private static bool IsHealthyReplica(ReplicaWrapper replica)
{
// TODO: Should we only consider replicas that Service Fabric reports as healthy (`replica.HealthState != HealthState.Error`)?
// That is precisely what Traefik does, see: https://github.com/containous/traefik-extra-service-fabric/blob/a5c54b8d5409be7aa21b06d55cf186ee4cc25a13/servicefabric.go#L219
// It seems misguided in our case, however, since we have an active health probing model
// that can determine endpoint health more reliably. In particular because Service Fabric "Error" states does not necessarily mean
// that the replica is unavailable, rather only that something in the cluster issued an "Error" report against it.
// Skipping the replica here because we *suspect* it might be unavailable could lead to snowball cascading failures.
return(replica.ReplicaStatus == ServiceReplicaStatus.Ready);
}
private static bool IsReplicaEligible(ReplicaWrapper replica, StatefulReplicaSelectionMode statefulReplicaSelectionMode)
{
if (replica.ServiceKind != ServiceKind.Stateful)
{
// Stateless service replicas are always eligible
return(true);
}
return(statefulReplicaSelectionMode switch
{
StatefulReplicaSelectionMode.Primary => replica.Role == ReplicaRole.Primary,
StatefulReplicaSelectionMode.ActiveSecondary => replica.Role == ReplicaRole.ActiveSecondary,
_ => true,
});