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Sat, 21 Mar 2026 10:12:28 -0400 (EDT) Received: from alpinetest.home.arpa (rp-intranet.home.arpa [192.168.0.21]) by smtp.home.arpa (OpenSMTPD) with ESMTPSA id 0e8b6378 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Sat, 21 Mar 2026 14:05:47 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on lists.libvirt.org X-Spam-Level: X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HELO_MISC_IP,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED,RCVD_IN_VALIDITY_RPBL_BLOCKED, RCVD_IN_VALIDITY_SAFE_BLOCKED,SPF_PASS autolearn=unavailable autolearn_force=no version=4.0.1 X-Greylist: delayed 399 seconds by postgrey-1.37 at lists.libvirt.org; Sat, 21 Mar 2026 10:12:28 EDT DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; s=home20250113; bh=OqYfXI/ 03MXnRjXOBYtrvuWXdOAELZo2r24Iom30/mY=; h=references:in-reply-to:date: subject:cc:to:from; d=gugod.fr; b=Pl+THjs07X9x9k/DvqhDGLL5coeLUCm6Yphv +hbP4NAwtfEZ0K6hDNbRid0B74snxn8VobBsJ0a4yaRK1taY1CbHpNL2bfjecS09CvInw2 QNYkPlx0BEA77dUI8Ou3g3cTDQ60GJrsKrQm3gCyu7YpenaJMAZ6Dz6l2m7I15YollqXEr H9v6ZibK5yymIrkgW3tERQeVSxox8TiP7FlMQhxR6jPT5WE4zwSkKCUmZagxH7rRwGkvhB cEZJb5PuidG1mLgM9kU5nG+StjDMYW2YpYu5fhp0kyGHBlGd9qZ5Qq+EVTGPnLwaxitOC4 e3iAwQWhFVwkq1KyxJOeiCzV7Q== To: devel@lists.libvirt.org Subject: [PATCHv2 3/4] qemu, libxl: migration: Call hook script on source host at migration start Date: Sat, 21 Mar 2026 15:05:14 +0100 Message-ID: <20260321140537.23568-4-guy.godfroy@gugod.fr> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260321140537.23568-1-guy.godfroy@gugod.fr> References: <20260321140537.23568-1-guy.godfroy@gugod.fr> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Message-ID-Hash: 6WMKG5MWZW25UJDF564KS6SBNSJDW24C X-Message-ID-Hash: 6WMKG5MWZW25UJDF564KS6SBNSJDW24C X-MailFrom: guy.godfroy@gugod.fr X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; loop; banned-address; header-match-devel.lists.libvirt.org-0; emergency; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: pkrempa@redhat.com, Guy Godfroy X-Mailman-Version: 3.3.10 Precedence: list List-Id: Development discussions about the libvirt library & tools Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: From: Guy Godfroy via Devel Reply-To: Guy Godfroy X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZM-MESSAGEID: 1774102456071154100 Content-Type: text/plain; charset="utf-8" Currently, the hook script with the "migrate" operation is only called on the destination host at the beginning of incoming migration. This makes it impossible for the source host to prepare for migration, for example to change storage locks from exclusive to shared mode when using shared LVM storage with lvmlockd. Add a hook call on the source host at the beginning of outgoing migration using the new "migrate-outgoing" operation. The hook is called with "source" as the extra argument and "begin" as the sub-operation. The script is not used as a filter; its output is ignored. If the script returns failure, the migration is canceled. The same change is also applied to the libxl driver for consistency. Signed-off-by: Guy Godfroy --- docs/hooks.rst | 32 ++++++++++++++++++++++++++++++-- src/libxl/libxl_migration.c | 17 +++++++++++++++++ src/qemu/qemu_migration.c | 17 +++++++++++++++++ 3 files changed, 64 insertions(+), 2 deletions(-) diff --git a/docs/hooks.rst b/docs/hooks.rst index 0310e0d82c..cff1711536 100644 --- a/docs/hooks.rst +++ b/docs/hooks.rst @@ -257,6 +257,18 @@ operation. There is no specific operation to indicate = a "restart" is occurring. is not valid, incoming migration will be canceled. This hook may be use= d, e.g., to change location of disk images for incoming domains. =20 +- :since:`Since 12.3.0`, the qemu hook script is also called at the begin= ning + of outgoing migration on the **source** host. It is called as: + + :: + + /etc/libvirt/hooks/qemu guest_name migrate-outgoing begin source + + with domain XML sent to standard input of the script. Unlike the destin= ation + hook, this script does not act as a filter and any output is ignored. I= f the + script returns failure, the migration will be canceled. This hook may b= e