mysql socket no longer accessible during overlayroot

[Cody Spraker]

Running on a Ubuntu 16.04.2 LTS
install mysql through apt-get
successfully run 'mysql' and connect
add "tmpfs" to /etc/overlayroot.conf
reboot the system to engage overlay
attempt 'mysql' command and get a fail to connect to socket error
this is repeatable by added and removing the overlay

[Cody Spraker (codyspraker)]

UPDATE: I have found some answers regarding possible solutions and causes.
It looks like this is rooted in Overlayfs only implementing a subset of the POSIX standards.
There are files, necessary to mysql, that can't be created due to abilities outside of the POSIX standards implemented by Overlayfs.
Overlayroot utilizes Overlayfs which is why the bug was seen here.
The simplest fix I see is to run the following commands:

find /var/lib/mysql -type f -exec touch {} \;
service restart mysql

This will fix the issue BUT WILL NOT persist between system restarts (even if written in chroot since it's part of the application startup).
It must be run on every boot.

My sources of info are the following:

https://github.com/sjp38/cloudsuite/commit/e48bc2434bc2d15fcec7f496245726a6a35ca000#diff-0ba6a4ef358d86a1f4610bc46f9f5e5c

https://docs.docker.com/engine/userguide/storagedriver/overlayfs-driver/#limitations-on-overlayfs-compatibility

[Christian Ehrhardt  (paelzer)]

Hi Cody,
that would be a bug (feature request) against (upstream) overlayfs then right?

I wonder this being against "cloud-initramfs-tools (Ubuntu)".
Lets retarget the bug at overlayfs for now to discuss in that context (which is the kernel package).

Or OTOH you meant to want us to consider picking [1] somewhere into mysql packaging so adding a task for that as well.

Please help to clarify further.

[Christian Ehrhardt  (paelzer)]

I thank you for your report and your help to make Ubuntu better.
But for now I'll mark it incomplete until it is clear what the requested action shall be.

Please feel free to set back to new when the clarification is provided.

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]

[Launchpad Janitor (janitor)]

[Expired for mysql-5.7 (Ubuntu) because there has been no activity for 60 days.]