Pre-seeded snaps are not necessarily available for use in cloud-init user-data

Bug #1767131 reported by Dan Watkins on 2018-04-26
This bug affects 1 person
Affects Status Importance Assigned to Milestone
cloud-init (Ubuntu)

Bug Description

With some cloud software being moved to snaps, cloud-init needs to ensure that snaps have been preseeded before user scripts are run, as those user scripts may rely on the software within the snap being available for use.

Related branches

Dan Watkins (daniel-thewatkins) wrote :

Ideally, we would be able to configure the images to specify whether or not they should block on preseeded snaps. We have some cases where command-line utilities are installed (and so we should block) but others where only a daemon is started (where there is limited utility in blocking).

Scott Moser (smoser) wrote :

The snap module, which processes 'snap' configuration [1] currently runs
just about as early as it can run. The snapd daemon is not available until
cloud_config_modules time frame [2], so use of 'snap' or any provided
commands is not possible before that.

This means that bootcmd cannot use snap provided commands, but runcmd
or user-scripts ('#!/bin/sh') can.

I'm marking this fix-released, if you disagree, please justify and re-open.


Changed in cloud-init (Ubuntu):
status: New → Fix Released
Dan Watkins (daniel-thewatkins) wrote :

There isn't currently a systemd target that indicates that snapd has completed its preseeding, so cloud-init can't be ensuring that they are available like that. Does cloud-init do something specific to confirm that pre-seeding has been completed before the user script point?

(Note that preseeded snaps are those that are in place on the filesystem during image build, which snapd detects and installs on boot; this isn't achieved through cloud-init at all.)

Changed in cloud-init (Ubuntu):
status: Fix Released → New
tags: added: id-5aea2721caa979edde9fb279
Scott Moser (smoser) on 2018-05-10
Changed in cloud-init:
status: New → Confirmed
importance: Undecided → Medium
Changed in cloud-init (Ubuntu):
status: New → Confirmed
importance: Undecided → Medium
Dan Watkins (daniel-thewatkins) wrote :

As we have preseeded snaps in bionic, we'll want this SRU'd there (at least).

Scott Moser (smoser) wrote :

An upstream commit landed for this bug.

To view that commit see the following URL:

Changed in cloud-init:
status: Confirmed → Fix Committed
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package cloud-init - 18.2-59-gcd1de5f4-0ubuntu1

cloud-init (18.2-59-gcd1de5f4-0ubuntu1) cosmic; urgency=medium

  * New upstream snapshot.
    - openstack: Allow discovery in init-local using dhclient in a sandbox.
      (LP: #1749717)
    - tests: Avoid using https in httpretty, improve HttPretty test case.
      (LP: #1771659)
    - yaml_load/schema: Add invalid line and column nums to error message
    - Azure: Ignore NTFS mount errors when checking ephemeral drive
      [Paul Meyer]
    - packages/brpm: Get proper dependencies for cmdline distro.
    - packages: Make rpm spec files patch in package version like in debs.
    - tools/run-container: replace tools/run-centos with more generic.
    - Update version.version_string to contain packaged version. (LP: #1770712)
    - cc_mounts: Do not add devices to fstab that are already present.
      [Lars Kellogg-Stedman]
    - ds-identify: ensure that we have certain tokens in PATH. (LP: #1771382)
    - tests: enable Ubuntu Cosmic in integration tests [Joshua Powers]
    - read_file_or_url: move to url_helper, fix bug in its FileResponse.
    - cloud_tests: help pylint
    - flake8: fix flake8 errors in previous commit.
    - typos: Fix spelling mistakes in log messages [Stephen Ford]
    - tests: restructure SSH and initial connections [Joshua Powers]
    - ds-identify: recognize container-other as a container, test SmartOS.
    - cloud-config.service: run After snap.seeded.service. (LP: #1767131)

 -- Chad Smith <email address hidden> Wed, 23 May 2018 16:16:53 -0600

Changed in cloud-init (Ubuntu):
status: Confirmed → Fix Released

This bug is believed to be fixed in cloud-init in version 18.3. If this is still a problem for you, please make a comment and set the state back to New

Thank you.

Changed in cloud-init:
status: Fix Committed → Fix Released
Scott Moser (smoser) on 2018-09-14
Changed in cloud-init (Ubuntu Bionic):
importance: Undecided → Low
status: New → Fix Released
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