I have some virtual machines with me. I want to write a script which automates the following process...
It mounts the virtual machine (with linux as the os) to a location say /mnt/image
It modifies the /etc/passwd (or the equivalent file) to change the password of the user
Unmount the virtual machine
Since, I am using libvirt I am having some qcow2 images of the virtual machine. to mount the image on my ubuntu, I am using nbd module. Here are the commands that I am trying :
modprobe nbd max_part=63
qemu-nbd -c /dev/nbd0 image.qcow2
mount /dev/nbd0p1 /mnt/image
It gives me the error:
mount: special device /dev/nbd0p1 does not exist
When I replace nbd0p1 with nbdo I am getting the following error (though I am not sure what I am trying to do by this)
mount: you must specify the filesystem type
Any suggestions so as what could be the problem... ?
Check that /sys/modules/nbd/parameters/max_part has the expected value. If it's 0 or too low, the partitions /dev/nbd0p1, etc. will not be made available by the kernel. This can happen if the nbd kernel module was already loaded (with a different max_part parameter) when you ran modprobe.
You can fix that by unloading the module and modprobing it again.
[Not a direct answer to the question, but an alternate]
You can try to convert qcow2 image to raw and then, mount the raw image.
convert:
qemu-img convert -f qcow2 image.qcow2 -O raw image_raw.raw
mount:
sudo losetup /dev/loop0 image_raw.raw
sudo kpartx -a /dev/loop0
sudo mount /dev/mapper/loop0p3 /mnt/image
sudo mount /dev/mapper/loop0p2 /mnt/image/boot
Could it be that the partition isn't in the first slot in the MBR, or an extended partition is in use? Check to see if any other nbdXpY device nodes are being created, or run fdisk on it and print the partition table.
I stumbled on the same issue and same error but on a vdi
qemu-nbd -c /dev/nbd0 image.vdi
for me the solution was simple I just changed nbd0 to nbd1
qemu-nbd -c /dev/nbd1 image.vdi
and then:
sudo mount /dev/nbd1p1 /media/eddie/virtual
worked.
Please leave a comment if this worked for you also and on what type of image.
Related
I would like to, on startup, copy contents of my bucket to the VM with the Container Optimized OS. When the server shuts down I'd like to save the changes back to the bucket.
I've tried making a startup script
#!/bin/bash
toolbox
gsutil cp -r gs://my-bucket/
However, this causes the VM to fail on startup despite this script working if I run it manually.
I think I found a reasonable solution. My script has changed to
#! /bin/bash
toolbox --bind=/home/username/bucket-folder:/my-bucket <<< "gsutil cp -r /my-bucket/* gs://my-bucket"
So what happens is we need to call toolbox --bind to bind a folder from the server to the toolbox container. Then we use <<< to pass the whole command to the container when it starts up so we copy to the newly bound directory so it goes back to the server.
Now when I bound the directory in my docker container, everything is there!
I just tried:
#! /bin/bash
gsutil cp -r gs://my-bucket /
And it worked for me. What is the toolbox command that you are executing previously?
Anyway you can see what is failing in the Serial Port Output.
EDIT: In the Container Optimized OS this does not work as this OS does not have the gsutil package preinstalled. Refer to #DanBaba answer.
I use Ubuntu 18 as WSL and everything was running well. Today I run the apache and started the application. When the app tried to perform chmod() on a file which was submited through form inside the folder project (I use Laravel), I received the following error:
chmod(): Operation not permitted
I have notice that this error happen when I try running chmod() from web server (www-data user). In the cli I dont have problems.
From other posts over the net, I understand that Windows has some changes regarding WSL permissions and drive mounts. But I didnt get answer or didnt succeed to resolve that issue.
sudo umount /mnt/c
sudo mount -t drvfs C: /mnt/c -o metadata
Reference: https://github.com/Microsoft/WSL/issues/3172#issuecomment-389157376
sudo umount /mnt/c
sudo mount -t drvfs C: /mnt/c -o metadata,uid=1000,gid=1000,umask=22,fmask=111
did the trick for me.
Ref: https://devblogs.microsoft.com/commandline/chmod-chown-wsl-improvements/
I'm trying to run the "screen" utility on Windows Subsystem for Linux on Windows 10 (Version 1703, OS Build 15063.483).
It seems that I need additional permissions to run it (it works if I "sudo" it), but I don't understand why that is necessary.
What is the recommended way to set this up?
Is there some reason why this isn't the default set up?
