Expected behaviour
yum install -y ccache works
Actual behaviour
See https://github.com/matthew-brett/multibuild/pull/212
Steps to reproduce
Reproduces consistently with skvark/manylinux1_i686.
See also https://travis-ci.community/t/not-using-downloaded-repomd-xml-because-it-is-older-than-what-we-have-on-yum-install/1001 .
I suspect that either Travis' system or the system where you generated the Docker image does not account for a leap second and produces a datetime that's one second off from the same UNIX timestamp, or vice versa.
In either of these cases, a workaround would be to do the same thing as the stock manylinux1 image does -- not store yum metadata at all -- i.e. add yum clean all to dockerfiles.
Or maybe it was but a transient problem and editing skvark/manylinux1_i686 (yum clean metadata && yum install ccache (say "no" to prompt)) will fix the file's timestamp. You can check the timestamps with find /var -name repomd\* -exec ls -ld --time-style=full-iso {} \;