Dmitriy,
It was my misunderstanding, I believe that setter is not enough and we need
a full-fledged entity.
We should also be able to check if BLTs are compatible. Interface looks
like this and use case for this functionality is described below.
interface BaselineTopology {
Collection<ClusterNode> nodes();
boolean isCompatibleWith(BaselineTopology blt);
}
Let's consider the following scenario:
1. We have a grid with N nodes: it is up, active and has data in it. ->
BLT #1 created.
2. We shutdown the grid. Then divide it into two parts: Part1_grid and
Part2_grid.
3. We start and activate Part1_grid . Topology has changed -> BLT#2
created.
After that we shutdown that Part1_grid.
4. We start and activate Part2_grid. Topology also has changed -> BLT#3
created.
5. Then we start Part1_grid and it's nodes try to join Part2_grid.
If join is successful we have an undefined state of the resulting grid:
values for the same key may (and will) differ between grid parts.
So to prevent this we should keep nodes with BLT#2 from joining the grid
with BLT#3. And we should fail nodes with an error message.
Thanks,
Sergey.
On Wed, Aug 23, 2017 at 5:47 AM, Dmitriy Setrakyan <[email protected]>
wrote:
> Sergey, I am still confused. What is the BaselineTopology interface in your
> example? I thought that you agreed with me that we simply need a setter for
> activation nodes, no?
>
> D.
>
> On Tue, Aug 22, 2017 at 4:47 AM, Sergey Chugunov <
> [email protected]>
> wrote:
>
> > Dmitriy,
> >
> > As I understand you use the term "minimalActivationNodes" as a synonym
> for
> > BaselineTopology concept.
> > In that case I agree with you that we can replace both "establish*"
> methods
> > with a simple setter method (see below in summary).
> >
> > Summing up the whole discussion I see the functionality as following:
> >
> > New concept BaselineTopology is introduced. The main features it enables
> > are:
> >
> > 1. automatic activation of cluster;
> >
> > 2. easy management of cluster topology changes (planned nodes
> > maintenance, adding new nodes etc);
> >
> > 3. eliminating of rebalancing traffic on short-term node failures.
> >
> >
> > Use cases to create BLT:
> >
> > 1. user starts up new cluster of desired number of nodes and activates
> > it using existing API. BLT is created with all nodes presented in the
> > cluster at the moment of activation, no API is needed;
> >
> > 2. user prepares BLT using web-console or visor CMD tools and sets it
> to
> > the cluster. New API setter is needed:
> > Ignite.activation().setBaselineTopology(BaselineTopology blt);
> >
> > 3. user provides via static configuration a list of nodes that are
> > expected to be in the cluster.
> > User starts nodes one by one; when all preconfigured nodes are started
> > cluster is activated and BLT is created.
> > As list of nodes may be huge it is provided via separate file to avoid
> > flooding main configuration.
> >
> >
> > Igniters, does this description match with your understanding of
> > functionality? If it does I'll create a set of tickets and start working
> on
> > implementation.
> >
> > Thanks,
> > Sergey.
> >
> >
> > On Sat, Aug 19, 2017 at 5:41 PM, Dmitriy Setrakyan <
> [email protected]>
> > wrote:
> >
> > > I still do not see why anyone would explicitly call these 2 methods:
> > >
> > > *Ignite::activation::establishBaselineTopology();*
> > > *Ignite::activation::establishBaselineTopology(BaselineTopology
> > bltTop);*
> > >
> > > For example, if a web console, or some other admin process, want to
> > > automatically set currently started nodes as the baseline topology,
> > > shouldn't they just call a setter for minimalActivationNodes?
> > >
> > > D.
> > >
> > > On Fri, Aug 18, 2017 at 10:18 AM, Alexey Dmitriev <
> > [email protected]>
> > > wrote:
> > >
> > > > API is proposed in the head of the thread by Sergey, as I understood:
> > > > ______________________________________________________
> > > >
> > > > API for BaselineTopology manipulation may look like this:
> > > >
> > > > *Ignite::activation::establishBaselineTopology();*
> > > > *Ignite::activation::establishBaselineTopology(BaselineTopology
> > > bltTop);*
> > > >
> > > > Both methods will establish BT and activate cluster once it is
> > > established.
> > > >
> > > > The first one allows user to establish BT using current topology. If
> > any
> > > > changes happen to the topology during establishing process, user will
> > be
> > > > notified and allowed to proceed or abort the procedure.
> > > >
> > > > Second method allows to use some monitoring'n'management tools like
> > > > WebConsole where user can prepare a list of nodes, using them create
> a
> > BT
> > > > and send to the cluster a command to finally establish it.
> > > >
> > > > From high level BaselineTopology entity contains only collection of
> > > nodes:
> > > >
> > > > *BaselineTopology {*
> > > > * Collection<TopologyNode> nodes;*
> > > > *}*
> > > >
> > > > *TopologyNode* here contains information about node - its consistent
> id
> > > and
> > > > set of user attributes used to calculate affinity function.
> > > > ____________________________________________
> > > >
> > > >
> > > >
> > > > --
> > > > View this message in context: http://apache-ignite-
> > > > developers.2346864.n4.nabble.com/Cluster-auto-activation-
> > > > design-proposal-tp20295p21066.html
> > > > Sent from the Apache Ignite Developers mailing list archive at
> > > Nabble.com.
> > > >
> > >
> >
>
