snapcraft-managed lxd containers do not respect parallel installs
Metadata
Current evaluation
Reported 2022 that parallel-installed snapcraft instances (e.g. snapcraft_7) launch the unsuffixed host snapcraft inside their managed LXD build container, causing '--build-for' build failures. Closed in 2026 after PR #5085 and 7.5 backport #5087.
Resolution: closed resolved
Reason: The reporter closed the bug citing merged PR canonical/snapcraft#5085, backported to the 7.5 branch via merged PR #5087 and released in 7.5.7. The fix makes craft-providers inject the aliased snapcraft snap so the invoking parallel instance is passed into the LXD build instance, matching the same problem tracked as snapcraft#4683 and #4927 (upstream craft-application#411).
Evaluated by: mr-cal-bot
No scores available.
Issue body
In the case when multiple instances of snapcraft are installed in parallel (https://snapcraft.io/docs/parallel-installs) instances suffixed with an instance key (e.g. _foo) appear to install the unsuffixed instance from the host into their managed lxd container. This then results in build failure.
Steps to reproduce:
1) enable parallel installs as described here: https://snapcraft.io/docs/parallel-installs
2) run `snap install snapcraft --channel=6.x/stable --classic` (revision 7201 at reporting time)
3) run `snap install snapcraft_7 --channel=7.x/stable --classic` (revision 8093 at reporting time)
4) initialize a fresh snap using `snapcraft init` and change the base to core22
5) try to run `snapcraft_7` to build that snap
$ snapcraft_7
Launching instance...
Usage: snapcraft pack [OPTIONS] DIRECTORY
Try 'snapcraft pack -h' for help.
Error: No such option: --build-for
Failed to execute pack in instance.
Full execution log: '/home/alex/.cache/snapcraft/log/snapcraft-20220811-135653.968445.log'
Execution log attached to bug report
Lines of interest: 63, 66
I have not tested this using other permutations of versions across parallel installs, or using multipass
Evaluation history
| Date | Model | Scores | Action | Summary |
|---|---|---|---|---|
| stealth/space-bunny-alpha | — | closed resolved | Reported 2022 that parallel-installed snapcraft instances (e.g. snapcraft_7) launch the unsuffixed host snapcraft inside their managed LXD build container, causing '--build-for' build failures. Closed in 2026 after PR #5085 and 7.5 backport #5087. | |
| stealth/space-bunny-alpha | — | closed resolved | Fixed by merged PR #5085 and its 7.5 backport #5087, which ensured managed LXD containers respected the invoking parallel Snapcraft instance. | |
| qwen/qwen3.6-35b-a3b | — | — | LXD containers ignored parallel install instance keys, causing build failures. Fixed and resolved via merged pull requests #5085 and #5087. | |
| qwen3.6-35b-a3b-mtp-q6 |
Impact:
60
Quick Win:
36
Staleness:
85
Complexity:
40
Confidence:
90
Support Request:
10
|
close not a bug | snapcraft-managed LXD containers do not respect parallel installs, causing build failures when using suffixed parallel installations | |
| qwen/qwen3.6-35b-a3b |
Staleness:
95
Complexity:
60
Confidence:
85
Support Request:
5
|
close stale | Bug where snapcraft-managed LXD containers ignore parallel install instance keys, causing host instance installation and build failures. Inactive for over four years with zero maintainer engagement. | |
| qwen/qwen3.6-35b-a3b |
Staleness:
95
Complexity:
65
Confidence:
85
Support Request:
5
|
close stale | Bug report detailing that snapcraft-managed LXD containers incorrectly use the unsuffixed host snapcraft instance instead of the parallel-installed suffixed version, causing build failures. Unlabeled and inactive for ~4 years. | |
| qwen3.6-35b-a3b-mtp-q6 |
Staleness:
98
Complexity:
65
Confidence:
90
Support Request:
5
|
close stale | Bug where snapcraft LXD containers incorrectly use the host's unsuffixed snapcraft instance instead of the parallel-installed suffixed version, causing build failures. Unaddressed for nearly 4 years. |
Update history
| Date | Change |
|---|---|
| created |
Related work
-
Likely Fixed By:
canonical/snapcraft#5085
(confidence 97%)
Merged PR 'fix: allow parallel installations of signed snapcraft snaps' cited directly in the closing comment; fixes #4683 and #4927.
