Paramiko exec_command not working with mkfs? - python-3.x

Question

Some issue executing the following bash with Paramiko:
def format_disk(self, device, size, dformat, mount, name):
stdin_, stdout_, stderr_ = self.client.exec_command(f"pvcreate {device};" \
f"vgcreate {name}-vg {device};" \
f"lvcreate -L {size} --name {name}-lv {name}-vg;" \
f"mkfs.{dformat} /dev/{name}-vg/{name}-lv;" \
f"mkdir {mount};" \
f"echo '/dev/{name}-vg/{name}-lv {mount} {dformat} defaults 0 0' >> /etc/fstab")
print(f"mkfs.{dformat} /dev/{name}-vg/{name}-lv;")
Print statement outputs: mkfs.ext4 /dev/first_try-vg/first_try-lv; If I copy and paste this exact command on the server there are no errors and it formats the disk as expected.
Troubleshooting steps
Server before running python script:
ls: cannot access /first_try: No such file or directory
[root#localhost ~]# vgs
[root#localhost ~]# lvs
[root#localhost ~]# cat /etc/fstab
#
# /etc/fstab
# Created by anaconda on Thu Feb 25 07:32:51 2021
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
UUID=38b7e96a-71e5-4089-a348-bd23828f9dc8 / xfs defaults 0 0
UUID=72fd2a6a-85db-4596-9fc2-6604d0d865a3 /boot xfs defaults 0 0
Server after running python script:
[root#localhost ~]# ls /first_try/
[root#localhost ~]# vgs
VG #PV #LV #SN Attr VSize VFree
first_try-vg 1 1 0 wz--n- <20.00g <15.00g
[root#localhost ~]# lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
first_try-lv first_try-vg -wi-a----- 5.00g
[root#localhost ~]# cat /etc/fstab
#
# /etc/fstab
# Created by anaconda on Thu Feb 25 07:32:51 2021
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
UUID=38b7e96a-71e5-4089-a348-bd23828f9dc8 / xfs defaults 0 0
UUID=72fd2a6a-85db-4596-9fc2-6604d0d865a3 /boot xfs defaults 0 0
/dev/first_try-vg/first_try-lv /first_try ext4 defaults 0 0
[root#localhost ~]# mount -a
mount: wrong fs type, bad option, bad superblock on /dev/mapper/first_try--vg-first_try--lv,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so.
The error from mount -a indicates that the disk is not formatted.
If I format the disk manually and run mount -a it works.
Example:
[root#localhost ~]# mkfs.ext4 /dev/first_try-vg/first_try-lv
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
327680 inodes, 1310720 blocks
65536 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=1342177280
40 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736
Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): mdone
Writing superblocks and filesystem accounting information: done
[root#localhost ~]# mount -a
[root#localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda3 18G 4.7G 14G 27% /
devtmpfs 471M 0 471M 0% /dev
tmpfs 487M 0 487M 0% /dev/shm
tmpfs 487M 8.4M 478M 2% /run
tmpfs 487M 0 487M 0% /sys/fs/cgroup
/dev/sda1 297M 147M 151M 50% /boot
tmpfs 98M 12K 98M 1% /run/user/42
tmpfs 98M 0 98M 0% /run/user/0
/dev/mapper/first_try--vg-first_try--lv 4.8G 20M 4.6G 1% /first_try

Answer 1

Pariminko could not handle the output from mkfs. I changed the command to use the -q quiet flag and was able to get the script to run successfully.
New commmand mkfs -q -t {dformat} /dev/{name}-vg/{name}-lv