set restart.strategy failed, unknown restart.strategy

Error message

set restart.strategy failed, unknown restart.strategy [{}],only support no,fixed-delay,failure-rate

What it means

EnvironmentUtil.setRestartStrategy applies the 'restart.strategy' env option to the Flink ExecutionEnvironment. When the strategy name is not 'no', 'fixed-delay', or 'failure-rate' (case-sensitive), it logs this warning and leaves Flink's default restart strategy unchanged. The whole call is also wrapped in a try/catch that swallows other errors.

Solutions

Set restart.strategy to exactly 'no', 'fixed-delay', or 'failure-rate'.
Provide the matching sub-options (e.g. fixed-delay delay/attempts, failure-rate thresholds) so the strategy actually applies.
Remove the key to keep Flink's default restart strategy.

Example fix

// before
env {
  restart.strategy = "fixed_delay"
}
// after
env {
  restart.strategy = "fixed-delay"
  restart.strategy.fixed-delay.attempts = 3
  restart.strategy.fixed-delay.delay = 10000
}

Defensive patterns

Strategy: validation

Validate before calling

String rs = config.getString("restart.strategy");
if (!java.util.Arrays.asList("no","fixed-delay","failure-rate").contains(rs)) {
    throw new IllegalArgumentException("restart.strategy must be no, fixed-delay, or failure-rate");
}

Prevention

Follow documented strategy names exactly (lowercase, hyphenated).
Include required sub-options for fixed-delay/failure-rate.
Lint env blocks in CI against allowed keys/values.

When it happens

Trigger: env block sets restart.strategy to an unknown value such as 'fixed_delay', 'none', 'FixedDelay', or 'exponential-delay'; called during environment setup for Flink batch/stream jobs.

Common situations: Copying Flink YAML-style restart strategy names with different casing/underscores; configs migrated from other engines; users expecting newer Flink strategies (e.g. exponential-delay) unsupported by this mapping.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/deae587c230cb397. Report an issue: GitHub.

Appendix: source

Thrown at seatunnel-core/seatunnel-flink-starter/seatunnel-flink-starter-common/src/main/java/org/apache/seatunnel/core/starter/flink/utils/EnvironmentUtil.java:67

                    case "fixed-delay":
                        int attempts = config.getInt(ConfigKeyName.RESTART_ATTEMPTS);
                        long delay = config.getLong(ConfigKeyName.RESTART_DELAY_BETWEEN_ATTEMPTS);
                        executionConfig.setRestartStrategy(
                                RestartStrategies.fixedDelayRestart(attempts, delay));
                        break;
                    case "failure-rate":
                        long failureInterval =
                                config.getLong(ConfigKeyName.RESTART_FAILURE_INTERVAL);
                        int rate = config.getInt(ConfigKeyName.RESTART_FAILURE_RATE);
                        long delayInterval = config.getLong(ConfigKeyName.RESTART_DELAY_INTERVAL);
                        executionConfig.setRestartStrategy(
                                RestartStrategies.failureRateRestart(
                                        rate,
                                        Time.of(failureInterval, TimeUnit.MILLISECONDS),
                                        Time.of(delayInterval, TimeUnit.MILLISECONDS)));
                        break;
                    default:
                        log.warn(
                                "set restart.strategy failed, unknown restart.strategy [{}],only support no,fixed-delay,failure-rate",
                                restartStrategy);
                }
            }
        } catch (Exception e) {
            log.warn("set restart.strategy in config '{}' exception", config, e);
        }
    }

    public static CheckResult checkRestartStrategy(Config config) {
        if (hasPathAndWaring(config, ConfigKeyName.RESTART_STRATEGY)) {
            String restartStrategy = config.getString(ConfigKeyName.RESTART_STRATEGY);
            switch (restartStrategy.toLowerCase()) {
                case "fixed-delay":
                    if (!(config.hasPath(ConfigKeyName.RESTART_ATTEMPTS)
                            && config.hasPath(ConfigKeyName.RESTART_DELAY_BETWEEN_ATTEMPTS))) {
                        return CheckResult.error(
                                String.format(

View on GitHub (pinned to cf67b549a7)