[libvirt] [PATCH 2/2] virsh: introduce flage --pipe for save command

From: Chen Hanxiao <chenhanxiao(a)gmail.com&gt; Base upon patches from Roy Keene <rkeene(a)knightpoint.com&gt; This patch introduces --pipe flag for save command. We could saving a VM state directly to Ceph RBD images without having an intermediate file. How to test: # fifo="$(mktemp -u)"; mkfifo "${fifo}" && virsh save --pipe cirros "${fifo}" & # cat "${fifo}" | rbd --id cinder import - rbd/test1234 & wait; rm -f "${fifo}" Cc: Roy Keene <rkeene(a)knightpoint.com&gt; Signed-off-by: Chen Hanxiao <chenhanxiao(a)gmail.com&gt; --- tools/virsh-domain.c | 6 ++++++ tools/virsh.pod | 6 +++++- 2 files changed, 11 insertions(+), 1 deletion(-) diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c index e359bfc..6ac3edf 100644 --- a/tools/virsh-domain.c +++ b/tools/virsh-domain.c @@ -4170,6 +4170,10 @@ static const vshCmdOptDef opts_save[] = { .type = VSH_OT_BOOL, .help = N_("set domain to be paused on restore") }, + {.name = "pipe", + .type = VSH_OT_BOOL, + .help = N_("the file being saved to is a pipe") + }, {.name = "verbose", .type = VSH_OT_BOOL, .help = N_("display the progress of save") @@ -4206,6 +4210,8 @@ doSave(void *opaque) flags |= VIR_DOMAIN_SAVE_RUNNING; if (vshCommandOptBool(cmd, "paused")) flags |= VIR_DOMAIN_SAVE_PAUSED; + if (vshCommandOptBool(cmd, "pipe")) + flags |= VIR_DOMAIN_SAVE_PIPE; if (vshCommandOptStringReq(ctl, cmd, "xml", &xmlfile) < 0) goto out; diff --git a/tools/virsh.pod b/tools/virsh.pod index 247d235..8419db8 100644 --- a/tools/virsh.pod +++ b/tools/virsh.pod @@ -1893,7 +1893,7 @@ have also reverted all storage volumes back to the same contents as when the state file was created. =item B<save> I<domain> I<state-file> [I<--bypass-cache>] [I<--xml> B<file>] -[{I<--running> | I<--paused>}] [I<--verbose>] +[{I<--running> | I<--paused>}] [I<--pipe>] [I<--verbose>] Saves a running domain (RAM, but not disk state) to a state file so that it can be restored @@ -1908,6 +1908,10 @@ with B<domjobabort> command (sent by another virsh instance). Another option is to send SIGINT (usually with C<Ctrl-C>) to the virsh process running B<save> command. I<--verbose> displays the progress of save. +Usually B<save> command will save the domain's state as a regular file. +Flag I<--pipe> could let B<save> dumps domain's state to a PIPE. +Try to write a PIPE without I<--pipe> would error out. + This is roughly equivalent to doing a hibernate on a running computer, with all the same limitations. Open network connections may be severed upon restore, as TCP timeouts may have expired. -- 2.7.4