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From Lianghwa Jou <>
Subject Re: [PROPOSAL] add native container orchestration service
Date Tue, 31 Jan 2017 08:05:43 GMT

There are many container orchestrators. Those container orchestrators are happy to run on
any VMs or bare metal machines. K8s is just one of them and there will be more in the future.
It may not be a good idea to make CloudStack to be k8s aware. IMO, the relationship between
k8s and cloudstack should be similar to application and os. It probably not a good idea to
make your OS to be aware of any specific applications so IMHO I don’t think k8s should be
native to CloudStack. It makes more sense to provide some generic services that many applications
can take advantages of. Some generic resource grouping service makes sense so a group of VMs,
baremetal machines or network can be treated as a single entity. Some life cycle management
will be necessary for these entities too. We can deploy k8s, swarm, dcos or even non-container
specific services on top of CloudStack. The k8s is changing fast. One single tenant installation
may need more than one VM group and may actually requires more (k8s federation). It will be
a struggle to be in sync if we try to bring k8s specific knowledge into cloudstack.


Lianghwa Jou
VP Engineering, Accelerite

On 1/29/17, 11:54 PM, "Murali Reddy" <> wrote:

    I agree with some good views Will has shared and I also agree to the concerns raised by
Wido and Eric. IMO we need balance of staying relevant/add new features vs stability of CloudStack
and take corrective action if needed. We have two good examples for both. When SDN was hot
technology CloudStack ended up with bunch of SDN controller integrations. Few years later,
now CloudStack is carrying baggage with no maintainers for those plugins, with probably not
many of CloudStack users needing overlays. On the other hand, other than attempt to liaison
with ETSI for NFV no effort was done. OpenStack has become de-facto for NFV. Now for OpenStack,
arguably NFV has become larger use case than cloud it self. I concur with Will’s point that
with minimal viable solution that does not change the core of CloudStack, and can keep CloudStack
relevant is worth to be taken in. 
    To your question of how different is from ShapeBlue’s container service, its design,
implementation and API semantics etc remain same. ShapeBlue’s container service was true
drop in plug-in to CloudStack, with this proposal I am trying to re-work to make it a core
CloudStack pluggable service which is part of CloudStack. 
    Key concepts that this proposal is trying to add
        - add notion of ‘container cluster’ as a first class entity in CloudStack. Which
is bacially collection of other CloudStack resources (like VM’s, networks, public ip, network
rules etc)
        - life cycle operation to manage ‘container cluster’ like create, delete, start,
stop, scale-up, scale-down, heal etc
        - orchestrate container orchestrator control plane on top of provisioned resources
    At-least for k8s (which is what this proposal is targeting), integration with k8s is bare
minimum. There are cloud-config scripts that automatically setup k8s cluster master and node
VM’s. All CloudStack is doing in passing the cloud-config to the core OS VM’s as user
    Murali Reddy
    On 29/01/17, 8:54 AM, "Will Stevens" < on behalf of>
    >I agree that we need to be careful what we take on and own inside
    >CloudStack.  I feel like some of the plugins or integrations which we have
    >been "maintaining" may serve us better to abandon, but I feel like that is
    >a whole discussion on its own.
    >In this case, I feel like there is a minimum viable solution which puts
    >CloudStack in a pretty good place to enable container orchestration.  For
    >example, one of the biggest challenges with K8S is the fact that it is
    >single tenant.  CloudStack has good multi tenancy support and has the
    >ability to orchestrate the underlying infra quite well.  We will have to be
    >very careful not to try to own too deep into the K8S world though, in my
    >opinion.  We only want to be responsible for providing the infra (and a way
    >to bootstrap K8S ideally) and be able to scale the infra, everything else
    >should be owned by the K8S on top.  That is the way I see it anyway, but
    >please add your input.
    >I think it is a liability to try to go too deep, for the same reasons Wido
    >and Erik have mentioned.  But I also think we need to take it seriously
    >because that train is moving and this may be a good opportunity to stay
    >relevant in a rapidly changing market.
    >*Will STEVENS*
    >Lead Developer
    >On Sat, Jan 28, 2017 at 1:13 PM, Wido den Hollander <> wrote:
    >> > Op 27 januari 2017 om 16:08 schreef Will Stevens <
    >> >:
    >> >
    >> >
    >> > Hey Murali,
    >> > How different is this proposal than what ShapeBlue already built.  It
    >> looks
