Skip to content

[Bugfix][Elastic EP] Clear scaling flag on failure to prevent permane… #50778

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
gagandhakrey wants to merge 2 commits into
base: main
Choose a base branch
from
+16 −14
Open

[Bugfix][Elastic EP] Clear scaling flag on failure to prevent permane… #50778

Changes from 1 commit
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
3ef6627
[Bugfix][Elastic EP] Clear scaling flag on failure to prevent permane…
gagandhakrey Aug 2, 2026
1991b64
Merge branch 'main' into fix/elastic-ep-scaling-flag-latch
gagandhakrey Aug 2, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
30 changes: 16 additions & 14 deletions vllm/v1/engine/async_llm.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1018,15 +1018,11 @@ async def wait_for_requests_to_drain(self, drain_timeout: int = 300):
)

async def _drain_requests_for_elastic_ep(self, drain_timeout: int) -> None:
try:
logger.info(
"VLLM_ELASTIC_EP_DRAIN_REQUESTS is set, "
"waiting for requests to drain before scaling"
)
await self.wait_for_requests_to_drain(drain_timeout)
except BaseException:
set_scaling_elastic_ep(False)
raise
logger.info(
"VLLM_ELASTIC_EP_DRAIN_REQUESTS is set, "
"waiting for requests to drain before scaling"
)
await self.wait_for_requests_to_drain(drain_timeout)

async def scale_elastic_ep(
self, new_data_parallel_size: int, drain_timeout: int = 300
Expand Down Expand Up @@ -1065,13 +1061,19 @@ async def _scale_elastic_ep(
self._logger_ref[0] = self.logger_manager
self.logger_manager.log_engine_initialized()

# ScalingMiddleware 503s every request while this is set, including the
# /scale_elastic_ep call that would clear it, so never leave it latched.
set_scaling_elastic_ep(True)
if envs.VLLM_ELASTIC_EP_DRAIN_REQUESTS:
await self._drain_requests_for_elastic_ep(drain_timeout)
try:
if envs.VLLM_ELASTIC_EP_DRAIN_REQUESTS:
await self._drain_requests_for_elastic_ep(drain_timeout)

await self.engine_core.commit_elastic_ep()
self.vllm_config.parallel_config.data_parallel_size = new_data_parallel_size
set_scaling_elastic_ep(False)
await self.engine_core.commit_elastic_ep()
self.vllm_config.parallel_config.data_parallel_size = (
new_data_parallel_size
)
finally:
set_scaling_elastic_ep(False)

async def handle_fault(
self, fault_tolerance_request: FaultToleranceRequest
Expand Down
Loading