[Libguestfs] [PATCH 16/67] FAQ: Tips about using direct backend and fixed appliance on Fedora/RHEL.
From: "Richard W.M. Jones" <rjones(a)redhat.com>
(cherry picked from commit 0c512a52bdc2a88296d04900625822b34d567112)
---
examples/guestfs-faq.pod | 60 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 60 insertions(+)
diff --git a/examples/guestfs-faq.pod b/examples/guestfs-faq.pod
index ce251e6..c563569 100644
--- a/examples/guestfs-faq.pod
+++ b/examples/guestfs-faq.pod
@@ -536,6 +536,66 @@ to ensure libguestfs is basically working.
=back
+=head2 Errors during launch on Fedora E<ge> 18, RHEL E<ge> 7
+
+In Fedora E<ge> 18 and RHEL E<ge> 7, libguestfs uses libvirt to manage
+the appliance. Previously (and upstream) libguestfs runs qemu
+directly:
+
+ +----------------------------------+
+ | libguestfs |
+ +----------------+-----------------+
+ | direct backend | libvirt backend |
+ +----------------+-----------------+
+ | |
+ v v
+ +-------+ +----------+
+ | qemu | | libvirtd |
+ +-------+ +----------+
+ |
+ v
+ +-------+
+ | qemu |
+ +-------+
+
+ upstream Fedora 18+
+ non-Fedora RHEL 7+
+ non-RHEL
+
+The libvirt backend is more sophisticated, supporting SELinux/sVirt
+(see above), hotplugging and more. It is, however, more complex and
+so less robust.
+
+If you have permissions problems using the libvirt backend, you can
+switch to the direct backend by setting this environment variable:
+
+ export LIBGUESTFS_BACKEND=direct
+
+before running any libguestfs program or virt tool.
+
+=head2 How can I switch to a fixed / prebuilt appliance?
+
+This may improve the stability and performance of libguestfs on Fedora
+and RHEL.
+
+Any time after installing libguestfs, run the following commands as
+root:
+
+ mkdir -p /usr/local/lib/guestfs/appliance
+ libguestfs-make-fixed-appliance /usr/local/lib/guestfs/appliance
+ ls -l /usr/local/lib/guestfs/appliance
+
+Now set the following environment variable before using libguestfs or
+any virt tool:
+
+ export LIBGUESTFS_PATH=/usr/local/lib/guestfs/appliance
+
+Of course you can change the path to any directory you want. You can
+share the appliance across machines that have the same architecture
+(eg. all x86-64), but note that libvirt will prevent you from sharing
+the appliance across NFS because of permissions problems (so either
+switch to the direct backend or don't use NFS).
+
=head2 How can I speed up libguestfs builds?
By far the most important thing you can do is to install and properly
--
1.8.3.1