used, + e.g., to change storage lock mode from exclusive to shared before migra= tion. + - :since:`Since 1.2.9`, the qemu hook script is also called when restorin= g a saved image either via the API or automatically when restoring a manage= d save machine. It is called as: @@ -430,6 +442,18 @@ operation. There is no specific operation to indicate = a "restart" is occurring. is not valid, incoming migration will be canceled. This hook may be use= d, e.g., to change location of disk images for incoming domains. =20 +- :since:`Since 12.3.0`, the libxl hook script is also called at the begi= nning + of outgoing migration on the **source** host. It is called as: + + :: + + /etc/libvirt/hooks/libxl guest_name migrate-outgoing begin source + + with domain XML sent to standard input of the script. Unlike the destin= ation + hook, this script does not act as a filter and any output is ignored. I= f the + script returns failure, the migration will be canceled. This hook may b= e used, + e.g., to change storage lock mode from exclusive to shared before migra= tion. + - :since:`Since 6.5.0`, you can also place several hook scripts in the directory ``/etc/libvirt/hooks/libxl.d/``. They are executed in alphabe= tical order after main script. In this case each script also acts as filter a= nd can @@ -566,10 +590,14 @@ Migration of a QEMU guest involves running hook scrip= ts on both the source and destination hosts: =20 #. At the beginning of the migration, the *qemu* hook script on the - **destination** host is executed with the "migrate" operation. + **source** host is executed with the "migrate-outgoing" operation and + "source" as the extra argument (:since:`since 12.3.0`). This allows the + source host to prepare for migration, e.g., changing storage locks. +#. Then, the *qemu* hook script on the **destination** host is executed + with the "migrate" operation. #. Before QEMU process is spawned, the two operations ("prepare" and "star= t") called for domain start are executed on **destination** host. -#. If both of these hook script executions exit successfully (exit status = 0), +#. If all of these hook script executions exit successfully (exit status 0= ), the migration continues. Any other exit code indicates failure, and the migration is aborted. #. The QEMU guest is then migrated to the destination host. diff --git a/src/libxl/libxl_migration.c b/src/libxl/libxl_migration.c index f5dee7627b..be51cfd316 100644 --- a/src/libxl/libxl_migration.c +++ b/src/libxl/libxl_migration.c @@ -411,6 +411,23 @@ libxlDomainMigrationSrcBegin(virConnectPtr conn, if (!libxlDomainMigrationIsAllowed(def)) goto endjob; =20 + /* Call hook to allow source host to prepare for migration */ + if (virHookPresent(VIR_HOOK_DRIVER_LIBXL)) { + g_autofree char *hookxml =3D NULL; + int hookret; + + if (!(hookxml =3D virDomainDefFormat(def, driver->xmlopt, + VIR_DOMAIN_DEF_FORMAT_SECURE))) + goto endjob; + + hookret =3D virHookCall(VIR_HOOK_DRIVER_LIBXL, def->name, + VIR_HOOK_LIBXL_OP_MIGRATE_OUTGOING, VIR_HOOK= _SUBOP_BEGIN, + "source", hookxml, NULL); + + if (hookret < 0) + goto endjob; + } + xml =3D virDomainDefFormat(def, driver->xmlopt, VIR_DOMAIN_DEF_FORMAT_= SECURE); /* Valid xml means success! EndJob in the confirm phase */ if (xml) diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c index fec808ccfb..e9ce2d8b8b 100644 --- a/src/qemu/qemu_migration.c +++ b/src/qemu/qemu_migration.c @@ -2870,6 +2870,23 @@ qemuMigrationSrcBeginPhase(virQEMUDriver *driver, vm->newDef && !qemuDomainVcpuHotplugIsInOrder(vm->newDef))) cookieFlags |=3D QEMU_MIGRATION_COOKIE_CPU_HOTPLUG; =20 + /* Call hook to allow source host to prepare for migration */ + if (virHookPresent(VIR_HOOK_DRIVER_QEMU)) { + g_autofree char *xml =3D NULL; + int hookret; + + if (!(xml =3D qemuDomainDefFormatLive(driver, priv->qemuCaps, vm->= def, + priv->origCPU, false, true))) + return NULL; + + hookret =3D virHookCall(VIR_HOOK_DRIVER_QEMU, vm->def->name, + VIR_HOOK_QEMU_OP_MIGRATE_OUTGOING, VIR_HOOK_= SUBOP_BEGIN, + "source", xml, NULL); + + if (hookret < 0) + return NULL; + } + if (qemuBlockNodesEnsureActive(vm, vm->job->asyncJob) < 0) return NULL; =20 --=20 2.53.0