LXC task monitoring - #6344
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Additional details and impacted files@@ Coverage Diff @@
## master #6344 +/- ##
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- Coverage 70.60% 70.51% -0.09%
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Files 207 207
Lines 23637 23772 +135
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+ Hits 16688 16763 +75
- Misses 6949 7009 +60 ☔ View full report in Codecov by Harness. 🚀 New features to boost your workflow:
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Even with external schedulers that manage the slot assignment on their own when it comes to remote or LXC task spawning, these will have to go through the default reserved slot registration and any additional safety checks provided by the LXC/remote spawners. If the scheduler has done such checks itself then there is nothing to worry about but the following provides safety for the ones that may not. Also add an auxiliary detection for double spawned tasks that relies on an actual process check rather than the slot registry. This case is not supposed to be possible but an explicit error would always help and save enormous time from debugging. Signed-off-by: Plamen Dimitrov <plamen.dimitrov@intra2net.com>
The async container command run was suspending the current coroutine via non-asyncio-loop-blocking `os.waitpid` but this would still not allow the current coroutine to continue to a task monitoring stage which is implicitly assumed by the overall avocado task state machine. Let's provide the full "async" (fire and forget) of the async container command runs by fully detaching from the container and returning the pid instead (as done in python-lxc as well). The previous `os.waitpid` is almost identical to python-lxc's `container.attach_wait()` instead of `container.attach()` and we could have used os.waitpid(pid, os.WNOHANG|os.WUNTRACED) but so far rely on our previous task pulse checking approach in order to minimize changes (too many for a single commit). Container setup needs waiting for completion instead and now uses the already properly defined sync container command run. Signed-off-by: Plamen Dimitrov <plamen.dimitrov@intra2net.com>
The task was never properly monitored before so this needed str conversion was never detected. Log additional outputs to improve debugging in case of nonzero status as well. Signed-off-by: Plamen Dimitrov <plamen.dimitrov@intra2net.com>
The task might not be started yet and reported as not alive or there can be other race conditions that should be properly handled this way. Signed-off-by: Plamen Dimitrov <plamen.dimitrov@intra2net.com>
We have to be more careful when comparing against other processes that may contain the task identifier as well. This makes sure the task identifier is detected in an actual task process. Signed-off-by: Plamen Dimitrov <plamen.dimitrov@intra2net.com>
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Inline comments:
In `@optional_plugins/spawner_remote/avocado_spawner_remote/__init__.py`:
- Line 232: Update the RemoteSpawner.run_remote_cmd() call in the remote task
spawning path to supply its required timeout argument, using the appropriate
existing timeout value or configuration. Preserve the current session and
command handling while ensuring the background launch command is sent without
raising TypeError.
- Around line 171-176: Update the liveness handling around the alive calculation
so RemoteSpawner.release_slot(session) runs only when the ps command succeeds
and confirms an empty or zombie process state; retain the slot whenever status
is nonzero or the process state is unavailable.
In `@static-checks`:
- Line 1: Update the static-checks dependency pin for Black to a release
compatible with Python 3.9, preserving the existing make
requirements-static-checks installation flow; do not raise Avocado’s minimum
Python version as part of this targeted fix.
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Included review availability: Your plan provides up to 2 included reviews per hour; 1 remains after this review. WalkthroughLXC and remote spawners now capture task PIDs, check process liveness, terminate tasks with bounded signal escalation, and release slots after failures or task completion. LXC asynchronous commands discard output, and temporary stream files close descriptors before removal. Slot reservation validates custom slots. Functional tests cover the updated LXC behavior, and the expected test count is updated. Estimated code review effort: 4 (Complex) | ~45 minutes Merge Risk: 🟡 Moderate · up to The PR adds PID-based remote task monitoring, termination, and slot cleanup. Stale or reused process identities could terminate the wrong process or free a slot for overlapping work, while probe failures may leave tasks waiting indefinitely; static checks also cannot install on supported Python 3.9. These issues should be fixed or explicitly accepted before merge. 🚥 Pre-merge checks | ✅ 4 | ❌ 1❌ Failed checks (1 warning)
✅ Passed checks (4 passed)
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Inline comments:
In `@optional_plugins/spawner_remote/avocado_spawner_remote/__init__.py`:
- Around line 228-231: Update the cancellation flow associated with
cmd_status_output() to terminate runtime_task.remote_task_pid instead of calling
session.sendcontrol("c"). After sending termination, poll is_task_alive() until
process status confirms the tracked remote task has exited, preserving the
remote slot cleanup behavior.
