alibaba/nacos · warning · NacosApiException

WEIGHT_ERROR

WEIGHT_ERROR

Error message

instance format invalid: The weights range from %s to %s

What it means

Thrown by ConsoleInstanceController.checkWeight, invoked from updateInstance (PUT /v3/console/ns/instance) when instanceForm.getWeight() is outside the allowed range. The bounds are naming Constants.MIN_WEIGHT_VALUE = 0.0 and MAX_WEIGHT_VALUE = 10000.0. It raises NacosApiException with HTTP 400 and ErrorCode.WEIGHT_ERROR.

Source

Thrown at console/src/main/java/com/alibaba/nacos/console/controller/v3/naming/ConsoleInstanceController.java:132

    @Since("3.2.2")
    @CanDistro
    @DeleteMapping
    @TpsControl(pointName = "NamingInstanceDeregister", name = "HttpNamingInstanceDeregister")
    @Secured(action = ActionTypes.WRITE, apiType = ApiType.CONSOLE_API)
    public Result<String> removeInstance(InstanceForm instanceForm) throws NacosException {
        // check param
        instanceForm.validate();
        checkDeleteInstanceEphemeral(instanceForm.getEphemeral());
        // build instance
        Instance instance = buildInstance(instanceForm);
        instanceProxy.removeInstance(instanceForm, instance);
        return Result.success("ok");
    }
    
    private void checkWeight(Double weight) throws NacosException {
        if (weight > com.alibaba.nacos.naming.constants.Constants.MAX_WEIGHT_VALUE
            || weight < com.alibaba.nacos.naming.constants.Constants.MIN_WEIGHT_VALUE) {
            throw new NacosApiException(HttpStatus.BAD_REQUEST.value(), ErrorCode.WEIGHT_ERROR,
                "instance format invalid: The weights range from "
                    + com.alibaba.nacos.naming.constants.Constants.MIN_WEIGHT_VALUE + " to "
                    + com.alibaba.nacos.naming.constants.Constants.MAX_WEIGHT_VALUE);
        }
    }
    
    private void checkDeleteInstanceEphemeral(Boolean ephemeral) throws NacosApiException {
        if (Boolean.TRUE.equals(ephemeral)) {
            throw new NacosApiException(HttpStatus.BAD_REQUEST.value(),
                ErrorCode.PARAMETER_VALIDATE_ERROR,
                "Console only supports deregistering persistent instances");
        }
    }
    
    private Instance buildInstance(InstanceForm instanceForm) throws NacosException {
        Instance instance =
            InstanceBuilder.newBuilder().setServiceName(buildCompositeServiceName(instanceForm))
                .setIp(instanceForm.getIp()).setClusterName(instanceForm.getClusterName())

View on GitHub (pinned to 9b989acdf1)

Solutions

1. Set instanceForm.setWeight to a value within [0.0, 10000.0] before the PUT.
2. Clamp the submitted weight to the legal range in the client UI.
3. If you intended a relative weight, remember the default is 1.0 and the max is 10000.0; rescale your input accordingly.

Example fix

// before
form.setWeight(50000.0); // exceeds MAX_WEIGHT_VALUE

// after
form.setWeight(Math.max(0.0, Math.min(10000.0, desiredWeight)));

// Clamp weight to the legal range before the PUT
final double MIN = 0.0, MAX = 10000.0;
Double w = instanceForm.getWeight();
if (w == null) { w = 1.0; }
if (w < MIN || w > MAX) {
    throw new IllegalArgumentException("weight must be in [0.0, 10000.0], got " + w);
}
instanceForm.setWeight(w);

// Java: boolean guard for valid weight range
boolean weightOk = instanceForm.getWeight() != null
    && instanceForm.getWeight() >= 0.0
    && instanceForm.getWeight() <= 10000.0;

try {
    controller.updateInstance(form);
} catch (NacosApiException e) {
    if (e.getDetailErrCode() == ErrorCode.WEIGHT_ERROR.getCode()) {
        form.setWeight(Math.max(0.0, Math.min(10000.0, form.getWeight())));
        controller.updateInstance(form);
    } else { throw e; }
}

When it happens

Trigger: Calling PUT /v3/console/ns/instance with a weight less than 0.0 or greater than 10000.0. (Note: updateInstance is the only caller of checkWeight; the DELETE path does not check weight.)

Common situations: Passing a percentage like 100 assuming it is a fraction when Nacos expects a large weight; negative weights from a form bug; a weight scaled by a multiplier that overflows the 10000 cap.

Related errors

• INVALID_PARAM
• WEIGHT_ERROR
• 10000
• 400
• PARAMETER_VALIDATE_ERROR

AI-assisted analysis of alibaba/nacos@9b989acdf1 (2026-08-14). Data as JSON: /api/errors/f28454dd1d7fa12f. Report an issue: GitHub.