Commit Graph
6 Commits
Author SHA1 Message Date
Chris LuandDevin 3fd8d0cf09 master: let location-constrained assigns wait for pending growth (#12167)
* topology: add AvailableSpaceWithinLocation for location-scoped free slots

AvailableSpaceFor answers for the whole topology; a location-constrained
assign needs to know whether the requested data center, rack, or data node
still has room before deciding growth can satisfy it.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* master: let location-constrained assigns wait for pending growth

An assign carrying a data center or rack constraint failed on the first
unsatisfied pick, even when the same request had just queued volume growth
for that location — so the first write into a fresh collection errored out
instead of picking up the volume growth landed a moment later.

Keep the fail-fast path only when growth cannot help: growth disabled, no
growth pending, or no free slots left inside the constraint. Otherwise the
request takes the same wait/shed path as an unconstrained assign.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* topology: sum leaf free slots in AvailableSpaceWithinLocation

Rolled-up rack and data center counters keep a maintenance-mode server's
capacity, and one overcommitted node can cancel a sibling's slots. Sum the
matching data nodes directly so the location check agrees with what growth
can actually use.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* master: let constrained growth initiators reach the shed path

When a constrained assign's own growth concluded unfulfilled, the fast-fail
check saw only that no grow was pending and returned the plain pick error —
a code the assign client does not retry, so the first write died instead of
re-triggering growth. Exclude the request's own initiated grow from the
no-pending-growth condition so it reaches the existing re-pick and
ResourceExhausted shed like an unconstrained assign.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* master: judge targeted grow requests by the location they name

A grow request carrying a data center, rack, or data node constraint was
discarded whenever the layout's writables elsewhere were healthy, so a
location with free slots but no writable could never receive the volume its
assign was waiting for. Add ShouldGrowVolumesWithinLocation and use it for
constrained requests; the layout-wide check still governs untargeted ones.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* topology: only positive leaf slots count in AvailableSpaceWithinLocation

An over-committed node reports negative free slots; summed plainly it\ncancelled a sibling's room and a constrained assign could fail fast\nwhile the location still had space to grow into.

* master: fail constrained assigns fast when growth cannot place

A constrained assign with free slots in its location still waited out\ngrowth that could never satisfy the replica placement — a single-rack\ndata center asked for 010 sheds the same doomed grow on every client\nretry. Run the grow-time node search as a dry run and return its\nplacement error instead of a retryable shed.

* master: judge constrained growth by layout, not free slots

A slot-level feasibility probe races with the grow it judges: a\npending grow consuming the last slot in one rack reports the\nplacement impossible while it mints the request's own volume, and\nthe hard error skips the re-pick that would find it. GrowthBlocker\nnow counts racks and data nodes inside the named location — shape a\ngrow cannot consume — so only genuinely unplaceable layouts fail\nfast.

* topology: GrowthBlocker mirrors the grow selector's feasibility

The location filter bound every replica tier, so a 010 request naming one rack needed two racks inside it while the selector constrains only the first placement and counts the rest by room. And counting nodes without free slots let a full location queue a grow it could never serve, so the assign shed ResourceExhausted at timeout instead of failing fast. GrowthBlocker now applies the option's location to the primary placement chain only and leaf-sums free slots the way the selector does, so it reports a blocker exactly when the grow can never place.

* master: repick once before surfacing a growth blocker

An in-flight grow can spend the last free slot minting the request's own volume: the blocker's slot counts predate that registration by a heartbeat, so returning the placement error on the first failed pick could reject a write whose volume lands a moment later. A pending grow now earns one repick grace before the blocker error is returned.

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Co-authored-by: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>
2026-10-28 08:10:45 -07:00
Nguyễn Đăng Minh LựcandChris Lu c462fffce6 master: name the unlabeled disk layout plainly in assign errors (#11290)
* master: name the unlabeled disk layout plainly in assign errors

When no volume server serves the layout an assign targets, the error
named the empty disk type as "hdd" (HardDriveType is the empty string),
sending operators looking for servers labeled hdd when the actual
mismatch is labeled (e.g. -disk=ssd) servers versus unlabeled clients.

- describe the layout as "default (unlabeled)" when the disk type is
  empty, keep %q naming for labeled types
- log the unserved-layout condition once per option instead of letting
  every failing write repeat an unactionable line

Observed in production: volume servers started with -disk=ssd while CSI
mounts assign with the unlabeled layout; the per-write error stream
pointed at a nonexistent hdd fleet.

* master: bound and expire the unserved-layout warning dedupe

The dedupe map retained every distinct option key permanently. Option
keys embed request-derived fields (collection, disk type), so repeated
assignments with distinct options would grow master memory without
bound, and a retained key suppressed the warning if the same option
went unserved again after the topology recovered.

Remember last-warned timestamps instead, expiring after an hour, with a
hard cap that resets the set when a client-driven key flood fills it.

* master: silence per-retry unserved-layout log and name explicit hdd

Addresses Devin Review comments on #11290.

