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README_libvirt.md

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LIBVIRT Setup instructions

libvirt is an openshift-ansible provider that uses libvirt to create local Fedora VMs that are provisioned exactly the same way that cloud VMs would be provisioned.

This makes libvirt useful to develop, test and debug OpenShift and openshift-ansible locally on the developer’s workstation before going to the cloud.

Install dependencies

  1.  Install [ansible](http://www.ansible.com/)
  2. Install dnsmasq
  3. Install ebtables
  4. Install qemu and qemu-system-x86
  5. Install libvirt-python and libvirt
  6. Install genisoimage
  7. Enable and start the libvirt daemon, e.g:
    • systemctl enable libvirtd
    • systemctl start libvirtd
  8. Grant libvirt access to your user¹
  9. Check that your $HOME is accessible to the qemu user²
  10. Configure dns resolution on the host³

¹ Depending on your distribution, libvirt access may be denied by default or may require a password at each access.

You can test it with the following command:

virsh -c qemu:///system pool-list

If you have access error messages, please read https://libvirt.org/acl.html and https://libvirt.org/aclpolkit.html .

In short, if your libvirt has been compiled with Polkit support (ex: Arch, Fedora 21), you can create /etc/polkit-1/rules.d/50-org.libvirt.unix.manage.rules as follows to grant full access to libvirt to $USER

sudo /bin/sh -c "cat - > /etc/polkit-1/rules.d/50-org.libvirt.unix.manage.rules" << EOF
polkit.addRule(function(action, subject) {
        if (action.id == "org.libvirt.unix.manage" &&
            subject.user == "$USER") {
                return polkit.Result.YES;
                polkit.log("action=" + action);
                polkit.log("subject=" + subject);
        }
});
EOF

If your libvirt has not been compiled with Polkit (ex: Ubuntu 14.04.1 LTS), check the permissions on the libvirt unix socket:

ls -l /var/run/libvirt/libvirt-sock
srwxrwx--- 1 root libvirtd 0 févr. 12 16:03 /var/run/libvirt/libvirt-sock

usermod -a -G libvirtd $USER
# $USER needs to logout/login to have the new group be taken into account

(Replace $USER with your login name)

² Qemu will run with a specific user. It must have access to the VMs drives

All the disk drive resources needed by the VMs (Fedora disk image, cloud-init files) are put inside ~/libvirt-storage-pool-openshift/.

As we’re using the qemu:///system instance of libvirt, qemu will run with a specific user:group distinct from your user. It is configured in /etc/libvirt/qemu.conf. That qemu user must have access to that libvirt storage pool.

If your $HOME is world readable, everything is fine. If your $HOME is private, ansible will fail with an error message like:

error: Cannot access storage file '$HOME/libvirt-storage-pool-openshift/lenaic-master-216d8.qcow2' (as uid:99, gid:78): Permission denied

In order to fix that issue, you have several possibilities:

  • set libvirt_storage_pool_path inside playbooks/libvirt/openshift-cluster/launch.yml and playbooks/libvirt/openshift-cluster/terminate.yml to a directory:
    • backed by a filesystem with a lot of free disk space
    • writable by your user;
    • accessible by the qemu user.
  • Grant the qemu user access to the storage pool.

On Arch or Fedora 22+:

setfacl -m g:kvm:--x ~

³ Enabling DNS resolution to your guest VMs with NetworkManager

  • Verify NetworkManager is configured to use dnsmasq:
$ sudo vi /etc/NetworkManager/NetworkManager.conf
[main]
dns=dnsmasq
  • Configure dnsmasq to use the Virtual Network router for example.com:
sudo vi /etc/NetworkManager/dnsmasq.d/libvirt_dnsmasq.conf
server=/example.com/192.168.55.1

Test The Setup

  1. cd openshift-ansible/
  2. Try to list all instances (Passing an empty string as the cluster_id argument will result in all libvirt instances being listed)
  bin/cluster list libvirt ''

Configuration

The following options can be passed via the -o flag of the create command or as environment variables:

  • image_url (default to http://cloud.centos.org/centos/7/images/CentOS-7-x86_64-GenericCloud.qcow2.xz): URL of the QCOW2 image to download
  • image_name (default to CentOS-7-x86_64-GenericCloud.qcow2): Name of the QCOW2 image to boot the VMs on
  • image_compression (default to xz): Source QCOW2 compression (only xz supported at this time)
  • image_sha256 (default to 9461006300d65172f5668d8875f2aad7b54f7ba4e9c5435d65a84a5a2d66e39b): Expected SHA256 checksum of the downloaded image
  • skip_image_download (default to no): Skip QCOW2 image download. This requires the image_name QCOW2 image to be already present in $HOME/libvirt-storage-pool-openshift-ansible

Creating a cluster

  1. To create a cluster with one master and two nodes
  bin/cluster create libvirt lenaic

Updating a cluster

  1. To update the cluster
  bin/cluster update libvirt lenaic

Terminating a cluster

  1. To terminate the cluster
  bin/cluster terminate libvirt lenaic