Can't build Core20 snaps on non-snap distros
Metadata
Current evaluation
Core20 LXD builds reject distro-installed LXD on NixOS/Arch; a maintainer specified a backport, while core20 support now requires Snapcraft 8.
Suggested action: keep open
Reason: The report provides exact versions, a command, and an error, and the maintainer pinpointed both the legacy LXD check and the craft-providers logic to backport. Commits fa7952b4d and ffb164b7a removed core20 and snapcraft_legacy from main, but the current release notes explicitly retain Snapcraft 8 for core20 builds, so the affected workflow is not demonstrably obsolete. No resolving commit was found; further action is needed in the Snapcraft 8 codebase.
Evaluated by: mr-cal-bot
Impact:
48
Quick Win:
24
Complexity:
42
Confidence:
91
Actionability:
88
Issue body
### Bug Description
When running on nixos, I get the following error from snapcraft despite lxd being installed:
```
[nix-shell:~/repos/grafana-agent-snap]$ snapcraft_legacy --use-lxd
You need 'LXD' set-up to build snaps: snap support is required to continue: https://docs.snapcraft.io/installing-snapd/6735.
```
### To Reproduce
Pack a core20 charm using the `--use-lxd` flag on nixos.
### Environment
snapcraft 8.2.5
lxd 5.21.1 LTS
### snapcraft.yaml
```shell
name: grafana-agent
version: '0.40.4'
summary: A telemetry collector for sending metrics, logs, and trace data
license: Apache-2.0
contact: simon.aronsson@canonical.com
issues: https://github.com/canonical/grafana-agent-snap/issues
source-code: https://github.com/canonical/grafana-agent-snap
website: https://grafana.com
description: "Grafana Agent is a telemetry collector for sending metrics, \nlogs, and trace data to the opinionated Grafana observability stack.\n"
base: core20
grade: stable
confinement: classic
compression: lzo
apps:
grafana-agent:
daemon: simple
command: "${SNAP}/agent -config.expand-env -config.file /etc/grafana-agent.yaml"
install-mode: disable
restart-condition: on-failure
architectures:
- build-on: amd64
- build-on: arm64
parts:
wrapper:
plugin: dump
source: ./snap/local
source-type: local
override-build: |
cp agent-wrapper $SNAPSNAPSNAPCRAFT_PART_INSTALL/
grafana-agent:
plugin: go
source: https://github.com/grafana/agent
source-type: git
source-tag: "v0.40.4"
build-snaps:
- go
build-packages:
- build-essential
- libsystemd-dev
stage-packages:
- libsystemd0
override-build: |
export USE_CONTAINER=0
export GOFLAGS="-mod=readonly -tags=promtail_journal_enabled"
make agent agentctl
cp build/grafana-agent $SNAPSNAPSNAPCRAFT_PART_INSTALL/agent
cp build/grafana-agentctl $SNAPSNAPSNAPCRAFT_PART_INSTALL/agentctl
```
### Relevant log output
```shell
-
```
### Additional context
_No response_
Evaluation history
| Date | Model | Scores | Action | Summary |
|---|---|---|---|---|
| stealth/space-bunny-alpha |
Impact:
48
Quick Win:
24
Complexity:
42
Confidence:
91
Actionability:
88
|
keep open | Core20 LXD builds reject distro-installed LXD on NixOS/Arch; a maintainer specified a backport, while core20 support now requires Snapcraft 8. | |
| qwen/qwen3.6-35b-a3b |
Impact:
10
Quick Win:
3
Complexity:
10
Confidence:
90
Actionability:
30
|
close resolved | Core20 snap builds fail on non-snap distros (NixOS) due to LXD snap detection. The issue proposed backporting craft-providers logic to snapcraft_legacy, but core20 support and snapcraft_legacy have since been removed from the project. | |
| qwen/qwen3.8-27b |
Impact:
25
Quick Win:
14
Staleness:
80
Complexity:
45
Confidence:
82
Support Request:
10
|
close stale | Core20 snap builds fail on non-snap distros (NixOS) due to LXD snap detection. Triaged with a proposed backport fix, but core20 support and snapcraft_legacy have since been removed from the project, making the issue no longer applicable. | |
| qwen/qwen3.6-35b-a3b |
Staleness:
25
Complexity:
50
Confidence:
85
Support Request:
5
|
keep open | Bug preventing core20 snap builds on non-snap distros due to LXD detection failures. Currently triaged with a maintainer-proposed backport solution and internal ticket tracking. | |
| qwen3.6-35b-a3b-mtp-q6 |
Staleness:
65
Complexity:
60
Confidence:
90
Support Request:
10
|
keep open | Bug reporting failure to build core20 snaps on non-snap distros like NixOS due to LXD snap dependency. Triaged, acknowledged by maintainer, linked to internal ticket, and discussed with a proposed backport solution. |
Update history
No update history recorded yet.
