Recently, as you could see in previous posts, oVirt got to my attention. oVirt is the upstream project of Red Hat Enterprise Visualization or RHEV. While oVirt it isn’t providing everything that competitor VMWare ESXi does, it comes close and is a very good alternative for smaller or home setups. For a long time, oVirt wasn’t supported on Enterprise Linux 7 (like RHEL 7 or CentOS 7) but since a short time it is. Here you can find how to install oVirt and get started.

VM-extensions

oVirt is using KVM under the hood and as KVM does, it requires your CPU to support VM-extensions. On the x86 platofrom, those are either AMD-V or Intel’s VT-X. In order to check if the installed CPU’s support those extensions, we need to check if the vmx (for VT-X) or svm (for AMD-V) flag exists in the cpuinfo-output:

[jensd@cen ~]$ egrep -c '(vmx|svm)' /proc/cpuinfo
 2

When the output is 0, meaning that neither vmx or svm is found in the flags, it probably means that your CPU doesn’t support those extensions and there is little you can do. When the extensions are listed, be sure to check if they are enabled in the systems BIOS.

Hostname

The oVirt installation will check if it can resolve it’s own hostname into an IP-address so make sure that your host can do so.

If needed, add the hostname to /etc/hosts:

127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
192.168.202.101 cen

Install oVirt

oVirt can’t be found in the base CentOS repositories and it requires quite a few more dependencies outside the standard repositories. The easiest is the install the ovirt-release RPM that will configure your system with all required package sources:

[jensd@cen ~]$ sudo yum -y install http://plain.resources.ovirt.org/pub/yum-repo/ovirt-release35.rpm
 ...
 Complete!

Now that the sources are available for the oVirt packages, we can install it:

[jensd@cen ~]$ sudo yum -y install ovirt-engine
 ...
 Complete!

Configure oVirt

Once oVirt is installed, the fastest way to get started is to run engine-setup. This script will ask questions about your environment and configure oVirt depending on your answers.

[jensd@cen ~]$ sudo engine-setup
[ INFO  ] Stage: Initializing
[ INFO  ] Stage: Environment setup
          Configuration files: ['/etc/ovirt-engine-setup.conf.d/10-packaging-jboss.conf', '/etc/ovirt-engine-setup.conf.d/10-packaging.conf']
          Log file: /var/log/ovirt-engine/setup/ovirt-engine-setup-20150330160057-ov9ojr.log
          Version: otopi-1.3.1 (otopi-1.3.1-1.el7)
[ INFO  ] Stage: Environment packages setup
[ INFO  ] Stage: Programs detection
[ INFO  ] Stage: Environment setup
[ INFO  ] Stage: Environment customization

          --== PRODUCT OPTIONS ==--

          Configure Engine on this host (Yes, No) [Yes]:
          Configure WebSocket Proxy on this host (Yes, No) [Yes]:

          --== PACKAGES ==--

[ INFO  ] Checking for product updates...
[ INFO  ] No product updates found

          --== ALL IN ONE CONFIGURATION ==--


          --== NETWORK CONFIGURATION ==--

          Setup can automatically configure the firewall on this system.
          Note: automatic configuration of the firewall may overwrite current settings.
          Do you want Setup to configure the firewall? (Yes, No) [Yes]:
[ INFO  ] firewalld will be configured as firewall manager.
          Host fully qualified DNS name of this server [cen]:
[WARNING] Host name cen has no domain suffix
[WARNING] Failed to resolve cen using DNS, it can be resolved only locally
[WARNING] Host name cen has no domain suffix
[WARNING] Failed to resolve cen using DNS, it can be resolved only locally

          --== DATABASE CONFIGURATION ==--

          Where is the Engine database located? (Local, Remote) [Local]:
          Setup can configure the local postgresql server automatically for the engine to run. This may conflict with existing applications.
          Would you like Setup to automatically configure postgresql and create Engine database, or prefer to perform that manually? (Automatic, Manual) [Automatic]:

          --== OVIRT ENGINE CONFIGURATION ==--

          Engine admin password:
          Confirm engine admin password:
          Application mode (Virt, Gluster, Both) [Both]:

          --== PKI CONFIGURATION ==--

          Organization name for certificate [Test]:

          --== APACHE CONFIGURATION ==--

          Setup can configure the default page of the web server to present the application home page. This may conflict with existing applications.
          Do you wish to set the application as the default page of the web server? (Yes, No) [Yes]:
          Setup can configure apache to use SSL using a certificate issued from the internal CA.
          Do you wish Setup to configure that, or prefer to perform that manually? (Automatic, Manual) [Automatic]:

          --== SYSTEM CONFIGURATION ==--

          Configure an NFS share on this server to be used as an ISO Domain? (Yes, No) [Yes]: no

          --== MISC CONFIGURATION ==--


          --== END OF CONFIGURATION ==--

[ INFO  ] Stage: Setup validation
[WARNING] Less than 16384MB of memory is available

