Zowe fails to start FSUMF315

Products

• Zowe

Issue/Introduction

ZWESLSTC fails to start with the following error:

FSUMF315 Cannot define temporary file

Cause

Zowe components require the use of temporary files, typically written to the global /tmp directory. If the service user (e.g., ZWESVUSR) lacks sufficient RWX permissions or if the /tmp directory is missing the sticky bit, the application cannot manage files correctly. The sticky bit is essential in shared directories like /tmp to ensure only file owners can rename or delete their own files. 

Without the sticky bit, z/OS UNIX security checks can become overly restrictive, causing the shell to completely reject the creation of temporary files and trigger the FSUMF315 failure.

Resolution

Ensure the temporary directory used by Zowe is correctly configured:

1. Verify Permissions: Check the /tmp directory permissions using: ls -ldL /tmp
2. Apply Sticky Bit: If the sticky bit is missing, set permissions to 1777: chmod 1777 /tmp
3. Alternative (Dedicated Temp Directory): If security policies prevent modifying the global /tmp, configure Zowe to use a dedicated directory:
   • Create a new directory (e.g., /var/zowe/tmp).
   • Set permissions: chmod 1777 /var/zowe/tmp.
   • Update your zowe.yaml configuration to point to this new location. More info here.