This is similar to waitForSegmentsToShowUp which is called during
Close/Commit. Intuitively, you wouldn't expect missing segments to be a
problem during read operations, since the previous Close/Commit
confirmed that all segments are there.
But due to the distributed nature of Swift, the read request could be
hitting a different storage node of the Swift cluster, where the
segments are still missing.
Load tests on my team's staging Swift cluster have shown this to occur
about once every 100-200 layer uploads when the Swift proxies are under
high load. The retry logic, borrowed from waitForSegmentsToShowUp, fixes
this temporary inconsistency.
Signed-off-by: Stefan Majewsky <stefan.majewsky@sap.com>
This commit refactors base.regulator into the 2.4 interfaces and adds a
filesystem configuration option `maxthreads` to configure the regulator.
By default `maxthreads` is set to 100. This means the FS driver is
limited to 100 concurrent blocking file operations. Any subsequent
operations will block in Go until previous filesystem operations
complete.
This ensures that the registry can never open thousands of simultaneous
threads from os filesystem operations.
Note that `maxthreads` can never be less than 25.
Add test case covering parsable string maxthreads
Signed-off-by: Tony Holdstock-Brown <tony@docker.com>
It's easily possible for a flood of requests to trigger thousands of
concurrent file accesses on the storage driver. Each file I/O call creates
a new OS thread that is not reaped by the Golang runtime. By limiting it
to only 100 at a time we can effectively bound the number of OS threads
in use by the storage driver.
Docker-DCO-1.1-Signed-off-by: Josh Hawn <josh.hawn@docker.com> (github: jlhawn)
Signed-off-by: Tony Holdstock-Brown <tony@docker.com>
Not just when Commit()ing the result. This fixes some errors I observed
when the layer (i.e. the DLO) is Stat()ed immediately after closing,
and reports the wrong file size because the container listing is not
yet up-to-date.
Signed-off-by: Stefan Majewsky <stefan.majewsky@sap.com>
In 326c3a9c49, which was only intended to
be a refactoring commit, the behavior of this block subtly changed so
that unknown types of errors would be swallowed instead of propagated.
I noticed this while investigating an error similar to #1539 aka
docker/docker#21290. It appears that during GetContent() for a
hashstate, the Swift proxy produces an error. Since this error was
silently swallowed, an empty []byte is used to restart the hash, then
producing the digest of the empty string instead of the layer's digest.
This PR will not fix the issue, but it should make the actual error more
visible by propagating it into `blobWriter#resumeDigest' and
'blobWriter#validateBlob', respectively.
Signed-off-by: Stefan Majewsky <stefan.majewsky@sap.com>
This commit adds context-specific documentation on StorageDriver,
StorageDriverFactory, and the factory’s Register func, explaining how
the internal registration mechanism should be used.
This documentation follows from the thread starting at
https://github.com/deis/builder/pull/262/files#r56720200.
cc/ @stevvooe
Signed-off-by: Aaron Schlesinger <aschlesinger@deis.com>
Updates registry storage code to use this for better resumable writes.
Implements this interface for the following drivers:
+ Inmemory
+ Filesystem
+ S3
+ Azure
Signed-off-by: Brian Bland <brian.bland@docker.com>
