Debian Linode not working after reboot

We've seen issues with older versions of Debian, specifically any version prior to Debian 8, where Linodes either have problems booting or have no network connectivity. This issue exists in two parts: there's a problem with udev not starting properly, and that the network configuration is missing.

The Investigation

You can always access your Linode by using our out-of-band Lish console if you ever find yourself unable to connect to your Linode.

Once you have access to your Linode, you can confirm these issues by investigating the output of the following commands:

sudo cat /var/log/boot.log | grep -i udev
ip addr show | grep inet

Note: Your system may have multiple boot logs in /var/log. You can list them all by running ls /var/log | grep boot.

In the output of /var/log/boot.log, the following error can be found:

udev requires hotplug support, not started ...failed!

And, in the output of ip addr show, your IP address won't be found in any inet lines.

The Fix

Both of these can be addressed with one reboot of your Linode. First, enable "Auto-configure Networking" in your Linode's Configuration Profile. This will automatically configure your Linode's network interfaces upon boot. Also, change your Linode's kernel to Grub2. This will utilize the distribution-supplied kernel instead of a Linode kernel.

Next Steps

If you're still experiencing some issues, first investigate the status of networking on your Linode:

sudo service network-manager status

You can reboot your network interface with the following:

sudo ifdown -a && sudo ifup -a

Connectivity could also be related to a firewall configuration. You can list all of the firewall rules by using:

`sudo iptables -S'

You can check out this guide on reading iptables if you want more information on how to interpret the output. Also, check out this great community site post that goes more in detail about checking services and other troubleshooting steps.

If you have any questions, don't hesitate to reach out to our Support Team. We're always happy to help.

Brandon L.
Linode Support Team

When I boot with GRUB2, I just see grub>. What now?

When selecting GRUB2 as the kernel in your Linode's Configuration Profile, the boot process looks to the Linode's operating system to provide the kernel. Images deployed before February 2017 don't have GRUB2 installed, so to fix this, the kernel will need to be installed.

First, change your Linode's kernel to an older version, reboot your Linode, and follow these instructions to install GRUB on your system. Once that's done, you can select GRUB2 as a kernel and boot properly.

Tips and Tricks

• Do not stay booted with an old kernel for long, as these kernels do not have the most up-to-date security patches. Only boot in an old kernel as long as necessary to install GRUB2 on your Linode.
• If you can't reboot while stuck on the grub> command line, the halt command will turn off your system, and Lassie, our Shutdown Watchdog will reboot your Linode.

We are in the process of implementing mitigation steps in response to Intel's MDS CPU Vulnerability. As our mitigation efforts involve host reboots, we're noticing that some customers running versions older than Debian 9 are experiencing the bug stated in this post.

Accordingly, we wanted to bring this post to the forefront as an added resource to help the Community. Please, feel free to add any relevant questions or comments below.

Is upgrading to debian 9 a solution? I understand this carries risk that services will not work after an upgrade.

(I am cloning my linode instance to see if an upgrade will work)

We can't be 100% positive that upgrading to Debian 9 will resolve the specific error you are seeing. However, you are on the right track! We always recommend making a new Linode when upgrading your distribution. This will allow you to check and see if your old files can be properly configured for the newer services. We suggest creating a fresh Linode from our Debian 9 image. Then, you can copy over the files from your old Linode using Rescue Mode.