[libvirt] [PATCH v7 16/23] backup: Implement virsh support for backup
Peter Krempa
pkrempa at redhat.com
Wed Mar 27 12:30:57 UTC 2019
On Wed, Mar 27, 2019 at 05:10:47 -0500, Eric Blake wrote:
> Introduce a few more new virsh commands for performing backup jobs, as
> well as creating a checkpoint atomically with a snapshot.
>
> At this time, I did not opt for a convenience command
> 'backup-begin-as' that cobbles together appropriate XML from the
> user's command line arguments, but that may be a viable future
> extension. Similarly, since backup is a potentially long-running
> operation, it might be nice to add some sugar that automatically
> handles waiting for the job to end, rather than making the user have
> to poll or figure out virsh event to do the same.
>
> Signed-off-by: Eric Blake <eblake at redhat.com>
> ---
> tools/virsh-domain.c | 247 ++++++++++++++++++++++++++++++++++++++++-
> tools/virsh-snapshot.c | 37 +++++-
> tools/virsh.pod | 64 ++++++++++-
> 3 files changed, 337 insertions(+), 11 deletions(-)
>
> diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c
> index 1970710c07..4ae456146b 100644
> --- a/tools/virsh-domain.c
> +++ b/tools/virsh-domain.c
> @@ -1,7 +1,7 @@
> /*
> * virsh-domain.c: Commands to manage domain
> *
> - * Copyright (C) 2005, 2007-2016 Red Hat, Inc.
> + * Copyright (C) 2005-2019 Red Hat, Inc.
This seems wrong. It's adding dates in the past. Ideally you disable
that script for libvirt altogether as it creates pointless churn.
> *
> * This library is free software; you can redistribute it and/or
> * modify it under the terms of the GNU Lesser General Public
[1] Using 'check' instead of 'checkpoint' in variable names may be
misleading below in multiple instances. It might evoke that it's
supposed to be checked rather than referring to a checkpoint.
> @@ -14039,6 +14039,233 @@ cmdDomFSInfo(vshControl *ctl, const vshCmd *cmd)
> return ret;
> }
>
> +
> +/*
> + * "backup-begin" command
> + */
> +static const vshCmdInfo info_backup_begin[] = {
> + {.name = "help",
> + .data = N_("Start a disk backup of a live domain")
> + },
> + {.name = "desc",
> + .data = N_("Use XML to start a full or incremental disk backup of a live "
> + "domain, optionally creating a checkpoint")
> + },
> + {.name = NULL}
> +};
> +
> +static const vshCmdOptDef opts_backup_begin[] = {
> + VIRSH_COMMON_OPT_DOMAIN_FULL(0),
> + {.name = "xmlfile",
> + .type = VSH_OT_STRING,
> + .help = N_("domain backup XML"),
> + },
> + {.name = "checkpointxml",
> + .type = VSH_OT_STRING,
> + .help = N_("domain checkpoint XML"),
> + },
> + {.name = "no-metadata",
> + .type = VSH_OT_BOOL,
> + .help = N_("create checkpoint but don't track metadata"),
> + },
> + {.name = "quiesce",
> + .type = VSH_OT_BOOL,
> + .help = N_("quiesce guest's file systems"),
> + },
> + /* TODO: --wait/--verbose/--timeout flags for push model backups? */
> + {.name = NULL}
> +};
> +
> +static bool
> +cmdBackupBegin(vshControl *ctl,
> + const vshCmd *cmd)
> +{
> + virDomainPtr dom = NULL;
> + bool ret = false;
> + const char *backup_from = NULL;
> + char *backup_buffer = NULL;
> + const char *check_from = NULL;
> + char *check_buffer = NULL;
[1]
> + unsigned int flags = 0;
> + int id;
> +
> + if (vshCommandOptBool(cmd, "no-metadata"))
> + flags |= VIR_DOMAIN_BACKUP_BEGIN_NO_METADATA;
> + if (vshCommandOptBool(cmd, "quiesce"))
> + flags |= VIR_DOMAIN_BACKUP_BEGIN_QUIESCE;
> +
> + if (!(dom = virshCommandOptDomain(ctl, cmd, NULL)))
> + goto cleanup;
> +
> + if (vshCommandOptStringReq(ctl, cmd, "xmlfile", &backup_from) < 0)
"backupxml"
> + goto cleanup;
> + if (!backup_from) {
> + backup_buffer = vshStrdup(ctl, "<domainbackup/>");
> + } else {
> + if (virFileReadAll(backup_from, VSH_MAX_XML_FILE, &backup_buffer) < 0) {
> + vshSaveLibvirtError();
> + goto cleanup;
> + }
> + }
> +
> + if (vshCommandOptStringReq(ctl, cmd, "checkpointxml", &check_from) < 0)
> + goto cleanup;
> + if (check_from) {
> + if (virFileReadAll(check_from, VSH_MAX_XML_FILE, &check_buffer) < 0) {
> + vshSaveLibvirtError();
> + goto cleanup;
> + }
> + }
> +
> + id = virDomainBackupBegin(dom, backup_buffer, check_buffer, flags);
> +
> + if (id < 0)
> + goto cleanup;
> +
> + vshPrint(ctl, _("Backup id %d started\n"), id);
> + if (backup_from)
> + vshPrintExtra(ctl, _("backup used description from '%s'\n"),
> + backup_from);
> + if (check_buffer)
> + vshPrintExtra(ctl, _("checkpoint created from '%s'\n"), check_from);
> +
> + ret = true;
> +
> + cleanup:
> + VIR_FREE(backup_buffer);
> + VIR_FREE(check_buffer);
> + virshDomainFree(dom);
> +
> + return ret;
> +}
> +
> +/* TODO: backup-begin-as? */
> +
> +/*
> + * "backup-dumpxml" command
> + */
> +static const vshCmdInfo info_backup_dumpxml[] = {
> + {.name = "help",
> + .data = N_("Dump XML for an ongoing domain block backup job")
> + },
> + {.name = "desc",
> + .data = N_("Backup Dump XML")
> + },
> + {.name = NULL}
> +};
> +
> +static const vshCmdOptDef opts_backup_dumpxml[] = {
> + VIRSH_COMMON_OPT_DOMAIN_FULL(0),
> + {.name = "id",
> + .type = VSH_OT_INT,
> + .help = N_("backup job id"),
> + /* TODO: Add API for listing active jobs, then adding a completer? */
> + },
> + /* TODO - worth adding this flag?
