With the release Cloudera Enterprise 6.1, we are limiting Cloudera Express customers using both CM6 and CDH6 to a maximum of 100 deployable nodes across all of their environments.   Each Cloudera Manager (CM) instance will monitor the total nodes of all CDH6 clusters it manages.   We believe customers will be better served and better protected by deploying a supported version of Cloudera Enterprise for these large (100+ node) clusters.   At the same time, it’s important for Cloudera to continue to provide potential customers the ability to trial our platform at a meaningful scale.    The following specific points are worth noting as it relates to this change.      Cloudera Manager will not allow you to add hosts to a CDH 6.x cluster if the total number of Express managed hosts across all CDH 6.x clusters will exceed 100.   Cloudera Manager will not allow you to upgrade any cluster to CDH 6.x if the total number of Express managed CDH6.x cluster hosts will exceed 100. If an upgrade from Cloudera Manager 6.0 to 6.1 fails due to this limitation, you must downgrade Cloudera Manager to version 6.0, remove some Express managed hosts so that the number of Express managed hosts is less than 100, then retry the upgrade.   If you downgrade from Cloudera Enterprise to Cloudera Express and the number of Express managed hosts exceeds 100, Cloudera Manager will disable all cluster management commands except for commands used to stop a cluster. You will not be able to restart or otherwise use clusters while the total number of Express managed hosts exceeds 100. Use the Cloudera Manager Admin Console to remove some hosts so that the number of hosts is less than 100. Release notes for this feature, and others can be found here ... View more