好久没用nacos，今天一用，竟然启动不了。最后的报错如下：

Caused by: java.net.UnknownHostException: jmenv.tbsite.net
        at java.base/java.net.InetAddress$CachedAddresses.get(InetAddress.java:797)
        at java.base/java.net.InetAddress.getAllByName0(InetAddress.java:1505)
        at java.base/java.net.InetAddress.getAllByName(InetAddress.java:1364)
        at java.base/java.net.InetAddress.getAllByName(InetAddress.java:1298)
        at org.apache.http.impl.conn.SystemDefaultDnsResolver.resolve(SystemDefaultDnsResolver.java:45)
        at org.apache.http.impl.conn.DefaultHttpClientConnectionOperator.connect(DefaultHttpClientConnectionOperator.java:111)
        at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.connect(PoolingHttpClientConnectionManager.java:353)
        at org.apache.http.impl.execchain.MainClientExec.establishRoute(MainClientExec.java:380)
        at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:236)
        at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:184)
        at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:88)
        at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:110)
        at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:184)
        at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:82)
        at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:107)
        at com.alibaba.nacos.common.http.BaseHttpClient.execute(BaseHttpClient.java:45)
        at com.alibaba.nacos.common.http.NacosSyncHttpClient.get(NacosSyncHttpClient.java:46)
        at com.alibaba.nacos.core.cluster.lookup.AddressServerMemberLookup.syncFromAddressUrl(AddressServerMemberLookup.java:155)
        at com.alibaba.nacos.core.cluster.lookup.AddressServerMemberLookup.run(AddressServerMemberLookup.java:101)
        ... 121 common frames omitted

查看/etc/hosts文件

[root@instance-8595xzys logs]# cat /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
192.168.16.5 instance-8595xzys instance-8595xzys.novalocal
[root@instance-8595xzys logs]# 

网上的方法都是改hosts文件，但是看起来，我这hosts文件也是正常的。

只好到github上搜下答案了，注意，github也是可以搜索答案的，不会的，加群，关注微信公众号，联系我。
看到，官方本来就有这个问题的解决方案：
https://github.com/alibaba/nacos/issues/2902
很遗憾，是启动模式没设置导致的。

sh startup.sh -m standalone

正常了。

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