As @daniel.pan noted, this is not recommended and not supported “out-of-the-box” with seafile.
However it is possible:
- You need to run the instances under different user ids.
- You need to change all seafile scripts so pgrep/pkill will work correctly: s/pgrep/pgrep -u $(id -u)/ and s/pkill/pkill -u $(id -u)/
- During install you need to choose different ports for all seafile instances.
- During install you need a separate database for all seafile instances.
- Don’t forget to apply 2. to the new code before updating an instance!
HTH and again: This is not recommended!