[jigneshmpatel]

I have following two errors from my application
Could not resolve the DNS name of unknowne4ce8f3898fc
hostname can't be null

-Jignesh

[jigneshmpatel]

My etc/hosts file looks as follows
127.0.0.1 localhost
255.255.255.255 broadcasthost
::1 localhost
fe80::1%lo0 localhost

[besson3c]

An app you wrote, or somebody else's app?

I'm not sure exactly how you want us to help, unknowne4ce8f3898fc is indeed an invalid hostname.

[jigneshmpatel]

I am trying to run the hadoop app, which was running perfectly fine till yesterday night.
Here is the output today of todays log file. As you can see one piece of recognizes the IP address.
EBUG org.apache.hadoop.hbase.master.handler.OpenedRegio nHandler: Opened region -ROOT-,,0.70236052 on 192.168.1.120,49235,1319134727150
2011-10-20 14:19:04,846 ERROR org.apache.hadoop.hbase.HServerAddress: Could not resolve the DNS name of unknowne4ce8f3898fc
2011-10-20 14:19:04,847 FATAL org.apache.hadoop.hbase.master.HMaster: Unhandled exception. Starting shutdown.
java.lang.IllegalArgumentException: hostname can't be null

[besson3c]

The first log entry just means it was able to contact a DNS root server.

You are going to need to contact the hadoop list about this, probably. I have no idea why it is trying to do lookups of invalid hostnames. My guess is either a misconfiguration or a bug.

[jigneshmpatel]

Thanks but looks like something wrong with my machine not with hadoop. When I open the terminal I see following

unknowne4ce8f3898fc:~ hadoop-user$ pwd
/Users/hadoop-user
unknowne4ce8f3898fc:~ hadoop-user$

Why would terminal prompt shows me unknowne4ce8f3898fc.

Please help to fix this.

[jigneshmpatel]

Surprisingly when I look at Web Sharing I got following message.

Your personal website, in the Sites folder in your home folder, is available at this address http://unknowne4ce8f3898fc/~jignesh/

And when I click on the link I am able to open folder by name Jignesh.

Same is applicable for remote login.
To login to this computer remotely type
ssh jignesh@unknowne4ce8f3898fc

For the remote management:On
other users can manage your computer using the address unknowne4ce8f3898fc

While my Computer name is Jignesh MacBookPro

Looks like while configuring ssh, proper name is not given and that is the problem. How to fix this? And even I fix this, does this screw up my ssh setup?

-Jignesh

[boy8cookie]

Sounds like your computer's hostname is borked...

sudo scutil --get ComputerName
sudo scutil --get HostName
sudo scutil --get LocalHostName

Try running these commands, I'm guessing at least one of them will return the "unknowne4ce8f3898fc"

[besson3c]

Try simply "hostname" too...

[jigneshmpatel]

Here is what I got

Jignesh-MacBookPro:~ jignesh$ sudo scutil --get ComputerName
Jignesh MacBookPro
Jignesh-MacBookPro:~ jignesh$ sudo scutil --get HostName
HostName: not set
Jignesh-MacBookPro:~ jignesh$ sudo scutil --get LocalHostName
Jignesh-MacBookPro
Jignesh-MacBookPro:~ jignesh$ sudo hostname
Jignesh-MacBookPro.local

[jigneshmpatel]

Originally Posted by jigneshmpatel 

Thanks but looks like something wrong with my machine not with hadoop. When I open the terminal I see following

unknowne4ce8f3898fc:~ hadoop-user$ pwd
/Users/hadoop-user
unknowne4ce8f3898fc:~ hadoop-user$

Why would terminal prompt shows me unknowne4ce8f3898fc.

Please help to fix this.

Seems my terminal prompt is fixed now

Jignesh-MacBookPro:hadoop-hbase hadoop-user$

But I still have same problem in my connection-
Could not resolve the DNS name of unknowne4ce8f3898fc

how to get rid of this unknowing domain name.

[besson3c]

Have you looked for a mailing list or IRC channel for hadoop?

[jigneshmpatel]

Ok now I am back to home and terminal prompt is changed again it shows "unknowne4ce8f3898fc'
but when I am in office it shows "Jignesh-MacBookPro.local"

Why would the computer or prompt name keep changing. I should have only one name. I think I need to fix this one earliest, then will go back to check why Hadoop maintains old name.

Please guide me.

[besson3c]

What appears in your terminal prompt is the reverse DNS entry of your hostname. Where there is no RDNS entry your hostname is determined in other ways.

For some reason your terminal thinks that your hostname is being changed to unknowne4ce8f3898fc.

[boy8cookie]

If it's changing based on where you connect your computer, it's probably coming from your router. See if your router is assigning a host name.

[jigneshmpatel]

I have DSL modem from AT &T. Don't know how to explore it. Can you provide any link to explore further.

-Jignesh

[jigneshmpatel]

Can I change something so my computer's jignesh-macbook.pro.local remains as it is forever,

[besson3c]

What are you trying to do? What makes you think that the hostname recognized by the terminal is any sort of problem? You might be spinning your tires with this...

[jigneshmpatel]

The terminal prompt shows "jignesh-macbook.pro.local" which is what I expect always
but when I am in my home network then the prompt shows "unknowne4ce8f3898fc".

[jigneshmpatel]

And "unknowne4ce8f3898fc" changes my machine name it makes the hadoop application stops working as it finds different name.

-Jignesh