public void add(AllocatedHosts allocatedHosts, Version version) {
        for (var newHost : allocatedHosts.getHosts()) {
            var presentHost = hosts.get(newHost.hostname());
            if (presentHost == null || version.isAfter(presentHost.getSecond()))
                hosts.put(newHost.hostname(), new Pair<>(newHost, version));
        }
    }
Adds the nodes allocated for a particular model version.
configserver/src/main/java/com/yahoo/vespa/config/server/modelfactory/AllocatedHostsFromAllModels.java