Vdsm Developers

Revision as of 15:30, 15 August 2012

Getting the source

Our public git repo is located on oVirt.org

you can clone it with

git clone http://gerrit.ovirt.org/p/vdsm.git

Building a Vdsm RPM

Vdsm uses autoconf and automake as it's build system.

 Fedora users should verify the following packages are installed before attempting to build:
 yum install autoconf automake pyflakes logrotate gcc python-pep8 libvirt-python python-devel python-nose rpm-build sanlock-python

To configure the build env:

./autogen.sh --system

To create an RPM do:

make rpm

or

make NOSE_EXCLUDE=.* rpm  #(As development only, avoid the unittests validation)

Note: To exclude a specific test (testStressTest):

make NOSE_EXCLUDE=testStressTest rpm

Vdsm automatically builds using the latest tagged version. If you want to explicitly define a version use

make rpmversion=4.9 rpmrelease=999.funkyBranch

Code Style

• variables and arguments are in mixedCase
• class names are in CamelCase
• all indentation is made of space characters
• a space character follows any comma
• spaces surround operators, but
• no spaces between

def f(arg=its_default_value)

• lines longer than 80 chars are frowned upon
• whitespace between functions and within stanza help to breath while reading code
• a space char follows a comment's hash char
• let logging method do the formatting for you:

logging.debug('hello %s', 'world')

rather than

logging.debug('hello %s' % 'world')

Sending patches

Send them to our gerrit server (see how). With your first major patch, do not forget to add yourself to the AUTHORS file. Do not be shy - it gives you a well-deserved recognition, and it shows to the team that you stand behind your code.

General development discussions are in vdsm-devel@lists.fedorahosted.org.

Creating local yum repo to test vdsm changes

1) First you will need to generate the rpm with your changes, from the vdsm source directory:

#vdsm> ./autogen.sh --system
#vdsm> make
#vdsm> make rpm

Note: all rpm files will be generated at rpmbuild dir, usually: /home/your-user/rpmbuild/RPMS

2) Setting environment:

• Install required package

# yum install createrepo -y

• Enable httpd service

# chkconfig httpd on

or

# ln -s '/lib/systemd/system/httpd.service' '/etc/systemd/system/multi-user.target.wants/httpd.service'

• Create the directory that will hold the rpm files (repo)

# mkdir /var/www/html/my-vdsm-changes

• Copy the vdsm packages to repo

# cp /home/your-user/rpmbuild/RPMS/noarch/* /var/www/html/my-vdsm-changes
# cp /home/your-user/rpmbuild/RPMS/x86_64/* /var/www/html/my-vdsm-changes

• Create the repo inside the yum.repos.d

# vi /etc/yum.repos.d/my-vdsm-changes.repo
[my-vdsm-changes]
name = my vdsm changes
baseurl = http://127.0.0.1/my-vdsm-changes
enabled = 1
gpgcheck = 0

• Execute createrepo tool

# createrepo /var/www/html/my-vdsm-changes

• Start httpd service

# service httpd start

• List all repos and see your new repo

# yum repolist

Note: SELinux might throw permission denied to repo located at /var/www/html/

Using VM console

If you want to use the console for a VM using the Spice protocol (VNC is not supported right now) Run the following command on the host running ovirt-engine:

# psql -U postgres engine -c "update vdc_options set option_value = 'false' 
where option_name = 'UseSecureConnectionWithServers';"

Fake KVM Support

As developer you might need to add many hosts into your environment for tests. VDSM provides a functionality called 'fake_kvm_support' for VDSM quality assurance/developers emulate a real host/kvm hardware without running real guests.

• 1) Create a guest as Fedora 17 (Tested on Fedora 17 but should work in higher versions as well)

• 2) Install required packages

# yum install vdsm-hook-faqemu -y 

• 3) Change vdsm config file to enable this feature

# vi /etc/vdsm/vdsm.conf 
 [vars]

 fake_kvm_support = true  

• 4) Restart the vdsmd daemon (Only required if you had previously VDSM installed)

# systemctl restart vdsmd.service 

• 5) Open the oVirt Engine portal and add the new 'Fake' Host

 Login with your admin user -> Hosts -> New 

• 6) The host should be UP

Troubleshooting Fake KVM Support

Failed: Server does not support virtualization

If during the installation of the host you received the message "Server does not support virtualization" from oVirt Engine, it's probably because your vdsm version doesn't include the patch: http://gerrit.ovirt.org/#/c/5611/3 (might be a bug as well).
This patch add the 'fake kvm' support to vds_bootstrap.

