Fix allocations default table type

In trying to figure out why I was unable to run
all of the test_migrations tests, I realized we need
to fix and clean up our unicode declarations.

Specifically, the way I found this was my local mysql
install was defaulted to using 4 Byte Unicode characters,
however some of our fields are 255 characters, which do not
fit inside of InnoDB tables.

They do, however fit with the "utf8" storage alias, which is
presently short for UTF8MB3, as opposed to UTF8MB4 which is
what my local database server was configured for. Because this
was in opportunistic tests, I wasn't able to really sort out
what was going on and thought we needed to shorten the fields.

In reality, it turns out we never defined the allocations
table to use UTF8 and Innodb for storage.

Storage engine wise, this is not a big deal, but may mean a
DBA will one day need to dump and reload the allocation table
of a deployment.

Character set wise... It is not great, but there is not a good
way for us to do this programatically. In my opinion, the chance
of an issue being encountered by an operator is unlikely, which
out weighs the risk and impact of dumping the entire table,
deleting the table, recreating the table with the updated schema
and then repopulating the entries. Of course, if operators are not
using allocations, then it really doesn't matter for them.

Along the way, I discovered we had used the "UTF8" type alias,
which may change one day, which would break Ironic. As such,
I've also updated the definitions used to create databases
and updated our documentation.

Recommended reading:
https://docs.sqlalchemy.org/en/14/dialects/mysql.html#unicode
https://dev.mysql.com/doc/refman/8.0/en/charset-unicode-utf8mb4.html

Story: 2010348
Task: 46492

Change-Id: I4103152489bf61e2d614eaa297da858f7b2112a3

2 files changed, 16 insertions, 1 deletions

diff --git a/doc/source/contributor/dev-quickstart.rst b/doc/source/contributor/dev-quickstart.rst
index 3fe03f02b..6f63104f9 100644
--- a/doc/source/contributor/dev-quickstart.rst
+++ b/doc/source/contributor/dev-quickstart.rst
@@ -131,6 +131,13 @@ The unit tests need a local database setup, you can use
 ``tools/test-setup.sh`` to set up the database the same way as setup
 in the OpenStack test systems.
 
+.. note::
+   If you encounter issues executing unit tests, specifically where errors
+   may indicate that a field is too long, check your database's default
+   character encoding. Debian specifically sets MariaDB to ``utf8mb4``
+   which utilizes 4 byte encoded unicode characters by default, which is
+   incompatible by default.
+
 Additional Tox Targets
 ----------------------
 
diff --git a/doc/source/install/include/common-prerequisites.inc b/doc/source/install/include/common-prerequisites.inc
index edaca46d0..718e80c9d 100644
--- a/doc/source/install/include/common-prerequisites.inc
+++ b/doc/source/install/include/common-prerequisites.inc
@@ -22,8 +22,16 @@ MySQL database that is used by other OpenStack services.
    .. code-block:: console
 
       # mysql -u root -p
-      mysql> CREATE DATABASE ironic CHARACTER SET utf8;
+      mysql> CREATE DATABASE ironic CHARACTER SET utf8mb3;
       mysql> GRANT ALL PRIVILEGES ON ironic.* TO 'ironic'@'localhost' \
              IDENTIFIED BY 'IRONIC_DBPASSWORD';
       mysql> GRANT ALL PRIVILEGES ON ironic.* TO 'ironic'@'%' \
              IDENTIFIED BY 'IRONIC_DBPASSWORD';
+
+.. note::
+   When creating the database to house Ironic, specifically on MySQL/MariaDB,
+   the character set *cannot* be 4 byte Unicode characters. This is due to
+   an internal structural constraint. UTF8, in these database platforms,
+   has traditionally meant ``utf8mb3``, short for "UTF-8, 3 byte encoding",
+   however the platforms are expected to move to ``utf8mb4`` which is
+   incompatible with Ironic.