[IGNITE-5850] Introduce an API for baseline topology for persistence-enabled clusters

• Type: New Feature
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.1
• Fix Version/s: 2.4
• Component/s: persistence
• Labels: IEP-4 Phase-1
• Assignee: Sergey Chugunov
• Reporter: Alexey Goncharuk
• Created: 27/Jul/17 09:03
• Updated: 17/Jan/18 11:05
• Resolved: 17/Jan/18 11:05

Description

Since the persistence was introduced, we require that cluster be started in an inactive mode and activation happens only manually.

We need to add a concept of baseline topology which is fixed on the first cluster activation and may be changed later by a user. We need to develop a consistent API facade for this purpose.

I suggest to make the following changes:

public interface BaselineNode {
    public Object consistentId();
    public <T> T attribute(String name);
    public Map<String, Object> attributes();
}

public interface IgniteCluster {
    // .....
    @Nullable public Collection<BaselineNode> currentBaselineTopology();
    public void setBaselineTopology(Collection<BaselineNode> baselineTop);
    public void setBaselineTopology(long topVer);
    // ....
}

public interface ClusterNode extends BaselineNode {
    // ....
}

This is a minimal yet sufficient API change allowing full-fledged baseline topology management both from API and from CLI or UI utilities.

The topology change would look like so:

IgniteCluster cluster = ignite.cluster();

Collection<BaselineNode> curTop = cluster.baselineTopology();
for (ClusterNode node : cluster.topology(cluster.currentTopologyVersion())) {
    if (shouldAdd(node))
        curTop.add(node);
}

cluster.setBaselineTopology(curTop);