[PATCH] libxl: Set auto-allocated graphics ports to used on reconnect
The libxl driver reconnects to all running VMs when libvirtd is restarted, but it failed to mark auto-allocated graphics ports as set in the port allocator. If many VMs are running that use port auto-allocation and libvirtd is restarted, the port allocator is likely to hand out a port already in use when a new VM is created that uses auto-allocation. VM creation will fail due to the port clash. When reconnecting to running VMs after a libvirtd restart, let the port allocator know about previously allocated ports. Signed-off-by: Jim Fehlig <jfehlig@suse.com> --- Like 31e937fb3b, another item unaccounted for when reconnecting to VMs after a daemon restart. src/libxl/libxl_driver.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c index 2d9385654c..97965aaf1d 100644 --- a/src/libxl/libxl_driver.c +++ b/src/libxl/libxl_driver.c @@ -393,6 +393,7 @@ libxlReconnectDomain(virDomainObj *vm, virHostdevManager *hostdev_mgr = driver->hostdevMgr; unsigned int hostdev_flags = VIR_HOSTDEV_SP_PCI; int ret = -1; + size_t i; hostdev_flags |= VIR_HOSTDEV_SP_USB; @@ -447,6 +448,28 @@ libxlReconnectDomain(virDomainObj *vm, libxlReconnectNotifyNets(vm->def); + /* Set any auto-allocated graphics ports to used */ + for (i = 0; i < vm->def->ngraphics; i++) { + virDomainGraphicsDef *graphics = vm->def->graphics[i]; + + switch (graphics->type) { + case VIR_DOMAIN_GRAPHICS_TYPE_VNC: + if (graphics->data.vnc.autoport) + virPortAllocatorSetUsed(graphics->data.vnc.port); + break; + case VIR_DOMAIN_GRAPHICS_TYPE_SPICE: + if (graphics->data.spice.autoport) + virPortAllocatorSetUsed(graphics->data.spice.port); + break; + case VIR_DOMAIN_GRAPHICS_TYPE_SDL: + case VIR_DOMAIN_GRAPHICS_TYPE_RDP: + case VIR_DOMAIN_GRAPHICS_TYPE_DESKTOP: + case VIR_DOMAIN_GRAPHICS_TYPE_EGL_HEADLESS: + case VIR_DOMAIN_GRAPHICS_TYPE_LAST: + break; + } + } + if (virDomainObjSave(vm, driver->xmlopt, cfg->stateDir) < 0) VIR_WARN("Cannot update XML for running Xen guest %s", vm->def->name); -- 2.34.1
On a Friday in 2022, Jim Fehlig wrote:
The libxl driver reconnects to all running VMs when libvirtd is restarted, but it failed to mark auto-allocated graphics ports as set in the port allocator. If many VMs are running that use port auto-allocation and libvirtd is restarted, the port allocator is likely to hand out a port already in use when a new VM is created that uses auto-allocation. VM creation will fail due to the port clash.
In the QEMU driver, we also mark user-specified ports in the allocator, to let it now it should skip them. But I suppose people worried about clashes do not use those.
When reconnecting to running VMs after a libvirtd restart, let the port allocator know about previously allocated ports.
Signed-off-by: Jim Fehlig <jfehlig@suse.com> ---
Like 31e937fb3b, another item unaccounted for when reconnecting to VMs after a daemon restart.
src/libxl/libxl_driver.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+)
Reviewed-by: Ján Tomko <jtomko@redhat.com> However, I did not find a virPortAllocatorRelease call for the spice port in src/libxl (for VNC it's done in libxlDomainCleanup ) Jano
On 2/7/22 06:38, Ján Tomko wrote:
On a Friday in 2022, Jim Fehlig wrote:
The libxl driver reconnects to all running VMs when libvirtd is restarted, but it failed to mark auto-allocated graphics ports as set in the port allocator. If many VMs are running that use port auto-allocation and libvirtd is restarted, the port allocator is likely to hand out a port already in use when a new VM is created that uses auto-allocation. VM creation will fail due to the port clash.
In the QEMU driver, we also mark user-specified ports in the allocator, to let it now it should skip them. But I suppose people worried about clashes do not use those.
On one hand I dislike the allocator keeping track of stuff it didn't allocated, but on the other it is a resiliency improvement to consider.
When reconnecting to running VMs after a libvirtd restart, let the port allocator know about previously allocated ports.
Signed-off-by: Jim Fehlig <jfehlig@suse.com> ---
Like 31e937fb3b, another item unaccounted for when reconnecting to VMs after a daemon restart.
src/libxl/libxl_driver.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+)
Reviewed-by: Ján Tomko <jtomko@redhat.com>
However, I did not find a virPortAllocatorRelease call for the spice port in src/libxl (for VNC it's done in libxlDomainCleanup )
Thanks a lot for checking and bringing it to my attention! I've sent a patch to improve the port release logic https://listman.redhat.com/archives/libvir-list/2022-February/msg00252.html Regards, Jim
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Ján Tomko