chmod: not found with example.json

[robbert229]

Environment:
I am running master branch, though I am experiencing this with older versions. I am running arch linux.

Observed
When I do sudo packer build ./example.json with the example packer file, I get the following output.

arm-image output will be in this color.

==> arm-image: Downloading or copying Image
    arm-image: Found already downloaded, initial checksum matched, no download needed: https://downloads.raspberrypi.org/raspbian_lite/images/raspbian_lite-2017-12-01/2017-11-29-raspbian-stretch-lite.zip
==> arm-image: Copying source image.
==> arm-image: Image is a zip file.
==> arm-image: Unzipping 2017-11-29-raspbian-stretch-lite.img
==> arm-image: Resizing the last partition 1073741824.
    arm-image: mappping output-arm-image/image
==> arm-image: kpartx -s -a -v output-arm-image/image
==> arm-image: partitions: [/dev/mapper/loop0p1 /dev/mapper/loop0p2]
==> arm-image: partitions: [/dev/mapper/loop0p1 /dev/mapper/loop0p2]
    arm-image: Mounting: /dev/mapper/loop0p2
    arm-image: Mounting: /dev/mapper/loop0p1
==> arm-image: Mounting additional paths within the chroot...
    arm-image: Mounting: /proc
    arm-image: Mounting: /sys
    arm-image: Mounting: /dev
    arm-image: Mounting: /dev/pts
    arm-image: Mounting: /proc/sys/fs/binfmt_misc
==> arm-image: Installing qemu-user-static in the chroot
==> arm-image: Provisioning with shell script: /tmp/packer-shell528078340
    arm-image: /bin/sh: 1: chmod: not found
    arm-image: /bin/sh: 1: /tmp/script_4790.sh: Permission denied
Build 'arm-image' errored: Script exited with non-zero exit status: 126

Hunch:
I assume that this has something to do with me running arch linux, and the chroot not getting set up correctly. Not sure, though I am digging through the source seeing if I can find why this is happening.

[JamieMagee]

I'm also running Arch Linux, and also seeing the same issue

arm-image output will be in this color.

==> arm-image: Downloading or copying Image
    arm-image: Found already downloaded, initial checksum matched, no download needed: http://director.downloads.raspberrypi.org/raspbian_lite/images/raspbian_lite-2018-11-15/2018-11-13-raspbian-stretch-lite.zip
==> arm-image: Copying source image.
==> arm-image: Image is a zip file.
==> arm-image: Unzipping 2018-11-13-raspbian-stretch-lite.img
    arm-image: mappping output-arm-image/image
==> arm-image: kpartx -s -a -v output-arm-image/image
==> arm-image: partitions: [/dev/mapper/loop0p1 /dev/mapper/loop0p2]
    arm-image: Mounting: /dev/mapper/loop0p2
    arm-image: Mounting: /dev/mapper/loop0p1
==> arm-image: Mounting additional paths within the chroot...
    arm-image: Mounting: /proc
    arm-image: Mounting: /sys
    arm-image: Mounting: /dev
    arm-image: Mounting: /dev/pts
    arm-image: Mounting: /proc/sys/fs/binfmt_misc
==> arm-image: Installing qemu-user-static in the chroot
==> arm-image: Provisioning with shell script: /tmp/packer-shell329101979
    arm-image: /bin/sh: 1: chmod: not found
    arm-image: /bin/sh: 1: /tmp/script_1618.sh: Permission denied

[JamieMagee]

@yuval-k Any suggestions?

[yuval-k]

this seems to be part of the shell provisioner in upstream packer:

https://github.com/hashicorp/packer/blob/14aa2afbb12a6f46164f199136d4b23da13709af/provisioner/shell/provisioner.go#L116

I think this error means that chmod is not found inside the image. can you confirm that?

[JamieMagee]

@yuval-k I think $PATH might not be set correctly. Setting "execute_command": "/bin/chmod +x {{ .Path }}; {{ .Vars }} {{ .Path }}", in the shell provisioner makes it work.

[yuval-k]

thanks for the hint. as you can see here https://github.com/solo-io/packer-builder-arm-image/blob/2a33747c943b22b1e6642a6f226f1ab88f81fb42/pkg/builder/communicator.go#L30
the command is wrapped in a chroot before being executed...
is there anything in archlinux that might strip the path env when doing a chroot?

[JamieMagee]

I haven't had a chance to look fully, but here's the Arch wiki page for chroot and here's the code for arch-chroot (normally used for installing arch and building packages)