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The current sanlock plugin requires a central management application to manually add <lease> elements to each guest, to protect resources that are assigned to it (eg writable disks). This makes the sanlock plugin useless for usage in more ad hoc deployment environments where there is no central authority to associate disks with leases. This patch adds a mode where the sanlock plugin will automatically create leases for each assigned read-write disk, using a md5 checksum of the fully qualified disk path. This can work pretty well if guests are using stable disk paths for block devices eg /dev/disk/by-path/XXXX symlinks, or if all hosts have NFS volumes mounted in a consistent pattern. The plugin will create one lockspace for managing disks with filename /var/lib/libvirt/sanlock/__LIBVIRT__DISKS__. For each VM disks, there will be another file to hold a lease /var/lib/libvirt/sanlock/5903e5d25e087e60a20fe4566fab41fd Each VM disk lease is usually 1 MB in size. The script virt-sanlock-cleanup should be run periodically to remove unused lease files from the lockspace directory. To make use of this capability the admin will need to do several tasks: - Mount an NFS volume (or other shared filesystem) on /var/lib/libvirt/sanlock - Configure 'host_id' in /etc/libvirt/qemu-sanlock.conf with a unique value for each host with the same NFS mount - Toggle the 'auto_disk_leases' parameter in qemu-sanlock.conf Technically the first step can be skipped, in which case sanlock will only protect against 2 vms on the same host using the same disk (or the same VM being started twice due to error by libvirt). * src/locking/libvirt_sanlock.aug, src/locking/sanlock.conf, src/locking/test_libvirt_sanlock.aug: Add config params for configuring auto lease setup * libvirt.spec.in: Add virt-sanlock-cleanup program, man page * tools/virt-sanlock-cleanup.in: Script to purge unused disk resource lease files
97 lines
2.1 KiB
Bash
97 lines
2.1 KiB
Bash
#!/bin/sh
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# A script to cleanup resource leases auto-created by
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# the libvirt lock plugin for sanlock
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verbose=1
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if test "x$1" = "x-q" ; then
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verbose=0
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fi
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LOCKSPACE="__LIBVIRT__DISKS__"
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LOCKDIR=`augtool print '/files@SYSCONFDIR@/libvirt/qemu-sanlock.conf/disk_lease_dir'`
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if test $? != 0 || "x$LOCKDIR" = "x" ; then
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LOCKDIR="@LOCALSTATEDIR@/lib/libvirt/sanlock"
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fi
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notify() {
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test $verbose = 1 || return
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if test "x$1" = "x-n"; then
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shift
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printf %s "$*"
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else
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printf %s\\n "$*"
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fi
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}
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cd "$LOCKDIR" || exit 1
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for MD5 in *
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do
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if test $MD5 != '*' && $MD5 != $LOCKSPACE ; then
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RESOURCE="$LOCKSPACE:$MD5:$LOCKDIR/$MD5:0"
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notify -n "Cleanup: $RESOURCE "
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sanlock client command -r $RESOURCE -c /bin/rm -f "$LOCKDIR/$MD5" 2>/dev/null
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if test $? = 0 ; then
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notify "PASS"
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else
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notify "FAIL"
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fi
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fi
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done
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exit 0
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: <<=cut
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=pod
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=head1 NAME
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virt-sanlock-cleanup - remove stale sanlock resource lease files
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=head1 SYNOPSIS
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virt-sanlock-cleanup
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=head1 DESCRIPTION
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This tool removes any resource lease files created by the sanlock
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lock manager plugin. The resource lease files only need to exist
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on disks when a guest using the resource is active. This script
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reclaims the disk space used by resources which are not currently
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active.
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=head1 EXIT STATUS
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Upon successful processing of leases cleanup, the exit status
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will be 0 will be set. Upon fatal error a non-zero status will
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be set.
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=head1 AUTHOR
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Daniel Berrange
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=head1 BUGS
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Report any bugs discovered to the libvirt community via the
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mailing list C<http://libvirt.org/contact.html> or bug tracker C<http://libvirt.org/bugs.html>.
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Alternatively report bugs to your software distributor / vendor.
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=head1 COPYRIGHT
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Copyright (C) 2011 Red Hat, Inc.
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=head1 LICENSE
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virt-sanlock-cleanup is distributed under the terms of the GNU GPL v2+.
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This is free software; see the source for copying conditions. There
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is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
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PURPOSE
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=head1 SEE ALSO
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C<virsh(1)>, online instructions C<http://libvirt.org/locksanlock.html>
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=cut
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