Nacos 报错：Request cannot be executed； I/O reactor status: STOPPED

时间：2025-02-28 07:09:33

报错信息

Nacos集群报错如下：

2021-07-13 16:21:56,363 ERROR [IP-DEAD] failed to delete ip automatically, ip: {"instanceId":"10.200.13.135#3012#DEFAULT#DEFAULT_GROUP@@service-ecs","ip":"10.200.13.135","port":3012,"weight":1.0,"healthy":false,"enabled":true,"ephemeral":true,"clusterName":"DEFAULT","serviceName":"DEFAULT_GROUP@@cloudproduct-service-ecs","metadata":{"":"SPRING_CLOUD"},"lastBeat":1625552931192,"marked":false,"app":"unknown","instanceHeartBeatInterval":5000,"instanceHeartBeatTimeOut":15000,"ipDeleteTimeout":30000}, error: {}

: Request cannot be executed; I/O reactor status: STOPPED
        at (:46)
        at (:90)
        at (:123)
        at (:75)
        at (:108)
        at (:92)
        at (:52)
        at (:364)
        at (:105)
        at (:193)
        at (:157)
        at (:142)
        at (:120)
        at $RunnableAdapter.call(:511)
        at (:308)
        at $ScheduledFutureTask.access$301(:180)
        at $ScheduledFutureTask.run(:294)
        at (:1149)
        at $Worker.run(:624)
        at (:748)

原因

  1. 从堆栈信息中可以看出来，这个错是 Apache HttpComponents 中发送的异步请求的http客户端报出的错，jar包如下
       <dependency>
            <groupId></groupId>
            <artifactId>httpasyncclient</artifactId>
        </dependency>
  1. 我们具体看一下报错的源代码，就明白问题所在了，抛出这个异常的类是 ，源代码如下，博主这里对源代码做了些删减，可以更加清晰的看出代码逻辑：
abstract class CloseableHttpAsyncClientBase extends CloseableHttpPipeliningClient {

    private final Log log = LogFactory.getLog(getClass());
	// 线程状态枚举
    static enum Status {INACTIVE, ACTIVE, STOPPED}

    private final NHttpClientConnectionManager connmgr;
	// 执行异步任务的线程
    private final Thread reactorThread;
	// 记录线程的状态
    private final AtomicReference<Status> status;
	
	// 构造函数，初始化执行异步任务的线程
    public CloseableHttpAsyncClientBase(
            final NHttpClientConnectionManager connmgr,
            final ThreadFactory threadFactory,
            final NHttpClientEventHandler handler) {
        super();
        this.connmgr = connmgr;
        if (threadFactory != null && handler != null) {
			// 初始化线程
            this.reactorThread = threadFactory.newThread(new Runnable() {

                @Override
                public void run() {
                    try {
                        final IOEventDispatch ioEventDispatch = new InternalIODispatch(handler);
                        connmgr.execute(ioEventDispatch);
                    } catch (final Exception ex) {
                        log.error("I/O reactor terminated abnormally", ex);
                    } finally {
                        status.set(Status.STOPPED);
                    }
                }

            });
        } else {
            this.reactorThread = null;
        }
        this.status = new AtomicReference<Status>(Status.INACTIVE);
    }

	// 开始运行线程
    @Override
    public void start() {
        if (this.status.compareAndSet(Status.INACTIVE, Status.ACTIVE)) {
            if (this.reactorThread != null) {
                this.reactorThread.start();
            }
        }
    }
	
	// 执行任务前判断线程的状态，如果线程关闭了，则抛出异常，
    protected void ensureRunning() {
        final Status currentStatus = this.status.get();
        Asserts.check(currentStatus == Status.ACTIVE, "Request cannot be executed; " +
                "I/O reactor status: %s", currentStatus);
    }
	
	// 关闭线程
    @Override
    public void close() {
        if (this.status.compareAndSet(Status.ACTIVE, Status.STOPPED)) {
            if (this.reactorThread != null) {
                try {
                    this.connmgr.shutdown();
                } catch (final IOException ex) {
                    this.log.error("I/O error shutting down connection manager", ex);
                }
                try {
                    this.reactorThread.join();
                } catch (final InterruptedException ex) {
                    Thread.currentThread().interrupt();
                }
            }
        }
    }


}
  1. 从代码中我们可以看到，抛出 I/O reactor status: STOPPED 异常的原因是执行异步任务的线程过早的结束了，再提交任务的时候，无法提交所以抛出异常。
  2. 这里也要说一下 Nacos 在设计NacosAsyncRestTemplate类的时候，这里有一个缺陷，NacosAsyncRestTemplate 类的主要做用是用来发送异步HTTP请求的，在 Nacos 中是将这个类设计为单例了，但是如果其中执行异步请求的线程挂掉了，整个工程中所有使用 NacosAsyncRestTemplate 的功能，都不可用了。
  3. Nacos 集群在同步数据时使用的就是这个类，当异步线程关闭后，nacos日志中就会持续的输出 I/O reactor status: STOPPED 异常了

解决

解决办法其实很简单了，异步线程挂掉了之后，Nacos是不会主动拉起这个线程的，所以就需要我们重启一下Nacos。

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