There are several ways to update your vds_bootstrap, for example:

• Yum update in oVirt Engine machine (if the repo is not updated, use the others approaches)

 # yum update vdsm-bootstrap 

• Clone vdsm tree and create an updated vdsm-bootstrap rpm and update the oVirt Engine system

  # git clone git://gerrit.ovirt.org/vdsm
  # cd vdsm
  (if required increase the Version/Release from vdsm.spec.in)
  # ./autogen.sh --system && make && make rpm
  # rpm -Uvh ~/rpmbuild/RPMS/noarch/vdsm-bootstrap* 

• Clone the vdsm tree, execute autogen/make and copy the vds_bootstrap/vds_bootstrap.py to /usr/share/vds_bootstrap

  # git clone git://gerrit.ovirt.org/vdsm
  # cd vdsm
  # ./autogen.sh --system && make
  # cp vds_bootstrap/vds_bootstrap.py /usr/share/vds_bootstrap 
           

• Manually backport the above http://gerrit.ovirt.org/5611 patch to your current vds_bootstrap (/usr/share/vds_bootstrap)

  # vi /usr/share/vds_bootstrap/vds_bootstrap.py
  Make the changes manually

Non Responsive status

• Check if vdsm and libvirt daemons are running
• Firewall?

Default networks, the following networks are missing on host 'ovirtmgmt'

Something goes wrong setting the bridge ovirtmgmt, check the logs (/tmp/vds*.log) in the host side.
If required, use the manual process to create the bridge and re-add the host: http://www.ovirt.org/wiki/Installing_VDSM_from_rpm#Configuring_the_bridge_Interface

Running Node as guest - Nested KVM

Following the below instructions you can use oVirt Node, Fedora Node and oVirt Engine as guests.

Requires: Processors with Full Virtualization embedded

Attention: The below steps were tested on Fedora 17 but should work in higher versions (maybe not even required in the future releases, hopefully virt-manager will handle that directly in the next versions)

"Nested VMX" feature adds this missing capability - of running guest hypervisors (which use VMX) with their own nested guests. It does so by allowing a guest to use VMX instructions, and correctly
and efficiently emulating them using the single level of VMX available in the hardware.

Finally, we are assuming you already have qemu-kvm/libvirt/virt-manager installed in your system

Intel

• 1) Check if nested KVM is enabled (should be Y)

 # cat /sys/module/kvm_intel/parameters/nested
  N

• 2) In that case, it's disabled, to enable (can be via modprobe conf as well):

 # vi /etc/default/grub

Add to the end of line GRUB_CMDLINE_LINUX kvm-intel.nested=1

Example:

 GRUB_CMDLINE_LINUX="rd.md=0 rd.dm=0  KEYTABLE=us SYSFONT=True rd.lvm.lv=vg/lv_root rd.luks=0 rd.lvm.lv=vg/lv_swap LANG=en_US.UTF-8 rhgb quiet kvm-intel.nested=1"

• 3) Save the changes:

 # grub2-mkconfig -o /boot/grub2/grub.cfg

• 4) Reboot the system:

 # reboot

• 5) Install oVirt Node as guest with virt-manager (or any other distro) and shutdown after the installation

• 6) Copy the cpu model, vendor and vmx flag from Hypervistor to the guest:

 # virsh capabilities  (collecting data from hypervisor)
  ...
    <cpu match='exact'>
      <model>Penryn</model>
      <vendor>Intel</vendor>
      <feature policy='require' name='vmx'/>
    </cpu>
  ....

Note that I have removed all flags from my Hypervisor, just leaving he vmx but you can use all of them if you want.

Alright, time to add to your virtual machine (guest) the vmx flag:

 # vi /etc/libvirt/qemu/ovirt-node-2-5.xml (or virsh edit?)
  <domain type='kvm'>
    <cpu match='exact'>
      <model>Penryn</model>
      <vendor>Intel</vendor>
      <feature policy='require' name='vmx'/>
    </cpu>

Of course, all the above steps could be automated/improved. Fell free to change it.

• 7) Test if it works:

  # virsh create ovirt-node-2-5.xml

• if the virtual machine starts check in the guest that vmx flag in the /proc/cpuinfo. Also, don't forget to define (save) the new xml:

  # virsh define /etc/libvirt/qemu/ovirt-node-2-5.xml

AMD

Works out of the box.

• 1) To check if nested KVM is enabled (should be 1)

 # cat /sys/module/kvm_amd/parameters/nested
  1

• 2) Install oVirt Node as guest with virt-manager (or any other distro).

• 3) After virtual machine starts, check in the guest that svm flag in the /proc/cpuinfo.

 # grep -m1 svm /proc/cpuinfo
  flags           : fpu de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx lm up nopl pni cx16 popcnt hypervisor lahf_lm svm abm sse4a

More info about nested-kvm: https://github.com/torvalds/linux/blob/master/Documentation/virtual/kvm/nested-vmx.txt