-
Likely Fixed By:
canonical/snapcraft#5087
(confidence 97%)
Backport of #5085 merged into hotfix/7.5, shipped in 7.5.7; also cited in the closing comment.
-
Duplicate Of:
canonical/snapcraft#4683
(confidence 88%)
'Cannot use parallel installations of snapcraft if a non-aliased version is not installed' — the GitHub-side equivalent of this 2022 Launchpad report.
-
Duplicate Of:
canonical/snapcraft#4927
(confidence 88%)
'Parallel installation of snapcraft not passed to LXD instance' — same LXD container symptom, closed by the same PRs.
Related issues
| Issue | Project | State | Summary | Similarity |
|---|---|---|---|---|
| #4927 Parallel installation of snapcraft not passed to LXD instance | snapcraft | closed | Parallel-installed (signed) snapcraft was not passed to the LXD build instance. Fixed by merged PR #5085 and backported via #5087 to hotfix/7.5, shipped in 7.5.7; also tracks upstream craft-application#411. | |
| #5420 Snapcraft 7 fails to launch a LXD container based on host apt sources entries | snapcraft | closed | Closed as a duplicate of canonical/snapcraft#4408; no separate fix was made for this report. | |
| #1997874 SNAPCRAFT_MAX_PARALLEL_BUILD_COUNT doesn't seem to be passed through to lxd container | snapcraft (launchpad) | closed | SNAPCRAFT_MAX_PARALLEL_BUILD_COUNT was not forwarded into the LXD/Multipass build instance. Fixed by merged PR snapcore/snapcraft#3997 (commit 31a3990c8, 'providers: pass SNAPCRAFT_MAX_PARALLEL_BUILD_COUNT to instance'), released in snapcraft 7.3. | |
| #5509 Odd behaviour with parallel snapcraft installs | snapcraft | closed | Closed as unreproducible: maintainer could not reproduce parallel-install failure after experimental.parallel-instances was re-set; reporter pointed to a snapd bug, filed as LP bug #2111940. | |
| #1795827 Snapcraft doesn't install snapcraft inside the lxd container | snapcraft (launchpad) | open | Historical LXD builds failed because Snapcraft was not injected into the container; the modern Craft Providers LXD path injects Snapcraft and resolves the legacy failure. | |
| #1839399 snapcraft not pulling snap from lxd container | snapcraft (launchpad) | open | Snapcraft 3.7.1 reported a successful --use-lxd build but left the generated snap absent on the host; a maintainer identified possible CWD handling, and the case remains unresolved. | |
| #1999321 Snapcraft is stuck on "launching instance..." indefinitely | snapcraft (launchpad) | open | Endless LXD startup on failed container DNS now times out via craft-providers; Snapcraft 7.5.4 is recorded as fixing the wait. Multipass arm64 and Docker diagnostics remain separately tracked. | |
| #719 Snapcraft fails initialization of build container | craft-providers | closed | LXD startup race was fixed by waiting for instance readiness in craft-providers PR #720; the fix shipped via Snapcraft PR #5247 in Snapcraft 8.6.2. | |
| #1746612 Snapcraft cleanbuild doesn't work if you're not using the LXD snap | snapcraft (launchpad) | closed | Closed after the missing hostfs behavior was fixed upstream in lxc/lxd#4183. Snapcraft PR #1912 offered a workaround but was not merged. | |
| #4683 Cannot use parallel installations of snapcraft if a non-aliased version is not installed | snapcraft | closed | Fixed by merged PR #5085 (main) and backported via #5087 to hotfix/7.5 (7.5.7); craft-providers now inject the aliased snapcraft snap correctly. Upstream bug tracked in craft-application#411. |