Add role label to weave containers so scope can filter

[tomwilkie]

As part of weaveworks/scope#337, I'd like to label the weave & scope containers and have them filtered out of the scope view by default.

Let the bike shedding begin...

[tomwilkie]

feedback from @rade - what happens with older versions of docker? Need to support docker 1.3.1

[tomwilkie]

To clarify, role=system is something I just made up.

[tomwilkie]

@errordeveloper how do kubernetes do labels? If there an existing schema / topology?

[tomwilkie]

@errordeveloper says k8s does something like this:

"Labels": {
    "io.kubernetes.pod.name": "kube-system/kube-dns-v8-zwokj"
}

[tomwilkie]

@rade labels seem to be backward compatible (this imports and runs on docker 1.3.1)

[awh]

Is there something contentious about this PR? It's a tiny change but has been open for nine days...

[tomwilkie]

@MikeB was against the approach of label containers then filtering based on
label.

On Friday, 21 August 2015, Adam Harrison [email protected] wrote:

Is there something contentious about this PR? It's a tiny change but has
been open for nine days...

—
Reply to this email directly or view it on GitHub
#1290 (comment).

[squaremo]

@MikeB was against the approach of label containers then filtering based on label.

weaveworks/scope#337 (comment):

If you want this to be a general mechanism for hiding containers from display in Scope, I think using labels is a poor choice. Firstly, it's indirect -- you're asking the user to go and change how a container is labelled (which involves recreating the container!), just to hide it in their display. Secondly, the user may not even have control over how containers are created -- that might be done by kubernetes, or marathon, or whatever.

If you want a hook on which to hang some by-default filtering of weave containers, then labels are fine, but you should give them a namespace.

[tomwilkie]

f you want a hook on which to hang some by-default filtering of weave containers, then labels are fine, but you should give them a namespace.

Thats exactly what we want - the filtering mechanism with be general, but
we need to filter on something, and we'd like that to be a label. I'll
namespace this one.

On Tue, Aug 25, 2015 at 1:34 PM, Michael Bridgen [email protected]
wrote:

@MikeB https://github.com/mikeb was against the approach of label
containers then filtering based on label.

weaveworks/scope#337 (comment)
weaveworks/scope#337 (comment):

If you want this to be a general mechanism for hiding containers from
display in Scope, I think using labels is a poor choice. Firstly, it's
indirect -- you're asking the user to go and change how a container is
labelled (which involves recreating the container!), just to hide it in
their display. Secondly, the user may not even have control over how
containers are created -- that might be done by kubernetes, or marathon, or
whatever.

If you want a hook on which to hang some by-default filtering of weave
containers, then labels are fine, but you should give them a namespace.

—
Reply to this email directly or view it on GitHub
#1290 (comment).

[tomwilkie]

Failures are unrelated, see #1360

[squaremo]

Merged on the understanding that this is not really intended to be a feature for end-users. (If it were, I would be concerned about being stuck with the terms "role" and "system".)