On Wed, May 31, 2017 at 12:02 PM, Graham Leggett <[email protected]> wrote:
> Hi all, > > I have a cloud-init template that deploys an Ubuntu Trusty 14.04 machine > that mounts an overlayfs at /var/spool/postfix, and this works great: > > fs_setup: > - label: postfix > device: /dev/xvde > filesystem: ext4 > mounts: > - [ /dev/xvde, /mnt/postfix-overlay ] > - [ overlayfs, /var/spool/postfix, "overlayfs", > "defaults,lowerdir=/var/spool/postfix,upperdir=/mnt/postfix-overlay", > "0", "2" ] > mount_default_fields: [ None, None, "auto", "defaults,nobootwait", "0", > "2” ] > > Upgrading the system image to Xenial 16.04 causes the overlayfs to fail to > mount with the error “missing ‘workdir’”. > > Turns out, between Trusty and Xenial, the “workdir” directory in overlayfs > went from optional to mandatory, and now the system no longer deploys. > Yes, the overlay module doesn't seem to have a way to find a default workdir value by itself. =( > > What needs to happen is that after the fs_setup step that creates > /mnt/postfix-overlay, but before the mounts section where the overlayfs is > created, the workdir and upperdir directories need to be created on the > /mnt/postfix-overlay disk as /mnt/postfix-overlay/upperdir and > /mnt/postfix-overlay/workdir (or something) respectively. > > Is there something that can be done in cloud-init to make this possible? > Surely it can; I think it's a matter of module timing: you need the directory to be created prior to the mounts module running. Looking at /etc/cloud/cloud.cfg, the cloud_init_modules list, shows that 'bootcmd'[1] will run before the 'mounts' stage, so it should be possible to include a command like this: bootcmd: - mkdir -p /mnt/postfix-overlay-workdir And to update the overlayfs mount command to specify the workdir path. That's untested, but I think should do what you need. 1. http://cloudinit.readthedocs.io/en/latest/topics/modules.html#bootcmd Ryan Harper > > Regards, > Graham > — > > > -- > Mailing list: https://launchpad.net/~cloud-init > Post to : [email protected] > Unsubscribe : https://launchpad.net/~cloud-init > More help : https://help.launchpad.net/ListHelp > >
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