The instructions in the varnish site are
isn't rpm --nosignature -i https://repo.varnish-cache.org/redhat/varnish-4.1.el6.rpm and yum install varnish doing the same thing? I finally installed varnish but I don't have a clear idea of what I did.Also the file varnish.params is missing (/etc/varnish/varnish.params).Why is that?I can see version with varnish -V command (varnishd (varnish-4.1.4 revision 4529ff7)
I found that "yum install https://repo.varnish-cache.org/redhat/varnish-4.1.el6.rpm" worked fine for me, rpm -i does install an RPM but yum will often complain that it's been installed outside yum which the above resolves.
Re the varnish.params file check /etc/sysconfig/varnish