These commands query and modify the contents of ovsdb tables.
They are a slight abstraction of the ovsdb interface and as such
they operate at a lower level than other ovn-nbctl commands.
Identifying Tables, Records, and Columns
Each of these commands has a table parameter to identify a table
within the database. Many of them also take a record parameter
that identifies a particular record within a table. The record
parameter may be the UUID for a record, which may be abbreviated
to its first 4 (or more) hex digits, as long as that is unique.
Many tables offer additional ways to identify records. Some
commands also take column parameters that identify a particular
field within the records in a table.
For a list of tables and their columns, see ovn-nb(5) or see the
table listing from the --help option.
Record names must be specified in full and with correct
capitalization, except that UUIDs may be abbreviated to their
first 4 (or more) hex digits, as long as that is unique within
the table. Names of tables and columns are not case-sensitive,
and - and _ are treated interchangeably. Unique abbreviations of
table and column names are acceptable, e.g. d or dhcp is
sufficient to identify the DHCP_Options table.
Database Values
Each column in the database accepts a fixed type of data. The
currently defined basic types, and their representations, are:
integer
A decimal integer in the range -2**63 to 2**63-1,
inclusive.
real A floating-point number.
Boolean
True or false, written true or false, respectively.
string An arbitrary Unicode string, except that null bytes
are not allowed. Quotes are optional for most
strings that begin with an English letter or
underscore and consist only of letters,
underscores, hyphens, and periods. However, true
and false and strings that match the syntax of
UUIDs (see below) must be enclosed in double quotes
to distinguish them from other basic types. When
double quotes are used, the syntax is that of
strings in JSON, e.g. backslashes may be used to
escape special characters. The empty string must be
represented as a pair of double quotes ("").
UUID Either a universally unique identifier in the style
of RFC 4122, e.g.
f81d4fae-7dec-11d0-a765-00a0c91e6bf6, or an @name
defined by a get or create command within the same
ovn-nbctl invocation.
Multiple values in a single column may be separated by spaces or
a single comma. When multiple values are present, duplicates are
not allowed, and order is not important. Conversely, some
database columns can have an empty set of values, represented as
[], and square brackets may optionally enclose other non-empty
sets or single values as well.
A few database columns are ``maps'' of key-value pairs, where the
key and the value are each some fixed database type. These are
specified in the form key=value, where key and value follow the
syntax for the column's key type and value type, respectively.
When multiple pairs are present (separated by spaces or a comma),
duplicate keys are not allowed, and again the order is not
important. Duplicate values are allowed. An empty map is
represented as {}. Curly braces may optionally enclose non-empty
maps as well (but use quotes to prevent the shell from expanding
other-config={0=x,1=y} into other-config=0=x other-config=1=y,
which may not have the desired effect).
Database Command Syntax
[--if-exists] [--columns=column[,column]...] list table
[record]...
Lists the data in each specified record. If no
records are specified, lists all the records in
table.
If --columns is specified, only the requested
columns are listed, in the specified order.
Otherwise, all columns are listed, in alphabetical
order by column name.
Without --if-exists, it is an error if any
specified record does not exist. With --if-exists,
the command ignores any record that does not exist,
without producing any output.
[--columns=column[,column]...] find table
[column[:key]=value]...
Lists the data in each record in table whose column
equals value or, if key is specified, whose column
contains a key with the specified value. The
following operators may be used where = is written
in the syntax summary:
= != < > <= >=
Selects records in which column[:key]
equals, does not equal, is less than, is
greater than, is less than or equal to, or
is greater than or equal to value,
respectively.
Consider column[:key] and value as sets of
elements. Identical sets are considered
equal. Otherwise, if the sets have different
numbers of elements, then the set with more
elements is considered to be larger.
Otherwise, consider a element from each set
pairwise, in increasing order within each
set. The first pair that differs determines
the result. (For a column that contains key-
value pairs, first all the keys are
compared, and values are considered only if
the two sets contain identical keys.)
{=} {!=}
Test for set equality or inequality,
respectively.
{<=} Selects records in which column[:key] is a
subset of value. For example,
flood-vlans{<=}1,2 selects records in which
the flood-vlans column is the empty set or
contains 1 or 2 or both.
{<} Selects records in which column[:key] is a
proper subset of value. For example,
flood-vlans{<}1,2 selects records in which
the flood-vlans column is the empty set or
contains 1 or 2 but not both.
{>=} {>}
Same as {<=} and {<}, respectively, except
that the relationship is reversed. For
example, flood-vlans{>=}1,2 selects records
in which the flood-vlans column contains
both 1 and 2.
For arithmetic operators (= != < > <= >=), when key
is specified but a particular record's column does
not contain key, the record is always omitted from
the results. Thus, the condition
other-config:mtu!=1500 matches records that have a
mtu key whose value is not 1500, but not those that
lack an mtu key.
For the set operators, when key is specified but a
particular record's column does not contain key,
the comparison is done against an empty set. Thus,
the condition other-config:mtu{!=}1500 matches
records that have a mtu key whose value is not 1500
and those that lack an mtu key.
