public ServerContainer getContainer(int index) {
    return containers.get(index);
  }
Get the positions of the containers with the given container state

@param state A string representing the Cargo state a container is in. The possible states can
       be found in as static variables in the {@link State} class.
@return the positions of the containers with the given container state
geode-assembly/geode-assembly-test/src/main/java/org/apache/geode/session/tests/ContainerManager.java