Troubleshooting

Troubleshooting and FAQ

A problem -> cause -> fix reference for common yacron2 failures, grounded in the source. Each entry names the exact config option, default, or code path involved. For full option semantics see the Configuration Reference; for deployment specifics see Production and Container Deployment.

Startup and configuration loading

"configuration file not found"

Symptom. yacron2 exits immediately with:

yacron2 error: configuration file not found, please provide one with the --config option

followed by the argument help, and exit code 1.

Cause. __main__.py defaults -c/--config to CONFIG_DEFAULT = "/etc/yacron2.d". When that default is in effect and the path does not exist (args.config == CONFIG_DEFAULT and not os.path.exists(args.config)), yacron2 prints the error and exits before constructing the scheduler.

Fix. Create /etc/yacron2.d/ and place *.yaml/*.yml files in it, or pass an explicit path with -c FILE-OR-DIR (a single file or a directory). Note the error text is only emitted for the default path; an explicit -c pointing at a missing file instead surfaces as a ConfigError (see below). The default changed from /etc/yacron.d to /etc/yacron2.d in 1.0.0; if you upgraded from yacron, move your config directory. See Migration from yacron and the Command-Line Reference.

"Configuration error" / a missing or unreadable explicit config file

Symptom. Configuration error: <message> is logged and yacron2 exits 1.

Cause. Any ConfigError raised during initial parse aborts startup (__main__.py wraps Cron(args.config) and exits on ConfigError). When -c points at a single file that is missing or unreadable, parse_config catches the OSError and re-raises it as a clean ConfigError with the OS message.

Fix. Correct the path/permissions or the YAML. Run yacron2 -v -c <path> to validate without starting the scheduler; on success it logs Configuration is valid. and exits 0. See Includes, Defaults, and Multi-File Config.

Reload errors do not crash a running daemon

Symptom. After editing a live config, the log shows Error in configuration file(s), so not updating any of the config.: (followed by the parse error) but jobs keep running with the old config.

Cause. This is by design. The scheduler re-reads the config each wakeup. If update_config() raises ConfigError, the loop logs it and keeps the previously-loaded cron_jobs (the assignment only happens on a successful parse). This applies only to reloads; a parse failure at initial startup still exits 1.

Fix. Fix the YAML; the next wakeup picks it up. A logging section that was broken and is later corrected is also re-applied on reload without a restart (logging config is only marked applied on success).

Standalone binary under a read-only root filesystem

Binary aborts at startup: "Could not create temporary directory" / "Operation not permitted"

Symptom. The downloaded standalone binary aborts at startup with Could not create temporary directory, or Error loading shared library …: Operation not permitted.

Cause. The standalone binary is a self-extracting PyInstaller executable: on each start it unpacks its embedded Python runtime into a temporary directory and loads shared libraries from there, so it needs a temp directory that is both writable and executable. Under a read-only root filesystem (a hardened container), /tmp is read-only too, and the unpack/exec fails. This requirement is unique to the standalone binary — the published container image and pip/pipx installs run yacron2 as an ordinary Python package and never self-extract.

Fix. Provide a small writable, executable temp mount. With Docker, note that --tmpfs defaults to noexec, so you must request exec explicitly:

docker run --rm --read-only \
  --tmpfs /tmp:rw,exec,nosuid,nodev,size=64m \
  -v "$PWD/yacron2tab.yaml:/etc/yacron2.d/yacron2tab.yaml:ro" \
  your-image-with-the-binary -c /etc/yacron2.d

On Kubernetes mount an emptyDir at /tmp (writable and executable by default; medium: Memory for a tmpfs). Alternatively point the binary at any other writable, executable directory with TMPDIR=/path. See Installation and Production and Container Deployment.

Per-job user/group switching

"yacron2 is not running as superuser"

Symptom. Startup (or reload) fails with:

Job <name> wants to change user or group, but yacron2 is not running as superuser

Cause. A job sets user and/or group. _resolve_user_group raises this ConfigError whenever self.uid or self.gid is set and os.geteuid() != 0. Dropping to another user requires the daemon itself to start as root.

