The document discusses OpenNebula, an open-source tool for building private and hybrid clouds. It provides tips for installing and configuring OpenNebula on CentOS 7, including disabling the firewall, using qemu instead of KVM for testing, allowing access to host devices from LXC containers, handling temporary directories, and using virtio for better performance. The document aims to help users get started with OpenNebula on CentOS 7.

1. Paris, France – August 25th 2014
OpenNebula
CentOS Dojo
OpenNebula and tips for CentOS 7
Javi Fontán
Project Engineer
© OpenNebula Project. Creative Commons Attribution-NonCommercial-ShareAlike License
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2. What is OpenNebula?

3. The OpenNebula Technology
An Uniform Management Layer
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4. The OpenNebula Technology
Cloud Architecture - The Internals of the Cloud
Interfaces Tools & API
• CLI & Sunstone (GUI)
• API
• Hybrid (EC2, Azure, SoftLayer)
• Service Management &Catalogs
Network
• VLAN
• Firewalling
• Multiple Technologies
Compute Hosts
• Grouped into logical clusters
• Multiple hypervisors
• Monitoring
Storage
• VM disks (file & block)
• Image Distribution
• Multiple Backends
Multi-tenancy
• AAA Services
• Scheduling
• Permissions & roles
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5. The OpenNebula Vision
The Power of Simplicity
Simple for Users
• Single-click provision, manage and access to virtual servers
• Just enough details of the underlying chaos
Simple for Sys Admins
• Do not hide the complexity
• Easy to inspect, understand and adapt
• Ease task automation
• Be prepared for different application types
• Just enough components and simple protocols
• Simplicity is the path to scale!
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6. Installing OpenNebula

7. A Typical OpenNebula Environment
Planning the Installation
• Repository of VM images
• Multiple Backends (LVM, Ceph)
Monitoring,Virtualization,
Storage and Network
• Provides physical resources for the VMs
• Must have a hypervisor installed
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8. Installation Frontend and Node
Installing
●Add EPEL repository
●Add OpenNebula repository
●Install Packages
# yum install opennebula-server opennebula-sunstone
opennebula-node-kvm opennebula-flow opennebula-gate
●Configure OpenNebula Services
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9. Installing GlusterFS
Planning the Installation
● CentOS 7 does not come with GlusterFS server
● qemu and libvirt packages support GlusterFS
● GlusterFS packages are compatible with stock
qemu/libvirt:
– curl -O /etc/yum.repos.d/glusterfs-epel.repo
http://download.gluster.org/pub/gluster/glusterfs/LATEST/CentOS/
glusterfs-epel.repo
– yum install glusterfs{,-server,-fuse,-geo-replication}
● Start GlusterFS daemon (systemctl start glusterd)
● Make sure there is a name for the local machine, gluster
wont let you use localhost
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10. More information
OpenNebula web pages
● http://opennebula.org
● http://opennebula.org/tryout
● http://docs.opennebula.org
● http://docs.opennebula.org/4.8/design_and_installation/q
uick_starts/qs_centos7_kvm.html
● http://dev.opennebula.org
● http://github.com/OpenNebula/one
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11. Tips for CentOS 7

12. Disable Firewall
Tips for CentOS 7
● Only do this for testing!
● Service iptables does not exist anymore
● Stop firewalld instead
– systemctl stop firewalld
● Enable it after finished testing!
– Systemctl start firewalld
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13. Use OpenNebula with qemu
Tips for CentOS 7
● When testing inside a VM you don't have VT extensions
● You can still test creation of VMs using qemu emulation
● Modify /etc/one/oned.conf:
– VM_MAD = [
– name = "kvm",
– executable = "one_vmm_exec",
– arguments = "-t 15 -r 0 kvm",
– default = "vmm_exec/vmm_exec_kvm.conf",
– type = "qemu" ]
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14. Use Host KVM from an LXC container
Tips for CentOS 7
● It's possible to allow the use of specific host devices
● KVM module creates a device (10, 232)
● Add this line to the LXC container config
– lxc.cgroup.devices.allow = c 10:232 rwm
● Create the device in your container:
– mknod /dev/kvm c 10 232
● Change de permissions
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15. TMP directories
Tips for CentOS 7
● lock and run directories now reside in memory
● Manually created directories won't exist anymore after a
reboot
● systemd has way to create those directories
● Create a .conf file in /etc/tmpfiles.d:
– d /var/run/one 0750 oneadmin oneadmin
● Execute directory creation manually:
– systemd-tmpfile --create
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16. qcow format
Tips for CentOS 7
● qemu creates qcow images with newer features by
default
● Use -o compat=0.10 so the image is compatible with
older qemu/kvm versions
● Create new image:
– qemu-img create -f qcow2 -o compat=0.10 image.qcow2 10G
● Convert image:
– qemu-img convert -f qcow2 -O qcow2 -o compat=0.10 image.qcow2
image2.qcow2
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17. Use virtio!
Tips for CentOS 7
● CentOS 6.x stock kernel supports virtio
● Greatly enhances performance
● User virtio-scsi for disks. You get the speed
improvements and the number of devices is increased
● virtio network interfaces are called ETH*!
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18. Questions?
We Will Be Happy to Answer Your Questions
OpenNebula.org @OpenNebula
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