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    VPS Fails to Boot

    Troubleshooting boot failures

    On This Page

    If your KVM VPS refuses to boot, and particularly if VNC refuses to load, make sure you have unmounted any ISOs/CDROMs from the SolusVM control panel and then try rebooting again.

    Quick Fix: Unmount ISOs

    The most common cause of boot failures is a mounted ISO that's preventing the VPS from booting from the hard disk.

    Steps to Unmount:

    1. Log into your SolusVM control panel
    2. Click the "Media" or "CDROMs" tab
    3. Look for any mounted ISOs
    4. Click "Unmount" next to any mounted media
    5. Go back to the main control panel
    6. Click "Reboot" to restart your VPS

    Why This Happens

    When an ISO is mounted, the VPS tries to boot from it instead of the hard disk. If the ISO doesn't contain a bootable system (like installation media after installation is complete), the VPS won't boot.

    Other Common Boot Issues

    Corrupted Bootloader

    If unmounting ISOs doesn't help, the bootloader (GRUB) may be corrupted:

    • Use VNC console to see boot error messages
    • Boot from a rescue ISO (SystemRescue or GParted)
    • Repair or reinstall GRUB

    Filesystem Corruption

    Unexpected shutdowns can cause filesystem corruption:

    • Boot from rescue media
    • Run filesystem check: fsck /dev/vda1
    • Follow prompts to repair errors

    Kernel Panic

    A kernel panic prevents the system from booting:

    • Check VNC console for panic messages
    • Try booting with a different kernel (if multiple kernels installed)
    • Boot to rescue mode to fix configuration
    • May require OS reinstallation if kernel is severely damaged

    Out of Disk Space

    A full disk can prevent booting:

    • Boot from rescue media
    • Mount your filesystem
    • Delete unnecessary files to free space
    • Check log files which can grow large

    Using VNC for Diagnosis

    VNC console access is essential for diagnosing boot problems:

    1. Access VNC through SolusVM control panel
    2. Reboot the VPS
    3. Watch the boot process
    4. Note any error messages or where it stops

    See our VNC Access guide for detailed instructions.

    Boot into Rescue Mode

    Using SystemRescue ISO

    Rescue mode allows you to fix problems without a full working system:

    1. Mount SystemRescue ISO in SolusVM
    2. Reboot VPS
    3. Access via VNC
    4. Mount your root filesystem: mount /dev/vda1 /mnt
    5. Chroot into system: chroot /mnt
    6. Perform repairs
    # Mount filesystem
mount /dev/vda1 /mnt

# Mount proc, sys, dev for chroot
mount --bind /proc /mnt/proc
mount --bind /sys /mnt/sys
mount --bind /dev /mnt/dev

# Chroot into system
chroot /mnt

# Now you can run commands as if booted normally

    Checking Boot Logs

    Boot logs contain valuable information about failures:

    # View system logs
journalctl -xb

# View kernel ring buffer
dmesg | less

# Check for filesystem errors
journalctl -u systemd-fsck*

    GRUB Rescue

    If you see a GRUB rescue prompt, the bootloader is damaged:

    # From GRUB rescue prompt
grub rescue> ls
grub rescue> set root=(hd0,1)
grub rescue> linux /boot/vmlinuz root=/dev/vda1
grub rescue> initrd /boot/initrd.img
grub rescue> boot

    After booting, reinstall GRUB:

    # Reinstall GRUB
grub-install /dev/vda
update-grub

    When to Reinstall

    Sometimes reinstalling is the fastest solution:

    • Severe corruption: Multiple system files damaged
    • Unknown changes: Suspicious modifications you can't undo
    • Time constraints: Faster than troubleshooting
    • Testing: Need a clean slate

    Backup Before Reinstalling

    Before reinstalling, try to backup your data using rescue media. Mount your disk, copy important files to another location, then reinstall.

    Preventing Boot Issues

    • Regular Backups: Can't be emphasized enough
    • Proper Shutdowns: Always shut down cleanly, don't force power off
    • Keep Systems Updated: Apply security and stability updates
    • Monitor Disk Space: Don't let root partition fill up
    • Test Changes: Test kernel and bootloader changes before rebooting
    • Unmount ISOs: Always unmount installation media after use

    Still Not Working?

    If your VPS still won't boot after trying these steps:

    1. Document the exact error messages from VNC
    2. Note what you've tried already
    3. Open a support ticket with this information
    4. Our team can investigate hardware issues or provide guided assistance

    Hardware vs Software Issues

    If you can boot from rescue media but not from your disk, it's likely a software issue you can fix. If rescue media also fails to boot, there may be a hardware problem - contact support.

    Boot issues can be complex. If you're stuck or unsure what to do, contact our support team. We can help diagnose the issue and guide you through the fix, or handle it for you if needed.