Fix. Run the daemon as root if you need per-job privilege drop, or remove the user/group fields from the job. Related ConfigErrors from the same code path:

• User not found: '<user>' — a string user is not in the passwd database (getpwnam raised KeyError).
• Group not found: '<group>' — a string group is not in the group database.

A numeric user without an explicit group derives its primary gid (and login name, used for supplementary groups) from the passwd database; if the uid is not in the database, the gid is left unset and supplementary groups are cleared. See Commands and Environment.

Web control API

API serves without authentication / refuses to start

Symptom (intended hardening). With web.authToken configured, yacron2 either logs web: requiring bearer-token authentication and requires Authorization: Bearer <token> on every route, or raises:

web.authToken is configured but resolved to an empty token; refusing to start the web API without authentication

Cause. _resolve_web_token fails closed. If authToken is present but resolves to an empty string — an unset fromEnvVar, an empty/missing fromFile, or an empty value — it raises ConfigError rather than silently serving the control API unauthenticated. A fromFile that cannot be read raises web.authToken.fromFile could not be read: …. If authToken is entirely absent, the API listens without auth (this is the default).

Fix. Ensure exactly one of value/fromFile/fromEnvVar resolves to a non-empty secret. Precedence is value, then fromFile, then fromEnvVar. The Bearer scheme is matched case-insensitively and the token is compared in constant time (hmac.compare_digest); a wrong/absent token returns 401. See HTTP Control API.

Web listen URL is ignored

Symptom. A web.listen entry never accepts connections; the log shows web: could not listen on <url>: <error> or Ignoring web listen url <url>: ….

Cause. Per-address failures are warned-and-skipped, not fatal. A malformed http:// URL (missing host or port) or an unsupported scheme raises ValueError internally and is skipped; a bind OSError (port in use, permission, bad socket path) is likewise skipped. Only http:// and unix:// schemes are supported. The web: started listening on <url> message is logged only after the bind succeeds.

Fix. Use a supported scheme with host and port (http://127.0.0.1:8080) or a unix:// path, and resolve the bind error. For a unix:// socket on a read-only root filesystem, point it at a writable volume and optionally set web.socketMode (octal string) for permissions.

Duplicate web or logging across a config directory

Symptom. Startup fails with Multiple 'web' configurations found: first in …, now in … (or the same for logging).

Cause. When -c is a directory, _parse_config_dir aggregates across files but allows at most one web block and one logging block total; a second one raises ConfigError. (Within include chains the equivalent errors are multiple web configs / multiple logging configs.)

Fix. Keep web and logging in a single file. See Includes, Defaults, and Multi-File Config and Logging Configuration.

Scheduling

A job runs immediately on startup (or never runs at startup)

Symptom. A job fires the moment yacron2 starts, or you expected one to fire at startup and it did not.

Cause. At startup (startup=True), job_should_run returns True only for jobs whose schedule is the literal string @reboot; all CronTab-scheduled jobs return False and wait for their next matching minute. yacron2 wakes aligned to the start of each minute and runs a CronTab job when crontab.test(now.replace(second=0)) matches.

Fix. Use schedule: "@reboot" for run-on-start behavior; use a normal crontab expression or schedule object otherwise. See Schedules and Timezones.

A disabled job never runs

Symptom. A job with enabled: false is skipped entirely; GET /status reports it as disabled; POST /jobs/<name>/start returns 409 Conflict (job '<name>' is disabled).

Cause. enabled defaults to true (new in yacron2 0.18). enabled: false jobs are treated "as if they aren't there" apart from config validation: job_should_run short-circuits to False, and the web API refuses to launch them.

Fix. Set enabled: true (or remove the field) to run the job.

Schedule object year appears ignored

Symptom. A schedule object that pins year still runs in other years.

Cause — confirmed behavior. _parse_schedule builds a five-field crontab string from minute, hour, dayOfMonth, month, and dayOfWeek only — it never reads the year key:

tab = f"{minute} {hour} {day} {month} {dow}"

The strictyaml schema accepts a year key (and the README example at "Configuration basics" sets year: 2017), but the parser drops it, so year has no effect on scheduling. This is a discrepancy between the schema/README and the code; document and rely on the five honored fields only.

