There was a building problem confused me for several days..
the info as below,
WARNING: installing package python-xml-2.7.1-2.23.armv7l needs 900KB on the / filesystem
WARNING: installing package tar-1:1.17-5.10.armv7l needs 2MB on the / filesystem
.........
ERROR: Could not run transaction.
then, the building ends..
does someone else ever meet this problem or the root reason..
thanks.