apache/dolphinscheduler · error · TaskException

Parse yaml-like commands and args failed

Error message

Parse yaml-like commands and args failed

What it means

K8sTaskExecutor.buildK8sJob() uses SnakeYAML to parse the task's 'command' and 'args' strings (expected to be YAML-like lists) into Java objects. If yaml.load() throws on malformed input, it wraps the exception in TaskException("Parse yaml-like commands and args failed"). The K8s Job spec cannot be built without these parsed values.

Source

Thrown at dolphinscheduler-task-plugin/dolphinscheduler-task-api/src/main/java/org/apache/dolphinscheduler/plugin/task/api/k8s/impl/K8sTaskExecutor.java:151

                EnvVar envVar = new EnvVar(param, paramValue, null);
                envVars.add(envVar);
            }
        }

        String commandString = k8STaskMainParameters.getCommand();
        String argsString = k8STaskMainParameters.getArgs();
        List<String> commands = new ArrayList<>();
        List<String> args = new ArrayList<>();

        try {
            if (!StringUtils.isEmpty(commandString)) {
                commands = yaml.load(commandString.trim());
            }
            if (!StringUtils.isEmpty(argsString)) {
                args = yaml.load(argsString.trim());
            }
        } catch (Exception e) {
            throw new TaskException("Parse yaml-like commands and args failed", e);
        }

        NodeSelectorTerm nodeSelectorTerm = new NodeSelectorTerm();
        nodeSelectorTerm.setMatchExpressions(k8STaskMainParameters.getNodeSelectorRequirements());

        Affinity affinity = k8STaskMainParameters.getNodeSelectorRequirements().size() == 0 ? null
                : new AffinityBuilder()
                        .withNewNodeAffinity()
                        .withNewRequiredDuringSchedulingIgnoredDuringExecution()
                        .addNewNodeSelectorTermLike(nodeSelectorTerm)
                        .endNodeSelectorTerm()
                        .endRequiredDuringSchedulingIgnoredDuringExecution()
                        .endNodeAffinity().build();

        job = new JobBuilder()
                .withApiVersion(API_VERSION)
                .withNewMetadata()
                .withName(k8sJobName)

View on GitHub (pinned to 02eac45a1b)

Solutions

  1. Rewrite the command/args fields as valid YAML list syntax, e.g. ["sh", "-c", "your command"].
  2. Validate the YAML locally (paste into a YAML parser) before saving the task definition.
  3. Replace tab indentation with spaces; quote values containing ':', '{', '}', '#', or leading special characters.
  4. Confirm the parsed result is a List (the code expects list-like output), not a scalar or map.

Example fix

// before (task params)
command: echo hello && date
// after
command: ["sh", "-c", "echo hello && date"]
Defensive patterns

Strategy: validation

Validate before calling

try (Yaml yaml = new Yaml()) {
    Object parsed = yaml.load(commandString == null ? "" : commandString.trim());
    if (!(parsed instanceof List)) {
        throw new IllegalArgumentException("command must be a YAML list, got: " + (parsed == null ? "null" : parsed.getClass().getSimpleName()));
    }
} catch (Exception e) {
    throw new IllegalArgumentException("Invalid YAML in command/args: " + e.getMessage(), e);
}

Type guard

boolean isValidYamlList(String s) {
    if (StringUtils.isEmpty(s)) return true; // treated as empty elsewhere
    try {
        return new Yaml().load(s.trim()) instanceof List;
    } catch (Exception e) {
        return false;
    }
}

Try / catch

try {
    Object commands = yaml.load(commandString.trim());
} catch (Exception e) {
    log.error("Invalid command/args YAML: {}", commandString, e);
    throw new IllegalArgumentException("Fix command/args to YAML list form, e.g. [\"sh\",\"-c\",\"...\"]");
}

Prevention

When it happens

Trigger: Calling submitJob2k8s/buildK8sJob when the K8sParameters' commandString or argsString is not valid YAML, e.g. plain text not formatted as a YAML list, tabs for indentation, unquoted special characters ('{', ':', '#'), or content that parses to a non-list type.

Common situations: Users typing shell-style commands (e.g. `echo hello` or comma-separated values) instead of YAML list syntax like `["sh","-c","echo hello"]`; hidden tab characters; strings starting with '{' or '*' that YAML treats specially.

Related errors

AI-assisted analysis of apache/dolphinscheduler@02eac45a1b (2026-09-06). Data as JSON: /api/errors/d9b604b275d19ce4. Report an issue: GitHub.