From 0094010f05ce37bce0ba945ea6dabd748b0c3d9d Mon Sep 17 00:00:00 2001 From: Daniel Berteaud Date: Thu, 6 Nov 2014 16:19:11 +0100 Subject: [PATCH] Support thin volumes and snapshots and allow alternative lock directory --- virt-backup | 44 ++++++++++++++++++++++++++++++++++---------- 1 file changed, 34 insertions(+), 10 deletions(-) diff --git a/virt-backup b/virt-backup index 56b129b..ff9345c 100644 --- a/virt-backup +++ b/virt-backup @@ -43,8 +43,12 @@ our @disks = (); $opts{action} = 'dump'; # Where backups will be stored. This directory must already exists $opts{backupdir} = '/var/lib/libvirt/backup'; +# Lockdir is where locks will be held when backing up a VM. The default is to put the lock +# in the backup dir of the VM, but in some situations, you want to put it elsewhere +$opts{lockdir} = ''; # Size of LVM snapshots (which will be used to backup VM with minimum downtime -# if the VM is backed by LVM) +# if the VM is backed by LVM). If size is set to 0, virt-backup will assume +# the volume is thinly provisioned and will create a thin snapshot $opts{snapsize} = '5G'; # If we should also dump the VM state (dump the memory, equivalent of virsh save) $opts{state} = 0; @@ -63,7 +67,7 @@ $opts{offline} = 1; # Compression used with the dump action (the compression is done on the fly) $opts{compress} = 'none'; # lvcreate path -$opts{lvcreate} = '/sbin/lvcreate -c 512'; +$opts{lvcreate} = '/sbin/lvcreate'; # lvremove path $opts{lvremove} = '/sbin/lvremove'; # lvs path @@ -101,6 +105,7 @@ GetOptions( "state" => \$opts{state}, "snapsize=s" => \$opts{snapsize}, "backupdir=s" => \$opts{backupdir}, + "lockdir=s" => \$opts{lockdir}, "lvm=s" => \$opts{lvm}, "vm=s" => \@vms, "action=s" => \$opts{action}, @@ -190,6 +195,12 @@ if (! -d $opts{backupdir} ){ exit 1; } +# Lockdir, if defined, must also exist +if ($opts{lockdir} ne '' && !-d $opts{lockdir}){ + print "$opts{lockdir} is not a valid directory\n"; + exit 1; +} + # Connect to libvirt print "\n\nConnecting to libvirt daemon using $connect[0] as URI\n" if ($opts{debug}); $libvirt1 = Sys::Virt->new( uri => $connect[0] ) || @@ -227,6 +238,7 @@ foreach our $vm (@vms){ } } our $backupdir = $opts{backupdir}.'/'.$vm; + our $lockdir = ($opts{lockdir} eq '') ? "$backupdir.meta" : $opts{lockdir}; our $time = "_".time(); if ($opts{action} eq 'cleanup'){ print "Running cleanup routine for $vm\n\n" if ($opts{debug}); @@ -270,7 +282,7 @@ sub prepare_backup{ my $data = $xml->XMLin( $dom->get_xml_description(), forcearray => ['disk'] ); # Stop here if the lock file is present, another dump might be running - die "Another backup is running\n" if ( -e "$backupdir.meta/$vm.lock" ); + die "Another backup is running\n" if ( -e "$lockdir/$vm.lock" ); # Lock VM: Create a lock file so only one dump process can run lock_vm(); @@ -517,8 +529,8 @@ sub run_dump{ } # And remove the lock file, unless the --keep-lock flag is present unlock_vm() unless ($opts{keeplock}); - # Cleanup snapshot and other tempm file - # but don't remove the dumps themself + # Cleanup snapshot and other temp files + # but don't remove the dumps themselves run_cleanup(0); } @@ -611,6 +623,7 @@ sub run_cleanup{ } close SNAPLIST; } + unlock_vm(); $meta = unlink <$backupdir.meta/*>; rmdir "$backupdir/"; rmdir "$backupdir.meta"; @@ -653,7 +666,8 @@ sub usage{ "dumped in the backup dir. That's why you should use a fast support for the backup dir (fast disks, RAID0 " . "or RAID10)\n\n" . "\t--snapsize=: The amount of space to use for snapshots. Use the same format as -L option of lvcreate. " . - "eg: --snapsize=15G. Default is 5G\n\n" . + "eg: --snapsize=15G. Default is 5G. If you specify a size of 0, virt-backup will assume the volume is thinly provisioned " . + "and will create a thin snapshot\n\n" . "\t--compress[=[gzip|bzip2|pbzip2|lzop|xz|lzip|plzip]]: On the fly compress the disks images during the dump. If you " . "don't specify a compression algo, gzip will be used. For the convert action, the compression uses " . "the internal qcow2 compression feature, and so, it ignores the compression format.\n\n" . @@ -662,6 +676,8 @@ sub usage{ "disk of a VM, but not the data one which can be backed up separatly, at the files level.\n\n" . "\t--backupdir=/path/to/backup: Use an alternate backup dir. The directory must exists and be writable. " . "The default is /var/lib/libvirt/backup\n\n" . + "\t--lockdir=/path/to/locks: Use an alternate lock dir. The directory must exists and be writable. " . + "The default is to put locks in the backup diretory, but you might want it elsewhere (on a shared storage for example)\n\n" . "\t--connect=: URI to connect to libvirt daemon (to suspend, resume, save, restore VM etc...). " . "The default is qemu:///system.\n\n" . "\t--keep-lock: Let the lock file present. This prevent another " . @@ -808,8 +824,16 @@ sub create_snapshot{ my $lock = $blk; $lock =~ s/\//\-/g; $lock = $opts{backupdir} . '/' . $lock . '.lock'; - my $cmd = "$opts{lvcreate} -s -n " . $blk . $suffix . - " -L $opts{snapsize} $blk > /dev/null 2>&1 < /dev/null\n"; + my $cmd = "$opts{lvcreate} -s -n " . $blk . $suffix; + # passing snapsize = 0 means don't allocate a fixed size, which will try to create a thin snapshot + if ($opts{snapsize} ne '0'){ + $cmd .= " -L $opts{snapsize}"; + } + else{ + # For thin snapshots, we need to tell LVM to enable the volume right away + $cmd .= " -kn"; + } + $cmd .= " $blk > /dev/null 2>&1 < /dev/null\n"; for ($cnt = 0; $cnt < 10; $cnt++ ){ print "Running: $cmd" if $opts{debug}; if (-e "$lock" . '.lock'){ @@ -854,7 +878,7 @@ sub destroy_snapshot{ # Just creates an empty lock file sub lock_vm{ print "Locking $vm\n" if $opts{debug}; - open ( LOCK, ">$backupdir.meta/$vm.lock" ) || die $!; + open ( LOCK, ">$lockdir/$vm.lock" ) || die $!; print LOCK ""; close LOCK; } @@ -863,6 +887,6 @@ sub lock_vm{ # Just removes the lock file sub unlock_vm{ print "Removing lock file for $vm\n\n" if $opts{debug}; - unlink <$backupdir.meta/$vm.lock>; + unlink <$lockdir/$vm.lock>; }