Month: August 2012

Credential errors, 401, 403 forbidden errors

A 403 forbidden error is caused by missing credentials. Through current installation methods, there are basically two ways to get the novarc file. The manual method requires getting it from within a project zipfile, and the scripted method just generates novarc out of the project zip file and sources it for you. If you do the manual method through a zip file, then the following novarc alone, you end up losing the creds that are tied to the user you created with nova-manage in the steps before.

When you run nova-api the first time, it generates the certificate authority information, including openssl.cnf. If it gets started out of order, you may not be able to create your zip file. Once your CA information is available, you should be able to go back to nova-manage to create your zipfile.

You may also need to check your proxy settings to see if they are causing problems with the novarc creation.

Instance errors

Sometimes a particular instance shows “pending” or you cannot SSH to it. Sometimes the image itself is the problem. For example, when using flat manager networking, you do not have a dhcp server, and an ami-tiny image doesn’t support interface injection so you cannot connect to it. The fix for this type of problem is to use an Ubuntu image, which should obtain an IP address correctly with FlatManager network settings. To troubleshoot other possible problems with an instance, such as one that stays in a spawning state, first check your instances directory for i-ze0bnh1q dir to make sure it has the following files:

Check the file sizes to see if they are reasonable. If any are missing/zero/very small then nova-compute has somehow not completed download of the images from objectstore.

Also check nova-compute.log for exceptions. Sometimes they don’t show up in the console output.

Next, check the /var/log/libvirt/qemu/i-ze0bnh1q.log file to see if it exists and has any useful error messages in it.

Finally, from the instances/i-ze0bnh1q directory, try virsh create libvirt.xml and see if you get an error there.

Let’s say you have a subnet 192.168.1.0 / 24 and you want to scan all ip’s to see if any hosts are up:

Type the following command, enter:

$ for ip in $(seq 1 254); do ping -c 1 192.168.1.$ip>/dev/null; [ $? -eq 0 ] && echo “192.168.1.$ip UP” || : ; done

Output:

192.168.1.65 UP
192.168.1.66 UP
192.168.1.70 UP
192.168.1.76 UP
192.168.1.253 UP
192.168.1.254 UP

While trying to run phptop after unzipping it I get the following error:

[root@torino phptop-0.5.3]# ./phptop 
Can't locate Term/Size.pm in @INC (@INC contains: /usr/local/lib/perl5 /usr/local/share/perl5 /usr/lib/perl5/vendor_perl /usr/share/perl5/vendor_perl /usr/lib/perl5 /usr/share/perl5 .) at ./phptop line 24.
BEGIN failed--compilation aborted at ./phptop line 24.
[root@torino phptop-0.5.3]#

To fix it I had to follow the coming steps:

[root@torino phptop-0.5.3]# yum install cpan
Loaded plugins: fastestmirror, refresh-packagekit, security
Loading mirror speeds from cached hostfile
 * base: it.centos.contactlab.it
 * epel: mirror.karneval.cz
 * extras: it.centos.contactlab.it
 * updates: mirror.bofh.so
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package perl-CPAN.i686 0:1.9402-127.el6 will be installed
--> Finished Dependency Resolution
Dependencies Resolved
================================================================================
 Package Arch Version Repository Size
================================================================================
Installing:
 perl-CPAN i686 1.9402-127.el6 base 244 k
Transaction Summary
================================================================================
Install 1 Package(s)
Total download size: 244 k
Installed size: 663 k
Is this ok [y/N]: y
Downloading Packages:
perl-CPAN-1.9402-127.el6.i686.rpm | 244 kB 00:00 
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
 Installing : perl-CPAN-1.9402-127.el6.i686 1/1 
 Verifying : perl-CPAN-1.9402-127.el6.i686 1/1
Installed:
 perl-CPAN.i686 0:1.9402-127.el6
Complete!
[root@torino phptop-0.5.3]#

Then run cpan

[root@torino phptop-0.5.3]#cpan

And you will be asked  whether to accept default answers just press <ENTER>/

Lots of test later you are presented with the cpan prompt tyoe install Term::Size as follows:

• ommit: wrote '/usr/share/perl5/CPAN/Config.pm'
  Terminal does not support AddHistory.
  cpan shell -- CPAN exploration and modules installation (v1.9402)
  Enter 'h' for help.
  cpan[1]> install Term::Size

After a long verbose build process assuming all went well ( you need internet connectivity to perform this step) type quit at the prompt as so:

cpan[2]> quit

This returns you to the shell prompt:

[root@torino phptop-0.5.3]# ./phptop 
No phptop records found.
[root@torino phptop-0.5.3]#

Voila !!! the program is working.The error is due to the lack of page reads as yet but the program compiled (JIT) and ran.