Tried:
plugin install license
plugin install graph
See errors:
root@vagrant-ubuntu-trusty-64:/usr/share/elasticsearch/bin# ./plugin install graph --verbose
-> Installing graph...
Trying https://download.elastic.co/elasticsearch/release/org/elasticsearch/plugin/graph/2.0.0/graph-2.0.0.zip ...
Failed: FileNotFoundException[https://download.elastic.co/elasticsearch/release/org/elasticsearch/plugin/graph/2.0.0/graph-2.0.0.zip]; nested: FileNotFoundException[https://download.elastic.co/elasticsearch/release/org/elasticsearch/plugin/graph/2.0.0/graph-2.0.0.zip];
ERROR: failed to download out of all possible locations..., use --verbose to get detailed information