We have an Azure Linux Virtual Machine that has suddenly become inaccessible.

Hello @Vipul Om,

Thank you for reaching out Q&A forum.

Step 1: Check the VM Power State

In the Azure Portal → Virtual Machines → your VM → Overview, confirm the Status field.

Status Meaning

Running OS-level or network issue

Stopped (deallocated) VM was stopped — just start it

Failed Platform-level provisioning failure

Step 2: Open Boot Diagnostics (Serial Console)

Azure Portal → VM → Support + troubleshooting → Boot diagnostics → Serial log

This is the fastest way to determine the root cause:

What you see in the serial log Likely cause

Kernel panic - not syncing OS/kernel corruption — needs rescue VM

GRUB menu stuck Boot loader issue

Give root password for maintenance fstab mount failure

Started Session / login prompt OS booted fine → network/NSG issue

cloud-init errors VM agent / provisioning failure

Blank / no output Host-level issue or GPU/disk failure

Step 3:

Kernel Panic or filesystem errors → OS-level recovery needed

Detach the OS disk and attach it to a Rescue VM as a data disk

Run fsck, audit /etc/fstab, check /boot for missing initramfs

See the detailed recovery steps in my previous response above

VM appears booted but SSH/HTTP still times out → Network issue

Check these in order:

NSG rules — Does an inbound rule allow port 22 (SSH) or 80/443 from your source IP? (Not just "any")

Azure Firewall / UDR — Is there a route table sending traffic to a firewall that may be blocking it?

sshd service — Use Azure Run Command (if available) to check:

bash

systemctl status sshd

Host-based firewall — Check iptables or firewalld rules inside the VM via Run Command

VM was recently resized, updated, or a disk was attached → Configuration change issue

Review Azure Activity Log (Portal → VM → Activity log) for any recent changes

Check if a failed apt upgrade / yum update broke a kernel or removed Python 3

If this answers your query, do click Accept Answer and Up-Vote for the same. And, if you have any further query do let us know.

Hello,

The issue may come from a broken initramfs or python3 not installed (which can break initramfs)

You can try to access the VM via Serial Console (bypasses NSG and SSH timeouts) then apply these steps:

1. When VM is booting up, repeatedly press ESC or Shift to show up GRUB
2. Select Recovery Mode if available, if not, select Previous Kernel Version
3. Fix python3/initramfs installation :
   apt update apt install --reinstall python3 python3-minimal initramfs-tools
4. Update initramfs: update-initramfs -u -f reboot

If kernel panic still appears after trying to enter Recovery Mode/Previous Kernel in GRUB, the initramfs is fully broken. You should create a rescue VM since you made a snapshot of the disk.