VCH Management APIs: Support concurrent read/write access to the VCH creation log

[zjs]

#6665 (comment) raises a potential issue around reading and writing the creation log via different hosts. We should verify (manually, if that's easiest, or by referencing documentation, if it covers this) that the issue affects us given that we're accessing the files via VC, and apply the suggested fix if so.

This will not be able to access the file if it is open via a different process (for example still being uploaded) if not accessed via the same host. I do not know if this is an issue or not.
If it is then a specific host can be chosen for the operation by setting a target host in the context: c.vm.Datastore.HostContext(op, h)
See

vic/lib/portlayer/exec/container.go

Line 525 in 0050c58

ctx = c.vm.Datastore.HostContext(ctx, h)

for usage.

[zjs]

Deferring from 1.3 after discussion with @hickeng. While this would be undesirable, it's not clear that it's (a) actually an issue, or (b) our issue.

[zjs]

Closing as we haven't seen any indication that this is actually an issue.