Getting error “/usr/bin/rebuild-security-providers is needed” while using yum to install tomcat ?

run the below command to fix it

rpm -Uvh http://plone.lucidsolutions.co.nz/linux/centos/images/jpackage-utils-compat-el5-0.0.1-1.noarch.rpm

Now continue with your installation

yum: TypeError: rpmdb open failed

Run the below command to resolve this issue.

rm /dev/urandom
mknod -m 644 /dev/urandom c 1 9

yum should start working correctly now.