$ screen
Cannot make directory '/var/run/screen': Permission denied
From an answer on SuperUser I discovered that you have to run
sudo /etc/init.d/screen-cleanup start
Then screen works fine for me.
EDIT: after installing Ubuntu 20.04 the problem went away (*).
As Krease pointed out, the best solution is the one described in this SuperUser post.
Add the following to your .bashrc:
export SCREENDIR=$HOME/.screen
[ -d $SCREENDIR ] || mkdir -p -m 700 $SCREENDIR
See also issue 1245 on github.
--
(*) now this warning comes up, but seems harmless:
sleep: cannot read realtime clock: Invalid argument
sudo screen # which creates dir /var/run/screen
chmod 777 /var/screen # so that non-root users can create their own screen dir in this dir.
I am getting the following error trying to mount a nfs export.
sudo mount 192.168.1.175:/mnt/nas /mnt/c/nas
mount.nfs: No such device
Any ideas on how to fix this?
As of October 2020: You can mount nfs with wsl2, but wsl2 itself requires a hardware virtualization available. See here: https://github.com/microsoft/WSL/issues/5838
If like me you are stuck on WSL1 you can work around this issue by mapping the drive in windows. Use the Map Network Drive feature and create a drive letter for your nfs mount e.g. G:
Now in WSL you can mount that drive letter:
sudo mkdir /mnt/g
sudo mount -t drvfs G: /mnt/g
from: How to Mount Windows Network Drives in WSL
I have not tested the access speed to a drive mapped through to WSL like this but I would expect it to be slow!
The error indicates the nfs kernel modules are not loaded correctly and
also verify the exported path "/mnt/nas" exists on sever "192.168.1.175" or not.
first of all,we understand nfs is one of tctp/ip protocol, so one client and one server are needed, So our purpose is sharing a dir on windows or wsl to a another linux, that means the windows or wsl is a server, all you guys are right about wsl nfs, it doesnt work if we use the wsl nfs inside, we can make a another nfs server on windows instead of wsl, and configure the share dirs right which we can find the dirs on wsl, e.g. /mnt/d/WORK/tftpserverDir, after that we can mount successfully. those are tips of me:
make a nfs server on windows
I dowwnload from this:
https://www.hanewin.net/nfs-e.htm
configure the shared dir in exports file
D:\WORK\tftpserverDir -name:nfsroot -umask:000 -public -mapall:0
mount the share dirs on your dst linux
mount -t nfs -o nolock -o tcp -o rsize=32768,wsize=32768 172.10.10.80:/nfsroot /sdcard/mnt
I have Arch Linux on /dev/sdb1 and NetBSD-7.0 on /dev/sdb2.
On Arch Linux when I run sudo grub-mkconfig -o /boot/grub/grub.cfg I get a message like Found unknown Linux distribution on /dev/sdb2 but when I reboot, there is no grub option for that unknown Linux distribution which I know it is NetBSD-7.0.
How can I add NetBSD-7.0 to my grub menu option when rebooting.
There is a similar post, currently looking into it.
UPDATE: I mounted NetBSD partition with sudo mount -t ufs -o ro,ufstype=ufs2 /dev/sdb2 /mnt/ (ufstype=44bsd did not work) and then ran grub-mkconfig -o /boot/grub/grub.cfg but yet the issue persists.
UPDATE: Rebooted and pressed c to get the grub command line. Following commands booted the NetBSD-7.0:
ls
Ran ls to see the correct name of disks and partitions, /dev/sdb2 on Linux was (hd0,gpt2) on Grub. Then ran the following:
insmod ufs2
set root=(hd0,gpt2)
knetbsd /netbsd
boot
And NetBSD-7.0 booted.
To add NetBSD option to Grub menu, modified file /etc/grub/40_custom on Arch Linux like below:
menuentry "NetBSD-7.0"{
insmod ufs2
set root=(hd0,gpt2)
knetbsd /netbsd
}
However, after modifying 40_custom like above, NetBSD option does not appear on Grub menu. I don't know why.
Unless you have a typo, it looks like the 40_custom file is in the wrong directory. it should be located at /etc/grub.d/40_custom, notice the .d.
If your /boot is located on a separate partition, make sure that it is mounted with mount /boot before generating the grub.cfg. Otherwise your new grub.cfg won't be used.
Check which partition grub is loading the configuration from by running echo ${prefix} within the grub command line. It's possible that grub is loading the configuration from a partition that you don't expect.
Verify that netbsd was added to the config with grep -i netbsd /boot/grub/grub.cfg before rebooting to avoid some frustration after generating grub.cfg