How to use MAAS constraints?

juju
, ,
1

Hello,

I’m trying to understand more how to specify machine tags, zones, and pools when deploying applications using Juju on a MAAS cloud.

We have something similar to this in our bundle.yaml that we juju deploy ./bundle.yaml:

applications:
    foo:
        charm: foo
        constraints: tags=foo,bar,^bla zones=a-1

I want to understand more about these constraints:

  1. tags=foo,bar means: "match machines with tag foo AND bar"?
  2. how do I specify an OR between tags? For example: "match machines with tag foo OR bar"? Can I use tags=foo|bar?
  3. how do I specify a more complex constraint, like: "(foo OR bar) AND (bla) AND NOT (x) "?
  4. what are the constrains that I can set/request when using Juju? i know I can specify MAAS tags and zones, can I also specify a pool and fabric vlan? What is the syntax for that?
  5. when specifying multiple constraints, they are all “joined” with a boolean AND?

(cross post from MAAS constraints when using Juju - Users - MAAS | Discourse)

Thank you,

Heitor

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2

Hi Heitor, answers below.

  1. Yes
  2. Arbitrary boolean logic is not supported. Only AND (the default), and NOT (the ^)
  3. You cannot. See #2
  4. See Juju constraints (apparently only available on Discourse for some reason)
  5. Yes

I suggest you file an RFE bug for the features you would like to see.

Hope this helps.

3

Hi Peter, thanks for the help!

This secret page for the constraints is very helpful. I wonder why is not on the Juju docs pages?

Filed a bug for that: Bug #1948959 “Enrich constraints for MAAS cloud” : Bugs : juju

Thanks again!

4

Apologies for having introduced confusion. The reference page is linked from this documentation page:

image

but it brings you to Discourse instead of staying in the documentation.

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5

Ping @tmihoc ^

1 Like
6

Thanks, I’ll make sure to list it.

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