- The unserved-layout branch already rate-limits its warning via
  assignUnservedLayoutWarning.Do, but the common epilogue still logged
  lastErr at V(0) on every retry, so the flood the dedup was meant to
  stop continued. Skip the epilogue log when the unserved-layout branch
  owns the logging; the error is still returned to the client.
- describeDiskLayout took the canonicalized option.DiskType, but
  ToDiskType folds both "" and "hdd" into HardDriveType, so an explicit
  disk=hdd request was mislabeled "default (unlabeled)". Pass the
  original request disk type instead: only an empty request is the
  unlabeled default; an explicit hdd is named "hdd".

Adds TestAssignFailsFastNamesExplicitHdd covering the explicit-hdd
wording.

---------

Co-authored-by: Chris Lu <chris.lu@gmail.com>
2026-09-13 11:56:32 -07:00
Chris Lu 0c59c0fb05 master: scope the startup capacity shed to a truly empty topology (#11058)
* master: scope the startup capacity shed to a truly empty topology

The retryable "no volume server capacity registered yet" shed checked
capacity for the requested disk type, so a cluster serving only other
media -- where that capacity will never register -- shed every assign
until the client's deadline instead of failing fast. An unsteered write
to such a cluster hung for its full HTTP deadline and surfaced "context
deadline exceeded" in place of "No writable volumes". Shed only while
no disk type has any registered capacity, and name the unserved medium
in the fast failure.

Claude-Session: https://claude.ai/code/session_01TF7FQghfDkpdoZgakTMX4R

* master: name the unserved medium for every fail-fast caller

The diagnostic sat in the growth-initiator block, so a follower joining
an in-flight growth and a growth-disabled master failed the same way
with only the generic pick error. Wrap at the fail-fast break instead,
which every caller reaches, and cover all three paths in the test.

Claude-Session: https://claude.ai/code/session_01TF7FQghfDkpdoZgakTMX4R
2026-08-31 21:29:27 -07:00
Chris Lu d3b8030a69 master: shed assigns retryably until volume servers register capacity (#11032)
An assign arriving before any volume server has heartbeated saw zero
available space and failed outright with a plain error no client retries,
so the first write to a fresh bucket answered 500 while the cluster was
still starting. Distinguish a topology with no registered capacity from a
genuinely full one: fail fast only when registered capacity is exhausted,
and shed ResourceExhausted otherwise so the client's retry budget rides
out the startup window.

Claude-Session: https://claude.ai/code/session_018G9kWFgy8BaBAEkYV3YL9n
2026-08-30 11:08:53 -07:00
Chris Lu 6206f60032 fix(master): let the growth initiator wait instead of shedding itself (#10202)
* fix(master): let the growth initiator wait for the growth it triggered

The growth-in-flight shed also fired on the request that initiated the
growth: it sets the pending flag right before the shed check, so a
cold-start assign enqueued growth and immediately failed itself with
"volume growth in progress". With no concurrent assigns around to pick
up the freshly grown volume, a single writer against an empty cluster
never completes a write despite ample free space.

Claim the pending flag with a compare-and-swap so exactly one request
becomes the initiator, triggering growth at most once, and let it wait
for that growth to land. Everyone else still sheds retryably instead of
pinning a goroutine: followers behind an in-flight growth, an initiator
whose growth concluded without yielding a writable volume, and an
initiator whose growth outlives the 10s wait budget, which previously
surfaced a non-retryable error (gRPC Unknown, HTTP 406) even though a
retry would have succeeded moments later.

* fix(master): stop assign waits when the request is cancelled

The assign retry loops slept through client cancellation, keeping a
goroutine spinning for the rest of the 10s budget after the caller had
gone; StreamAssign also ran assigns on a background context detached
from the stream. Wait on the request context and pass the stream
context through.

* topology: drop the unconditional grow-request setter

Growth is only claimed through AddGrowRequestIfAbsent's compare-and-swap
now; keeping the raw Store(true) around invites the check-then-set race
back.

* test: cover cold-start first write with a real cluster

Boot a fresh master plus three empty volume servers and require the very
first assign - HTTP and gRPC, each on a cold volume layout, no client
retries - to complete a write. The assign that triggers volume growth
must wait for it rather than answering "volume growth in progress";
unit tests stub the topology, so only a real cluster exercises the
assign-grow-wait path end to end.
2026-07-02 15:13:46 -07:00
Chris Lu f643893891 fix(master): shed assign load when volume growth is already in flight (#10121)
Under a herd of concurrent assigns with no writable volume, Assign spun
PickForWrite for the full 10s timeout, pinning a goroutine per request and
starving the master of the cycles it needs to process growth and answer
heartbeats. When growth is the relevant remedy and already in flight, stop
spinning: if free space exists, shed with a fast retryable error so clients
back off and retry once growth lands; if the cluster is out of space, fail fast
with the real out-of-space error instead of masking it as retryable.

The gRPC shed uses ResourceExhausted, not Unavailable: operation.Assign retries
it, but the client connection layer doesn't treat it as a dead channel, so a
per-request shed across a herd doesn't tear down the shared master connection
and cancel every other in-flight assign. The HTTP dirAssignHandler sheds with
503 + Retry-After.
2026-06-26 14:23:40 -07:00