During an attempt to upgrade from 9.6P6 to 9.7P1 via system manager we recently hit the same error "the request body must have conent type multipart/form-data with field named "file"" on a client install.
What was the workaround to get the image uploaded successfully?
The default staging directory size for ONTAP software images on each node's root volume in ONTAP 9.6 and earlier is set to 2GB. The ONTAP 9.7 image is greater than 2GB. When attempting to upgrade a cluster to ONTAP 9.7 with a local software image upload from System Manager, the image upload fails with the following error message: Failed to add the software image to the cluster. The request body must have content type multipart/form-data with a field named "file" containing the file to upload.
Resize the default staging directory size for ONTAP software images to 4GB on all the nodes in the cluster. The staging directory uses space taken from the root volume. Therefore, the root volume size shrinks due to the resize operation. Ensure that there is at least 10GB of space available in the root volume before attempting the resize operation. Use the "volume show -volume -fields available" command to monitor the available space in the root volume. Use the following (privilege: diagnostic) command to resize the staging directory to 4GB before uploading the software image:
::> set diagnostic; system services web file-uploads config modify -node * -size 4GB
The command returns a job ID you can use to track the status of the operation. The value "*" for "node" field specifies all nodes in the cluster. Example:
::> set diagnostic; system services web file-uploads config modify -node * -size 4GB ::> job show -id