title: elasticache how to duplicate the configuration group default.redis3.2 in order to change one parameter without writing the 103 unchanged keys
body: <p>I use AWS elasticache  using this parameter group <code>default.redis3.2</code>,  as you can see in this cloudformation sample : </p>
  
  <pre><code>"itophubElastiCacheReplicationGroup" : {
    "Type" : "AWS::ElastiCache::ReplicationGroup",
    "Properties" : {
      "ReplicationGroupDescription" : "Hub WebServer redis cache cluster",
      "AutomaticFailoverEnabled" : "false",
      "AutoMinorVersionUpgrade" : "true",
      "CacheNodeType" : "cache.t2.small",
      "CacheParameterGroupName" : "default.redis3.2",
      "CacheSubnetGroupName" :  { "Ref": "cachesubnethubprivatecachesubnetgroup" },
      "Engine" : "redis",
      "EngineVersion" : "3.2.4",
      "NumCacheClusters" : { "Ref" : "ElasticacheRedisNumCacheClusters" },
      "PreferredMaintenanceWindow" : "sun:04:00-sun:05:00",
      "SecurityGroupIds" : [ { "Fn::GetAtt": ["sgpHubCacheSG",  "GroupId"] } ]
    }
  },
  </code></pre>
  
  <p>what I want to achieve is to have more than the default 16 databases, to do so, I have to change the key <code>databases</code> in the parameter group. Since <code>default.redis3.2</code> is read only, I have to create my own, I want to have every parameters but  <code>databases</code> identical to <code>default.redis3.2</code>. 
  It represent 104 parameters, I don't want to copy past each one of them by hand, so : </p>
  
  <p>I'd like to know if there is a way to copy/inherit the parameters of  <code>default.redis3.2</code> created by aws ? </p>
  
  <p>(If possible using cloudformation)</p>