address.
If an element includes an IPv4 address, but no IPv6 addresses, then
IPv6 traffic is not allowed. If an element includes an IPv6 address,
but no IPv4 address, then IPv4 and ARP traffic is not allowed.
This column uses the same lexical syntax as the column in the OVN Southbound
database's table. Multiple
addresses within an element may be space or comma separated.
This column is provided as a convenience to cloud management systems,
but all of the features that it implements can be implemented as ACLs
using the table.
Examples:
80:fa:5b:06:72:b7
-
The host may send traffic from and receive traffic to the specified
MAC address, and to receive traffic to Ethernet multicast and
broadcast addresses, but not otherwise. The host may not send ARP or
IPv6 Neighbor Discovery packets with inner source Ethernet addresses
other than the one specified.
80:fa:5b:06:72:b7 192.168.1.10/24
-
This adds further restrictions to the first example. The host may
send IPv4 packets from or receive IPv4 packets to only 192.168.1.10,
except that it may also receive IPv4 packets to 192.168.1.255 (based
on the subnet mask), 255.255.255.255, and any address in 224.0.0.0/4.
The host may not send ARPs with a source Ethernet address other than
80:fa:5b:06:72:b7 or source IPv4 address other than 192.168.1.10.
The host may not send or receive any IPv6 (including IPv6 Neighbor
Discovery) traffic.
"80:fa:5b:12:42:ba", "80:fa:5b:06:72:b7 192.168.1.10/24"
-
The host may send traffic from and receive traffic to the
specified MAC addresses, and
to receive traffic to Ethernet multicast and broadcast addresses,
but not otherwise. With MAC 80:fa:5b:12:42:ba, the host may
send traffic from and receive traffic to any L3 address.
With MAC 80:fa:5b:06:72:b7, the host may send IPv4 packets from or
receive IPv4 packets to only 192.168.1.10, except that it may also
receive IPv4 packets to 192.168.1.255 (based on the subnet mask),
255.255.255.255, and any address in 224.0.0.0/4. The host may not
send or receive any IPv6 (including IPv6 Neighbor Discovery) traffic.
This column defines the DHCPv4 Options to be included by the
ovn-controller
when it replies to the DHCPv4 requests.
Please see the table.
This column defines the DHCPv6 Options to be included by the
ovn-controller
when it replies to the DHCPv6 requests.
Please see the table.
See External IDs at the beginning of this document.
Each row in this table represents a named set of addresses.
An address set may contain Ethernet, IPv4, or IPv6 addresses
with optional bitwise or CIDR masks.
Address set may ultimately be used in ACLs to compare against
fields such as ip4.src
or ip6.src
.
A single address set must contain addresses of the
same type. As an example, the following would create an address set
with three IP addresses:
ovn-nbctl create Address_Set name=set1 addresses='10.0.0.1 10.0.0.2 10.0.0.3'
Address sets may be used in the column
of the table. For syntax information, see the details
of the expression language used for the column in the table of the database.
A name for the address set. This must be unique among all address sets.
The set of addresses in string form.
See External IDs at the beginning of this document.
Each row represents one load balancer.
A map of virtual IPv4 addresses (and an optional port number with
:
as a separator) associated with this load balancer and
their corresponding endpoint IPv4 addresses (and optional port numbers
with :
as separators) separated by commas. If
the destination IP address (and port number) of a packet leaving a
container or a VM matches the virtual IPv4 address (and port number)
provided here as a key, then OVN will statefully replace the
destination IP address by one of the provided IPv4 address (and port
number) in this map as a value. Examples for keys are "192.168.1.4"
and "172.16.1.8:80". Examples for value are "10.0.0.1, 10.0.0.2" and
"20.0.0.10:8800, 20.0.0.11:8800".
Valid protocols are tcp
or udp
. This column
is useful when a port number is provided as part of the
vips
column. If this column is empty and a port number
is provided as part of vips
column, OVN assumes the
protocol to be tcp
.
See External IDs at the beginning of this document.
Each row in this table represents one ACL rule for a logical switch
that points to it through its column. The column for the highest-
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 0, 0
as
, and deny
as .)
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 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.
The packets that the ACL should match, in the same expression
language used for the column in the OVN Southbound database's
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.
Note that when localnet
port exists in a lswitch, for
to-lport
direction, the inport
works only if
the to-lport
is located on the same chassis as the
inport
.
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
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 .
Logging is not yet implemented.
See External IDs at the beginning of this document.
Each row represents one L3 logical router.
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.
The router's ports.
One or more static routes for the router.
This column is used to administratively set router state. If this column
is empty or is set to true
, the router is enabled. If this
column is set to false
, the router is disabled. A disabled
router has all ingress and egress traffic dropped.
One or more NAT rules for the router. NAT rules only work on the
Gateway routers.
Load balance a virtual ipv4 address to a set of logical port ipv4
addresses. Load balancer rules only work on the Gateway routers.
Additional options for the logical router.
If set, indicates that the logical router in question is a Gateway
router (which is centralized) and resides in the set chassis. The
same value is also used by ovn-controller
to
uniquely identify the chassis in the OVN deployment and
comes from external_ids:system-id
in the
Open_vSwitch
table of Open_vSwitch database.
The Gateway router can only be connected to a distributed router
via a switch if SNAT and DNAT are to be configured in the Gateway
router.
See External IDs at the beginning of this document.
A port within an L3 logical router.
Exactly one row must reference a given
logical router port.
