Update to EL6 and the Pain of 10Gbps Networking in AWS

In a previous post, EL6 and the Pain of 10Gbps Networking in AWS, EL6 and the Pain of 10Gbps Networking in AWS, I discussed how to enable using third-party ixgbevf drivers to support 10Gbps networking in AWS-hostd RHEL 6 and CentOS 6 instances. Under further testing, it turns out that this is overkill. The native drivers may be used, instead, with minimal hassle.

It turns out that, in my quest to ensure that my CentOS and RHEL AMIs contained as many of the AWS utilities present in the Amazon Linux AMIs, that I included two RPMS - ec2-net and ec2-net-util - that were preventing use of the native drivers. Skipping these two RPMs (and possibly sacrificing ENI hot-plug capabilities) allows a much more low-effort support of 10Gpbs networking in AWS-hosted EL6 instances.

Absent those RPMS, 10Gbps support becomes a simple matter of:

1. Add add_drivers+="ixgbe ixgbevf" to the AMI's /etc/dracut.conf file
2. Use dracut to regenerate the AMI's initramfs.
3. Ensure that there are no persistent network device mapping entries in /etc/udev/rules.d.
4. Ensure that there are no ixgbe or ixgbevf config directives in /etc/modprobe.d/* files.
5. Enable sr-iov support in the instance-to-be-registered
6. Register the AMI 

The resulting AMIs (and instances spawned from them) should support 10Gbps networking and be compatible with M4-generation instance-types.