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
45       removed  database.  The  server also cancels any outstanding monitoring
46       initiated 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, either clustered or standalone
59       schema                        optional string
60       Clustered Databases:
61         connected                   boolean
62         leader                      boolean
63         cid                         optional uuid
64         sid                         optional uuid
65         index                       optional integer
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67   Details:
68       name: string
69              The database’s name, as specified in its schema.
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71       model: string, either clustered or standalone
72              The storage model: standalone for a standalone or  active-backup
73              database, clustered for a clustered database.
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75       schema: optional string
76              The  database  schema,  as a JSON string. In the case of a clus‐
77              tered database, this is empty  until  it  finishes  joining  its
78              cluster.
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80     Clustered Databases:
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82       These  columns are most interesting and in some cases only relevant for
83       clustered databases, that is, those where the  model  column  is  clus‐
84       tered.
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86       connected: boolean
87              True  if  the database is connected to its storage. A standalone
88              or active-backup database is always connected. A clustered data‐
89              base is connected if the server is in contact with a majority of
90              its cluster. An unconnected database cannot be modified and  its
91              data might be unavailable or stale.
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93       leader: boolean
94              True  if the database is the leader in its cluster. For a stand‐
95              alone or active-backup database, this is always true.
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97       cid: optional uuid
98              The cluster ID for this database, which is the same for  all  of
99              the  servers that host this particular clustered database. For a
100              standalone or active-backup database, this is empty.
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102       sid: optional uuid
103              The server ID for this database, different for each server  that
104              hosts  a particular clustered database. A server that hosts more
105              than one clustered database will have a different  sid  in  each
106              one. For a standalone or active-backup database, this is empty.
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108       index: optional integer
109              For  a  clustered database, the index of the log entry currently
110              exposed to clients. For a given server, this increases monotoni‐
111              cally.  When  a  client switches from one server to another in a
112              cluster, it can ensure that it never sees an older  snapshot  of
113              data  by  avoiding servers that have index less than the largest
114              value they have already observed.
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116              For a standalone or active-backup database, this is empty.
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120Open vSwitch 2.10.1             DB Schema 1.1.0                ovsdb-server(5)
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