Redis 7.4+ is RSALv2/SSPL and 8.0+ adds AGPLv3. None of the three works
for a closed-source commercial cloud service, and SSPL section 13
specifically targets offering the software's functionality as a service,
which is what a control plane does. Valkey is BSD-3-Clause, under the
Linux Foundation, forked from Redis 7.2.4.
Deciding this now rather than after step 3 of PLAN.md stands up real
infrastructure makes it free: Valkey speaks the same RESP protocol, so
`ioredis` is untouched and only names change. `REDIS_URL` becomes
`VALKEY_URL`, the exported client becomes `valkey`, and `/health`
reports a `valkey` field.
Two things deliberately do not change, documented in place so they are
not "fixed" later: the `redis://` URL scheme, which names the wire
protocol and is what every client actually parses (none understands
`valkey://`), and `ioredis` itself, which is a RESP client whose name
refers to the protocol's origin and not to the server we run.
docker-compose.yml is new, pinning valkey/valkey:8-alpine alongside
pgvector/pgvector:pg17 - the plain postgres image lacks the extension
`frame_embeddings` needs. It makes the Valkey choice concrete rather
than a note someone has to remember.
octoturge