          --== CONFIGURATION PREVIEW ==--

          Application mode                        : both
          Firewall manager                        : firewalld
          Update Firewall                         : True
          Host FQDN                               : cen
          Engine database name                    : engine
          Engine database secured connection      : False
          Engine database host                    : localhost
          Engine database user name               : engine
          Engine database host name validation    : False
          Engine database port                    : 5432
          Engine installation                     : True
          PKI organization                        : Test
          Configure local Engine database         : True
          Set application as default page         : True
          Configure Apache SSL                    : True
          Configure WebSocket Proxy               : True
          Engine Host FQDN                        : cen

          Please confirm installation settings (OK, Cancel) [OK]:
[ INFO  ] Stage: Transaction setup
[ INFO  ] Stopping engine service
[ INFO  ] Stopping ovirt-fence-kdump-listener service
[ INFO  ] Stopping websocket-proxy service
[ INFO  ] Stage: Misc configuration
[ INFO  ] Stage: Package installation
[ INFO  ] Stage: Misc configuration
[ INFO  ] Initializing PostgreSQL
[ INFO  ] Creating PostgreSQL 'engine' database
[ INFO  ] Configuring PostgreSQL
[ INFO  ] Creating/refreshing Engine database schema
[ INFO  ] Creating CA
[ INFO  ] Configuring WebSocket Proxy
[ INFO  ] Generating post install configuration file '/etc/ovirt-engine-setup.conf.d/20-setup-ovirt-post.conf'
[ INFO  ] Stage: Transaction commit
[ INFO  ] Stage: Closing up

          --== SUMMARY ==--

[WARNING] Less than 16384MB of memory is available
          SSH fingerprint: C8:CE:BA:5B:6F:CA:5E:A8:BA:2F:E1:BC:FB:99:30:8F
          Internal CA D6:C7:60:F6:57:5A:1B:1B:2E:E8:9F:71:D3:0B:09:5D:DE:F3:42:9C
          Web access is enabled at:
              http://cen:80/ovirt-engine
              https://cen:443/ovirt-engine
          Please use the user "admin" and password specified in order to login

          --== END OF SUMMARY ==--

[ INFO  ] Starting engine service
[ INFO  ] Restarting httpd
[ INFO  ] Stage: Clean up
          Log file is located at /var/log/ovirt-engine/setup/ovirt-engine-setup-20150330160057-ov9ojr.log
[ INFO  ] Generating answer file '/var/lib/ovirt-engine/setup/answers/20150330160239-setup.conf'
[ INFO  ] Stage: Pre-termination
[ INFO  ] Stage: Termination
[ INFO  ] Execution of setup completed successfully

 

After running engine-setup, oVirt is available via it’s webinterface on the IP or hostname of the oVirt-host:

Navigate with your browser to the IP-address or hostname of the oVirt host. You should be presented with an oVirt page. Click on “Administration Portal” and login with admin and the password which your provided during engine-setup:

The first thing we need to do with the webinterface is to add the host to the default cluster. This can be done by navigating to “System -> Data Centers -> Default -> Clusters -> Default -> Hosts -> New”:

It takes a while for everything to be installed on the host. When the process is finished, the host should change it’s status to “Up”

Prepare NFS shares for oVirt

As you saw in the previous step, I explicitly didn’t configure the ISO domain in order to have my storage using different naming and mount points and to avoid the need to stop oVirt to be able to configure my NFS storage.

oVirt supports a variety of storage types like NFS, Gluster, Local and iSCSI. For a simple node, you would think that the local storage option is a good choice but I noticed it only introduces limitations. When using local storage, the host requires it’s own datacenter and you loose a lot of functionality for multi-host setups and that’s what makes oVirt so powerful. If that limitation isn’t enough, when using local storage, you can only configure one storage location. So if you have, for example an SSD and conventional disks, you have no choice but grouping them together in one logical volume which obviously isn’t a very good idea.

To overcome these limitations, I decided to setup NFS locally. This gives us the flexibility of a shared filesystem and the oVirt support for it without a (big) performance impact.

First I added the actual mountpoints:

[jensd@cen ~]$ sudo mkdir -p /srv/ovirt/{iso,export,sata,ssd}

Then, I added the mountpoints to my /etc/fstab configuration in order to make the mounts persistent:

/dev/mapper/vg_sys-lv_sata /srv/ovirt/sata      ext4    defaults       0 0
/dev/mapper/vg_sys-lv_iso /srv/ovirt/iso        ext4    defaults       0 0
/dev/mapper/vg_sys-lv_export /srv/ovirt/export  ext4    defaults       0 0
/dev/mapper/vg_ssd-lv_ssd /srv/ovirt/ssd        ext4    defaults       0 0

To avoid a reboot, let’s mount the above mountpoints manually:

[jensd@cen ~]$ for i in $(ls -1 /srv/ovirt); do sudo mount /srv/ovirt/$i; done

Now that the mounts that we’ll use for oVirt are available locally, we need to export them over NFS by putting the following in /etc/exports:

