shwstppr commented on a change in pull request #4068:
URL: https://github.com/apache/cloudstack/pull/4068#discussion_r438683406
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File path: scripts/storage/qcow2/managesnapshot.sh
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@@ -187,6 +187,7 @@ backup_snapshot() {
local snapshotname="$2"
local destPath=$3
local destName=$4
+ local forceShareFlag="-U"
Review comment:
@rhtyd `qemu-img` with QEMU 2.1 is not able to read QCOW2 file when it
is already have a read lock by another process (libvirt). Due to this, both
Ubuntu and CentOS8 fail to snapshot a running VM.
For a running VM and volume snapshot, as per code (and my understanding), we
create an external snapshot for VM using libvirt, then this script is used to
read, convert (to a new file) and backup that snapshot to secondary storage
using qemu-img. Since we are not making any change as such in original QCOW2
disk file, we can open it shared open (`-U`) flag which will prevent regression
from CentOS7 or distros with older QEMU.
I've added checks in code avoid any failures if `-U` is not supported
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