73 lines
5.4 KiB
Markdown
73 lines
5.4 KiB
Markdown
---
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id: "bug-1968"
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status: "fixed"
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status_updated: "2026-10-10"
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status_note: ""
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component: "apiserver"
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severity: "wrong-result"
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timestamp: "2026-10-10T11:55:48Z"
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last_seen: "2026-10-10T11:55:48Z"
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occurrences: 1
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files: ["src/frontend/apiserver/controllers/jobs.go"]
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tags: ["apiserver", "restart", "submit"]
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related: ["bug-1936"]
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fix_commits: ["6a2c69f8"]
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gitea_issue: 399
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gitea_synced_status: "open"
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gitea_synced_hash: "a735a6546a0b"
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---
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# bug-1968: apiserver job restart copies asked hosts, begin/term time and I/O paths it can never pass on
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## Description
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**Observed:** (source reading, 2026-10-10; found while fixing bug-1936)
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`RestartJobByID()` (`src/frontend/apiserver/controllers/jobs.go:832`) builds the new job from the request plus the old job's row, and copies options that bug-1936 now refuses at submit because no field carries them to the controller or worker:
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```go
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if newJob.AskedHosts == "" {
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if v, ok := oldJob["asked_hosts"].(string); ok { newJob.AskedHosts = v }
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}
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if v, ok := oldJob["begin_time"].(time.Time); ok { ... } // also term_time,
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if v, ok := oldJob["out_dir"].(string); ok { ... } // in_file, err_file, out_file
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```
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`preCheckJobRestartRequest()` (`:1350`) validates `-m` asked hosts but does not refuse them the way `preCheckSubmitOptions()` (`:1307`, bug-1936) does for submit, so `xcecli jobs restart -m host ...` returns success and the host request is silently dropped.
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**Expected:** restart, like submit, either passes each option on to the job or rejects it with 400 (`preCheckSubmitOptions`-style); options copied from the old job that cannot be honoured are not silently kept in apiserver memory only.
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**Impact:** wrong result: a restarted job ignores the asked hosts, begin/term time and I/O paths the user gave, with no error.
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**Found by:** review during the bug-1936 fix, 2026-10-10.
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UPDATE (2026-10-10, during the fix): the same rebuild also lost options the job DOES get. Rows come from `store.StructToOrderMap`, which keeps each field's Go type, so `oldJob["chkpnt_info"].(string)` and `oldJob["extend_data"].(string)` never matched `models.Jsonb`: env/limits (exdata) were dropped on every restart and a checkpointed job never restarted from its checkpoint (`restart_command`, `XCE_JOB_CHECKPOINT_PID`). It also read `oldJob["res_req"]` (the column is `resreq`), dropping the resource requirement, and never copied `exec_home`.
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## Environment
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- OS: no /etc/os-release; Docker container; NixOS kernel; kernel Linux 6.18.33 x86_64
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- libc: glibc 2.42-47 (n/a: Go apiserver, CGO_ENABLED=0 tests)
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- Toolchain: gcc (GCC) 15.2.0, meson 1.9.1
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- Build: asan (xce.build)
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- Code: scheduler-framework @ edad8c73-dirty
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- Deployment: any (found by source reading)
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## Reproduction
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1. Submit a job, let it finish.
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2. `POST /xce/v1/jobs/<jobid>/restart` with body `{"asked_hosts":"<host>"}` (xcecli `jobs restart` has no `-m` flag and sends none), or restart a job whose row has out_file/out_dir set.
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3. The restart returns success; the new job is placed without regard to `<host>` (scheduler never receives asked hosts).
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- Frequency: deterministic (code path)
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- Evidence: the code quoted in Description; no logs kept.
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## Root cause
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`RestartJobByID()` (`src/frontend/apiserver/controllers/jobs.go`) rebuilds the new job by copying fields out of the old job's stored row. Its copy list predates bug-1936: it accepted `asked_hosts` in the request and copied asked hosts, begin/term time, in/out/err files and `out_dir`, none of which any job gets. The list was also never checked against the row's real keys and types: JSONB columns are `models.Jsonb` (not `string`) and the resource requirement key is `resreq` (not `res_req`), so those copies silently did nothing. Pre-existing, origin not bisected.
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## Fix
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`controllers/jobs.go`:
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- `preCheckJobRestartRequest()` refuses a non-blank `asked_hosts` with 400 ("job restart option asked_hosts not supported"), like `preCheckSubmitOptions()` (bug-1936); the request field stays so the client gets that message, not "unknown field". `processJobRestartRequest()` (which only copied asked hosts) is removed.
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- The restart no longer carries over asked hosts, begin/term time, in/out/err files or `out_dir`.
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- New `rowJSON()` reads a JSONB row column as `models.Jsonb` or string; used for `chkpnt_info` and `extend_data`, so a checkpointed job restarts with its restart command and checkpoint pid, and every restart keeps the old job's extended data (env, limits).
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- Copies `resreq` (was `res_req`) and `exec_home`.
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## Verification
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- Test: `TestJobHandler_RestartRejectsAskedHosts`, `TestJobHandler_RestartCarriesOnlyHonouredOptions`, `TestJobHandler_RestartFromCheckpoint` (`src/frontend/apiserver/controllers/jobs_handler_test.go`): RED before (`jobs_handler_test.go:1537: status = 200, want 400`; `:1592: restarted job kept asked_hosts, which no job gets` (also in_file/out_file/err_file/out_dir); `:1597: ExtendData = "", want ...`; `:1606: ResReq = "", want rusage[mem=100]`; `:1637: Command = "sleep 1", want the checkpoint's restart command`), GREEN after; with the fix stashed the three fail again. `TestJobHandler_RestartNamedJob` (bug-1898) still passes.
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- Suites: `xce-build.sh apiserver asan xce.build --incremental` (CGO build; apiserver + xcecli Go tests all ok), 2026-10-10; apiserver `CGO_ENABLED=0 go test ./...` all packages ok
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- Live: n/a: handler-level fixture tests only; no live restart of a checkpointed job was run (needs CRIU on a real worker)
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## References
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- Fix commit: `6a2c69f8`
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- Related: bug-1936 (submit-side rejection), bug-1898 (restart identity)
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