ECS startup failure: Causes and solutions - - Alibaba Cloud Documentation Center

Identify and resolve ECS instance startup failures caused by missing boot files or OS release files.

Symptoms

The instance fails to start and displays an error message like the following:

[  OK  ] Reached target Remote File Systems (Pre).
[  OK  ] Reached target Remote File Systems.
[    1.575629] EXT4-fs (vda1): mounted filesystem with ordered data mode. Opts: (null)
[  OK  ] Mounted /sysroot.
[  OK  ] Reached target Initrd Root File System.
         Starting Reload Configuration from the Real Root...
[  OK  ] Started Reload Configuration from the Real Root.
[  OK  ] Reached target Initrd File Systems.
[  OK  ] Reached target Initrd Default Target.
         Starting dracut pre-pivot and cleanup hook...
[    1.661164] tsc: Refined TSC clocksource calibration: 2499.915 MHz
[  OK  ] Started dracut pre-pivot and cleanup hook.
         Starting Cleaning Up and Shutting Down Daemons...
[  OK  ] Stopped dracut pre-pivot and cleanup hook.
[  OK  ] Stopped target Timers.
[  OK  ] Stopped target Remote File Systems.
[  OK  ] Stopped target Remote File Systems (Pre).
         Starting Plymouth switch root service...
[  OK  ] Stopped dracut initqueue hook.
[  OK  ] Stopped target Initrd Default Target.
[  OK  ] Stopped target Basic System.
[  OK  ] Stopped target System Initialization.
         Stopping udev Kernel Device Manager...
[  OK  ] Stopped target Sockets.
[  OK  ] Stopped target Paths.
[  OK  ] Stopped Apply Kernel Variables.
[  OK  ] Stopped target Slices.
[  OK  ] Stopped target Local File Systems.
[  OK  ] Stopped udev Coldplug all Devices.
[  OK  ] Stopped target Swap.
[  OK  ] Stopped udev Kernel Device Manager.
[  OK  ] Stopped dracut pre-udev hook.
[  OK  ] Stopped dracut cmdline hook.
[  OK  ] Stopped Create Static Device Nodes in /dev.
[  OK  ] Stopped Create list of required sta...ce nodes for the current kernel.
[  OK  ] Closed udev Control Socket.
[  OK  ] Closed udev Kernel Socket.
         Starting Cleanup udevd DB...
[  OK  ] Started Cleaning Up and Shutting Down Daemons.
[  OK  ] Started Cleanup udevd DB.
[  OK  ] Reached target Switch Root.
[  OK  ] Started Plymouth switch root service.
         Starting Switch Root...
[FAILED] Failed to start Switch Root.
See 'systemctl status initrd-switch-root.service' for details.

Causes

The /boot directory is missing key boot files, such as the kernel image vmlinuz or the rootfs image initramfs.
The /etc/os-release and /usr/lib/os-release files are missing, which prevents systemd from detecting the operating system.

Note

These steps are verified on Alibaba Cloud Linux 3.2 64-bit. Steps may vary by OS distribution. See your distribution's official documentation.

Solution 1: Restore the system disk from a snapshot

Restore the system disk from a snapshot.

See How to restore data on a system disk using a snapshot of the original system disk after the system disk is replaced.
Roll back a disk from a snapshot.

See Roll back a disk using a snapshot.

Solution 2: Copy boot files from another instance

The instance has started

Use SCP or OSS to copy the required boot files from another instance that uses the same image.

The instance fails to start

Copy the boot files from another instance that uses the same image and attach the repaired disk back.

Identify the missing boot files.
Create an ECS instance with the same image.

See Create an instance using a custom image.
Detach the system disk from the affected instance. Record the disk ID.

See Detach a system disk.
Attach the detached system disk to the new instance.

See Attach a data disk.
Copy the missing boot files to the attached system disk.
Detach the repaired system disk and reattach it to the original instance.

See steps 3 to 4.