Fix. Do not depend on year. To restrict a job to a single date, combine dayOfMonth and month and gate the job by other means (for example, disable it after the date). Unspecified schedule-object fields default to *.

Unknown timezone

Symptom. Startup fails with unknown timezone: <value>.

Cause. _resolve_timezone calls ZoneInfo(timezone); a ZoneInfoNotFoundError/ValueError is re-raised as ConfigError. On slim images that lack the system tz database, yacron2 depends on the bundled tzdata package to resolve names.

Fix. Use a valid IANA name (for example America/Los_Angeles). The timezone option (since yacron2 0.11) takes precedence over utc; with neither set, scheduling uses local time only when utc: false (the default utc is true, i.e. UTC). See Schedules and Timezones.

"include cycle detected"

Symptom. Startup fails with include cycle detected at <path>.

Cause. parse_config_file tracks visited absolute paths in a per-top-level-parse _seen set; a file that includes itself directly or transitively raises this ConfigError instead of recursing to RecursionError. Two independent files including a common file are not flagged (the set is scoped per top-level parse).

Fix. Break the include cycle. Remember that a top-level defaults block does not retro-apply to jobs pulled in via include — included jobs arrive fully constructed with only their own file's defaults. See Includes, Defaults, and Multi-File Config.

Jobs in a config directory are not loaded

Symptom. Some files in the -c directory are silently ignored.

Cause. _parse_config_dir skips a directory entry when the base name's first character is _ or . (so _inc.yaml and dotfiles are excluded), or when the extension is not .yml or .yaml. Entries are processed in sorted filename order.

Fix. Name loadable configs with a non-_/non-. leading character and a .yml/.yaml extension. Files meant only to be included (conventionally _*.yaml) are intentionally skipped as top-level configs and pulled in by the file that includes them.

Failure detection and output

A job is marked failed on nonzero exit or any stderr

Symptom. A job that "worked" is reported as failed; the log shows a fail_reason such as failsWhen=nonzeroReturn and retcode=<n> or failsWhen=producesStderr and stderr is not empty.

Cause. fail_reason is computed from failsWhen. The defaults are:

failsWhen key	Type	Default	Effect when true
producesStdout	Bool	false	Any captured stdout marks the job failed
producesStderr	Bool	true	Any captured stderr marks the job failed
nonzeroReturn	Bool	true	A nonzero exit code marks the job failed
always	Bool	false	The job is always considered failed when it exits

A job whose command cannot be launched at all (for example, the executable does not exist) is reported as an ordinary failure with exit code 127, not an internal error. Note producesStderr/producesStdout only apply when the corresponding stream is captured — and they also fire when output was discarded (saveLimit: 0 still counts discarded lines as output).

Fix. Adjust failsWhen. To stop stderr from marking a job failed, set producesStderr: false. Note producesStdout is the only required key in the failsWhen map (strictyaml-required); the other three are optional and take the defaults above. See Failure Detection and Retries.

stderr capture vs. routing

Symptom. A job's output does not appear where expected, or is not in failure reports.

Cause. Defaults are captureStderr: true, captureStdout: false. A stream that is not captured is passed through to yacron2's own stdout/stderr (job stderr to yacron2 stderr); only captured streams are saved and available to failsWhen and to report templates. Captured lines are prefixed per streamPrefix (default "[{job_name} {stream_name}] ").

Fix. Enable captureStdout: true / keep captureStderr: true for the streams you need in reports or in producesStdout/producesStderr checks. See Output Capturing.

"ignored a very long line"

Symptom. Log warning job <name>: ignored a very long line, and that line is absent from captured output.

Cause. Captured streams use an asyncio reader limited to maxLineLength (default 16 * 1024 * 1024 = 16 MiB). A line longer than the limit raises ValueError in the reader, which logs the warning and skips that line.

Fix. Raise maxLineLength (must be > 0; _validate_numeric_ranges rejects non-positive values with a ConfigError). Distinct from saved-output truncation: saveLimit (default 4096 lines, 0 disables saving) caps how many lines are kept, inserting a [.... N lines discarded ...] marker. See Output Capturing.

