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ovsdb-server(5)		      Open vSwitch Manual	       ovsdb-server(5)

       ovsdb-server - _Server database schema

       Every  ovsdb-server  (version 2.9 or later) always hosts	an instance of
       this schema, which holds	information on the status and configuration of
       the  server  itself. This database is read-only.	This manpage describes
       the schema for this database.

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

       Table	 Purpose
       Database	 Databases.

Database TABLE
       This table describes the	databases hosted by the	database server,  with
       one row per database. As	its database configuration and status changes,
       the server automatically	and immediately	updates	the table to match.

       The OVSDB protocol specified in RFC 7047	does not provide a way for  an
       OVSDB  client  to  find	out about some kinds of	configuration changes,
       such as about databases added or	removed	while a	client is connected to
       the  server, or databases changing between read/write and read-only due
       to a transition between active and backup roles.	This table provides  a
       solution:  clients  can	monitor	the table's contents to	find out about
       important changes.

       Traditionally, ovsdb-server disconnects all of its clients when a  sig-
       nificant	configuration change occurs, because this prompts a well-writ-
       ten client to reassess what is available	from the server	when it	recon-
       nects.  Because	this  table provides an	alternative and	more efficient
       way to find out about  those  changes,  OVS  2.9	 also  introduces  the
       set_db_change_aware   RPC,  documented  in  ovsdb-server(7),  to	 allow
       clients to suppress this	disconnection behavior.

       When a database is removed from the server, in addition to Database ta-
       ble  updates,  the  server sends	canceled messages, as described	in RFC
       7047 section 4.1.4, in reply to outstanding transactions	 for  the  re-
       moved database. The server also cancels any outstanding monitoring ini-
       tiated by monitor or monitor_cond requested on  the  removed  database,
       sending	the  monitor_canceled  RPC  described in ovsdb-server(7). Only
       clients that disable  disconnection  with  set_db_change_aware  receive
       these messages.

       Clients	can use	the _uuid column in this table as a generation number.
       The server generates a fresh _uuid every	time it	adds  a	 database,  so
       that  removing  and  then re-adding a database to the server causes its
       row _uuid to change.

       name			     string
       model			     string,  one  of  clustered,  relay,   or
       schema			     optional string
       connected		     boolean
       Clustered Databases:
	 leader			     boolean
	 cid			     optional uuid
	 sid			     optional uuid
	 index			     optional integer

       name: string
	      The database's name, as specified	in its schema.

       model: string, one of clustered,	relay, or standalone
	      The  storage model: standalone for a standalone or active-backup
	      database,	clustered for a	clustered database, relay for a	 relay

       schema: optional	string
	      The  database  schema,  as a JSON	string.	In the case of a clus-
	      tered database, this is empty  until  it	finishes  joining  its
	      cluster. In the case of a	relay database,	this is	empty until it
	      connects to the relay source.

       connected: boolean
	      True if the database is connected	to its storage.	 A  standalone
	      database	is always connected. A clustered database is connected
	      if the server is in contact with a majority of  its  cluster.  A
	      relay database is	connected if the server	is in contact with the
	      relay source, i.e. is connected to the server it syncs from.  An
	      unconnected  database  cannot  be	modified and its data might be
	      unavailable or stale.

     Clustered Databases:

       These columns are most interesting and in some cases only relevant  for
       clustered  databases,  that  is,	 those where the model column is clus-

       leader: boolean
	      True if the database is the leader in its	cluster. For a	stand-
	      alone  or	active-backup database,	this is	always true. For a re-
	      lay database, this is always false.

       cid: optional uuid
	      The cluster ID for this database,	which is the same for  all  of
	      the  servers that	host this particular clustered database. For a
	      standalone, active-backup	or relay database, this	is empty.

       sid: optional uuid
	      The server ID for	this database, different for each server  that
	      hosts  a particular clustered database. A	server that hosts more
	      than one clustered database will have a different	 sid  in  each
	      one.  For	a standalone, active-backup or relay database, this is

       index: optional integer
	      For a clustered database,	the index of the log  entry  currently
	      exposed to clients. For a	given server, this increases monotoni-
	      cally. When a client switches from one server to	another	 in  a
	      cluster,	it  can	ensure that it never sees an older snapshot of
	      data by avoiding servers that have index less than  the  largest
	      value they have already observed.

	      For  a  standalone,  active-backup  or  relay  database, this is

Open vSwitch 2.16.0		DB Schema 1.2.0		       ovsdb-server(5)


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