On 12/15/2016 12:18 PM, Josh Berkus wrote:
Dan, Dusty, Vivek:
So far nobody has defined (technically) the exact problem with overlayfs
and how it affects applications which want to write data inside the
container.
Note that just saying "don't use Overlay for persistent data" really
isn't good enough. Apps in containers frequently write data to places
users aren't aware of, such as writing port information to /var/run.
While this data may not be important to the user, the app will fail if
it errors out.
Pushing a change which will cause 30% of a user's containers to start
failing for reasons which are opaque to them is not something we should
do lightly.
Josh. More likely this will cause .0001% of users to fail. But it is
not a Posix
compliant database, so their could be issues.
Only other issues I know of now are the handling of "special" files things
like sock_files, character devices etc. But these should almost always
be on
tmpfs places like /dev and /run.