Seems like you have issues like this post: Fail upgrade from 14.0.12 to 14.8.2 - #6 by stevets
Try this:
sudo gitlab-rake gitlab:background_migrations:finalize[CopyColumnUsingBackgroundMigrationJob,events,id,'[["id"]\, ["id_convert_to_bigint"]]']
sudo gitlab-rake gitlab:background_migrations:finalize[CopyColumnUsingBackgroundMigrationJob,ci_builds,id,'[["id"\, "stage_id"]\, ["id_convert_to_bigint"\, "stage_id_convert_to_bigint"]]']
sudo gitlab-rake gitlab:background_migrations:finalize[CopyColumnUsingBackgroundMigrationJob,ci_job_artifacts,id,'[["id"\, "job_id"]\, ["id_convert_to_bigint"\, "job_id_convert_to_bigint"]]']
sudo gitlab-rake gitlab:background_migrations:finalize[CopyColumnUsingBackgroundMigrationJob,ci_stages,id,'[["id"]\, ["id_convert_to_bigint"]]']
sudo gitlab-rake gitlab:background_migrations:finalize[CopyColumnUsingBackgroundMigrationJob,ci_builds_metadata,id,'[["id"]\, ["id_convert_to_bigint"]]']
sudo gitlab-rake gitlab:background_migrations:finalize[CopyColumnUsingBackgroundMigrationJob,ci_builds_metadata,id,'[["build_id"]\, ["build_id_convert_to_bigint"]]']
sudo gitlab-rake gitlab:background_migrations:finalize[CopyColumnUsingBackgroundMigrationJob,push_event_payloads,event_id,'[["event_id"]\, ["event_id_convert_to_bigint"]]']
sudo gitlab-rake gitlab:background_migrations:finalize[CopyColumnUsingBackgroundMigrationJob,deployments,id,'[["deployable_id"]\, ["deployable_id_convert_to_bigint"]]']
sudo gitlab-rake gitlab:background_migrations:finalize[CopyColumnUsingBackgroundMigrationJob,taggings,id,'[["id"\, "taggable_id"]\, ["id_convert_to_bigint"\, "taggable_id_convert_to_bigint"]]']
once you’ve done that, do:
gitlab-ctl reconfigure
gitlab-ctl restart