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Actionable comments posted: 3
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Inline comments:
In `@optional_plugins/spawner_remote/avocado_spawner_remote/__init__.py`:
- Around line 175-185: Update is_task_alive and its wait_task polling state to
track consecutive failures from run_remote_cmd, including statuses 2 and 3,
while preserving the existing alive response for a limited retry window. Once
the configured failure threshold is reached, log the non-recoverable ps probe
failure, release the slot, and return false so _wait_task_exit can complete;
reset the counter after a successful probe.
- Around line 241-245: Update the background command construction in the remote
task launch flow around RemoteSpawner.run_remote_cmd to redirect stderr to
/dev/null alongside stdout, ensuring the detached process cannot contaminate
reused session command output or is_task_alive parsing.
- Around line 315-319: Remove the RemoteSpawner.release_slot call from
check_task_requirements so it only validates requirements and returns success.
Ensure slot release occurs only after a valid reservation with a non-None
spawner handle, preserving reserve_slot initialization and preventing None from
entering slots_cache.
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Move from a 10-second blocking checks in order not to miss a pgrep line to a more reliable and simpler PID checks by either extracting the background forked remote PID or the direct LXC attached process PID. There can be no races in need of short loop-range checks as the PID is provided earlier on and repeated checks introduce only minimal pulse check overhead. The pulse check is protective of the occupancy in either spawner case so that invalid checks cannot result in the slot being deemed free and compound errors. This means that OSError in LXC/waitpid and >1 status in remote/ps as well as other malformations would deem the task still alive and the slot still occupied. Signed-off-by: Plamen Dimitrov <plamen.dimitrov@intra2net.com>
This subbranch unified the LXC and remote task pulse detection.
The respective `reserve_slot` context manager from the respective `with_slot_reservation` decorator is no longer fully utilized for both slot setup and cleanup and the `finally` clause there will immediately free a slot with a task that was only recently spawned and still running (unlike asynchronously completing in the past). This means that the newly added double occupied slot detection will error out the moment slot gets reused twice. Therefore, let's respect the now-extra-validated slot occupancy flags of both spawners and release a slot in four cases: 1) If task was not spawned (spawn_task returned False). 2) If reserving slot raised an exception. 3) If a task was terminated. 4) If a task is no longer alive (most frequent and usual case). The test contracts are now updated to expect occupied slots instead of the previously rather trivial unoccupied slot cache. The task termination should be improved later on in order to release the slot properly. Signed-off-by: Plamen Dimitrov <plamen.dimitrov@intra2net.com>
Make sure to close two leaked file descriptors per LXC stream file as well as delete any temporary paths for both sync and async runs and to redirect partial outputs (ending up as anonymous files on POSIX systems) to /dev/null in the case of async runs where we detach from the containerized process. Signed-off-by: Plamen Dimitrov <plamen.dimitrov@intra2net.com>
Perform three rounds of escalation starting with SIGTERM, moving on to SIGKILL, and ultimately shutting down LXC containers as a fallback otherwise not available for remote tasks. Signed-off-by: Plamen Dimitrov <plamen.dimitrov@intra2net.com>
Signed-off-by: Plamen Dimitrov <plamen.dimitrov@intra2net.com>
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Summary by CodeRabbit
Bug Fixes
Tests