Permission issues on '/tmp' in many docker containers

Hi! Lately, a bunch of my docker containers started having trouble writing to their /tmp folders. They always mention permission denied. Dockers with this problem include but are not limited to Nextcloud, WordPress, MariaDB, Baikal, ... I haven't been able to find a fix for this, neither have I been able to identify why this is happening. However, I need this fixed ASAP. I am using unRAID version 9.6.2 Thanks!

By maartenweyns, October 27, 2021
14 replies

/tmp on the host is in OS rootfs. OS rootfs is in RAM. The OS is unpacked fresh from the archives on flash at each reboot, and runs completely in RAM. Think of it as firmware. So using /tmp on the host will not survive. Also if you fill up rootfs the OS will misbehave since it won't be able to work with its own files. Only mounted storage persists.