umount: /tmp: target is busy - payload files?

[Georg Großmann]

Hi!

I am using a playbook `from github created by Reiner Nippes to setup a nextcloud server. I changed quite some things to be able to run it on OpenSuse Tumbleweed.

Before running the playbook, /etc/fstab looks like the following:

UUID=a34c85bd-79d2-4145-8772-04be970fe413  /                       btrfs  defaults                      0  0
UUID=a34c85bd-79d2-4145-8772-04be970fe413  /.snapshots             btrfs  subvol=/@/.snapshots          0  0
UUID=9d812efe-44e4-4594-affe-37299672ad9e  swap                    swap   defaults                      0  0
UUID=a34c85bd-79d2-4145-8772-04be970fe413  /var                    btrfs  subvol=/@/var                 0  0
UUID=a34c85bd-79d2-4145-8772-04be970fe413  /usr/local              btrfs  subvol=/@/usr/local           0  0
UUID=a34c85bd-79d2-4145-8772-04be970fe413  /srv                    btrfs  subvol=/@/srv                 0  0
UUID=a34c85bd-79d2-4145-8772-04be970fe413  /root                   btrfs  subvol=/@/root                0  0
UUID=a34c85bd-79d2-4145-8772-04be970fe413  /opt                    btrfs  subvol=/@/opt                 0  0
UUID=a34c85bd-79d2-4145-8772-04be970fe413  /home                   btrfs  subvol=/@/home                0  0
UUID=a34c85bd-79d2-4145-8772-04be970fe413  /boot/grub2/x86_64-efi  btrfs  subvol=/@/boot/grub2/x86_64-efi  0  0
UUID=a34c85bd-79d2-4145-8772-04be970fe413  /boot/grub2/i386-pc     btrfs  subvol=/@/boot/grub2/i386-pc  0  0
UUID=7388-F693                             /boot/efi               vfat   defaults                      0  0

In the playbook there is a task to mount /tmp as tmpfs:

- name: mount tmp fs
  mount:
    src: "tmpfs"
    path: "{{ item }}"
    fstype: tmpfs
    opts: "defaults,noatime,nosuid,nodev,noexec,mode=1777"
    passno: "0"
    state: mounted
  with_items:
    - /tmp
    - /var/tmp

The first time I run the playbook, I get this error:

failed: [nextcloud] (item=/tmp) => {"ansible_loop_var": "item", "changed": false, "item": "/tmp", "msg": "Error mounting /tmp: umount: /tmp: target is busy.

and the file /etc/fstab has a new entry afterwards:

UUID=a34c85bd-79d2-4145-8772-04be970fe413  /                       btrfs  defaults                      0  0
UUID=a34c85bd-79d2-4145-8772-04be970fe413  /.snapshots             btrfs  subvol=/@/.snapshots          0  0
UUID=9d812efe-44e4-4594-affe-37299672ad9e  swap                    swap   defaults                      0  0
UUID=a34c85bd-79d2-4145-8772-04be970fe413  /var                    btrfs  subvol=/@/var                 0  0
UUID=a34c85bd-79d2-4145-8772-04be970fe413  /usr/local              btrfs  subvol=/@/usr/local           0  0
UUID=a34c85bd-79d2-4145-8772-04be970fe413  /srv                    btrfs  subvol=/@/srv                 0  0
UUID=a34c85bd-79d2-4145-8772-04be970fe413  /root                   btrfs  subvol=/@/root                0  0
UUID=a34c85bd-79d2-4145-8772-04be970fe413  /opt                    btrfs  subvol=/@/opt                 0  0
UUID=a34c85bd-79d2-4145-8772-04be970fe413  /home                   btrfs  subvol=/@/home                0  0
UUID=a34c85bd-79d2-4145-8772-04be970fe413  /boot/grub2/x86_64-efi  btrfs  subvol=/@/boot/grub2/x86_64-efi  0  0
UUID=a34c85bd-79d2-4145-8772-04be970fe413  /boot/grub2/i386-pc     btrfs  subvol=/@/boot/grub2/i386-pc  0  0
UUID=7388-F693                             /boot/efi               vfat   defaults                      0  0
tmpfs /tmp tmpfs defaults,noatime,nosuid,nodev,noexec,mode=1777 0 0

When I run the playbook a second time, I don't get the error anymore and all is fine.

I executed "watch -n 1 ls -l /tmp/" to perodically check if ansible is writing anything to /tmp, and yes, it is!

There are some temporary files which appear and disapear during the execution. I already added the following two lines to my ansible.cfg file:

local_tmp = /tmp2
remote_tmp = /tmp2

Unfortunately, there are still these "payload" files appearing in /tmp.

1. Where do they come from? What do they contain and how can I change the directory for these files?

I guess these payload files are the reason why the mount module fails in the first place.

2. Am I doing something wrong?

3. Is a workaround possible?

4. Has it something to do with the BTRFS filesystem? On Ubuntu this mount task is working...

5. Why is it trying to umount at all? I want it to mount /tmp

I have also made a desktop capture of this behavior: https://drive.google.com/open?id=1Ta2-x4wUgoz1Ig3jabooHwVJV4l-SyQ1

Thanks a lot for your help!

[Kai Stian Olstad]

On 13.06.2019 21:21, 'Georg Großmann' via Ansible Project wrote:
> Hi!
>
> I am using a playbook `from github created by Reiner Nippes to setup a
> nextcloud server. I changed quite some things to be able to run it on
> OpenSuse Tumbleweed.
>

<snip />

> In the playbook there is a task to mount /tmp as tmpfs:
>
> - name: mount tmp fs
> mount:
> src: "tmpfs"
> path: "{{ item }}"
> fstype: tmpfs
> opts: "defaults,noatime,nosuid,nodev,noexec,mode=1777"
> passno: "0"
> state: mounted
> with_items:
> - /tmp
> - /var/tmp

/var/tmp is defined as a persistent tmp, and changing this to tmpfs might break other software that depends on /var/tmp being persistent.

And changing them on a running system is not recommended since other software might be using the tmp.
The best approach is to use state: present and reboot.

> I executed "watch -n 1 ls -l /tmp/" to perodically check if ansible is
> writing anything to /tmp, and yes, it is!
> There are some temporary files which appear and disapear during the
> execution. I already added the following two lines to my ansible.cfg file:
> local_tmp = /tmp2
> remote_tmp = /tmp2

Default they are pointing to ~/.ansible/tmp

> Unfortunately, there are still these "payload" files appearing in /tmp.
> 1. Where do they come from? What do they contain and how can I change the
> directory for these files?
> I guess these payload files are the reason why the mount module fails in
> the first place.

A grep in the source it seams that some module and plugins have /tmp hard coded and maybe the code you are running is creating files in tmp.

> 2. Am I doing something wrong?

Sort of, use present and reboot.

> 3. Is a workaround possible?

See 2.

> 4. Has it something to do with the BTRFS filesystem? On Ubuntu this mount
> task is working...

No.


--
Kai Stian Olstad

[Georg Großmann]

Ok, I just googled a bit and I think I will only mount /tmp as tmpfs. I will not change the mount for /var/tmp.

So now I am using:

- name: mount tmp fs
  mount:
    src: "tmpfs"
    path: "{{ item }}"
    fstype: tmpfs
    opts: "defaults,noatime,nosuid,nodev,noexec,mode=1777"

    passno: "0"
    state: present
  with_items:
    - /tmp

Thanks a lot, you are awesome!