Endpoints trials + MAAS charms

James Beedy jamesbeedy at gmail.com
Mon Nov 27 13:17:09 UTC 2017


Thanks for the response.

When taking into account the overhead to get MAAS deployed as charms, it
definitely makes the LXD provider method you have described seem very
appealing. Some issues I've experienced trying to get MAAS HA deployed are
such that it seems like just a ton of infrastructure is needed to get MAAS
HA standing using the manual provider deploying the MAAS charms. You have
to provision/maintain the manual Juju controller cluster underneath MAAS,
just to have MAAS .... ugh

I found not only the sheer quantity of servers needed to get this working
quite unnerving, but also the manual ops I had to undergo to get it all
standing #snowflakes #custom.

I iterated on this a few times to see if I could come up with something
more manageable, and this is where I landed (brace yourself) [0]

What's going on there?

I created a model in JAAS, manually added 3 physical hosts across different
racks, then bootstrapped 4 virtual machines on each physical host (1 vm for
each postgresql, maas-region, maas-rack [1], juju-controller (juju
controllers for maas provider, to be checked into maas)) on each host.

I then also added my vms to my JAAS model so I could deploy the charms to
them (just postgresql and ubuntu at the time - the MAAS stuff got manually
installed and configured after the machiens had ubuntu deployed to them in
the model).

(ASIDE: I'm seeing I could probably do this one better by combining my
region and rack controller to the same vm, and colocating the postgresql
charm with the region+rack on the same vm, giving me ha of all components
using single vm on each host.)

I know there are probably a plethora of issues with what I've done here,
but it solved a few primary issues that seemed to outweigh the misuse.

The issues were:

1) Too many machines needed to get MAAS HA
2) Chicken or egg?
3) Snowflakes!!!
4) No clear path to support MAAS HA

My idea behind this was such that by using JAAS I am solving the chicken or
the egg issue, and reducing the machines/infra needed to get MAAS HA.
Deploying the MAAS infra with Juju eliminates the snowflake/lack of
tracking and chips at the "No clear path to support MAAS HA".



[0] http://paste.ubuntu.com/25891429/
[1] http://paste.ubuntu.com/26058033/

On Mon, Nov 27, 2017 at 12:09 AM, Dmitrii Shcherbakov <
dmitrii.shcherbakov at canonical.com> wrote:

> Hi James,
> This is an interesting approach, thanks for taking a shot at solving this
> problem!
> I thought of doing something similar a few months ago. The problematic
> aspect here is the assumption of having a provider/substrate already
> present for MAAS to be deployed - this is the chicken or the egg type of
> problem.
> If you would like to take the MAAS charm route, manual provider could be
> used with Juju to do that with pre-created hosts (which may be
> containers/VMs/hosts all in a single model with this provider, regardless
> of how they were deployed). There would be hosts for a Juju controller(s)
> and MAAS region/rack controllers in the end.
> If you put both Juju controller and MAAS into containers, it gives you
> some flexibility. If you are careful, you can even migrate those
> containers. Running MAAS in an unprivileged container should be perfectly
> possible https://github.com/CanonicalLtd/maas-docs/issues/700 - I am not
> sure that the instructions that require a privileged container with loop
> devices passed to it are relevant anymore.
> An alternative is to use the lxd provider (which can connect to a remote
> daemon, not only localhost) but this is only one daemon per provider. For
> HA purposes you would need several LXDs on different hosts and for this
> provider to support network spaces because you may have MAAS hosts located
> in different layer 2 networks with different subnets used. Cross-model
> relations could be used to have a model per LXD provider but I am not sure
> this is the best approach - units would be on different models with no
> shared unit-level leadership.
> https://github.com/juju/juju/tree/develop/provider/lxd
> With the new LXD clustering work it might be possible overcome this
> limitation as well. I would assume LXD clustering to work on a per-rack
> basis due to latency constraints while with MAAS in a data center you would
> surely place different region controllers and rack controllers on different
> racks (availability zones).
> https://insights.ubuntu.com/2017/10/23/lxd-weekly-status-
> 20-authentication-conferences-more/
> "Distributed database for LXD clustering"
> If, by the time of LXD clustering release, there was support for
> availability zones it would have solved the problem with a single control
> plane for a Juju provider in the absence of MAAS.
> An alternative to the above is just usage of bootstrap automation to set
> up MAAS and then usage of Juju with charms for the rest of what you need.
> Best Regards,
> Dmitrii Shcherbakov
> Field Software Engineer
> IRC (freenode): Dmitrii-Sh
> On Sun, Nov 26, 2017 at 4:14 AM, James Beedy <jamesbeedy at gmail.com> wrote:
>> Hello all,
>> I've got an HA maas setup at the datacenter, I had some trouble getting
>> the full HA bits super solid in the past, and thought it appropriate to try
>> charming up the new 2.3 MAAS snaps to see if I could make my life a bit
>> easier going forward.
>> I just took a quick first swipe at this, so please excuse the lack of any
>> tests.
>> I'm hoping I can kill 2 birds with 1 stone here by a) possibly getting
>> some feedback from @cory_fu on how I'm using the new Endpoints stuff
>> landing soon in reactive (and disseminate that feedback so others will be
>> in the know too), and b) possibly someone from @MAAS team might give me a
>> nod if the steps I've taken here look to be moving in the right direction?
>> # Interface and layer
>> interface-maas: https://github.com/jamesbeedy/interface-maas
>> layer-maas: https://github.com/jamesbeedy/layer-maas
>> # MAAS charm
>> charmstore: https://jujucharms.com/u/jamesbeedy/maas/8
>> # Sample bundle
>> sample bundle: http://paste.ubuntu.com/26046016/ - (only for reference,
>> this won't actually deploy)
>> # juju status
>> `juju status`: http://paste.ubuntu.com/26045880/
>> Thanks,
>> James
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