You would be better served by opening the file as "immutable", assuming that it is, in fact, immutable (this effectively means readonly and nolock) during the time it is open (that is, nothing will change the file, as if it were on WORM media that has been finalized (ie, a closed CD, for example)). This is a good thing since Docker does not implement the locking semantics necessary for reliable concurrency -- and an "immutable" file does not require any locking.