/srv/ovirt/iso          cen(rw,sync,no_subtree_check,all_squash,anonuid=36,anongid=36)
/srv/ovirt/sata         cen(rw,sync,no_subtree_check,all_squash,anonuid=36,anongid=36)
/srv/ovirt/ssd          cen(rw,sync,no_subtree_check,all_squash,anonuid=36,anongid=36)
/srv/ovirt/export       cen(rw,sync,no_subtree_check,all_squash,anonuid=36,anongid=36)

After adding the exports, refresh them and check their existence:

[jensd@cen ~]$ sudo vi /etc/exports
[jensd@cen ~]$ sudo exportfs -a
[jensd@cen ~]$ showmount -e
Export list for cen:
/srv/ovirt/export cen
/srv/ovirt/ssd    cen
/srv/ovirt/sata   cen
/srv/ovirt/iso    cen

To give the correct access rights for oVirt, make vdsm owner and kvm group owern of the mountpoints and files:

[jensd@cen ~]$ sudo chown -R vdsm:kvm /srv/ovirt/
[jensd@cen ~]$ sudo chmod -R 770 /srv/ovirt/

Be sure to let NFS start with your host otherwise oVirt won’t be very happy without it’s required storage domains:

[jensd@cen ~]$ sudo systemctl start {nfs-server,nfs-lock,nfs-idmap}
[jensd@cen ~]$ sudo systemctl enable {nfs-server,nfs-lock,nfs-idmap}
ln -s '/usr/lib/systemd/system/nfs-server.service' '/etc/systemd/system/nfs.target.wants/nfs-server.service'
ln -s '/usr/lib/systemd/system/nfs-idmap.service' '/etc/systemd/system/nfs.target.wants/nfs-idmap.service'

Since the default NFS version from CentOS 7 is NFS v4, oVirt can experience problems when trying to mount the ISO or export domain. The message you get when this appears is:

ERROR: mount.nfs: access denied by server while mounting cen:/srv/ovirt/iso

To overcome this error, you need to change the default NFS version for mounting (without specifiyng) to v3. This can be done in /etc/nfsmount.conf:

[ NFSMount_Global_Options ]
# This statically named section defines global mount
# options that can be applied on all NFS mount.
#
# Protocol Version [2,3,4]
# This defines the default protocol version which will
# be used to start the negotiation with the server.
Defaultvers=3
#
# Setting this option makes it mandatory the server supports the
# given version. The mount will fail if the given version is
# not support by the server.
Nfsvers=3

Configure storage domains in oVirt

Now that the NFS-exports are available, we can add them in oVirt. Login to the webinterface and navigate to “System -> Data Centers -> Default -> Storage -> New Domain”:

Do the same for the SSD, SATA, ISO and export domain. Don’t forget to change the type of the ISO and export domain to ISO / NFS and Export / NFS respectively.

If all goes well, you should end up with something like this:

Manage ISO-files

Unfortunately, you can’t just give a path to an ISO-file in oVirt but you need to import the ISO first into the ISO-domain. The advantage is that, when using multiple oVirt-hosts in a datacenter, the ISO becomes available everywhere.

Importing ISO-files into the ISO-domain needs to be done via the command line. First let’s make sure that we’ve got the correct name of our ISO-domain:

[jensd@cen ~]$ sudo engine-iso-uploader list
Please provide the REST API password for the admin@internal oVirt Engine user (CTRL+D to abort):
ISO Storage Domain Name   | Datacenter                | ISO Domain Status
ovirt-iso                 | Default                   | active

Now, let’s upload a CentOS 7 netinstall ISO:

[jensd@cen ~]$ sudo engine-iso-uploader upload -i ovirt-iso CentOS-7.0-1406-x86_64-NetInstall.iso
Please provide the REST API password for the admin@internal oVirt Engine user (CTRL+D to abort):
Uploading, please wait...
INFO: Start uploading CentOS-7.0-1406-x86_64-NetInstall.iso
INFO: CentOS-7.0-1406-x86_64-NetInstall.iso uploaded successfully

Create and install a new VM

At this point, we’ve got our host configured, a storage domain, an ISO domain, containing a bootable ISO and it’s time to create a new VM in the oVirt environment. Navigate to “System -> Data Centers -> Default -> Clusters -> Default -> VMs -> New VM”.

Fill in the General information about the VM and select the network:

Click on “Show Advanced Options” and go to system to configure the amount of memory and the number of virtual CPUs. To let this VM boot from the ISO-image which we just added to the ISO-domain, go to “Boot Options”, check “Attach CD” and select the ISO from the dropdown:

Press OK to add the VM and click on “Configure Virtual Disks” to add a virtual disk to the VM:

Select the host from the list and click on Run (the green arrow pointing upwards) to start the VM.

To access the console, right click on the VM and choose “Console”. On Windows, this requires the virt-viewer to be installed. You can download it here: https://virt-manager.org/download/.

Install the guest agent

After installing the OS on the VM. It’s a good idea to install the package ovirt-guest-agent-common from EPEL. This is similar to the VMWare-tools but for oVirt.

Logfiles

When you’re running into some weird or unclear error messages, which unfortunately sometimes seem to appear, it’s a good idea to check one of these logfiles:

• /var/log/ovirt-engine/engine.log
• /var/log/vdsm/vdsm.log