1ovsdb-server(5)               Open vSwitch Manual              ovsdb-server(5)
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NAME

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

14       The following list summarizes the purpose of each of the tables in  the
15       _Server  database.   Each  table is described in more detail on a later
16       page.
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18       Table     Purpose
19       Database  Databases.
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Database TABLE

22       This table describes the databases hosted by the database server,  with
23       one row per database. As its database configuration and status changes,
24       the server automatically and immediately updates the table to match.
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26       The OVSDB protocol specified in RFC 7047 does not provide a way for  an
27       OVSDB  client  to  find  out about some kinds of configuration changes,
28       such as about databases added or removed while a client is connected to
29       the  server, or databases changing between read/write and read-only due
30       to a transition between active and backup roles. This table provides  a
31       solution:  clients  can  monitor the table’s contents to find out about
32       important changes.
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34       Traditionally, ovsdb-server disconnects all of its clients when a  sig‐
35       nificant configuration change occurs, because this prompts a well-writ‐
36       ten client to reassess what is available from the server when it recon‐
37       nects.  Because  this  table provides an alternative and more efficient
38       way to find out about  those  changes,  OVS  2.9  also  introduces  the
39       set_db_change_aware   RPC,  documented  in  ovsdb-server(7),  to  allow
40       clients to suppress this disconnection behavior.
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42       When a database is removed from the server, in addition to Database ta‐
43       ble  updates,  the  server sends canceled messages, as described in RFC
44       7047 section 4.1.4, in reply to outstanding transactions  for  the  re‐
45       moved database. The server also cancels any outstanding monitoring ini‐
46       tiated by monitor or monitor_cond requested on  the  removed  database,
47       sending  the  monitor_canceled  RPC  described in ovsdb-server(7). Only
48       clients that disable  disconnection  with  set_db_change_aware  receive
49       these messages.
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51       Clients  can use the _uuid column in this table as a generation number.
52       The server generates a fresh _uuid every time it adds  a  database,  so
53       that  removing  and  then re-adding a database to the server causes its
54       row _uuid to change.
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56   Summary:
57       name                          string
58       model                         string,  one  of  clustered,  relay,   or
59                                     standalone
60       schema                        optional string
61       connected                     boolean
62       Clustered Databases:
63         leader                      boolean
64         cid                         optional uuid
65         sid                         optional uuid
66         index                       optional integer
67
68   Details:
69       name: string
70              The database’s name, as specified in its schema.
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72       model: string, one of clustered, relay, or standalone
73              The  storage model: standalone for a standalone or active-backup
74              database, clustered for a clustered database, relay for a  relay
75              database.
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77       schema: optional string
78              The  database  schema,  as a JSON string. In the case of a clus‐
79              tered database, this is empty  until  it  finishes  joining  its
80              cluster. In the case of a relay database, this is empty until it
81              connects to the relay source.
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83       connected: boolean
84              True if the database is connected to its storage.  A  standalone
85              database  is always connected. A clustered database is connected
86              if the server is in contact with a majority of  its  cluster.  A
87              relay database is connected if the server is in contact with the
88              relay source, i.e. is connected to the server it syncs from.  An
89              unconnected  database  cannot  be modified and its data might be
90              unavailable or stale.
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92     Clustered Databases:
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94       These columns are most interesting and in some cases only relevant  for
95       clustered  databases,  that  is,  those where the model column is clus‐
96       tered.
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98       leader: boolean
99              True if the database is the leader in its cluster. For a  stand‐
100              alone  or active-backup database, this is always true. For a re‐
101              lay database, this is always false.
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103       cid: optional uuid
104              The cluster ID for this database, which is the same for  all  of
105              the  servers that host this particular clustered database. For a
106              standalone, active-backup or relay database, this is empty.
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108       sid: optional uuid
109              The server ID for this database, different for each server  that
110              hosts  a particular clustered database. A server that hosts more
111              than one clustered database will have a different  sid  in  each
112              one.  For a standalone, active-backup or relay database, this is
113              empty.
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115       index: optional integer
116              For a clustered database, the index of the log  entry  currently
117              exposed to clients. For a given server, this increases monotoni‐
118              cally. When a client switches from one server to  another  in  a
119              cluster,  it  can ensure that it never sees an older snapshot of
120              data by avoiding servers that have index less than  the  largest
121              value they have already observed.
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123              For  a  standalone,  active-backup  or  relay  database, this is
124              empty.
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128Open vSwitch 3.1.1              DB Schema 1.2.0                ovsdb-server(5)
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