FAQ

:!: Please feel free to add and/or update questions in the following list. This is a collaborative effort between all the members of the community, please share your experiences installing, configuring and using OpenNebula.


Currently answered questions:


Do I need to install any software on the worker nodes?

OpenNebula doesn't need to install any additional software in the nodes. It just needs to have access passwordlessly via ssh using the <oneadmin> account.


I get a "User cannot be authenticated" error, where do I set my username and password?

Check that the $ONE_AUTH environment variable points to a file containing just one line, with your username and password separated by a colon.

$ cat ~/.one/one_auth oneadmin:opennebula

Also, OpenNebula commands should be run as the unix oneadmin user. Running OpenNebula as root is not recommended and has been reported to be the source of this type of problem.


Should I run OpenNebula as root?

Absolutely not! OpenNebula should run under the <oneadmin> account.


I get a "Connection refused - connect(2)" error, what is the problem?

Probably the OpenNebula daemon is not running. You should start it using the following command:

$ one start

If the daemon is running check that the ONE_XMLRPC environment variable is correctly set.


My VM is running but I get no answer from pings, what's wrong?

There are several reasons for this, check:

  • You have created a network with a valid bridge in the nodes of your cluster
  • You have defined a NIC attribute in your VM attached to that network
  • The VM is prepared to configure the interface to use a valid IP in that network. You can:
    • Configure the VM to dynamically configure the IP using its MAC address (Contextualzation)
    • Configure the VM to statically set a given IP of the network
    • Put a DHCP server attached to that network
  • Also be sure that you are pinging the VM from a host with a route to the network

You may find useful the networking tutorial.


Why does ''onevm saveas'' fail to save the images after a ''onevm delete/cancel'' action?

If you delete/cancel a running VM, it is assumed that you do not want to keep the VM, or that somehow it failed and needed a forced deletion. That's why the images are saved back only after a graceful shutdown.


Why my VM ends up in Fail? I'm using VM_DIR and NFS

The VM_DIR is only needed if the $ONE_LOCATION/var mountpoint shared in the front-end is different from the mountpoint in the nodes. If both locations share the same path, the VM_DIR is not needed, try uncommenting it, restarting OpenNebula and launching the VM again. One corollary and golden rule: never set VM_DIR to the same path as $ONE_LOCATION/var.


My machine stays in pending state. What can i do?

OpenNebula keeping the VMs in pending is due to the scheduler not finding available capacity in the hosts to perform the deploy. You should check:

  • The hosts shown in “onehost list” are correctly monitorized (ie they are not in error state)
  • The VM requirements in terms of CPU and MEMORY can be satisfied with the existing hosts. If not, try shutting down some VMs
  • The VM template REQUIREMENTS section may contain an expressin impossible to satisfy with the infrastructure.


When I start Sunstone/OCCI/EC2 servers I get this error in the log: /usr/lib/ruby/gems/1.8/gems/rack-1.2.2/lib/rack/utils.rb:138:in `union': can't convert Array into String (TypeError)

There is a compatibility problem with last versions of sinatra and rack using ruby 1.8.7.

You can fix this issue in two ways:

  • Upgrading ruby to 1.9
  • Downgrading rack version to 1.2.0:

# gem uninstall rack
Select gem to uninstall:
 1. rack-1.0.0
 2. rack-1.0.1
 3. rack-1.2.1
 4. All versions
> 4
# gem install rack --version '1.2.0'
Successfully installed rack-1.2.0
1 gem installed


Will I lose all my information if I stop the OpenNebula daemon?

No, all resources (e.g. Hosts, Virtual Networks, Virtual Machines) are stored in the DB. The running VMs monitoring will be resumed as if nothing happened.


Sunstone server does not work

There are several reasons why the Sunstone server may not work, or may not be reachable. Therefore it is good to check a few things:

  • The server starts properly: after sunstone-server start check $ONE_LOCATION/var/sunstone.log (self-contained) or var/log/one/sunstone.log (system-wide) for any messages. One common cause for exceptions at start-up is missing ruby gems. Check the list of dependencies here.
  • Ubuntu issue: If you are using an Ubuntu distribution be aware that the gems bin/ folder is not included in the PATH variable by default. This usually means a Command rackup not found when running sunstone-server start. To fix it please add the folder to the current PATH (change ruby version accordingly to your needs):

export PATH="/var/lib/gems/1.8/bin":$PATH

  • Rack and Sinatra issue: There have been reports of Ruby 1.8.7 + Sinatra + rack 1.2.1/1.2.2 throwing can't convert Array into String (TypeError) exceptions. If encountered, solutions are downgrading rack to 1.2.0 or upgrading Ruby to 1.9.x.
  • The server is reachable: if you are trying to reach the server from somewhere other than localhost, you need to specify the IP address on which to listen for connections with the -H option: sunstone-server -H 0.0.0.0 start should make the server reachable from everywhere.
  • Firewalls in the way: Sunstone server runs by default on port 4567. Note it may be blocked by a firewall, and therefore not reachable. You can change the default listen port with the -p option.
  • Browser compatible?: Sunstone supports Firefox >= 3.5 and Chrome. Using other browsers may simply not work.

That should get you to the login screen at least. Remember that you need a working installation of OpenNebula running (one start) and user credentials to go pass that point.


The Sunstone 2.2 interface shows all resources from all users. Is there a way I can make it show only the resources owned by the logged-in user?

This is not the default behaviour of Sunstone, as (of version 2.2) it is intended to be just a replacement for the CLI. However, there is a way. Just change user_flag to -1 in line 69 of the SunstoneServer.rb file:

SunstoneServer.rb:69
68:    def get_pool(kind)
69:        user_flag = -2 <----HERE
70:        pool = case kind


I can create VMs, but sched.log shows the error "Could not retrieve pool info from ONE". What's wrong?

If the scheduler does not deploy the pending VMs, and messages like these are found in sched.log

[HOST][E]: Exception raised: Unable to transport XML to server and
get XML response back.  HTTP response code is 404, not 200
[POOL][E]: Could not retrieve pool info from ONE

Then you need to unset the http_proxy environment variable, or set the no_proxy accordingly.


I just installed OpenNebula, but it doesn't detect the existing VMs. Why?

OpenNebula assumes the complete control of the infrastructure and the VMs. If you had previous VMs in your hypervisor, OpenNebula won't try to detect or import them.


VNC console access in Sunstone does not work. Whats the problem?

Please check the VNC troubleshooting section of the Sunstone documentation.


Listing VMs takes a lot of time. Why?

Command line interface gets information from OpenNebula sing XML. The default XML library that comes with ruby is a bit slow and while it is ok for small installations it can be a big overhead with a certain amount of VMs are registered. To speedup your installation you need to install nokogiri gem. This can be done with one of this options:

  • Execute /usr/share/one/install_gems optional
  • Install nokogiri package
  • Execute sudo gem install nokogiri

After the installation of this library OpenNebula will automatically use of it.


faq · Last modified: 2012/04/09 16:28 by Javi Fontan
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