The Nodepool instances lack pkg-config which used at least by Node / gyp. For graphoid repo that causes:
> canvas@1.3.10 install /home/jenkins/workspace/npm-node-4.2/node_modules/vega/node_modules/canvas > node-gyp rebuild ./util/has_lib.sh: line 30: pkg-config: command not found gyp: Call to './util/has_lib.sh freetype' returned exit status 0 while in binding.gyp. ...