Book Image

Mastering KVM Virtualization

Book Image

Mastering KVM Virtualization

Overview of this book

A robust datacenter is essential for any organization – but you don’t want to waste resources. With KVM you can virtualize your datacenter, transforming a Linux operating system into a powerful hypervisor that allows you to manage multiple OS with minimal fuss. This book doesn’t just show you how to virtualize with KVM – it shows you how to do it well. Written to make you an expert on KVM, you’ll learn to manage the three essential pillars of scalability, performance and security – as well as some useful integrations with cloud services such as OpenStack. From the fundamentals of setting up a standalone KVM virtualization platform, and the best tools to harness it effectively, including virt-manager, and kimchi-project, everything you do is built around making KVM work for you in the real-world, helping you to interact and customize it as you need it. With further guidance on performance optimization for Microsoft Windows and RHEL virtual machines, as well as proven strategies for backup and disaster recovery, you’ll can be confident that your virtualized data center is working for your organization – not hampering it. Finally, the book will empower you to unlock the full potential of cloud through KVM. Migrating your physical machines to the cloud can be challenging, but once you’ve mastered KVM, it’s a little easie.
Table of Contents (22 chapters)
Mastering KVM Virtualization
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Enabling lockd


For image-based storage pools which are POSIX compliant, you can enable it easily by uncommenting lock_manager = "lockd" in /etc/libvirt/qemu.conf or on both hypervisors:

Now, enable and start the virtlockd service on both the hypervisors. Also, restart libvirtd on both the hypervisors.

# systemctl enable virtlockd; systemctl start virtlockd
# systemctl restart libvirtd
# systemctl status virtlockd

Starting vm1 on f22-02:

[root@f22-02]# virsh start vm1
Domain vm1 started

Starting the same vm1 on f22-01:

[root@f22-01]# virsh start vm1
error: Failed to start domain vm1
error: resource busy: Lockspace resource '/var/lib/libvirt/images/testvms/vm1.qcow2' is locked

Another method to enable lockd is to use a hash of the disk's file path. Locks are saved in a shared directory that is exported through the NFS, or similar sharing, to the hypervisors. This is very useful when you have virtual disks, which are created and attached using multipath LUN. fcntl() cannot be used in these cases...