[libvirt] [PATCH] qemu.conf: Mention virtlockd in @lock_manager description
When I played with virtlockd I was stunned by lacking documentation. My frustration got bigger when I had to read the patches to get the correct value to set in qemu.conf. Moreover, from pure libvirt-pride I'm changing commented value from sanlock to lockd. We want to favor our own implementation after all. Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- src/qemu/qemu.conf | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/src/qemu/qemu.conf b/src/qemu/qemu.conf index e436084..f0e802f 100644 --- a/src/qemu/qemu.conf +++ b/src/qemu/qemu.conf @@ -402,11 +402,13 @@ #allow_disk_format_probing = 1 -# To enable 'Sanlock' project based locking of the file -# content (to prevent two VMs writing to the same -# disk), uncomment this +# In order to prevent accidentally starting two domains that +# share one writable disk, libvirt offers two approaches for +# locking files. The first one is sanlock, the other one, +# virtlockd, is then our own implementation. Accepted values +# are "sanlock" and "lockd". # -#lock_manager = "sanlock" +#lock_manager = "lockd" -- 1.9.0
On Wed, Mar 12, 2014 at 08:59:42AM +0100, Michal Privoznik wrote:
When I played with virtlockd I was stunned by lacking documentation. My frustration got bigger when I had to read the patches to get the correct value to set in qemu.conf.
Moreover, from pure libvirt-pride I'm changing commented value from sanlock to lockd. We want to favor our own implementation after all.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- src/qemu/qemu.conf | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/src/qemu/qemu.conf b/src/qemu/qemu.conf index e436084..f0e802f 100644 --- a/src/qemu/qemu.conf +++ b/src/qemu/qemu.conf @@ -402,11 +402,13 @@ #allow_disk_format_probing = 1
-# To enable 'Sanlock' project based locking of the file -# content (to prevent two VMs writing to the same -# disk), uncomment this +# In order to prevent accidentally starting two domains that +# share one writable disk, libvirt offers two approaches for +# locking files. The first one is sanlock, the other one, +# virtlockd, is then our own implementation. Accepted values +# are "sanlock" and "lockd". # -#lock_manager = "sanlock" +#lock_manager = "lockd"
ACK, I did actually have a patch floating around to turn on virtlockd by default out of the box. I wonder if we should actually do that finally.... ? Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
On 12.03.2014 11:31, Daniel P. Berrange wrote:
On Wed, Mar 12, 2014 at 08:59:42AM +0100, Michal Privoznik wrote:
When I played with virtlockd I was stunned by lacking documentation. My frustration got bigger when I had to read the patches to get the correct value to set in qemu.conf.
Moreover, from pure libvirt-pride I'm changing commented value from sanlock to lockd. We want to favor our own implementation after all.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- src/qemu/qemu.conf | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/src/qemu/qemu.conf b/src/qemu/qemu.conf index e436084..f0e802f 100644 --- a/src/qemu/qemu.conf +++ b/src/qemu/qemu.conf @@ -402,11 +402,13 @@ #allow_disk_format_probing = 1
-# To enable 'Sanlock' project based locking of the file -# content (to prevent two VMs writing to the same -# disk), uncomment this +# In order to prevent accidentally starting two domains that +# share one writable disk, libvirt offers two approaches for +# locking files. The first one is sanlock, the other one, +# virtlockd, is then our own implementation. Accepted values +# are "sanlock" and "lockd". # -#lock_manager = "sanlock" +#lock_manager = "lockd"
ACK, I did actually have a patch floating around to turn on virtlockd by default out of the box. I wonder if we should actually do that finally.... ?
Sure, why not? Michal
On Wed, Mar 12, 2014 at 11:47:24AM +0100, Michal Privoznik wrote:
On 12.03.2014 11:31, Daniel P. Berrange wrote:
On Wed, Mar 12, 2014 at 08:59:42AM +0100, Michal Privoznik wrote:
When I played with virtlockd I was stunned by lacking documentation. My frustration got bigger when I had to read the patches to get the correct value to set in qemu.conf.
Moreover, from pure libvirt-pride I'm changing commented value from sanlock to lockd. We want to favor our own implementation after all.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- src/qemu/qemu.conf | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/src/qemu/qemu.conf b/src/qemu/qemu.conf index e436084..f0e802f 100644 --- a/src/qemu/qemu.conf +++ b/src/qemu/qemu.conf @@ -402,11 +402,13 @@ #allow_disk_format_probing = 1
-# To enable 'Sanlock' project based locking of the file -# content (to prevent two VMs writing to the same -# disk), uncomment this +# In order to prevent accidentally starting two domains that +# share one writable disk, libvirt offers two approaches for +# locking files. The first one is sanlock, the other one, +# virtlockd, is then our own implementation. Accepted values +# are "sanlock" and "lockd". # -#lock_manager = "sanlock" +#lock_manager = "lockd"
ACK, I did actually have a patch floating around to turn on virtlockd by default out of the box. I wonder if we should actually do that finally.... ?
Sure, why not?
Main reason is that it is a slight pain for developers running out of GIT builds, to have to launch two daemons. I guess they can easily just turn it off in the config file though. Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
On 03/12/2014 01:59 AM, Michal Privoznik wrote:
When I played with virtlockd I was stunned by lacking documentation. My frustration got bigger when I had to read the patches to get the correct value to set in qemu.conf.
Moreover, from pure libvirt-pride I'm changing commented value from sanlock to lockd. We want to favor our own implementation after all.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- src/qemu/qemu.conf | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/src/qemu/qemu.conf b/src/qemu/qemu.conf index e436084..f0e802f 100644 --- a/src/qemu/qemu.conf +++ b/src/qemu/qemu.conf @@ -402,11 +402,13 @@ #allow_disk_format_probing = 1
-# To enable 'Sanlock' project based locking of the file -# content (to prevent two VMs writing to the same -# disk), uncomment this +# In order to prevent accidentally starting two domains that +# share one writable disk, libvirt offers two approaches for +# locking files. The first one is sanlock, the other one, +# virtlockd, is then our own implementation. Accepted values
I'm not sure about that wording of that sentence. Maybe: ..offers two approaches for locking files: 'sanlock' uses the external sanlock daemon, and 'virtlockd' is implemented as part of libvirt. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
participants (3)
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Daniel P. Berrange -
Eric Blake -
Michal Privoznik