Description
When running scripts using the shell provisioner, environment variables from the Packer's parent process are available within running scripts.
From https://www.packer.io/docs/provisioners/shell
There are a bunch of configs related to how environment variables should be injected into a provisioner from Packer, and documented behaviour would appear to be that host env vars shouldn't end up inside the child process unless explicitly configured.
This is how I've seen it work with other plugins, but because of how this particular plugin works I can see how we've ended up with this happening.
This plugin uses v0.2.11 of the plugin SDK
https://github.com/solo-io/packer-plugin-arm-image/blob/master/go.mod#L7
From https://github.com/hashicorp/packer-plugin-sdk/blob/main/CHANGELOG.md, v0.2.12 added some more configuration around env vars, so it may be as simple as updating to the latest version of the SDK and it'll be fixed automatically by that. Or it may be more complex, requiring plugin-specific logic. I'm not entirely sure.
Either way, here's an example packer config:
packer {
required_plugins {
arm-image = {
# https://github.com/solo-io/packer-plugin-arm-image
source = "github.com/solo-io/arm-image"
version = "<= 1.0.0"
}
}
}
source "arm-image" "raspios" {
iso_url = "https://downloads.raspberrypi.org/raspios_lite_arm64/images/raspios_lite_arm64-2022-04-07/2022-04-04-raspios-bullseye-arm64-lite.img.xz"
iso_checksum = "sha256:35f1d2f4105e01f4ca888ab4ced6912411e82a2539c53c9e4e6b795f25275a1f"
}
build {
sources = ["source.arm-image.raspios"]
provisioner "shell" {
script = "provision.sh"
}
}
provision.sh
#!/bin/bash
# Debugging
set -ex
env | sort
# ... and a bunch of things after that we don't care about for now
Packer output:
arm-image.raspios: output will be in this color.
==> arm-image.raspios: Image type: raspberrypi
==> arm-image.raspios: Retrieving Image
==> arm-image.raspios: Trying https://downloads.raspberrypi.org/raspios_lite_arm64/images/raspios_lite_arm64-2022-04-07/2022-04-04-raspios-bullseye-arm64-lite.img.xz
==> arm-image.raspios: Trying https://downloads.raspberrypi.org/raspios_lite_arm64/images/raspios_lite_arm64-2022-04-07/2022-04-04-raspios-bullseye-arm64-lite.img.xz?checksum=sha256%3A35f1d2f4105e01f4ca888ab4ced6912411e82a2539c53c9e4e6b795f25275a1f
==> arm-image.raspios: https://downloads.raspberrypi.org/raspios_lite_arm64/images/raspios_lite_arm64-2022-04-07/2022-04-04-raspios-bullseye-arm64-lite.img.xz?checksum=sha256%3A35f1d2f4105e01f4ca888ab4ced6912411e82a2539c53c9e4e6b795f25275a1f => /root/.cache/packer/9d8ad4fe8b6f43457efbb1512fc630e91f8b50ba.iso
==> arm-image.raspios: Copying source image.
==> arm-image.raspios: Image is a xz file.
...
arm-image.raspios: mapping output-raspios/image
==> arm-image.raspios: losetup --show -f -P output-raspios/image
==> arm-image.raspios: partitions: [/dev/loop1p1 /dev/loop1p2]
arm-image.raspios: Mounting: /dev/loop1p2
arm-image.raspios: Mounting: /dev/loop1p1
==> arm-image.raspios: Mounting additional paths within the chroot...
arm-image.raspios: Mounting: /proc
arm-image.raspios: Mounting: /sys
arm-image.raspios: Mounting: /dev
arm-image.raspios: Mounting: /dev/pts
arm-image.raspios: Mounting: /proc/sys/fs/binfmt_misc
==> arm-image.raspios: Provisioning with shell script: provision.sh
==> arm-image.raspios: + env
==> arm-image.raspios: + sort
arm-image.raspios: HOME=/root
arm-image.raspios: INVOCATION_ID=077ab4453d2c4305bc165e9f6bf32724
arm-image.raspios: JOURNAL_STREAM=8:20164
arm-image.raspios: LANG=en_GB.UTF-8
arm-image.raspios: LOGNAME=root
arm-image.raspios: NOMAD_ALLOC_DIR=/opt/nomad/alloc/875e21c9-1832-e784-bbd3-ea8949b654d6/alloc
arm-image.raspios: NOMAD_ALLOC_ID=875e21c9-1832-e784-bbd3-ea8949b654d6
arm-image.raspios: NOMAD_ALLOC_INDEX=0
arm-image.raspios: NOMAD_ALLOC_NAME=build/periodic-1664892598.packer[0]
arm-image.raspios: NOMAD_CPU_LIMIT=2000
arm-image.raspios: NOMAD_DC=davnet
And those NOMAD_ env vars above come from the parent process.
I'm using:
+ ./local/packer version
Packer v1.8.3
+ ./local/packer plugins installed
/root/.config/packer/plugins/github.com/solo-io/arm-image/packer-plugin-arm-image_v0.2.6_x5.0_linux_arm64
Lemme know if there's any further information you need, and if there's much we can do about this.
I've been able to work around this issue.
- in my case, the problematic env var is TMPDIR, which I'm using to set where Packer stores its temporary files for the build (leaving it at the default means I run out of space real fast building new images)
- workaround =
unset TMPDIR
But in the general case, this could cause other unexpected problems