|
|
@@ -0,0 +1,84 @@
|
|
|
+<!--[metadata]>
|
|
|
++++
|
|
|
+title = "Migrate to Engine 1.10"
|
|
|
+description = "Migrate to Engine 1.10"
|
|
|
+keywords = ["docker, documentation, engine, upgrade, migration"]
|
|
|
+[menu.main]
|
|
|
+parent = "engine_use"
|
|
|
+weight=79
|
|
|
++++
|
|
|
+<![end-metadata]-->
|
|
|
+
|
|
|
+# Migrate to Engine 1.10
|
|
|
+
|
|
|
+Starting from version 1.10 of Docker Engine, we completely change the way image
|
|
|
+data is addressed on disk. Previously, every image and layer used a randomly
|
|
|
+assigned UUID. In 1.10 we implemented a content addressable method using an ID,
|
|
|
+based on a secure hash of the image and layer data.
|
|
|
+
|
|
|
+The new method gives users more security, provides a built-in way to avoid ID
|
|
|
+collisions and guarantee data integrity after pull, push, load, or save. It also
|
|
|
+brings better sharing of layers by allowing many images to freely share their
|
|
|
+layers even if they didn’t come from the same build.
|
|
|
+
|
|
|
+Addressing images by their content also lets us more easily detect if something
|
|
|
+has already been downloaded. Because we have separated images and layers, you
|
|
|
+don’t have to pull the configurations for every image that was part of the
|
|
|
+original build chain. We also don’t need to create layers for the build
|
|
|
+instructions that didn’t modify the filesystem.
|
|
|
+
|
|
|
+Content addressability is the foundation for the new distribution features. The
|
|
|
+image pull and push code has been reworked to use a download/upload manager
|
|
|
+concept that makes pushing and pulling images much more stable and mitigate any
|
|
|
+parallel request issues. The download manager also brings retries on failed
|
|
|
+downloads and better prioritization for concurrent downloads.
|
|
|
+
|
|
|
+We are also introducing a new manifest format that is built on top of the
|
|
|
+content addressable base. It directly references the content addressable image
|
|
|
+configuration and layer checksums. The new manifest format also makes it
|
|
|
+possible for a manifest list to be used for targeting multiple
|
|
|
+architectures/platforms. Moving to the new manifest format will be completely
|
|
|
+transparent.
|
|
|
+
|
|
|
+## Preparing for upgrade
|
|
|
+
|
|
|
+To make your current images accessible to the new model we have to migrate them
|
|
|
+to content addressable storage. This means calculating the secure checksums for
|
|
|
+your current data.
|
|
|
+
|
|
|
+All your current images, tags and containers are automatically migrated to the
|
|
|
+new foundation the first time you start Docker Engine 1.10. Before loading your
|
|
|
+container, the daemon will calculate all needed checksums for your current data,
|
|
|
+and after it has completed, all your images and tags will have brand new secure
|
|
|
+IDs.
|
|
|
+
|
|
|
+**While this is simple operation, calculating SHA256 checksums for your files
|
|
|
+can take time if you have lots of image data.** On average you should assume
|
|
|
+that migrator can process data at a speed of 100MB/s. During this time your
|
|
|
+Docker daemon won’t be ready to respond to requests.
|
|
|
+
|
|
|
+## Minimizing migration time
|
|
|
+
|
|
|
+If you can accept this one time hit, then upgrading Docker Engine and restarting
|
|
|
+the daemon will transparently migrate your images. However, if you want to
|
|
|
+minimize the daemon’s downtime, a migration utility can be run while your old
|
|
|
+daemon is still running.
|
|
|
+
|
|
|
+This tool will find all your current images and calculate the checksums for
|
|
|
+them. After you upgrade and restart the daemon, the checksum data of the
|
|
|
+migrated images will already exist, freeing the daemon from that computation
|
|
|
+work. If new images appeared between the migration and the upgrade, those will
|
|
|
+be processed at time of upgrade to 1.10.
|
|
|
+
|
|
|
+[You can download the migration tool
|
|
|
+here.](https://github.com/docker/v1.10-migrator/releases)
|
|
|
+
|
|
|
+The migration tool can also be run as a Docker image. While running the migrator
|
|
|
+image you need to expose your Docker data directory to the container. If you use
|
|
|
+the default path then you would run:
|
|
|
+
|
|
|
+ $ docker run --rm -v /var/lib/docker:/var/lib/docker docker/v1.10-migrator
|
|
|
+
|
|
|
+If you use the
|
|
|
+devicemapper storage driver, you also need to pass the flag `--privileged` to
|
|
|
+give the tool access to your storage devices.
|
Ben Firshman