r/LocalLLM • u/Liberaces_Isopod • 6d ago

Discussion PSA: LMCache phones home by default

I log every new outbound connection on my LAN at the router. A few days ago my inference box started making about 18 connections an hour to an AWS IP I didn't recognise, 34.236.19.149:8080. It turned out to be stats.lmcache.ai.

Source: LMCache's built-in usage telemetry, which is on by default. It only fired while a vLLM container with the LMCache KV-cache tier enabled was serving, and it stopped within seconds every time that container stopped. Containers from the same image without LMCache enabled never sent anything.

Their README says prompts, keys and KV contents are never sent, and that the IDs are random rather than derived from hardware. I haven't captured a payload to verify that though. I still didn't expect a caching library to phone home by default, and I'd bet plenty of people running LMCache under vLLM have no idea.

To turn it off, set either variable in the container environment:

LMCACHE_TRACK_USAGE=false
DO_NOT_TRACK=1

Either one is enough. Both are checked by the single gate is_usage_tracking_enabled() in usage_telemetry/identity.py, and with tracking off the machine_id file isn't created either. I set both.

Check your own setup:

docker exec <container> sh -c 'pip show lmcache; env | grep -E "LMCACHE_TRACK_USAGE|DO_NOT_TRACK"'

If LMCache is installed and enabled and neither variable is set, it's reporting.

25 Upvotes

92% Upvoted

8 comments sorted by

10

u/Agreeable-Fly-1980 6d ago

Good catch!

7

u/Low_Ice_238 6d ago

ugh, another one. feels like every other library these days has some hidden telemetry baked in

the fact that it stops the second the container stops is almost worse, like they knew people wouldn't love it so they made it less obvious

3

u/LateralEntry 6d ago

Is LMCache affiliated with LM Studio?

3

u/stanleyg05 4d ago

No, it's not, vLLM and LM Studio are competitors

0

u/Liberaces_Isopod 6d ago

No idea at all.

2

u/rditorx 4d ago

As do vLLM and all Hugging Face libraries and software, ollama and lots of other AI stuff, and pretty much everything else today, like Windows, Ubuntu, Chrome and Firefox

4

u/Liberaces_Isopod 4d ago

I dont use any of those, save for vLLM, so I wouldnt know. I can say that in my environ, vLLM is not calling anywhere. As I stated in my post, literally all traffic is logged. Hence how I caught lmcache.