Related work
-
Related To:
canonical/snapcraft#6019
(confidence 95%)
PR #6019 removed core20 support from current Snapcraft, while the release notes still direct core20 builds to Snapcraft 8.
Related issues
| Issue | Project | State | Summary | Similarity |
|---|---|---|---|---|
| #1866300 snapcraft fails to build core20 snap | snapcraft (launchpad) | closed | Closed without a documented fix after core20 Multipass/LXD failures; core20 build-base support was unavailable and the workaround was destructive mode. | |
| #2012074 snapcraft cannot build snap by default on aarch64 | snapcraft (launchpad) | open | ARM64 default builds failed on Snapcraft 7.3.1 because core20 selected amd64-only Multipass images; later defaults use core22/LXD on Linux, addressing the reported path. | |
| #1862256 snapcraft should complain loudly when building base: core20 snap on i386 | snapcraft (launchpad) | closed | Closed as superseded: improved architecture parsing rejects unsupported core20/i386 builds, making a dedicated check unnecessary; snapcraft#4392 improved this handling. | |
| #1982420 libdevmapper-dev fails to install as build-package using snapcraft:core20 (Multipass) | snapcraft (launchpad) | open | core20 Multipass builds can retain libdevmapper1.02.1 from focal-backports, breaking libdevmapper-dev installation. Acknowledged and externally tracked; LXD and explicit backports workarounds exist. | |
| #2009520 core18/20: inconsistent architecture parsing | snapcraft (launchpad) | closed | Superseded by snapcore/snapcraft#4340 and #4341. Core22+ overlapping build-on handling merged in #3821 (4876b53); core20 support was declined. | |
| #2099923 Snapcraft builds are failing: install of snap "snapcraft" failed | snapcraft (launchpad) | open | Reported Launchpad Bionic non-i386 builds cannot install Snapcraft 7.x/stable because core20 needs snapd 2.61; the issue remains open, untriaged, and unanswered. | |
| #1943603 snapcraft --target-arch=i386 does not build i386 images, because core20 does not support i386 and yet the build starts and wastes time | snapcraft (launchpad) | open | Legacy Snapcraft accepted an unsupported core20/i386 target, wasted build time, and produced an amd64 snap; current validation excludes i386 and drops core20. | |
| #1996508 snapcraft try with core22 doesn't support lxd | snapcraft (launchpad) | closed | Core22 support for snapcraft try --use-lxd was added by merged PR snapcore/snapcraft#3981 (commit 2691262b8) and released on edge. | |
| #5003 Building snap with `core20` failed with non-informative error message | snapcraft | open | The misleading core20 snapcraft-pack error was fixed by merged PR #5616 (commit b511004af), which ran the lifecycle for legacy core20 snaps. | |
| #4408 Snapcraft 7 fails with inline deb822 signing blocks | snapcraft | open | Snapcraft 7's core20 LXD fallback failed on valid inline deb822 Signed-By keys; the affected legacy/core20 code has since been removed. |