[magnum] Docker Swarm errors on Yoga Ubuntu using Install Guide cut-n-paste

Vince Mulhollon vince.mulhollon at springcitysolutions.com
Fri Jun 10 13:29:15 UTC 2022

I'm trying to use Magnum on a fresh Yoga install on Ubuntu to run some
non-load balanced docker swarm workloads.  Its a long story but the parts
of the swarm workload are heterogeneous so a cluster would just get in the

Everything else about the cluster is working fine, all is well, etc.  I'm a
small time VMware and OS admin with years of experience but absolute zero
experience with Magnum.  Also I have "some" experience with Docker Swarm
clusters mostly created and assembled with Ansible.  So I know quite well
how to look at log files or configs in a general sense, but I have no idea
what to expect from Magnum specifically as a "glue" technology.

I've followed every detail of the "Magnum Installation Guide" for Yoga as
seen at:


When provisioning a docker swarm, I very literally cut and paste from:


cluster creation fails every time with "Property allowed_cidrs not
assigned" exactly as seen on this mailing list post from 2021-August-20
about ten months ago on a Wallaby install, they were also using Ubuntu.


Advice at that point ranged from, try installing Octavia, which I was
trying to avoid and I definitely do NOT want a load balancer in front of
that particular workload, to Docker swarm is no longer tested for Magnum
and it's in practice a K8S exclusive product.

I played around for an afternoon and got nowhere WRT configuring the
allowed cidrs for a k8s load balancer on a config that does not use a load
balancer and does not use k8s.

Heat works fine, its super fun, and one alternative is I could give up on
Magnum and use some Heat templates, which I know how to do and seems
simpler than getting Magnum to work at this point.  Or I could brave the
scary looking mostly-undocumented world of kuryr and zun, which I was
attempting to avoid by using Magnum which is at least simple and easy to
install.  Or just keep spinning up manual images and letting ansible turn
them into docker swarms for me.  But, ideally, I'd like to use Magnum to
spin up some Docker Swarms for personal curiosity reasons, if nothing else,
it would be very convenient if it worked.

So the point of this long ramble is, can anyone successfully running Docker
Swarm on Yoga on Ubuntu using a very typical "Install Guide" installation
provide a pointer or link or github or something that Google searches is
not finding to get it to work?

Also I hate to piggyback multiple questions but this paragraph also
interests me, does anyone have any information and experience with this:


"Sample cluster driver

To help developers in creating new COE drivers, a minimal cluster driver is
provided as an example. The ‘docker’ cluster driver will simply deploy a
single VM running Ubuntu with the latest Docker version installed. It is
not a true cluster, but the simplicity will help to illustrate the key

To be filled in"

That "To be filled in" part would also be very interesting to me as worst
case I could shove the Docker Swarm's workload onto a single Docker host,
although then I'm back to orchestrating with Heat and presumably Ansible
but via a different path.
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