Qemu stderr: qemu-system-x86_64: Display 'sdl' is not available.

[lelutin]

Hi, I'm having a weird issue: packer has been working great for many hours up to now, but some minutes ago it started refusing to build because of a qemu error: Qemu stderr: qemu-system-x86_64: Display 'sdl' is not available.

I'm using packer 1.1.3 from the debian sid package with qemu 1:2.12~rc3+dfsg-1 also from debian sid

From the logline with the options to qemu, it looks like packer somehow "forgets" to add in the first two numbers in the vnc port (e.g. it chose 5966, but it passes in port 66):

Executing /usr/bin/qemu-system-x86_64: []string{"-name", "centos-6.9-amd64", "-m", "512M", "-netdev", "user,id=user.0,hostfwd=tcp::2701-:22", "-boot", "once=d", "-device", "virtio-net,netdev=user.0", "-vnc", "127.0.0.1:66", "-display", "sdl", "-drive", "file=../packer-centos-6.9-amd64-qemu/centos-6.9-amd64,if=virtio,cache=writeback,discard=ignore,format=qcow2", "-cdrom", "/home/gabster/dev/vagrant-boxes/centos/packer_cache/aaf74b57886035c053bfed4b4ae61a8cf04f6d07f291467677930f200372f1c7.iso", "-machine", "type=pc,accel=kvm"}

as stated above packer was working perfectly fine before that for many hours. I've been running many builds to test out each change in templates, so maybe packer ended up overflowing some state that has to do with the port that it chooses?

the output with PACKER_LOG : https://gist.github.com/lelutin/933793d131a18f3f027055e66997dee3

I'm using this template https://gitlab.com/LeLutin/vagrant-boxes/tree/master/centos -- but I can also reproduce on the debian templates in the same repository (which was also working fine before).

[lelutin]

I just realized that version 1.1.3 was not from the debian sid package, but from a previously downloaded version archive from the packer website in /usr/local/bin.

I've just downloaded packer 1.2.2 and it is producing the same issue.

[lelutin]

I've tried rebooting my computer to see if it would clear some funky state but the issue is still present.

[SwampDragons]

This looks to me like a QEMU issue -- http://lists.busybox.net/pipermail/buildroot/2017-June/193544.html

You can work around with Packer by setting "use_default_display" to false.

[mwhooker]

clarified docs in 747d1eb

[lelutin]

Hi, thanks for the quick response!

I've tried setting use_default_display to false as recommended, and it produced exactly the same error.

I've tried chaning it to true, and the build started but no display showed up (and no instruction about which port I should use to connect with vnc since headless is set to false)

If I don't have the use_default_display setting at all, but set "headless" to true, then build proceeds and I get instructions on how to connect to the display with vnc.

... so I have two options to do my builds now, that's great!
however, the workaround for the display bug didn't really bring it back.

The qemu bug report seems to be about a build-time option that needs to needs to be enabled. in my case though this was working well, but then stopped working without a package upgrade or a template change.. so maybe the cause is different.
it might be that it's rather a qemu bug though..

[SwampDragons]

It could absolutely be a Packer bug, but I wouldn't know where to begin reproducing; your build used to work and then stopped working without a change to the version of Packer. The error message you're seeing is coming from qemu, not Packer. I think something changed on your local environment to cause this. If you can figure out what changed we might be able to make Packer resilient to it, but without knowing what caused it I don't know how to begin fixing this.

[lelutin]

@SwampDragons you're totally right! the issue is that I have no clue what could have changed.. also it must be something that's being carried on across reboots.

Is qemu keeping any kind of state or cache somewhere?

[lelutin]

oh ... I just found out that there were package upgrades on my laptop on the morning that I started having issues (I didn't even remember installing unattended-upgrades!)

qemu was upgraded that morning, so I tried downgrading to the version that was there before and ta-da! sdl display is back.

so that's definitely a regression on the qemu debian packages in sid. I'll report a bug there.

at least now we know that it's not a packer issue!

thanks for your support

[lelutin]

to give a bit more of a technical context to the source of the problem, it seems as though the qemu-system-x86 package in debian sid (unstable) recently made a switch from SDL1 to SDL2 and this brought on multiple glitches, crashes and mouse grab issues, so package maintainers decided to disable sdl.

See the changelog especially for version 1:2.12~rc3+dfsg-1 http://metadata.ftp-master.debian.org/changelogs/main/q/qemu/qemu_2.12~rc3+dfsg-2_changelog

I don't know yet if they plan to reenable sdl at some point.

[SwampDragons]

Interesting -- thanks for the follow-up!

[Hnasar]

To workaround, add this to your packer json file:

            "qemuargs": [
                ["-display", "gtk"]
            ]

[asauber]

If you're experiencing this on macOS the argument to use is

            "qemuargs": [
                ["-display", "cocoa"]
            ]

[ghost]

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