    >> > pretty consistent with the functionality that you guys open sourced in
    >> > Seville.
    >> >
    >> > I have not yet used this functionality, but I have reports that it works
    >> > quite well.
    >> >
    >> > I believe the premise here is to only orchestrate the VM layer and
    >> > basically expose a "group" of running VMs to the user.  The user is
    >> > responsible for configuring K8S or whatever other container orchestrator
    >> on
    >> > top.  I saw mention of the "cloud-config" scripts in the FS, how are
    >> those
    >> > exposed to the cluster?  Maybe the FS can expand on that a bit?
    >> >
    >> > I believe the core feature that is being requested to be added is the
    >> > ability to create a group of VMs which will be kept active as a group if
    >> at
    >> > all possible.  ACS would be responsible for making sure that the number
    >> of
    >> > VMs specified for the group are in running state and it would spin up new
    >> > VMs as needed in order to satisfy the group settings.  In general, it is
    >> > understood that any application running on this group would have to be
    >> > fault tolerant enough to be able to rediscover a new VM if one fails and
    >> is
    >> > replaced by a fresh copy.  Is that fair to say?  How is it expected that
    >> > this service discovery is done, just by VMs being present on the network?
    >> >
    >> > As for some of the other people's concerns in this thread.
    >> >
    >> > - Regarding Wido's remarks.  I understand that there is some added
    >> > complexity, but I don't feel like the scope of the addition is
    >> > unrealistic.  I think the LXC integration was a lot farther out of the
    >> > scope of what ACS does then this is.  This does not change the "things"
    >> > which ACS orchestrates, it just adds the concept of a grouping of things
    >> > which ACS already manages.  I think this is the right approach since it
    >> is
    >> > not trying to be a container orchestrator.  We will never compete with
    >> K8S,
    >> > for example, and we should not try, but K8S is here and the market wants
    >> > it.  I do think we should be keeping our head up about that fact because
    >> > being able to provide a the underlay for K8S is very valuable in the
    >> > current marketplace.  I see this functionality as a way to enable K8S
    >> > adoption on top of ACS without changing our core values.
    >> >
    >> > - Regarding Erik's remarks.  The container space is moving fast, but so
    >> is
    >> > the industry.  If we want to remain relevant, we need to be able to
    >> adapt a
    >> > bit.  I don't think this is a big shift in what we do, but it is one that
    >> > enables people to be able to start running with something like K8S on top
    >> > of their existing ACS.  This is something we are interested in doing and
    >> so
    >> > are our customers.  If we can have a thin layer in ACS which helps enable
    >> > the use of K8S (or other container orchestrators) by orchestrating
    >> > infrastructure, as we already do, and making it easier to adopt a
    >> container
    >> > orchestrator running on top of ACS, I think that gives us a nice foothold
    >> > in the market.  I don't really feel it is fair to compare containers to
    >> > IPv6.  IPv6 has been out forever and it has taken almost a decade to get
    >> > anyone to adopt it.  Containers have really only been here for like 2
    >> years
    >> > and they are changing the market landscape in a very real way.
    >> >
    >> > Kind of on topic and kind of off topic.  I think understanding our
    >> approach
    >> > to containers is going to be important for the ACS community as a whole.
    >> > If we don't offer that market anything, then we will not be considered
    >> and
    >> > we will lose market share we can't afford to lose.  If we try to hitch
    >> our
    >> > horse to that cart too much, we will not be able to be agile enough and
    >> > will fail.  I feel like the right approach is for us to know that it is
    >> > thriving market and continue to do what we do, but to extend an olive
    >> > branch to that market.  I think this sort of implementation is the right
    >> > approach because we are not trying to do too much.  We are simply giving
    >> a
    >> > foundation on which the next big thing in the container orchestration
    >> world
    >> > can adopt without us having to compete directly in that space.  I think
    >> we
    >> > have to focus on what we do best, but at the same time, think about what
    >> we
    >> > can do to enable that huge market of users to adopt ACS as their
    >> > foundation.  The ability to offer VMs and containers in the same data
    >> plane
    >> > is something we have the ability to do, especially with this approach,
    >> and
    >> > is something that most other softwares can not do.  The adoption of
    >> > containers by bigger organizations will be only part of their workload,
