private void noteNewMember(GemFireVM member) {
    InetAddress hostIpAddress = member.getHost();
    List members = (List) hostMembers.get(hostIpAddress);
    if (members == null) {
      members = new ArrayList();
      hostMembers.put(hostIpAddress, members);
    }
    members.add(member);

  }
Makes note of the newly-joined member
geode-core/src/main/java/org/apache/geode/admin/internal/GemFireHealthImpl.java