Azure Linux Support Team

Support for Linux on Azure

Linux Recovery: Fixing non-boot issues related to Kernel problems using chroot

In a previous article, it was described how to manually fix kernel related issues that could cause a Linux VM to not boot properly. There is also an option where you can use steps to use CHROOT and then use tools to automatically fix these same issues without the need to manually edit files. Assuming… Read more

Linux Recovery: Manually fixing non-boot issues related to Kernel problems

You have a Linux VM that had kernel changes applied recently such as a kernel upgrade and is no longer starting up properly due to kernel errors during the boot process. Kernel messages will vary; some examples could be: no root device found, kernel timeouts, null pointer, kernel panic errors. Most of the time the recovery steps… Read more

Linux Recovery: SSH daemon is not starting up properly

You have noticed that you lost SSH connectivity to a Linux VM and after examining the boot diagnostics you see messages related to errors in the SSHD configuration. The error around invalid configuration might be simply: Starting sshd: [FAILED] There were a few instances seen in SUSE and Red Hat where errors are seen due… Read more

Linux Recovery: Cannot SSH to Linux VM due to file system errors (fsck, inodes)

When a Linux VM requires fsck to repair possible file system issues, manual intervention will be required. Below you can see four examples on how to identify file system issues by looking at the boot diagnostics on a given VM under: Virtual Machines > VMNAME >  All settings > Boot diagnostics Example (1) Checking all file systems. [/sbin/fsck.ext4… Read more

Linux Recovery: Using CHROOT steps to recover VMs that are not accessible

You are facing an issue where you might need to basically delete a virtual machine (VM) , keep its OSDisk and attach it to another Linux VM where you can then repair whatever is wrong on that old VM, however in some instances you would also be able to have network access and some way… Read more

Linux Recovery: Cannot SSH to Linux VM due to FSTAB errors.

There are a few cases where a VM might stop booting up properly if the syntax in fstab is not correct and also if a data disk is missing (not attached to the VM) as well as other reasons. Traditionally in Linux you can mount a scsi device by using the following format in fstab:… Read more