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
or another logical router port in
.
The IP addresses and netmasks of the router. 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.
A logical router port always adds a link-local IPv6 address
(fe80::/64) automatically generated from the interface's MAC
address using the modified EUI-64 format.
The Ethernet address that belongs to this router port.
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.
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
of type router
.
The value of is set as
router-port
in column of
. In this case 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
column. No refers to
the router port.
For a router port used to connect two logical routers, this
identifies the other router port in the pair by .
For a router port attached to a logical switch, this column is empty.
See External IDs at the beginning of this document.
Each record represents a static route.
IP prefix of this route (e.g. 192.168.100.0/24).
Nexthop IP address for this route. Nexthop IP address should be the IP
address of a connected router port or the IP address of a logical port.
The name of the via which the packet
needs to be sent out. This is optional and when not specified,
OVN will automatically figure this out based on the
.
Each record represents a NAT rule in a Gateway router.
Type of the NAT rule.
-
When
is dnat
, the externally
visible IP address is DNATted to the IP
address in the logical space.
-
When
is snat
, IP packets
with their source IP address that either matches the IP address
in or is in the network provided by
is SNATed into the IP address in
.
-
When
is dnat_and_snat
, the
externally visible IP address is
DNATted to the IP address in the
logical space. In addition, IP packets with the source IP
address that matches is SNATed into
the IP address in .
An IPv4 address.
An IPv4 network (e.g 192.168.1.0/24) or an IPv4 address.
OVN implements native DHCPv4 support which caters to the common
use case of providing an IPv4 address to a booting instance by
providing stateless replies to DHCPv4 requests based on statically
configured address mappings. To do this it allows a short list of
DHCPv4 options to be configured and applied at each compute host
running ovn-controller
.
OVN also implements native DHCPv6 support which provides stateless
replies to DHCPv6 requests.
The DHCPv4/DHCPv6 options will be included if the logical port has its
IP address in this .
The CMS should define the set of DHCPv4 options as key/value pairs
in the column of this table. For
ovn-controller
to include these DHCPv4 options, the
of
should refer to an entry in this table.
The following options must be defined.
The IP address for the DHCP server to use. This should be in the
subnet of the offered IP. This is also included in the DHCP offer as
option 54, ``server identifier.''
The Ethernet address for the DHCP server to use.
The IP address of a gateway for the client to use. This should be
in the subnet of the offered IP. The DHCPv4 option code for this
option is 3.
The offered lease time in seconds,
The DHCPv4 option code for this option is 51.
Below are the supported DHCPv4 options whose values are an IPv4
address, e.g. 192.168.1.1
. Some options accept multiple
IPv4 addresses enclosed within curly braces, e.g. {192.168.1.2,
192.168.1.3}
. Please refer to RFC 2132 for more details on
DHCPv4 options and their codes.
The DHCPv4 option code for this option is 1.
The DHCPv4 option code for this option is 6.
The DHCPv4 option code for this option is 7.
The DHCPv4 option code for this option is 9.
The DHCPv4 option code for this option is 16.
The DHCPv4 option code for this option is 21.
The DHCPv4 option code for this option is 32.
The DHCPv4 option code for this option is 41.
The DHCPv4 option code for this option is 42.
The DHCPv4 option code for this option is 66.
The DHCPv4 option code for this option is 121.
This option can contain one or more static routes, each of which
consists of a destination descriptor and the IP address of the
router that should be used to reach that destination. Please see
RFC 3442 for more details.
Example: {30.0.0.0/24,10.0.0.10, 0.0.0.0/0,10.0.0.1}
The DHCPv4 option code for this option is 249. This option is
similar to classless_static_route
supported by
Microsoft Windows DHCPv4 clients.
These options accept a Boolean value, expressed as 0
for
false or 1
for true.
The DHCPv4 option code for this option is 19.
The DHCPv4 option code for this option is 31.
The DHCPv4 option code for this option is 36.
These options accept a nonnegative integer value.
The DHCPv4 option code for this option is 23.
The DHCPv4 option code for this option is 37.
The DHCPv4 option code for this option is 26.
This specifies the time interval from address assignment until the
client begins trying to renew its address. The DHCPv4 option code
for this option is 58.
This specifies the time interval from address assignment until the
client begins trying to rebind its address. The DHCPv4 option code
for this option is 59.
OVN also implements native DHCPv6 support. The CMS should define
the set of DHCPv6 options as key/value pairs. The define DHCPv6
options will be included in the DHCPv6 response to the DHCPv6
Solicit/Request/Confirm packet from the logical ports having the
IPv6 addresses in the .
The following options must be defined.
The Ethernet address for the DHCP server to use. This is also
included in the DHCPv6 reply as option 2, ``Server Identifier''
to carry a DUID identifying a server between a client and a server.
ovn-controller
defines DUID based on
Link-layer Address [DUID-LL].
Below are the supported DHCPv6 options whose values are an IPv6
address, e.g. aef0::4
. Some options accept multiple
IPv6 addresses enclosed within curly braces, e.g. {aef0::4,
aef0::5}
. Please refer to RFC 3315 for more details on
DHCPv6 options and their codes.
The DHCPv6 option code for this option is 23. This option specifies
the DNS servers that the VM should use.
These options accept string values.
The DHCPv6 option code for this option is 24. This option specifies
the domain search list the client should use to resolve hostnames
with DNS.
Example: "ovn.org"
.
See External IDs at the beginning of this document.