If you are a slow internet connection, Riak build would fail to download Solr from Amazon S3. As of Riak 2.0 rc1, the Solr download URL is http://s3.amazonaws.com/files.basho.com/solr/solr-4.7.0-yz-1.tgz.
Looking through the download script, it checks for a local cached copy in $TMP_DIR and also checks the env var $SOLR_PKG_DIR for the dir path in which Solr pkg can be found. For a slow internet connection like mine, I prefer downloading Solr pkg manually with wget.
Then build Riak using the following command:
SOLR_PKG_DIR=$HOME/src make rel
where $HOME/src is the dir into which I’ve downloaded the Solr pkg.
