Add Redis password support to KV cache scorer

[relyt0925]

Introduced handling for a new environment variable KVCACHE_INDEXER_REDIS_PWD to enable optional Redis password configuration. This improves flexibility for connecting to secured Redis instances.

[elevran]

Thanks for the PR @relyt0925 !
I think there is an unintended cut-n-paste error - please see suggestion.

Please also let us know what you think regarding the use of the Redis connection to encode the needed parameters. If you agree with the comment - please consider opening a PR to fix the documentation and extend it to show how one might go about adding the username, password, etc. to the connection string.

[elevran]

Suggested change

	config.KVBlockIndexerConfig.RedisPassword = redisAddr
	config.KVBlockIndexerConfig.RedisPassword = redisPassword

?

[elevran]

I would expect the PR to also contain a change where password is used in the Redis connection. Otherwise, the environment variable has no effect on the connection.

Redis connection string format is redis[s]://[[username][:password]@][host][:port][/db-number].
So we either encode all information in the kvCacheRedisEnvVar variable (which I think is the current intent), or we should expose different variables for each URL element to make it completely configurable.

At this time, the use of a single connection string is simpler and allows setting all needed components, including the password.
Perhaps documentation should make this clearer with some examples.

CC: @vMaroon

[relyt0925]

Oh my gosh sorry for that basic error will fix!

[elevran]

No problem. That's what PR reviews are for.
Would appreciate your thoughts on the use of connection string to capture all needed aspects, not just the password

[relyt0925]

I like using the connection string for all of it! can edit

[elevran]

Per @vMaroon 👍on #131 (comment) - I think this was the intent: the Redis Address would capture all needed parameters and there's no need for a per element environment variable.

I think this means that no code changes are required, and we should emphasize this in the documentation, possibly with examples.

I like using the connection string for all of it! can edit

Do you mean that you will create a documentation PR update?

[relyt0925]

@elevran let me double check with a test that the connection string is fully passing today (we use a secure redis deployment using rediss protocol with user pass. If so: yep I can just add a reference in the doc on how to specify that!

[relyt0925]

Right now seeing

{"level":"error","ts":"2025-05-27T15:45:15Z","caller":"pd/scheduler.go:167","msg":"KVCache scorer creation failed","error":"failed to create KVCacheIndexer: failed to create RedisKVBlockIndexer: could not connect to Redis: dial tcp: address rediss://XXXXXXXXXX:XXXXX@bd73f810-0eea-46a9-b330-84c9bc36d00d.blrrvkdw0thh68l98t20.private.databases.appdomain.cloud:31394/0: too many colons in address","stacktrace":"github.com/llm-d/llm-d-inference-scheduler/pkg/scheduling/pd.(*Scheduler).pluginsFromConfig\n\t/workspace/pkg/scheduling/pd/scheduler.go:167\ngithub.com/llm-d/llm-d-inference-scheduler/pkg/scheduling/pd.(*Scheduler).generateSchedulerConfig\n\t/workspace/pkg/scheduling/pd/scheduler.go:216\ngithub.com/llm-d/llm-d-inference-scheduler/pkg/scheduling/pd.NewScheduler\n\t/workspace/pkg/scheduling/pd/scheduler.go:79\nmain.run\n\t/workspace/cmd/epp/main.go:185\nmain.main\n\t/workspace/cmd/epp/main.go:122\nruntime.main\n\t/usr/local/go/src/runtime/proc.go:283"}

[vMaroon]

Apologies for missing this earlier, @relyt0925 the option Etai referred to would go as follows (from redis-go docs):

opt, err := redis.ParseURL("redis://<user>:<pass>@localhost:6379/<db>")
if err != nil {
	panic(err)
}

client := redis.NewClient(opt)

While that was the intention originally, the code uses:

	redisClient := redis.NewClient(&redis.Options{
		Addr:     config.RedisAddr,
		Password: config.RedisPassword,
		DB:       config.RedisDB,
	})

The configuration that feeds that can be seen here: https://github.com/llm-d/llm-d-kv-cache-manager/blob/aecde47b630d5f85d5fe27716b2bbed558d00e80/pkg/kv-cache/kvblock-indexer.go#L61

I propose that you:

1. Implement the parsing here. The returned object contains the address, password and rest of fields that can feed into the config linked above. Alternatively, can revert back to a password env-var temporarily.
   • The tradeoff is a go-redis module import
2. Follow-up on a "fix" in the llm-d-kv-cache-manager repo
3. Come back with a clean-up and import version bump in a follow-up PR here

If you and @elevran agree, this should be tracked in an issue.

[relyt0925]

Yes agreed let me move this to issue and copy discussion and will implement!

[relyt0925]

closing for now: likely will reopen to a document only pr if address var passes all variables through

[relyt0925]

Moving to issue and will adjust implementation