54efd31239
This adds the new command 'ironic-dbsync online_data_migrations'. To limit downtime during upgrades, data migrations will be done online with migration scripts that could be run during normal operation of an ironic cluster, after the upgrade but before the next one. Each migration script should ensure that all related DB records are migrated to the new format. Scripts can detect the format based on the object version which is stored in the version column. The online data migration has one script; a function that backfills the new version column, using versions of objects from the release prior to this. This includes code to check the object versions for compatibility with an ironic release. However, the check is turned off (and will be turned on in Queens), since we need to boot-strap the new version column before we can turn the check on. To do this check, we need to keep a list of all supported versions for every object; release_mapping.RELEASE_MAPPING was modified so that the object versions is now a list instead of one value. Change-Id: I1a9fa829951ecf98cae6896d82ba20cf89062394 Closes-Bug: #1585141 Partial-bug: #1526283 Co-Authored-By: Ruby Loo <ruby.loo@intel.com>
6.1 KiB
ironic-dbsync
The ironic-dbsync utility is used to create the
database schema tables that the ironic services will use for storage. It
can also be used to upgrade existing database tables when migrating
between different versions of ironic.
The Alembic library is used to perform the database migrations.
Options
This is a partial list of the most useful options. To see the full list, run the following:
ironic-dbsync --helpironic-dbsync
-h, --help
Show help message and exit.
--config-dir <DIR>
Path to a config directory with configuration files.
--config-file <PATH>
Path to a configuration file to use.
-d, --debug
Print debugging output.
--version
Show the program's version number and exit.
upgrade, stamp, revision, version, create_schema, online_data_migrations
The command <dbsync_cmds> to run.
Usage
Options for the various commands <dbsync_cmds> for ironic-dbsync are listed
when the -h or --help option is used
after the command.
For example:
ironic-dbsync create_schema --helpInformation about the database is read from the ironic configuration
file used by the API server and conductor services. This file must be
specified with the --config-file option:
ironic-dbsync --config-file /path/to/ironic.conf create_schemaThe configuration file defines the database backend to use with the connection database option:
[database]
connection=mysql+pymysql://root@localhost/ironicIf no configuration file is specified with the --config-file option,
ironic-dbsync
assumes an SQLite database.
Command Options
ironic-dbsync is
given a command that tells the utility what actions to perform. These
commands can take arguments. Several commands are available:
create_schema
create_schema
-h, --help
Show help for create_schema and exit.
This command will create database tables based on the most current version. It assumes that there are no existing tables.
An example of creating database tables with the most recent version:
ironic-dbsync --config-file=/etc/ironic/ironic.conf create_schemaonline_data_migrations
online_data_migrations
-h, --help
Show help for online_data_migrations and exit.
--max-count <NUMBER>
The maximum number of objects (a positive value) to migrate. Optional. If not specified, all the objects will be migrated (in batches of 50 to avoid locking the database for long periods of time).
This command will migrate objects in the database to their most recent versions. This command must be successfully run (return code 0) before upgrading to a future release.
It returns:
- 1 (not completed) if there are still pending objects to be migrated. Before upgrading to a newer release, this command must be run until 0 is returned.
- 0 (success) after migrations are finished or there are no data to migrate
- 127 (error) if max-count is not a positive value
- 2 (error) if the database is not compatible with this release. This command needs to be run using the previous release of ironic, before upgrading and running it with this release.
revision
revision
-h, --help
Show help for revision and exit.
-m <MESSAGE>, --message <MESSAGE>
The message to use with the revision file.
--autogenerate
Compares table metadata in the application with the status of the database and generates migrations based on this comparison.
This command will create a new revision file. You can use the --message option to
comment the revision.
This is really only useful for ironic developers making changes that require database changes. This revision file is used during database migration and will specify the changes that need to be made to the database tables. Further discussion is beyond the scope of this document.
stamp
stamp
-h, --help
Show help for stamp and exit.
--revision <REVISION>
The revision number.
This command will 'stamp' the revision table with the version
specified with the --revision option. It will not run any
migrations.
upgrade
upgrade
-h, --help
Show help for upgrade and exit.
--revision <REVISION>
The revision number to upgrade to.
This command will upgrade existing database tables to the most recent
version, or to the version specified with the --revision option.
If there are no existing tables, then new tables are created,
beginning with the oldest known version, and successively upgraded using
all of the database migration files, until they are at the specified
version. Note that this behavior is different from the create_schema command that
creates the tables based on the most recent version.
An example of upgrading to the most recent table versions:
ironic-dbsync --config-file=/etc/ironic/ironic.conf upgradeNote
This command is the default if no command is given to ironic-dbsync.
Warning
The upgrade command is not compatible with SQLite databases since it uses ALTER TABLE commands to upgrade the database tables. SQLite supports only a limited subset of ALTER TABLE.
version
version
-h, --help
Show help for version and exit.
This command will output the current database version.