when no block device mapping is specified, the `grep -v` in first line of code will return 1, but that doesn't mean the script fails.
when no block device mapping is specified, the `grep -v` in first line of code will return 1, but that doesn't mean the script fails.

madanadit/alluxio,maboelhassan/alluxio,PasaLab/tachyon,jsimsa/alluxio,bf8086/alluxio,ChangerYoung/alluxio,calvinjia/tachyon,Alluxio/alluxio,ChangerYoung/alluxio,EvilMcJerkface/alluxio,WilliamZapata/alluxio,apc999/alluxio,maobaolong/alluxio,Alluxio/alluxio,bf8086/alluxio,riversand963/alluxio,apc999/alluxio,ChangerYoung/alluxio,Alluxio/alluxio,maobaolong/alluxio,Reidddddd/mo-alluxio,maobaolong/alluxio,EvilMcJerkface/alluxio,jswudi/alluxio,bf8086/alluxio,PasaLab/tachyon,apc999/alluxio,wwjiang007/alluxio,ChangerYoung/alluxio,riversand963/alluxio,ShailShah/alluxio,PasaLab/tachyon,ShailShah/alluxio,Reidddddd/alluxio,uronce-cc/alluxio,Reidddddd/alluxio,yuluo-ding/alluxio,bf8086/alluxio,uronce-cc/alluxio,madanadit/alluxio,yuluo-ding/alluxio,Reidddddd/mo-alluxio,Alluxio/alluxio,maobaolong/alluxio,aaudiber/alluxio,EvilMcJerkface/alluxio,ShailShah/alluxio,bf8086/alluxio,Alluxio/alluxio,madanadit/alluxio,maobaolong/alluxio,apc999/alluxio,PasaLab/tachyon,jsimsa/alluxio,yuluo-ding/alluxio,calvinjia/tachyon,aaudiber/alluxio,jswudi/alluxio,jsimsa/alluxio,bf8086/alluxio,jsimsa/alluxio,Reidddddd/alluxio,riversand963/alluxio,WilliamZapata/alluxio,riversand963/alluxio,maboelhassan/alluxio,Reidddddd/alluxio,jsimsa/alluxio,maobaolong/alluxio,EvilMcJerkface/alluxio,wwjiang007/alluxio,uronce-cc/alluxio,ShailShah/alluxio,madanadit/alluxio,aaudiber/alluxio,Alluxio/alluxio,ShailShah/alluxio,maobaolong/alluxio,uronce-cc/alluxio,apc999/alluxio,maboelhassan/alluxio,wwjiang007/alluxio,wwjiang007/alluxio,calvinjia/tachyon,EvilMcJerkface/alluxio,maobaolong/alluxio,WilliamZapata/alluxio,Reidddddd/mo-alluxio,EvilMcJerkface/alluxio,EvilMcJerkface/alluxio,WilliamZapata/alluxio,wwjiang007/alluxio,jswudi/alluxio,jswudi/alluxio,calvinjia/tachyon,aaudiber/alluxio,aaudiber/alluxio,maboelhassan/alluxio,Reidddddd/alluxio,Alluxio/alluxio,ChangerYoung/alluxio,maboelhassan/alluxio,Reidddddd/alluxio,WilliamZapata/alluxio,Reidddddd/mo-alluxio,aaudiber/alluxio,maobaolong/alluxio,madanadit/alluxio,madanadit/alluxio,wwjiang007/alluxio,PasaLab/tachyon,uronce-cc/alluxio,jsimsa/alluxio,uronce-cc/alluxio,EvilMcJerkface/alluxio,maobaolong/alluxio,apc999/alluxio,yuluo-ding/alluxio,wwjiang007/alluxio,bf8086/alluxio,riversand963/alluxio,maboelhassan/alluxio,jswudi/alluxio,bf8086/alluxio,calvinjia/tachyon,yuluo-ding/alluxio,maboelhassan/alluxio,aaudiber/alluxio,Reidddddd/mo-alluxio,jswudi/alluxio,calvinjia/tachyon,PasaLab/tachyon,wwjiang007/alluxio,madanadit/alluxio,riversand963/alluxio,calvinjia/tachyon,WilliamZapata/alluxio,PasaLab/tachyon,Alluxio/alluxio,ShailShah/alluxio,yuluo-ding/alluxio,wwjiang007/alluxio,Reidddddd/mo-alluxio,apc999/alluxio,madanadit/alluxio,ChangerYoung/alluxio,Alluxio/alluxio,calvinjia/tachyon,Reidddddd/alluxio,wwjiang007/alluxio,Alluxio/alluxio