If we use a single shared volume, I'd be a little worried about
Prometheus
data filling up all the space and causing problems in the hawkular-services
container. We've seen some runaway Prometheus storage issues in open shift.
One component eating all the space of the other is something we might want
to be worried about.
Prometheus considers its metrics storage to not be durable and that is our
stance with Hawkular Services as well.
The only thing we can really do is to give recommendations to users for how
much storage they should need. Since we are tightly coupling Hawkular
Services with Prometheus, it might be easier to just keep them together and
give the recommendation for both running.
On Dec 5, 2017 2:13 PM, "Matthew Wringe" <mwringe(a)redhat.com> wrote:
Going with the all-in-one pod approach, there is also the question of how
many volumes we want to use.
We can have everything in one volume with multiple directories (eg /p8s,
/hawkular-inventory, etc). This would make it easier to install as we only
have to have one directory to deal with.
Of we could have multiple volumes, one for Hawkular Services and one for
Prometheus. This might give us some more flexibility in the future, but I
can't see why we would need this extra complexity at the moment.
Any thoughts on this? Or maybe some perspective I am missing?
On Mon, Dec 4, 2017 at 5:35 AM, Thomas Heute <theute(a)redhat.com> wrote:
> +1
>
> On Thu, Nov 30, 2017 at 2:56 PM, Matthew Wringe <mwringe(a)redhat.com>
> wrote:
>
>> Yeah, I think we should go with the all-in-one pod approach for now. If
>> we discover certain use cases that wont work properly we can re-evaluate.
>>
>> On Thu, Nov 30, 2017 at 5:15 AM, Lucas Ponce <lponce(a)redhat.com> wrote:
>>
>>>
>>>
>>> On Thu, Nov 30, 2017 at 10:55 AM, Lucas Ponce <lponce(a)redhat.com>
>>> wrote:
>>>
>>>>
>>>>
>>>> On Mon, Nov 27, 2017 at 4:38 PM, Matthew Wringe
<mwringe(a)redhat.com>
>>>> wrote:
>>>>
>>>>> With the changes that are now going to include Prometheus, how do we
>>>>> want to deploy this in OpenShift?
>>>>>
>>>>> We can have a few options:
>>>>>
>>>>> ALL-IN-ONE CONTAINER
>>>>> We put both Hawkular Services and Prometheus in the same container.
>>>>>
>>>>> Pros:
>>>>> - easy to deploy in plain docker (but this doesn't appear to be
a
>>>>> usecase we are targetting anyways)
>>>>> - shares the same network connection (even localhost) and ip address
>>>>> (eg but both services are on the different ports).
>>>>> - Does't require any special wiring of components.
>>>>> - Can share the same volume mount
>>>>> - version of components can't get out of sync.
>>>>>
>>>>> Cons:
>>>>> - workflow doesn't work nicely. Docker containers are meant to
only
>>>>> run a single application and running two can cause problems. Eg
lifecycle
>>>>> events would become tricky and require some hacks to get around
things.
>>>>> - can't independently deploy things
>>>>> - can't reuse or share any existing Prometheus docker
containers.
>>>>>
>>>>> ALL-IN-ONE POD
>>>>> Hawkular Services and Prometheus are in their own containers, but
>>>>> they are both deployed within the same pod.
>>>>>
>>>>> Pros:
>>>>> - shares the same network connection.
>>>>> - bound to the same machine (useful if sharing the same hostpath pv)
>>>>> and don' need to worry about external network configurations (eg
firewalls
>>>>> between OpenShift nodes)
>>>>> - pvs can be shared or separate.
>>>>> - lifecycle events will work properly.
>>>>>
>>>>> Cons:
>>>>> - lifecycle hooks will mean that both containers will have to pass
>>>>> before either one will enter the ready state. So if Prometheus is
failing
>>>>> for some reason, Hawkular Services will not be available under the
service.
>>>>> - cannot independently update one container. If we need to deploy a
>>>>> new container we will need to bring down the whole pod.
>>>>> - are stuck with a 1:1 ratio between Hawkular Services and
Prometheus
>>>>>
>>>>>
>>>> One technical requeriment is that Hawkular Services needs to now where
>>>> is Prometheus server at initialization.
>>>>
>>>
>>> One technical requeriment is that Hawkular Services needs to *know*
>>> where is Prometheus server at initialization.
>>>
>>> [Sorry, typing fast]
>>>
>>> So, I guess that all-in-one pod will simplify things on this case.
>>>>
>>>> I would start with this architecture first and harden the basic
>>>> scenarios.
>>>>
>>>>
>>>>>
>>>>> SEPARATE PODS
>>>>> Hawkular Services and Prometheus have their own separate pods.
>>>>>
>>>>> Pros:
>>>>> - can independently run components and each component has its own
>>>>> separate lifecycle
>>>>> - if in the future we want to cluster Hawkular Services. this will
>>>>> make it a lot easier and will also allow for running an n:m ratio
between
>>>>> Hawkular Services and Prometheus
>>>>> - probably the more 'correct' way to deploy things as we
don't have a
>>>>> strong requirement for Hawkular Services and Prometheus to run
together.
>>>>>
>>>>> Cons:
>>>>> - more complex wiring. We will need to have extra services and
routes
>>>>> created to handle this. This mean more things running and more
chances for
>>>>> things to go wrong. Also more things to configure
>>>>> - reusing a PV between Hawkular Services and Prometheus could be
more
>>>>> challenging (especially if we are using hostpath pvs). Updating the
>>>>> Prometheus scrape endpoint may require a new component and
container.
>>>>>
>>>>> _______________________________________________
>>>>> hawkular-dev mailing list
>>>>> hawkular-dev(a)lists.jboss.org
>>>>>
https://lists.jboss.org/mailman/listinfo/hawkular-dev
>>>>>
>>>>>
>>>>
>>>
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>>>
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>>>
>>>
>>
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>>
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