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   ovn-nbctl    ( 8 )

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DATABASE COMMANDS

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.