Bug 1755303
| Summary: | 'autostart' domain goes to running state when any client app connects under system libvirtd daemon | ||
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| Product: | Red Hat Enterprise Linux Advanced Virtualization | Reporter: | Yanqiu Zhang <yanqzhan> |
| Component: | libvirt | Assignee: | Michal Privoznik <mprivozn> |
| Status: | CLOSED ERRATA | QA Contact: | yafu <yafu> |
| Severity: | unspecified | Docs Contact: | |
| Priority: | unspecified | ||
| Version: | 8.1 | CC: | berrange, chhu, dyuan, jdenemar, jsuchane, mprivozn, xuzhang, yafu, yanqzhan |
| Target Milestone: | rc | Keywords: | Upstream |
| Target Release: | 8.1 | ||
| Hardware: | x86_64 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | libvirt-5.6.0-7.el8 | Doc Type: | Bug Fix |
| Doc Text: |
Cause:
Libvirt offers so called 'autostart' feature which can be set on some objects that libvirt manages (e.g. domains, networks, storage pools). If an object is marked as 'autostart' then the idea is that such object is started automatically on host boot. Historically this was done by libvirtd - when it was starting up, it also started all objects that were marked as autostart. But with recent work on daemon split and socket activation this old approach was not good enough. Thing is, libvirtd can be now socket activated and after some period of inactivity it shuts down again (this is achieved by adding --timeout onto the libvirtd's command line). Therefore, libvirtd may start up and shut down multiple times which would also start all autostarted objects again.
Consequence:
For instance, let's assume I have a domain A, makred as autostart, the host boots up and the domain is started automatically. But then I shut the domain down (virsh shutdown A). Now, after some time of inactivity, I call a libvirt API (say virsh list) which starts the daemon again, which also starts the domain A again.
Fix:
On first autostart, libvirtd creates a dummy file (under a location that doesn't survive reboots), and if the file already exists autostart is suppressed. This means, that no matter how many times libvirtd starts and shuts down, the autostart is done exactly once.
Result:
Autostart feature works as designed again.
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | 2020-02-04 18:28:50 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
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Description
Yanqiu Zhang
2019-09-25 08:38:29 UTC
Yikes, that is an annoying an unintended side effect of making libvirtd automatically timeout & shutdown after 120 seconds After thinking about this I think I might have an idea how to fix this. The autostart feature is there basically to start domains on host startup or when the daemon starts for the first time. What we could do is to have a per driver file stored under /var/run (or some other location that is cleaned between host reboots) and on the first run of the per-driver autostart callback the file is created and the managed objects are autostarted. Then, if a deamon starts for the second time, the file is already there and no autostart is attempted. That's a much nicer idea than what I was going to suggest which was to simply ignore the --timeout arg if any guests marked auto-started exist. It will nicely fix the same problem we've always had with a user who manually stops & starts libvirtd, and also provide an approach that can fix the autostart problem with the session daemon too. Patches proposed upstream: https://www.redhat.com/archives/libvir-list/2019-October/msg00214.html And I've just pushed patches upstream: 897d8b34c8 Revert "src: Document autostart for session demon" 19b1b14f17 news: Document autostart fix bab464f8ea lib: autostart objects exactly once ee16a195d9 driver: Introduce virDriverShouldAutostart() e0b90162c9 qemu_driver: Fix comment of qemuStateCleanup() v5.8.0-45-g897d8b34c8 Verified with libvirt-5.6.0-8.el8.x86_64. Test steps: 1.Configure a domain to be automatically started at boot: #virsh autostart vm1 2.Reboot the host: #reboot 3.Check the guest status after booting: #virsh list Id Name State -------------------------------- 1 vm1 running 4.Check the autostart dir for qemu driver: #ll /var/run/libvirt/qemu/autostarted -rw-------. 1 root root 0 Nov 25 04:23 /var/run/libvirt/qemu/autostarted 5.Destroy the guest: #virsh destroy vm1 6.Restart libvirtd service #systemctl restart libvirtd 7.Check the guest status: #virsh list no running guest 8.Remove the autostart dir for qemu driver: #rm -rf /var/run/libvirt/qemu/autostarted 9.Restart libvirtd service #systemctl restart libvirtd 10.Check the guest status: #virsh list Id Name State -------------------------------- 1 vm1 running Verified with libvirt-5.6.0-10.el8.x86_64. Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2020:0404 |