Don't forget to escape < or > from interpretation
by the shell.
If --columns is specified, only the requested
columns are listed, in the specified order.
Otherwise all columns are listed, in alphabetical
order by column name.
The UUIDs shown for rows created in the same
ovn-nbctl invocation will be wrong.
[--if-exists] [--id=@name] get table record
[column[:key]]...
Prints the value of each specified column in the
given record in table. For map columns, a key may
optionally be specified, in which case the value
associated with key in the column is printed,
instead of the entire map.
Without --if-exists, it is an error if record does
not exist or key is specified, if key does not
exist in record. With --if-exists, a missing record
yields no output and a missing key prints a blank
line.
If @name is specified, then the UUID for record may
be referred to by that name later in the same
ovn-nbctl invocation in contexts where a UUID is
expected.
Both --id and the column arguments are optional,
but usually at least one or the other should be
specified. If both are omitted, then get has no
effect except to verify that record exists in
table.
--id and --if-exists cannot be used together.
[--if-exists] set table record column[:key]=value...
Sets the value of each specified column in the
given record in table to value. For map columns, a
key may optionally be specified, in which case the
value associated with key in that column is changed
(or added, if none exists), instead of the entire
map.
Without --if-exists, it is an error if record does
not exist. With --if-exists, this command does
nothing if record does not exist.
[--if-exists] add table record column [key=]value...
Adds the specified value or key-value pair to
column in record in table. If column is a map, then
key is required, otherwise it is prohibited. If key
already exists in a map column, then the current
value is not replaced (use the set command to
replace an existing value).
Without --if-exists, it is an error if record does
not exist. With --if-exists, this command does
nothing if record does not exist.
[--if-exists] remove table record column value...
[--if-exists] remove table record column key...
[--if-exists] remove table record column
key=value... Removes the specified values or key-
value pairs from column in record in table. The
first form applies to columns that are not maps:
each specified value is removed from the column.
The second and third forms apply to map columns: if
only a key is specified, then any key-value pair
with the given key is removed, regardless of its
value; if a value is given then a pair is removed
only if both key and value match.
It is not an error if the column does not contain
the specified key or value or pair.
Without --if-exists, it is an error if record does
not exist. With --if-exists, this command does
nothing if record does not exist.
[--if-exists] clear table record column...
Sets each column in record in table to the empty
set or empty map, as appropriate. This command
applies only to columns that are allowed to be
empty.
Without --if-exists, it is an error if record does
not exist. With --if-exists, this command does
nothing if record does not exist.
[--id=@name] create table column[:key]=value...
Creates a new record in table and sets the initial
values of each column. Columns not explicitly set
will receive their default values. Outputs the UUID
of the new row.
If @name is specified, then the UUID for the new
row may be referred to by that name elsewhere in
the same \*(PN invocation in contexts where a UUID
is expected. Such references may precede or follow
the create command.
Caution (ovs-vsctl as example)
Records in the Open vSwitch database are
significant only when they can be reached
directly or indirectly from the Open_vSwitch
table. Except for records in the QoS or
Queue tables, records that are not reachable
from the Open_vSwitch table are
automatically deleted from the database.
This deletion happens immediately, without
waiting for additional ovs-vsctl commands or
other database activity. Thus, a create
command must generally be accompanied by
additional commands within the same
ovs-vsctl invocation to add a chain of
references to the newly created record from
the top-level Open_vSwitch record. The
EXAMPLES section gives some examples that
show how to do this.
[--if-exists] destroy table record...
Deletes each specified record from table. Unless
--if-exists is specified, each records must exist.
--all destroy table
Deletes all records from the table.
Caution (ovs-vsctl as example)
The destroy command is only useful for
records in the QoS or Queue tables. Records
in other tables are automatically deleted
from the database when they become
unreachable from the Open_vSwitch table.
This means that deleting the last reference
to a record is sufficient for deleting the
record itself. For records in these tables,
destroy is silently ignored. See the
EXAMPLES section below for more information.
wait-until table record [column[:key]=value]...
Waits until table contains a record named record
whose column equals value or, if key is specified,
whose column contains a key with the specified
value. Any of the operators !=, <, >, <=, or >= may
be substituted for = to test for inequality, less
than, greater than, less than or equal to, or
greater than or equal to, respectively. (Don't
forget to escape < or > from interpretation by the
shell.)
If no column[:key]=value arguments are given, this
command waits only until record exists. If more
than one such argument is given, the command waits
until all of them are satisfied.
Caution (ovs-vsctl as example)
Usually wait-until should be placed at the
beginning of a set of ovs-vsctl commands.
For example, wait-until bridge br0 -- get
bridge br0 datapath_id waits until a bridge
named br0 is created, then prints its
datapath_id column, whereas get bridge br0
datapath_id -- wait-until bridge br0 will
abort if no bridge named br0 exists when
ovs-vsctl initially connects to the
database.
Consider specifying --timeout=0 along with
--wait-until, to prevent ovn-nbctl from terminating
after waiting only at most 5 seconds.
comment [arg]...
This command has no effect on behavior, but any
database log record created by the command will
include the command and its arguments.
