Amazon EC2 how to install ixgbevf on a Centos 7 instance?

Question

I'm trying to install the ixgbevf on a Amazon EC2 CentOS7 instance. The steps looks good, but everytime when I run the instance in a Enhanced Networking enabled type, such as M4.xlarge, the network seems fail(I can not connect to the instance after startup).

Here's what I did:

wget http://elrepo.org/linux/elrepo/el7/x86_64/RPMS/kmod-ixgbevf-2.16.1-1.el7.elrepo.x86_64.rpm
rpm -ivh kmod-ixgbevf-2.16.1-1.el7.elrepo.x86_64.rpm
cp -p /boot/initramfs-$(uname -r).img /boot/initramfs-$(uname -r).img.bak
dracut -f

Then shutdown the instance, and set the sriov

ec2-modify-instance-attribute instance_id --sriov simple

That all. Whenever the type(such as T2.micro) doesn't support Enhanced Networking, the instance works fine. But if I change the type to Enhanced Networking enabled(such as M4.xlarge), the instance simply can't be accessed. Anyone have any idea about this? Did I miss something?

Answer 1

The answer lies buried into this section of the original documentation:

http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/enhanced-networking.html#enhanced-networking-linux

In a nutshell, CentOS 7 already ships with the ixgbevf module, although not with the latest version, but this is hardly a problem. What was causing my instance to be unreachable after a reboot were the "predictable network interfaces", enabled by default.

To disable them, simply visit that link, jump straight to step number 6 and type:

$ rpm -qa | grep -e '^systemd-[0-9]\+\|^udev-[0-9]\+'
$ sudo sed -i '/^GRUB\_CMDLINE\_LINUX/s/\"$/\ net\.ifnames\=0\"/' /etc/default/grub
$ sudo grub2-mkconfig -o /boot/grub2/grub.cfg

After that:

1. Stop the instance
2. Enable the Enhanced Networking via the aws CLI
3. Restart it

You should now be able to log in!