在使用dubbo注册服务时会遇到IP解析错误导致无法正常访问.
比如: 本机设置的IP为172.16.11.111, 但实际解析出来的是180.20.174.11
这样就导致这个Service永远也无法被访问到, 而调用方一直报错.
当然若发现服务无法访问, 最好先通过dubbo-admin后台排查下注册的服务是否正常.
IP解析异常时的解决方法:
绑定hostname+ip
1. 先查看机器的hostname2. 修改hosts文件, 增加hostname 172.16.11.111
配置nameserver
排查机器上配置的nameserver是否有问题, 若存在无用的nameserver则直接删掉
在dubbo的配置文件中写死host
<dubbo:protocol host="172.16.11.111"/>
或者在每个provider中绑定host
<dubbo:provider host="172.16.11.111">
最好不要用第三种方式, 限制太多. 而且如果这样做了就不支持集群了.
dubbo的官网也不建议使用这种方式. 请慎用.
dubbo获取IP源码分析
/**
* 判断host是否为不可用的本地Host
*/ public static boolean isInvalidLocalHost(String host) {
return host == null
|| host.length() == 0 || host.equalsIgnoreCase("localhost")
|| host.equals("0.0.0.0")
|| (LOCAL_IP_PATTERN.matcher(host).matches());
}
/**
* 获取本地Host.
* 若address == null ? "127.0.0.1" : InetAddress.getHostAddress();
*/ public static String getLocalHost(){
InetAddress address = getLocalAddress();
return address == null ? LOCALHOST : address.getHostAddress();
}
private void doExportUrlsFor1Protocol(ProtocolConfig protocolConfig, List<URL> registryURLs) {
...
...
//1. 先从ProtocolConfig中取host. 若没有配置则为null String host = protocolConfig.getHost();
//2. 再从ProviderConfig中取host. 若没有配置则为null if (provider != null && (host == null || host.length() == 0)) {
host = provider.getHost();
}
boolean anyhost = false;
//3. 若取出的是本地host, 则继续取host if (NetUtils.isInvalidLocalHost(host)) {
anyhost = true;
try {
//4. 通过InetAddress的方式获取Host //默认读取本机hosts中hostname对应的IP //如: 你在hosts中配置了 leo 172.16.11.111 //则读取的IP就是172.16.11.111 host = InetAddress.getLocalHost().getHostAddress();
} catch (UnknownHostException e) {
logger.warn(e.getMessage(), e);
}
if (NetUtils.isInvalidLocalHost(host)) {
if (registryURLs != null && registryURLs.size() > 0) {
for (URL registryURL : registryURLs) {
try {
Socket socket = new Socket();
try {
//5. 通过Socket的方式获取Host //一般解析到这里, 都会获取到正确的本地IP, 除非你有多网卡, 或者有VPN, 导致无法正常解析. SocketAddress addr = new InetSocketAddress(registryURL.getHost(), registryURL.getPort());
socket.connect(addr, 1000);
host = socket.getLocalAddress().getHostAddress();
break;
} finally {
try {
socket.close();
} catch (Throwable e) {}
}
} catch (Exception e) {
logger.warn(e.getMessage(), e);
}
}
}
//6. 遍历本地网卡, 返回第一个合理的Host //最后一个大招. 当上述都解析不到时, 则会遍历本地网卡. //逐个获取IP, 直到有一个合理的IP为止. if (NetUtils.isInvalidLocalHost(host)) {
host = NetUtils.getLocalHost();
}
}
}
...
}
/**
* 遍历本地网卡，返回第一个合理的IP。
* @return 本地网卡IP
*/ public static InetAddress getLocalAddress() {
if (LOCAL_ADDRESS != null)
return LOCAL_ADDRESS;
InetAddress localAddress = getLocalAddress0();
LOCAL_ADDRESS = localAddress;
return localAddress;
}
/**
* 遍历本地网卡，返回第一个合理的IP。
* @return 本地网卡IP
*/ private static InetAddress getLocalAddress0() {
InetAddress localAddress = null;
try {
localAddress = InetAddress.getLocalHost();
if (isValidAddress(localAddress)) {
return localAddress;
}
} catch (Throwable e) {
logger.warn("Failed to retriving ip address, " + e.getMessage(), e);
}
try {
Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
if (interfaces != null) {
while (interfaces.hasMoreElements()) {
try {
NetworkInterface network = interfaces.nextElement();
Enumeration<InetAddress> addresses = network.getInetAddresses();
if (addresses != null) {
while (addresses.hasMoreElements()) {
try {
InetAddress address = addresses.nextElement();
if (isValidAddress(address)) {
return address;
}
} catch (Throwable e) {
logger.warn("Failed to retriving ip address, " + e.getMessage(), e);
}
}
}
} catch (Throwable e) {
logger.warn("Failed to retriving ip address, " + e.getMessage(), e);
}
}
}
} catch (Throwable e) {
logger.warn("Failed to retriving ip address, " + e.getMessage(), e);
}
logger.error("Could not get local host ip address, will use 127.0.0.1 instead.");
return localAddress;
}
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