> + {.name = "checkpoint",
> + .type = VSH_OT_BOOL,
> + .help = N_("if the backup created a checkpoint, also dump that XML")
> + },
> + */
> + {.name = NULL}
> +};
> +
> +static bool
> +cmdBackupDumpXML(vshControl *ctl,
> + const vshCmd *cmd)
> +{
> + virDomainPtr dom = NULL;
> + bool ret = false;
> + char *xml = NULL;
> + unsigned int flags = 0;
> + int id = 0;
> +
> + if (vshCommandOptBool(cmd, "security-info"))
This option is not mentioned in opts_backup_dumpxml.
> + flags |= VIR_DOMAIN_XML_SECURE;
> +
> + if (vshCommandOptInt(ctl, cmd, "id", &id) < 0)
> + return false;
> +
> + if (!(dom = virshCommandOptDomain(ctl, cmd, NULL)))
> + return false;
> +
> + if (!(xml = virDomainBackupGetXMLDesc(dom, id, flags)))
> + goto cleanup;
> +
> + vshPrint(ctl, "%s", xml);
> + ret = true;
> +
> + cleanup:
> + VIR_FREE(xml);
> + virshDomainFree(dom);
> +
> + return ret;
> +}
[...]
> diff --git a/tools/virsh-snapshot.c b/tools/virsh-snapshot.c
> index f6bb38bc96..57ab80251b 100644
> --- a/tools/virsh-snapshot.c
> +++ b/tools/virsh-snapshot.c
> @@ -40,18 +40,26 @@
>
> /* Helper for snapshot-create and snapshot-create-as */
> static bool
> -virshSnapshotCreate(vshControl *ctl, virDomainPtr dom, const char *buffer,
> - unsigned int flags, const char *from)
> +virshSnapshotCreate(vshControl *ctl,
> + virDomainPtr dom,
> + const char *buffer,
> + const char *check_buffer,
> + unsigned int flags,
> + const char *from)
> {
> bool ret = false;
> virDomainSnapshotPtr snapshot;
> bool halt = false;
> const char *name = NULL;
>
> - snapshot = virDomainSnapshotCreateXML(dom, buffer, flags);
> + if (check_buffer)
[1]
> + snapshot = virDomainSnapshotCreateXML2(dom, buffer, check_buffer,
> + flags);
> + else
> + snapshot = virDomainSnapshotCreateXML(dom, buffer, flags);
>
> /* Emulate --halt on older servers. */
> - if (!snapshot && last_error->code == VIR_ERR_INVALID_ARG &&
> + if (!check_buffer && !snapshot && last_error->code == VIR_ERR_INVALID_ARG &&
> (flags & VIR_DOMAIN_SNAPSHOT_CREATE_HALT)) {
> int persistent;
>
> @@ -117,6 +125,10 @@ static const vshCmdOptDef opts_snapshot_create[] = {
> .type = VSH_OT_STRING,
> .help = N_("domain snapshot XML")
> },
> + {.name = "checkpointxml",
> + .type = VSH_OT_STRING,
> + .help = N_("domain checkpoint XML"),
> + },
> {.name = "redefine",
> .type = VSH_OT_BOOL,
> .help = N_("redefine metadata for existing snapshot")
> @@ -157,7 +169,9 @@ cmdSnapshotCreate(vshControl *ctl, const vshCmd *cmd)
> bool ret = false;
> const char *from = NULL;
> char *buffer = NULL;
> + const char *check_from = NULL;
[...]
> unsigned int flags = 0;
> + VIR_AUTOFREE(char *check_buffer) = NULL;
VIR_AUTOFREE and legacy code is used inconsistently in this patch.
>
> if (vshCommandOptBool(cmd, "redefine"))
> flags |= VIR_DOMAIN_SNAPSHOT_CREATE_REDEFINE;
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