The temporary upload location [/tmp/tomcat.4296537502689403143.5000/work/Tomcat/localhost/ROOT] is not valid

1. The http POST methods will use these temp locations to store the post data.
2. Some OSs like centOS will delete the temp dir frequently. So, even you set that location's permission, after some time that dir will be removed by the OS. And after you reboot, the temp dir will be different.

You can set the multipart location in application.yml:

spring:
  http:
    multipart:
      location: /data/upload_tmp

Update

As per comment by Vivek Sethi above property didn't work for me but the below one.

spring.servlet.multipart.location=/data/upload_tmp

Just restart your application in the server. It is a bug between spring and tomcat servers. Once the application restarts it consume a temp directory in the server.

This Issue was fixed a couple of days ago.
Spring Boot: 2.1.4 or 1.5.20

This version bump fixes an issue when the tmp dir was deleted
by the OS and the spring boot app tries to handle a multifile
upload.

Issue: https://github.com/spring-projects/spring-boot/issues/9616

https://github.com/MeiSign/Copy-Pasta/commit/1200fb353a48a3d0c92038dee7cced7cebf3acfe