This happened to me just today. I stopped my droplet, made a snapshot, then tried to bring it back up again. I could not SSH in. The console showed me that eth0 was not up. When I typed in the command:
it told me "failed to bring up eth0." I grepped around in the
dmesg output, and found this line of interest:
[ 0.889859] virtio_net virtio0 ens3: renamed from eth0
/etc/network/interfaces and changed
ens3 and viola!,
ifup ens3 worked.
So it looks like the more modern kernels are changing the main interface names.
I had a similar issue. I tried the instructions above but it didn't work for me. There were too many incompatibilities between the kernel was using and the kernels installed on my droplet.
In the end, DO Support fixed this for me. They manually installed the kernel.
It took DO Support a long time (i.e., more than 3 hours) to reply to my ticket, however they were able to fix it quickly once they started working on it. It should be helpful for others to know that DO Support is able to fix this manually.
I had to follow this to get my Kernels matching and eth0 back up, running Centos 6.7 Final
Use the command uname to print system information in Linux.uname -r
The –r option will print the kernel release.uname -s
-s prints the kernel name.uname -n
Print the node name or hostname.uname -p
Print the processor type, the i686 signifies a 32 bit processor. If it was a 64 processor it would display x86_64 instead.uname -a
Linux myserver.wiivil.com 2.6.18-194.32.1.el5 #1 SMP Wed Jan 5 17:53:09 EST 2011 i686 i686 i386 GNU/Linux
Print all the information except omit –o and –I if unknown.cat /etc/redhat-release
CentOS release 5.5 (Final)
This will give you the version of RedHat Linux you are running.cat /proc/version
Linux version 2.6.18-194.32.1.el5 (firstname.lastname@example.org) (gcc version 4.1.2 20080704 (Red Hat 4.1.2-48)) #1 SMP Wed Jan 5 17:53:09 EST 2011
This will give you who and when compiled the kernel and what gcc compiler was used to build it.rpm -q kernel
This will list all the kernels installed on your system.
If the new kernel causes issues then you have the option to revert to the older version. You may have to boot the system with the boot media and re-configure the boot loader. The AMD and Intel architecture uses GRUB boot loader. You will need to make changes to /boot/grub/grub.conf to activate a different default kernel.
Please not that when the kernel is installed using rpm, the kernel package creates an entry in the boot loader configuration file for the new kernel. But the rpm does not configure the new kernel to boot as the default kernel, this must be done manually.
Below is an example of /boot/grub/grub.conf. The directive default=0 means that default boot kernel is 0, which is the first stanza that starts with the title entry.
So in this case title CentOS (2.6.18-194.32.1.el5) is stanza 0. When the system boots this kernel will be used. The title contains the kernel version number 2.6.18-194.32.1.el5, which must match with the version number in the kernel /vmlinuz-2.6.18-194.32.1.el5 (this is the line below root.
If a separate /boot/ partition was created, the paths to the kernel and the initramfs image are relative to /boot/. This is the case in Example 23.2, “/boot/grub/grub.conf”, above. Therefore the initrd /initramfs-2.6.32-22.el6.x8664.img line in the first kernel stanza means that the initramfs image is actually located at /boot/initramfs-2.6.32-22.el6.x8664.img when the root file system is mounted, and likewise for the kernel path (for example: kernel /vmlinuz-2.6.32-22.el6.x86_64) in each stanza of grub.conf
To clarify further, stanza 0 starts with title CentOS (2.6.18-194.32.1.el5)
Stanza 1 starts with title CentOS (2.6.18-194.26.1.el5)
Stanza 2 is title CentOS (2.6.18-194.11.3.el5)
To change the default boot kernel to stanza 2 simply change the line default=0 to default=2.grub.conf generated by anaconda Note that you do not have to rerun grub after making changes to this file NOTICE: You have a /boot partition. This means that all kernel and initrd paths are relative to /boot/, eg. root (hd0,0) kernel /vmlinuz-version ro root=/dev/VolGroup00/LogVol00 initrd /initrd-version.img boot=/dev/sda
title CentOS (2.6.18-194.32.1.el5)
kernel /vmlinuz-2.6.18-194.32.1.el5 ro root=/dev/VolGroup00/LogVol00 rhgb quiet
title CentOS (2.6.18-194.26.1.el5)
kernel /vmlinuz-2.6.18-194.26.1.el5 ro root=/dev/VolGroup00/LogVol00 rhgb quiet
title CentOS (2.6.18-194.11.3.el5)
kernel /vmlinuz-2.6.18-194.11.3.el5 ro root=/dev/VolGroup00/LogVol00 rhgb quiet