Types of container execution 

There are two types of container, as follows:

• Guaranteed containers: These containers correspond to the existing YARN containers. They are assigned by the capacity scheduler. They are transmitted to a node if and only if there are resources available to begin their execution immediately. 
• Opportunistic containers: Unlike guaranteed containers, in this case we cannot guarantee that there will be resources available to begin their execution once they are dispatched to a node. On the contrary, they will be queued at the NodeManager itself until resources become available.