    >> > they will still be running VMs for the foreseeable future. Being able to
    >> > appeal to that market is going to be important for us.
    >> >
    >> > Hopefully I don't have too many strong opinions here, but I do think we
    >> > need to be thinking about how we move forward in a world which is
    >> adopting
    >> > containers in a very real way.
    >> >
    >> Understood. I just want to prevent that we add more features to CloudStack
    >> which are poorly maintained. Not judging Murali here at all, but I'd rather
    >> see CloudStack loose code then have it added.
    >> Thinking about LXC, would like to see that removed together with various
    >> other network plugins which I think are rarely used.
    >> Now, the idea of Murali was misunderstood by me. I think it would be worth
    >> more if we would improve our cloud-init support and integration in various
    >> tools which makes it much easier to deploy VMs running containers ON
    >> CloudStack.
    >> Not so much changing CloudStack code, but rather tooling around it.
    >> If we have CloudStack talking to Kubernetes we suddenly have to maintain
    >> that API integration. Who's going to do that. Realistically.
    >> That's my main worry in this regard.
    >> We have so much more work to do in ACS in total that I don't know if this
    >> is the realistic route. I talk to many people who are not looking at
    >> containers and are still working with VMs.
    >> There is not a single truth which is true, it really depends on who you
    >> ask.
    >> Wido
    >> > Cheers,
    >> >
    >> > Will
    >> >
    >> > *Will STEVENS*
    >> > Lead Developer
    >> >
    >> > <>
    >> >
    >> > On Fri, Jan 27, 2017 at 5:38 AM, Erik Weber <>
    >> >
    >> > > On Fri, Jan 27, 2017 at 7:20 AM, Murali Reddy <
    >> >
    >> > > wrote:
    >> > > > All,
    >> > > >
    >> > > > I would like propose native functionality into CloudStack to provide
    >> a
    >> > > container service through which users out-of-the box can use to launch
    >> > > container based application. Idea is to support ability to orchestrate
    >> the
    >> > > resources and automate aspects of setting up container orchestrator
    >> through
    >> > > CloudStack. Public IAAS service providers AWS with its ECS [1] and
    >> google
    >> > > with GKE [2] already provides ability container applications.
    >> Competitive
    >> > > cloud orchestration platforms already have native support for container
    >> > > service. Users of CloudStack both as public cloud providers and users
    >> with
    >> > > private clouds will benefit with such functionality.
    >> > > >
    >> > > > While container orchestrator of user choice can be provisioned
    >> top of
    >> > > CloudStack (with out CloudStack being involved) with tools like
    >> > > TerraForm[3], Ansible[4] etc, advantage of having native orchestration
    >> is
    >> > > giving user a nice cohesive integration. This proposal would like add
    >> > > notion of first class CloudStack entity called container cluster which
    >> can
    >> > > be used to provision resources, scale up, scale down, start and stop
    >> the
    >> > > cluster of VM’s on which containerised applications can be run. For
    >> actual
    >> > > container orchestration we will still need container orchestrator like
    >> > > docker swarm, marathon, kubernetes, but CloudStack container service
    >> can
    >> > > automate setting up of control place automatically.
    >> > > >
    >> > >
    >> > > To be honest I'm torn on this one.
    >> > >
    >> > > Containers are a rapid changing thing, and while docker swam,
    >> > > kubernetes, rancher or whatnot is popular today, they might not be
    >> > > tomorrow.
    >> > > They might use CoreOS today, but might not tomorrow.
    >> > >
    >> > > We have a rather poor track record of staying up to date with new
    >> > > features/versions, and adding a feature that is so rapidly changing
    >> > > is, I fear, going to be hard to maintain.
    >> > > Want an example, look at xenserver. It is one of the most used
    >> > > hypervisors we support, yet it took 6 months or so for us to support
    >> > > the latest release.
    >> > > Or IPv6...
    >> > >
    >> > > I don't mean to bash at maintainers/implementers of those features,
    >> > > appreciate all the work being done in every aspect, but I believe we
    >> > > should be realistic and realize that we have issues with keeping stuff
    >> > > up to date.
    >> > >
    >> > > I'd say focus on making sure other tools can do their job well against
    >> > > CloudStack (kops, rancher, ++), but that does not mean I will -1 the
    >> > > idea if anyone really wants to go through with it.
    >> > >
    >> > > --
    >> > > Erik
    >> > >
    53 Chandos Place, Covent Garden, London  WC2N 4HSUK

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