4 ms·

> its not true that libvirt adds nothing of value, it adds easy networking support, easy snapshots, a nice gui interface, a very nice remote protocol and client

by antocv 7y ago

> its not true that libvirt adds nothing of value, it adds easy networking support, easy snapshots, a nice gui interface, a very nice remote protocol and clients (that seamlessly support both graphical and serial output, aswell as on the fly reconfiguration of VMs without restarting them), template VMs (including one time initial provision setup), easy support for storage pools including remote ones, an easy way to manipulate RAM usage on live VMs, easy PCI and USB passthrough, live migration to other hosts, etc etc. everything libvirt does can be done without it by talking to qemu directly. and yes, Ive done many of the above "by hand", it was easier to read man qemu and other qemu docs than to swallow libvirt.

throwaway2048 7y ago
No, not everything it does can be done by qemu directly, plenty of it lies outside of the scope of QEMU entirely, like managing networks (not just network devices), or storage pools, setting up permissions for device redirection, or doing the legwork for VM provisioning and configuration (including net booting and automatically running appropriate scripts), or managing access to VMs both locally and remotely. Its fine if your use cases are covered by plain QEMU, but libvirt does a hell of a lot more than plain QEMU alone is capable of. Again all of that is possible via other means, but when other means involve recreating half of libvirt in shell scripts or other code, id rather let somebody else do the work for me. QEMU is designed to run virtual machines, libvirtd is designed to manage VM server infrastructure.
- fulafel 7y ago
  The alternative is not that many commands: https://blog.elastocloud.org/2015/07/qemukvm-bridged-network-with-tap.html https://blog.elastocloud.org/2015/07/qemukvm-bridged-network...
  - throwaway2048 7y ago
    For one static network, what about complicated inter VM networking schemes (including firewalling) that need to be dynamically adjusted as VMs go on and offline? Libvirtd is much better suited to managing that sort of complexity.
    - fulafel 7y ago
      I have the luxury of opining that such complicated networking schemes should be reined in, and not served with baroque management software. Complexity is the arch enemy of security, because systems must be kept easy to reason about.
- deleted 7y ago
  [deleted]

by antocv 7y ago

throwaway2048 7y ago

No, not everything it does can be done by qemu directly, plenty of it lies outside of the scope of QEMU entirely, like managing networks (not just network devices), or storage pools, setting up permissions for device redirection, or doing the legwork for VM provisioning and configuration (including net booting and automatically running appropriate scripts), or managing access to VMs both locally and remotely. Its fine if your use cases are covered by plain QEMU, but libvirt does a hell of a lot more than plain QEMU alone is capable of. Again all of that is possible via other means, but when other means involve recreating half of libvirt in shell scripts or other code, id rather let somebody else do the work for me. QEMU is designed to run virtual machines, libvirtd is designed to manage VM server infrastructure.

fulafel 7y ago
The alternative is not that many commands: https://blog.elastocloud.org/2015/07/qemukvm-bridged-network-with-tap.html https://blog.elastocloud.org/2015/07/qemukvm-bridged-network...
- throwaway2048 7y ago
  For one static network, what about complicated inter VM networking schemes (including firewalling) that need to be dynamically adjusted as VMs go on and offline? Libvirtd is much better suited to managing that sort of complexity.
  - fulafel 7y ago
    I have the luxury of opining that such complicated networking schemes should be reined in, and not served with baroque management software. Complexity is the arch enemy of security, because systems must be kept easy to reason about.
deleted 7y ago
[deleted]