openstack/ironic
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Document the check done in "ironic-dbsync upgrade"

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This adds documentation about the version check done by the
"ironic-dbsync upgrade" command.

Change-Id: Id213784602658692ea452edebfb874b26f127c58
This commit is contained in:
Ruby Loo 2017-12-19 12:00:29 -05:00
parent 77246085af
commit 7e38a08ee2
1 changed files with 18 additions and 0 deletions
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18
doc/source/contributor/rolling-upgrades.rst
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@ -51,6 +51,9 @@ Ironic supports rolling upgrades as described in the
The upgrade process will cause the ironic services to be running the ``FromVer``
and ``ToVer`` releases in this order:
0. Upgrade ironic code and run database schema migrations via the
``ironic-dbsync upgrade`` command.
1. Upgrade code and restart ironic-conductor services, one at a time.
2. Upgrade code and restart ironic-api services, one at a time.
@ -433,6 +436,9 @@ following needs to be considered:
Online data migrations
----------------------
The ``ironic-dbsync online_data_migrations`` command will perform online
data migrations.
Keep in mind the `Policy for changes to the DB model`_.
Future incompatible changes in SQLAlchemy models, like removing or renaming
columns and tables can break rolling upgrades (when ironic services are run
@ -482,3 +488,15 @@ longer contains references to the old schema. Before removing any resources
from the database by modifying the schema, make sure that your implementation
checks that all objects in the affected tables have been migrated. This check
can be implemented using the version column.
"ironic-dbsync upgrade" command
-------------------------------
The ``ironic-dbsync upgrade`` command first checks that the versions of the
objects are compatible with the (new) release of ironic, before it will make
any DB schema changes. If one or more objects are not compatible, the upgrade
will not be performed.
This check is done by comparing the objects' ``version`` field in the database
with the expected (or supported) versions of these objects. The supported
versions are the versions specified in
``ironic.common.release_mappings.RELEASE_MAPPING``.