When running yum or curl commands on a CentOS 6 XenServer Virtual Machine you might be getting an “Illegal instruction (core dumped)” error returned in your console output.
root@server [~]# yum update Loaded plugins: fastestmirror, rhnplugin Setting up Update Process Loading mirror speeds from cached hostfile * base: mirror.us.leaseweb.net * cloudlinux-x86_64-server-6: xmlrpc.cln.cloudlinux.com * extras: mirror.teklinks.com * updates: mirror.teklinks.com Illegal instruction (core dumped)
The issue is due to Python attempting to execute a CPU opcode advertised as available by the server’s host node virtualization system (XEN), but is not actually supported by the host node’s hardware.
Workaround
Issue can be resolved by running export NSS_DISABLE_HW_AES=1, and then running yum update, to update to newer packages, after which issue should not be happening anymore.
root@server [~]# export NSS_DISABLE_HW_AES=1 root@server [~]# yum -y update