question Serve Namenode UI to localhost only. in Support Questions

Serve Namenode UI to localhost only.

DanHosier — Fri, 16 Sep 2022 14:43:29 GMT

We have a need to serve our Namenode UI through a proxy and prevent direct access to the UI. There seems to be 2 ways we could do that but I'm having difficulty in implementing.

1. Set dfs.namenode.http-address to 127.0.0.1 :9870 Unfortunately, it appears that cloudera's implementation does not allow an address in dfs.namenode.http-address, but instead only accept a port number. This is then combined with the namenode hostname to build the http address. I attempted to override via a safety valve configuration but that appears to be intercepted as well.

2. Configure the jetty-web.xml with an IPAccessHandler that only allows connections from the local server. I'm having difficulty finding where in the filesystem I'd set this so that cdh6 will pick this up for the namenode role.

This is Cloudera Enterprise 6.3.3 on Centos 7

Re: Serve Namenode UI to localhost only.

willx — Sun, 12 Sep 2021 05:00:04 GMT

Hi @DanHosier,

Just provide you a possible solution to bind the namenode http to localhost.

Add following property to service side advanced hdfs-site.xml and restart hdfs.

HDFS Service Advanced Configuration Snippet (Safety Valve) for hdfs-site.xml
<property>
<name>dfs.namenode.http-bind-host</name>
<value>127.0.0.1</value>
</property>

Then the property is added into /var/run/cloudera-scm-agent/process/<Latest process of NN>/hdfs-site.xml:

# grep -C2 "dfs.namenode.http-bind-host" hdfs-site.xml
</property>
<property>
<name>dfs.namenode.http-bind-host</name>
<value>127.0.0.1</value>
</property>

And then test curl commands:

# curl `hostname -f`:9870
curl: (7) Failed connect to xxxx.xxxx.xxxx.com:9870; Connection refused
# curl localhost:9870
<!--
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The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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limitations under the License.
-->
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="REFRESH" content="0;url=dfshealth.html" />
<title>Hadoop Administration</title>
</head>
</html>

Now the webUI only served on NN's localhost.

But you will see this alert on CM because Service Monitor cannot reach to NN WebUI:
NameNode summary: xxxx.xxxx.xxxx.com (Availability: Unknown, Health: Bad). This health test is bad because the Service Monitor did not find an active NameNode.

So this solution has side effects for service monitor, but actually hdfs is running well.

Regards,

Will

If the answer helps, please accept as solution and click thumbs up.

Re: Serve Namenode UI to localhost only.

DanHosier — Mon, 13 Sep 2021 15:14:49 GMT

That sounds like a good first step. Is there a way to configure the service monitor to use a different port (port of a proxy)?

Re: Serve Namenode UI to localhost only.

DanHosier — Mon, 13 Sep 2021 15:49:30 GMT

Actually, this should work fine regardless. We'll monitor what NameNodeHealth would monitor ourselves and just suppress that health test.

Thanks Will!