ovsdb-server

NAME

ovsdb-server - _Server database schema Every ovsdb-server (version 29 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

TABLE SUMMARY

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 page.

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 significant configuration change occurs, because this prompts a well-written client to reassess what is available from the server when it reconnects Because this table provides an alternative and more efficient way to find out about those changes, OVS 29 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 table updates, the server sends canceled messages, as described in RFC 7047 section 414, in reply to outstanding transactions for the removed database The server also cancels any outstanding monitoring initiated 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

Summary:

name

string

 

model

string, one of clustered, relay, or standalone

 

schema

optional string

 

connected

boolean

 

Clustered Databases:

Details:

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 database

schema: optional string

The database schema, as a JSON string In the case of a clustered 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, ie is connected to the server it syncs from An unconnected database cannot be modified and its data might be unavailable or stale

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

leader: boolean

True if the database is the leader in its cluster For a standalone or active-backup database, this is always true For a relay 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 empty

index: optional integer

For a clustered database, the index of the log entry currently exposed to clients For a given server, this increases monotonically 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 empty