alibaba/nacos · critical · NacosException

-400

-400

Error message

No server list provider found.

What it means

Thrown by AbstractServerListManager.start() with error code CLIENT_INVALID_PARAM (-400) when none of the SPI-loaded ServerListProvider implementations match the supplied NacosClientProperties. The manager iterates providers sorted by descending order and calls each provider's match(properties) method; if all return false, the client cannot determine how to discover servers. The log line includes the SPI load size for diagnosis.

Source

Thrown at client-basic/src/main/java/com/alibaba/nacos/client/address/AbstractServerListManager.java:103

        Collection<ServerListProvider> serverListProviders =
            NacosServiceLoader.load(ServerListProvider.class);
        Collection<ServerListProvider> sorted = serverListProviders.stream()
            .sorted((a, b) -> b.getOrder() - a.getOrder()).collect(Collectors.toList());
        for (ServerListProvider each : sorted) {
            boolean matchResult = each.match(properties);
            LOGGER.info("Load and match ServerListProvider {}, match result: {}",
                each.getClass().getCanonicalName(),
                matchResult);
            if (matchResult) {
                this.serverListProvider = each;
                LOGGER.info("Will use {} as ServerListProvider",
                    this.serverListProvider.getClass().getCanonicalName());
                break;
            }
        }
        if (null == serverListProvider) {
            LOGGER.error("No server list provider found, SPI load size: {}", sorted.size());
            throw new NacosException(NacosException.CLIENT_INVALID_PARAM,
                "No server list provider found.");
        }
        this.serverListProvider.init(properties, getNacosRestTemplate());
    }
    
    public String getServerName() {
        return getModuleName() + "-" + serverListProvider.getServerName();
    }
    
    public String getContextPath() {
        return serverListProvider.getContextPath();
    }
    
    public String getNamespace() {
        return serverListProvider.getNamespace();
    }
    
    public String getAddressSource() {

View on GitHub (pinned to 9b989acdf1)

Solutions

1. Ensure your client Properties include either PropertyKeyConst.SERVER_ADDR (a comma-separated host:port list) or PropertyKeyConst.ENDPOINT.
2. Check the log for 'SPI load size: 0' — if 0, verify META-INF/nacos/com.alibaba.nacos.client.address.ServerListProvider is on the classpath (common in fat-jar / shading setups).
3. If using a custom ServerListProvider, verify its match() method returns true for your configuration and the SPI file lists it.
4. Upgrade or re-bundle the nacos-client JAR to ensure all provider modules are included.

Example fix

// before
Properties props = new Properties();
props.setProperty("namespace", "test");
NamingService ns = NamingFactory.createNamingService(props);

// after
Properties props = new Properties();
props.setProperty(PropertyKeyConst.SERVER_ADDR, "127.0.0.1:8848");
props.setProperty("namespace", "test");
NamingService ns = NamingFactory.createNamingService(props);

String serverAddr = properties.getProperty(PropertyKeyConst.SERVER_ADDR);
String endpoint = properties.getProperty(PropertyKeyConst.ENDPOINT);
if (StringUtils.isBlank(serverAddr) && StringUtils.isBlank(endpoint)) {
    throw new IllegalArgumentException("Either SERVER_ADDR or ENDPOINT must be set in client properties.");
}

try {
    serverListManager.start();
} catch (NacosException e) {
    if (e.getErrCode() == NacosException.CLIENT_INVALID_PARAM) {
        // Provide a clear message about missing serverAddr or endpoint
        throw new IllegalStateException("No ServerListProvider matched. Set SERVER_ADDR or ENDPOINT.", e);
    }
    throw e;
}

When it happens

Trigger: The client properties do not contain a server address list (PropertyKeyConst.SERVER_ADDR) and no endpoint is configured (PropertyKeyConst.ENDPOINT), so no ServerListProvider's match() returns true. This can also happen if the SPI configuration file (META-INF/nacos/...) for ServerListProvider is missing from the classpath, e.g. due to a fat-jar shading issue.

Common situations: Missing 'serverAddr' or 'endpoint' property when constructing NamingService/ConfigService; classpath shading strips SPI metadata files; custom ServerListProvider implementations whose match() logic has a bug; running in environments where only a subset of nacos-client modules are on the classpath.

Related errors

• [http-client] invalid read timeout:{}
• invalid PER_TASK_CONFIG_SIZE, expected value type double
• Illegal url path expression
• 400
• 500

AI-assisted analysis of alibaba/nacos@9b989acdf1 (2026-08-14). Data as JSON: /api/errors/2c390e7138bb2f03. Report an issue: GitHub.