Juju ignores constraints set in the bundle and deploys KVMs with default values

[Ante Karamatić]

I have a bundle that, among other things, deploys KVM instance:

    physical-machine:
        series: trusty
        charm: cs:trusty/ubuntu
        num_units: 1
    kvm-machine:
        series: trusty
        charm: cs:trusty/ubuntu
        constraints: "cpu-cores=12 mem=64G root-disk=15G"
        num_units: 1
        to:
            - kvm:physical-machine/0

My KVM machine ends up with 512MB of RAM and 1 CPU core. Expectation was that KVM will be created with 12 cores, 64GB of RAM and 15GB disk.

It looks like constraints are ignored in the bundle if placement is defined.

This is all with MAAS provider and with juju2 b15.

[Michael Foord (mfoord)]

Also applies to LXD containers.

[Michael Foord (mfoord)]

Note that placement at the command line works fine: juju deploy ubuntu --constraints="mem=4G" --to kvm:0

Placement does not work with constraints with bundles. The example given in this bug report is not quite correct as you can only specify machines with digits as names. Containers are not created as machine definitions. What should work is a constraint at the application level with a placement directive. For example:

series: trusty
applications:
  "ubuntu-kvm":
    charm: "cs:ubuntu-8"
    num_units: 1
    constraints: "mem=4"
    to:
      - "kvm:ubuntu-root/0"
  "ubuntu-root":
    charm: "cs:ubuntu-8"
    num_units: 1
    to:
      - "0"
relations: []
machines:
  "0":
    series: xenial
    constraints: "mem=8"

This doesn't work and I believe it is because the bundlechanges package is ignoring the constraints where there is placement. These constraints do not reach the provisioner.

The bundlechanges entry point is the FromData function, this takes data from charm.ReadBundleData - charm package documents the restriction that constraints are ignored with placement but does return both. So if we fix this in the bundledata package we'd want to also update the comment/documentation in the charm package.

[Michael Foord (mfoord)]

I have manually verified that this change in bundlechanges fixes the issue for juju and that application constraints in bundles are honoured for KVM placement:

    https://github.com/juju/bundlechanges/pull/29

There are a couple of other *known issues* stopping this for working with lxd, we will address those separately.

[Michael Foord (mfoord)]

Landed in bundlechanges, PR for juju 2.1:

https://github.com/juju/juju/pull/6723

[Ante Karamatić (ivoks)]

I've tested 2.2-alpha1~20170111~4707~ad41e0ea-20170111+4707+ad41e0ea~16.04
and I can confirm this works fine now.

On Fri, Dec 16, 2016 at 1:07 AM Curtis Hovey <email address hidden> wrote:

> ** Changed in: juju
> Milestone: 2.1.0 => 2.1-beta3
>
> ** Changed in: juju
> Status: Fix Committed => Fix Released
>
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> https://bugs.launchpad.net/bugs/1626597
>
> Title:
> Juju ignores constraints set in the bundle and deploys KVMs with
> default values
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--
Ante Karamatić
<email address hidden>
Canonical