正文
ElasticSearch 问题分析：No data nodes with HTTP-enabled available
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环境：ES-5.4.0版本，部署方式：3master node+2client node+3data node
说明：data node和client node都配置了 http.enabled: false ，程序在写数据时报错：No data nodes with HTTP-enabled available
源码分析：
public static void filterNonDataNodesIfNeeded(Settings settings, Log log) {
if (!settings.getNodesDataOnly()) {
return;
}
RestClient bootstrap = new RestClient(settings);
try {
String message = "No data nodes with HTTP-enabled available";
List<NodeInfo> dataNodes = bootstrap.getHttpDataNodes();
// 找不到dataNodes就会报错
if (dataNodes.isEmpty()) {
throw new EsHadoopIllegalArgumentException(message);
}
...
} finally {
bootstrap.close();
}
}
接下来看看RestClient.getHttpDataNodes()方法的取值逻辑
public List<NodeInfo> getHttpDataNodes() {
List<NodeInfo> nodes = getHttpNodes(false);
// 遍历上面获取到的节点
Iterator<NodeInfo> it = nodes.iterator();
while (it.hasNext()) {
NodeInfo node = it.next();
// 如果不是数据节点，则移除
if (!node.isData()) {
it.remove();
}
}
return nodes;
}
// 获取http节点_nodes/http
public List<NodeInfo> getHttpNodes(boolean clientNodeOnly) {
// 通过es接口“_nodes/http”来获取nodes的信息
Map<String, Map<String, Object>> nodesData = get("_nodes/http", "nodes");
List<NodeInfo> nodes = new ArrayList<NodeInfo>();
for (Entry<String, Map<String, Object>> entry : nodesData.entrySet()) {
NodeInfo node = new NodeInfo(entry.getKey(), entry.getValue());
// 如果不是查找client节点，则只要节点运行网络访问就可以add了；如果查找client节点，则还要通过isClient验证才能add
if (node.hasHttp() && (!clientNodeOnly || node.isClient())) {
nodes.add(node);
}
}
return nodes;
}
最后再来看看node.hasHttp()，isClient()，isData()的方法
private final String id;
private final String name;
private final String host;
private final String ip;
private final String publishAddress;
private final boolean hasHttp;
private final boolean isClient;
private final boolean isData;
private final boolean isIngest; public NodeInfo(String id, Map<String, Object> map) {
this.id = id;
EsMajorVersion version = EsMajorVersion.parse((String) map.get("version"));
this.name = (String) map.get("name");
this.host = (String) map.get("host");
this.ip = (String) map.get("ip");
// 5.0以下版本的分支
if (version.before(EsMajorVersion.V_5_X)) {
Map<String, Object> attributes = (Map<String, Object>) map.get("attributes");
if (attributes == null) {
this.isClient = false;
this.isData = true;
} else {
String data = (String) attributes.get("data");
this.isClient = data == null ? true : !Boolean.parseBoolean(data);
this.isData = data == null ? true : Boolean.parseBoolean(data);
}
this.isIngest = false;
// 5.0版本以上的分支
} else {
List<String> roles = (List<String>) map.get("roles");
// 如果roles列表中不包含"data"，则此节点是client
this.isClient = roles.contains("data") == false;
// 如果roles列表中包含"data"，则此节点是data
this.isData = roles.contains("data");
// 如果roles列表中包含"ingest"，则此节点是ingest
this.isIngest = roles.contains("ingest");
}
Map<String, Object> httpMap = (Map<String, Object>) map.get("http");
// 如果节点数据中包含key：http
if (httpMap != null) {
String addr = (String) httpMap.get("publish_address");
// 如果http数据中包含key：publish_address
if (addr != null) {
StringUtils.IpAndPort ipAndPort = StringUtils.parseIpAddress(addr);
this.publishAddress = ipAndPort.ip + ":" + ipAndPort.port;
// 则此节点可以提供http服务，即：http.enabled: true
this.hasHttp = true;
} else {
this.publishAddress = null;
this.hasHttp = false;
}
} else {
this.publishAddress = null;
this.hasHttp = false;
}
}
从上面的源码分析可以得出：如果一个data节点不配置 http.enabled：true ，则此节点不会被getHttpDataNodes()方法搜索到，那么就会直接抛出异常：No data nodes with HTTP-enabled available
解决的方法无非两种：
第一：数据节点配置 http.enabled：true
第二：绕过filterNonDataNodesIfNeeded()校验，需要settings.getNodesDataOnly()返回false；看下面源码可知，默认es.nodes.data.only是true，在客户端中将其设置为false即可。
/** Clients only */
String ES_NODES_CLIENT_ONLY = "es.nodes.client.only";
String ES_NODES_CLIENT_ONLY_DEFAULT = "false"; /** Data only */
String ES_NODES_DATA_ONLY = "es.nodes.data.only";
String ES_NODES_DATA_ONLY_DEFAULT = "true"; /** Ingest only */
String ES_NODES_INGEST_ONLY = "es.nodes.ingest.only";
String ES_NODES_INGEST_ONLY_DEFAULT = "false"; /** WAN only */
String ES_NODES_WAN_ONLY = "es.nodes.wan.only";
String ES_NODES_WAN_ONLY_DEFAULT = "false"; ... public boolean getNodesDataOnly() {
// by default, if not set, return a value compatible with the other settings
// 默认es.nodes.data.only是true，在客户端中将其设置为false即可
return Booleans.parseBoolean(getProperty(ES_NODES_DATA_ONLY), !getNodesWANOnly() && !getNodesClientOnly() && !getNodesIngestOnly());
} public boolean getNodesIngestOnly() {
return Booleans.parseBoolean(getProperty(ES_NODES_INGEST_ONLY, ES_NODES_INGEST_ONLY_DEFAULT));
} public boolean getNodesClientOnly() {
return Booleans.parseBoolean(getProperty(ES_NODES_CLIENT_ONLY, ES_NODES_CLIENT_ONLY_DEFAULT));
} public boolean getNodesWANOnly() {
return Booleans.parseBoolean(getProperty(ES_NODES_WAN_ONLY, ES_NODES_WAN_ONLY_DEFAULT));
}
最后附上一段"_nodes/http"接口的返回值：
"nodes": {
"YgwRm4j1RwiK3jjDHY8Hzw": {
"name": "node-02",
"transport_address": "192.168.100.10:9300",
"host": "192.168.100.10",
"ip": "192.168.100.10",
"version": "5.4.0",
"build_hash": "780f8c4",
"roles": [
"master",
"ingest"
],
"attributes": {
"ml.enabled": "true"
},
"http": {
"bound_address": [
"192.168.100.10:9200"
],
"publish_address": "192.168.100.10:9200",
"max_content_length_in_bytes": 104857600
}
}
...
}
