The master-is-stable indicator will retrieve useful information
regarding the discovery. This will be useful even if the local
cluster state is not recovered.

We currently do not evaluate the instance-has-master indicator
if the cluster state is not recovered, but we should remove this
constraint once master-is-stable is merged
server/src/main/java/org/elasticsearch/node/Node.java
+ "in plugin ["
                            + entry.getKey()
                            + "], already added in plugin ["
                            + oldPlugin
                            + "]"
                    );
                }
            }
            builder.put(settings);
        }
        return builder.put(originalSettings).build();
    }
    /**
     * Creates a new {@link CircuitBreakerService} based on the settings provided.
     *
     * @see #BREAKER_TYPE_KEY
     */
    private static CircuitBreakerService createCircuitBreakerService(
        Settings settings,
        List<BreakerSettings> breakerSettings,
        ClusterSettings clusterSettings
    ) {
        String type = BREAKER_TYPE_KEY.get(settings);
        if (type.equals("hierarchy")) {
            return new HierarchyCircuitBreakerService(settings, breakerSettings, clusterSettings);
        } else if (type.equals("none")) {
            return new NoneCircuitBreakerService();
        } else {
            throw new IllegalArgumentException("Unknown circuit breaker type [" + type + "]");
        }