Hi Kevin.
Puppet not only creates config files but also executes a service dependent steps, like db sync, so neither '[base] -> [puppet]' nor '[base] -> [service]' would not be enough on its own. That requires some services specific code to be included into *config* images as well.

PS. There is a related spec [0] created by Dan, please take a look and propose you feedback

[0] https://review.openstack.org/620062

On 11/30/18 6:48 PM, Fox, Kevin M wrote:
Still confused by:
[base] -> [service] -> [+ puppet]
[base] -> [puppet]
[base] -> [service]

From: Bogdan Dobrelya [bdobr...@redhat.com]
Sent: Friday, November 30, 2018 5:31 AM
To: Dan Prince; openstack-dev@lists.openstack.org; 
Subject: Re: [openstack-dev] [TripleO][Edge] Reduce base layer of containers 
for security and size of images (maintenance) sakes

On 11/30/18 1:52 PM, Dan Prince wrote:
On Fri, 2018-11-30 at 10:31 +0100, Bogdan Dobrelya wrote:
On 11/29/18 6:42 PM, Jiří Stránský wrote:
On 28. 11. 18 18:29, Bogdan Dobrelya wrote:
On 11/28/18 6:02 PM, Jiří Stránský wrote:

Reiterating again on previous points:

-I'd be fine removing systemd. But lets do it properly and
not via 'rpm
-ev --nodeps'.
-Puppet and Ruby *are* required for configuration. We can
certainly put
them in a separate container outside of the runtime service
but doing so would actually cost you much more
space/bandwidth for each
service container. As both of these have to get downloaded to
each node
anyway in order to generate config files with our current
I'm not sure this buys you anything.

+1. I was actually under the impression that we concluded
yesterday on
IRC that this is the only thing that makes sense to seriously
But even then it's not a win-win -- we'd gain some security by
production images, but pay for it with space+bandwidth by
image content (IOW we can help achieve one of the goals we had
in mind
by worsening the situation w/r/t the other goal we had in

Personally i'm not sold yet but it's something that i'd
consider if we
got measurements of how much more space/bandwidth usage this
consume, and if we got some further details/examples about how
are the security concerns if we leave config mgmt tools in

IIRC the other options (that were brought forward so far) were
dismissed in yesterday's IRC discussion and on the reviews.
Bin/lib bind
mounting being too hacky and fragile, and nsenter not really
solving the
problem (because it allows us to switch to having different
available, but it does not allow merging the availability of
from two containers into a single context).

We are going in circles here I think....

+1. I think too much of the discussion focuses on "why it's bad
to have
config tools in runtime images", but IMO we all sorta agree
that it
would be better not to have them there, if it came at no cost.

I think to move forward, it would be interesting to know: if we
do this
(i'll borrow Dan's drawing):

base container| --> |service container| --> |service
container w/
Puppet installed|

How much more space and bandwidth would this consume per node
separately per controller, per compute). This could help with

As I've already evaluated in the related bug, that is:

puppet-* modules and manifests ~ 16MB
puppet with dependencies ~61MB
dependencies of the seemingly largest a dependency, systemd

that would be an extra layer size for each of the container
images to be
downloaded/fetched into registries.

Thanks, i tried to do the math of the reduction vs. inflation in
as follows. I think the crucial point here is the layering. If we
this image layering:

base| --> |+ service| --> |+ Puppet|

we'd drop ~267 MB from base image, but we'd be installing that to
topmost level, per-component, right?

Given we detached systemd from puppet, cronie et al, that would be
267-190MB, so the math below would be looking much better

Would it be worth writing a spec that summarizes what action items are
bing taken to optimize our base image with regards to the systemd?

Perhaps it would be. But honestly, I see nothing biggie to require a
full blown spec. Just changing RPM deps and layers for containers
images. I'm tracking systemd changes here [0],[1],[2], btw (if accepted,
it should be working as of fedora28(or 29) I hope)

[0] https://review.rdoproject.org/r/#/q/topic:base-container-reduction
[1] https://bugzilla.redhat.com/show_bug.cgi?id=1654659
[2] https://bugzilla.redhat.com/show_bug.cgi?id=1654672

It seems like the general consenses is that cleaning up some of the RPM
dependencies so that we don't install Systemd is the biggest win.

What confuses me is why are there still patches posted to move Puppet
out of the base layer when we agree moving it out of the base layer
would actually cause our resulting container image set to be larger in


In my basic deployment, undercloud seems to have 17 "components"
containers), overcloud controller 15 components (48 containers),
overcloud compute 4 components (7 containers). Accounting for
the total number of "components" used seems to be 19. (By
here i mean whatever uses a different ConfigImage than other
services. I
just eyeballed it but i think i'm not too far off the correct

So we'd subtract 267 MB from base image and add that to 19 leaf
used in this deployment. That means difference of +4.8 GB to the
image sizes. My /var/lib/registry dir on undercloud with all the
currently has 5.1 GB. We'd almost double that to 9.9 GB.

Going from 5.1 to 9.9 GB seems like a lot of extra traffic for the
(both external and e.g. internal within OpenStack Infra CI clouds).

And for internal traffic between local registry and overcloud
nodes, it
gives +3.7 GB per controller and +800 MB per compute. That may not
be so
critical but still feels like a considerable downside.

Another gut feeling is that this way of image layering would take
time to build and to run the modify-image Ansible role which we use
CI, so that could endanger how our CI jobs fit into the time limit.
could also probably measure this but i'm not sure if it's worth
the time.

All in all i'd argue we should be looking at different options

Given that we should decouple systemd from all/some of the
(an example topic for RDO [0]), that could save a 190MB. But it
seems we
cannot break the love of puppet and systemd as it heavily relies
on the
latter and changing packaging like that would higly likely affect
baremetal deployments with puppet and systemd co-operating.

Ack :/

Long story short, we cannot shoot both rabbits with a single
shot, not
with puppet :) May be we could with ansible replacing puppet
So splitting config and runtime images is the only choice yet to
the raised security concerns. And let's forget about edge cases
for now.
Tossing around a pair of extra bytes over 40,000 WAN-distributed
computes ain't gonna be our the biggest problem for sure.






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Best regards,
Bogdan Dobrelya,
Irc #bogdando

Best regards,
Bogdan Dobrelya,
Irc #bogdando

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