JUJU Charm Certification

[Mark Shuttleworth]

On 13/09/16 08:29, SivaRamaPrasad Ravipati wrote:
> Hi marcoceppi,
>
> Here we are doing vertical Scaling. I mean same copy of the charm
> deployed multiple times to a single cinder node. every time it will
> add unique backend per charm to the same cinder node. This OK.
>
> But If I want to do Horizontal Scaling . I mean adding more cinder
> charms as nodes to the existing OpenStack setup. And then same copy of
> the charm I have to deploy to different cinder nodes. I mean In High
> avaialabilty case, what are the consequences probably we will face.
> And how can we deploy it to different cinder nodes separately. What
> was the best solution for this. How can we achieve horizontal scalinf
> here. Could you please provide me the information with respect to this.

When you 'juju deploy <foo>' you create a new application, 'foo', with a
single 'unit', usually a machine from the cloud.

TO scale up 'foo' you use 'juju add-unit -n X' where X is a number, like:

  juju add-unit hdfs -n 15

That will add 15 machines to the hdfs application.

You can see the scale of the app in the 'juju status' output.

There are more clever things you can do with containers which start to
blur the line between the number of machines and the number of units,
but that's the basic idea.

Mark