[linux-lvm] lvm commands hanging when run from inside a kubernetes pod

[Abhishek Agarwal]

1. Yes, use_lvmetad is 0, and its systemd units for it are stopped/disabled.
2. Yes, everything on the host machine i.e(/proc, /sys etc) are getting
mounted on the pod.

*ubuntu at ip-172-31-89-47*:*~*$ kubectl exec -it openebs-lvm-node-v6jrb -c
openebs-lvm-plugin  -n kube-system -- sh

# ls

bin  boot  dev etc  home  host  lib  lib32  lib64  libx32  media  mnt opt
plugin  proc  root  run  sbin  srv  sys  tmp  usr var

# cd /host

# ls

bin  boot  dev etc  home  lib lib32  lib64  libx32  lost+found  media  mnt
opt  proc  root  run  sbin  snap srv  sys  tmp  usr  var

#
3. The detail output of `strace -f -ttt` command:
https://pastebin.com/raw/VFyXLNaC

On Fri, 3 Jun 2022 at 12:48, Roger Heflin <rogerheflin at gmail.com> wrote:

> Random thoughts.
>
> Make sure  use_lvmetad is 0, and its systemd units for it are
> stopped/disabled.
>
> Are you mounting /proc and /sys and /dev into the /host chroot?
>
> /run may also be needed.
>
> you might add a "-ttt" to the strace command to give timing data.
>
>
>
> On Thu, Jun 2, 2022 at 1:41 AM Abhishek Agarwal <
> mragarwal.developer at gmail.com> wrote:
>
>> These are not different LVM processes. The container process is using the
>> LVM binary that the node itself has. We have achieved this by using scripts
>> that point to the same lvm binary that is used by the node.
>>
>> Configmap(~shell script) used for the same has the following contents
>> where `/host` refers to the root directory of the node:
>>
>> get_bin_path: |
>>   #!/bin/sh
>>   bin_name=$1
>>   if [ -x /host/bin/which ]; then
>>     echo $(chroot /host /bin/which $bin_name | cut -d ' ' -f 1)
>>   elif [ -x /host/usr/bin/which ]; then
>>     echo $(chroot /host /usr/bin/which $bin_name | cut -d ' ' -f 1)
>>   else
>>     $(chroot /host which $bin_name | cut -d ' ' -f 1)
>>   fi
>>
>> lvcreate: |
>>   #!/bin/sh
>>   path=$(/sbin/lvm-eg/get_bin_path "lvcreate")
>>   chroot /host $path "$@"
>>
>> Also, the above logs in the pastebin link have errors because the vg lock
>> has not been acquired and hence creation commands will fail. Once the lock
>> is acquired, the `strace -f` command gives the following output being
>> stuck. Check out this link for full details ->
>> https://pastebin.com/raw/DwQfdmr8
>>
>> P.S: We at OpenEBS are trying to provide lvm storage to cloud native
>> workloads with the help of kubernetes CSI drivers and since all these
>> drivers run as pods and help dynamic provisioning of kubernetes
>> volumes(storage) for the application, the lvm commands needs to be run from
>> inside the pod. Reference -> https://github.com/openebs/lvm-localpv
>>
>> Regards
>>
>> On Wed, 1 Jun 2022 at 13:06, Demi Marie Obenour <
>> demi at invisiblethingslab.com> wrote:
>>
>>> On Wed, Jun 01, 2022 at 12:20:32AM +0530, Abhishek Agarwal wrote:
>>> > Hi Roger. Thanks for your reply. I have rerun the command with `strace
>>> -f`
>>> > as you suggested. Here is the pastebin link containing the detailed
>>> output
>>> > of the command: https://pastebin.com/raw/VRuBbHBc
>>>
>>> Even if you can get LVM “working”, it is still likely to cause data
>>> corruption at some point, as there is no guarantee that different LVM
>>> processes in different namespaces will see each others’ locks.
>>>
>>> Why do you need to run LVM in a container?  What are you trying to
>>> accomplish?
>>> --
>>> Sincerely,
>>> Demi Marie Obenour (she/her/hers)
>>> Invisible Things Lab
>>> _______________________________________________
>>> linux-lvm mailing list
>>> linux-lvm at redhat.com
>>> https://listman.redhat.com/mailman/listinfo/linux-lvm
>>> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>>>
>> _______________________________________________
>> linux-lvm mailing list
>> linux-lvm at redhat.com
>> https://listman.redhat.com/mailman/listinfo/linux-lvm
>> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>>
> _______________________________________________
> linux-lvm mailing list
> linux-lvm at redhat.com
> https://listman.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listman.redhat.com/archives/linux-lvm/attachments/20220606/96471466/attachment-0001.htm>