This PR is an introductory step towards enforcing
RF-rack-valid keyspaces in Scylla.
The scope of changes:
* defining RF-rack-valid keyspaces,
* introducing a configuration option enforcing RF-rack-valid
keyspaces,
* restricting the CREATE and ALTER KEYSPACE statements
so that they never lead to RF-rack invalid keyspaces,
* during the initialization of a node, it verifies that all existing
keyspaces are RF-rack-valid. If not, the initialization fails.
We provide tests verifying that the changes behave as intended.
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Note that there are a number of things that still need to be implemented.
That includes, for instance, restricting topology operations too.
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Implementation strategy (going beyond the scope of this PR):
1. Introduce the new configuration option `rf_rack_valid_keyspaces`.
2. Start enforcing RF-rack-validity in keyspaces if the option is enabled.
3. Adjust the tests: in the tree and out of it. Explicitly enable the option in all tests.
4. Once the tests have been adjusted, change the default value of the option to enabled.
5. Stop explicitly enabling the option in tests.
6. Get rid of the option.
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Fixesscylladb/scylladb#20356Fixesscylladb/scylladb#23276Fixesscylladb/scylladb#23300
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Backport: this is part of the requirements for releasing 2025.1.
Closesscylladb/scylladb#23138
* github.com:scylladb/scylladb:
main: Refuse to start node when RF-rack-invalid keyspace exists
cql3: Ensure that CREATE and ALTER never lead to RF-rack-invalid keyspaces
db/config: Introduce RF-rack-valid keyspaces
7646e1448a