Found a dos partition table in /dev/nvme1n1

We have a setup at Amazon where we use the 16.04 LTS AMI. Today we planned to change to the newer 18.04 LTS AMI. We do this by updating the Cloudformation template with the latest AMI-ID. But when running the Cloudformation template we get this error at the backup volume setup,

2019-02-21 09:25:17,234 P8657 [INFO] Set up backup volume
2019-02-21 09:25:17,234 P8657 [INFO] mke2fs 1.44.1 (24-Mar-2018)
2019-02-21 09:25:17,234 P8657 [INFO] Found a dos partition table in
/dev/nvme1n1 2019-02-21 09:25:17,234 P8657 [INFO] Proceed anyway?
(y,N) 2019-02-21 09:25:17,235 P8657 [INFO]
------------------------------------------------------------
2019-02-21 09:25:17,235 P8657 [ERROR] Exited with error code 1 

Doing the same thing with the latest 16.04 LTS AMI is working without any problems. The first thing that I saw was that the mke2fs versions are different, mke2fs 1.42.13 for 16.04 and mke2fs 1.44.1 for 18.04. Are there any big differences for the way those versions handles the filesystems? The volumes are already created, we just want them attached again.

Here is some output from the 16.04 LTS installation.

fdisk output:

Disk /dev/nvme1n1: 1 TiB, 1099511627776 bytes, 2147483648 sectors
Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical):
512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512
bytes
Disk /dev/nvme0n1: 32 GiB, 34359738368 bytes, 67108864 sectors Units:
sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512
bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos Disk identifier: 0x30c871d7
Device Boot Start End Sectors Size Id Type
/dev/nvme0n1p1 * 2048 67108830 67106783 32G 83 Linux
Disk /dev/nvme2n1: 1000 GiB, 1073741824000 bytes, 2097152000 sectors
Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical):
512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512
bytes

parted output:

Model: NVMe Device (nvme) Disk /dev/nvme0n1: 34.4GB Sector size
(logical/physical): 512B/512B Partition Table: msdos Disk Flags:
Number Start End Size Type File system Flags 1
1049kB 34.4GB 34.4GB primary ext4 boot
Model: NVMe Device (nvme) Disk /dev/nvme1n1: 1100GB Sector size
(logical/physical): 512B/512B Partition Table: loop Disk Flags:
Number Start End Size File system Flags 1 0.00B
1100GB 1100GB ext4
Model: NVMe Device (nvme) Disk /dev/nvme2n1: 1074GB Sector size
(logical/physical): 512B/512B Partition Table: loop Disk Flags:
Number Start End Size File system Flags 1 0.00B
1074GB 1074GB ext4

fstab output:

LABEL=cloudimg-rootfs / ext4 defaults,discard 0 0
/dev/nvme1n1 /backup auto noatime 0 0
/dev/nvme2n1 /data auto noatime 0 0

2 Answers

The problem is that you have asked mke2fs to create a filesystem on the disk device itself (i.e. /dev/nvme1n1), where the partition table resides, rather than inside one of its partitions (i.e. /dev/nvme1n1p1). If you change the /dev/nvme1n1 to /dev/nvme1n1p1, it won't complain, and it should do what you want.

I'm not sure if this will help in your particular case, but I used this command to find an available NVME disk that hasn't had a partition created on it yet, assuming that there are at most two NVME disks and that the one used for the disk root has a *p1 partition created for it already:

$ lsblk | egrep -o 'nvme\w+' | grep -v $(lsblk | egrep -o 'nvme\w+p1' | egrep -o 'nvme.{3}')
# prints: `nvme0n1` or `nvme1n1`, depending on chance