Invalid numeric option values

Symptom. Startup fails with Job <name>: <field> must be ….

Cause. _validate_numeric_ranges enforces ranges strictyaml's type check cannot: saveLimit >= 0, maxLineLength > 0, killTimeout >= 0, executionTimeout > 0 when set, onFailure.retry.maximumRetries >= -1 (-1 = retry forever), initialDelay >= 0, maximumDelay > 0, backoffMultiplier > 0.

Fix. Use values within those ranges. See Concurrency and Timeouts and Failure Detection and Retries.

Reporting

SMTP TLS certificate failures after upgrading from yacron

Symptom. Mail that delivered fine under yacron now fails with a TLS/certificate validation error.

Cause. In yacron2 1.0.0 the mail validate_certs default changed to True (_REPORT_DEFAULTS["mail"]["validate_certs"] = True). The mail reporter passes validate_certs=mail["validate_certs"] to aiosmtplib.SMTP, so delivery to servers with self-signed or otherwise invalid certificates that previously worked silently now fails.

Fix. Fix the server certificate, or set validate_certs: false on the mail report block to restore the old behavior. Related mail TLS keys: tls (default false, implicit TLS), starttls (default false). See Reporting (Mail, Sentry, Shell). Reporter exceptions are logged (Problem reporting job <name> failure) and never crash the scheduler; reporters run concurrently with return_exceptions=True.

A report (Sentry / mail / shell) is silently skipped

Symptom. No report is sent and there is no exception.

Cause. Each reporter early-returns when not configured: Sentry returns unless a DSN resolves (and logs sentry: dsn env var '<name>' is not set; not reporting when fromEnvVar is unset); mail returns unless both to and from are set (and logs mail: password env var is not set; not sending email when a fromEnvVar password is unset); the shell reporter returns when command is None. A successful-job mail with an empty rendered body is also skipped.

Fix. Provide the required fields. See Reporting (Mail, Sentry, Shell).

Metrics

No statsd metrics arrive

Symptom. Expected metrics never reach statsd. yacron2 emits four per job: start, stop, and success as gauges (|g) and duration as a timer (|ms|@0.1), prefixed by the job's statsd.prefix. At most a log warning Job <name>: failed to send statsd … metric or an error UDP error received: <exc>.

Cause. statsd is best-effort: metrics go out over fire-and-forget UDP, and an OSError on send (for example an unresolvable host) is logged as a warning rather than propagated. If the statsd block is absent, no metrics are emitted at all.

Fix. Configure the job's statsd block (host, port, prefix, all required) and verify the host resolves and the UDP path is open. See Metrics with statsd.

Concurrency and termination

Overlapping runs, skipped runs, or a job killed mid-run

Symptom. Two instances of a job run at once, the next run is skipped while one is in progress, or a running instance is terminated when the next is due.

Cause. concurrencyPolicy (default Allow) governs overlap: Allow runs concurrently; Forbid skips the new run while one is still running; Replace cancels the running instance (marking it replaced so it is not reported as a failure or retried) and starts a new one.

Fix. Set concurrencyPolicy to the desired policy. See Concurrency and Timeouts.

A timed-out job is killed forcefully

Symptom. Log shows Job <name> exceeded its executionTimeout …, cancelling it… and possibly Job <name> did not gracefully terminate after <n> seconds, killing it….

Cause. executionTimeout (default unset/None) cancels a job still running after N seconds (recorded internally as retcode -100). Cancellation sends SIGTERM, then SIGKILL if the process is still alive after killTimeout seconds (default 30).

Fix. Raise executionTimeout, or give the process more graceful-shutdown time via killTimeout. See Concurrency and Timeouts.

Reference: exit codes used internally

Code	Meaning
127	Command could not be launched (e.g. executable not found)
-100	Job cancelled because it exceeded executionTimeout

These appear in logs and in report template exit_code. See Architecture and Internals for the scheduler and job-lifecycle details, and Logging Configuration for raising the log level (-l DEBUG) when diagnosing scheduling decisions.