我是新使用Kafka和Kafka连接器。我一直在尝试使用elastic search作为接收器，使用kafka连接器从我的应用程序流式传输数据。我可以看到Kafka中的信息，但我的连接器不断抛出以下错误：

ERROR WorkerSinkTask{id=elasticsearch-sink-0} Task threw an uncaught and unrecoverable exception (org.apache.kafka.connect.runtime.WorkerTask:179)
org.apache.kafka.connect.errors.ConnectException: Couldn't start ElasticsearchSinkTask due to connection error:
    at io.confluent.connect.elasticsearch.jest.JestElasticsearchClient.<init>(JestElasticsearchClient.java:159)
    at io.confluent.connect.elasticsearch.jest.JestElasticsearchClient.<init>(JestElasticsearchClient.java:142)
    at io.confluent.connect.elasticsearch.ElasticsearchSinkTask.start(ElasticsearchSinkTask.java:122)
    at io.confluent.connect.elasticsearch.ElasticsearchSinkTask.start(ElasticsearchSinkTask.java:51)
    at org.apache.kafka.connect.runtime.WorkerSinkTask.initializeAndStart(WorkerSinkTask.java:300)
    at org.apache.kafka.connect.runtime.WorkerSinkTask.execute(WorkerSinkTask.java:189)
    at org.apache.kafka.connect.runtime.WorkerTask.doRun(WorkerTask.java:177)
    at org.apache.kafka.connect.runtime.WorkerTask.run(WorkerTask.java:227)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
Caused by: io.searchbox.client.config.exception.CouldNotConnectException: Could not connect to http://elasticsearch:9200
    at io.searchbox.client.http.JestHttpClient.execute(JestHttpClient.java:73)
    at io.searchbox.client.http.JestHttpClient.execute(JestHttpClient.java:63)
    at io.confluent.connect.elasticsearch.jest.JestElasticsearchClient.getServerVersion(JestElasticsearchClient.java:247)
    at io.confluent.connect.elasticsearch.jest.JestElasticsearchClient.<init>(JestElasticsearchClient.java:151)
    ... 12 more
Caused by: org.apache.http.conn.HttpHostConnectException: Connect to elasticsearch:9200 [elasticsearch/172.20.0.7] failed: Connection refused (Connection refused)
    at org.apache.http.impl.conn.DefaultHttpClientConnectionOperator.connect(DefaultHttpClientConnectionOperator.java:159)
    at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.connect(PoolingHttpClientConnectionManager.java:359)
    at org.apache.http.impl.execchain.MainClientExec.establishRoute(MainClientExec.java:381)
    at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:237)
    at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:185)
    at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:89)
    at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:111)
    at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:185)
    at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:83)
    at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:108)
    at io.searchbox.client.http.JestHttpClient.executeRequest(JestHttpClient.java:136)
    at io.searchbox.client.http.JestHttpClient.execute(JestHttpClient.java:70)
    ... 15 more
Caused by: java.net.ConnectException: Connection refused (Connection refused)
    at java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
    at java.net.Socket.connect(Socket.java:589)
    at org.apache.http.conn.socket.PlainConnectionSocketFactory.connectSocket(PlainConnectionSocketFactory.java:75)
    at org.apache.http.impl.conn.DefaultHttpClientConnectionOperator.connect(DefaultHttpClientConnectionOperator.java:142)
    ... 26 more
[2020-09-22 08:16:32,656] ERROR WorkerSinkTask{id=elasticsearch-sink-0} Task is being killed and will not recover until manually restarted (org.apache.kafka.connect.runtime.WorkerTask:180)

我已经对接了所有东西，我有4个容器，一个用于我的应用程序，一个用于elasticsearch，一个用于kafka，一个用于连接器，如下所示：

zookeeper:
    container_name: zookeeper
    image: wurstmeister/zookeeper:latest
    env_file:
      - ".env"
    ports:
      - 2181:2181
    networks:
      - "main_net"

  kafka:
    container_name: kafka
    image: wurstmeister/kafka:2.11-1.0.2
    env_file:
      - ".env"
    depends_on:
      - zookeeper
    links:
      - zookeeper
    ports:
      - 9092:9092
      - 9094:9094
    networks:
      - "main_net"

  connector_standalone:
    container_name: container_standalone
    build:
      context: kafka/
      dockerfile: Dockerfile
    depends_on:
      - kafka
    ports:
      - 8083:8083
    networks:
      - "main_net"

elasticsearch:
    container_name: elasticsearch
    build:
      context: elasticsearch/
    ports:
      - "9200:9200"
      - "9300:9300"
    env_file:
      - ".env"
    environment:
      discovery.type: single-node
    networks:
      - "main_net"

website:
    container_name: "application"
    build: "./"
    command: >
    volumes:
      - "./application:/app"
    ports:
      - "8000:8000"
    networks:
      - "main_net"

据我所知，我已经给出了连接url，基于它应该连接到的主机，即elasticsearch容器。但我很困惑，基于错误什么是错的。下面是我的配置文件：

name=elasticsearch-sink
connector.class=io.confluent.connect.elasticsearch.ElasticsearchSinkConnector
tasks.max=1
topics=vehicle
topic.index=vehicles
connection.url=http://elasticsearch:9200/
connection.user=elastic
connection.password=changeme
type.name=log
key.ignore=true
schema.ignore=true