To support multi-tenancy, containerd allows the collection of metadata
and runtime objects within a heirarchical storage primitive known as
namespaces. Data cannot be shared across these namespaces, unless
allowed by the service. This allows multiple sets of containers to
managed without interaction between the clients that management. This
means that different users, such as SwarmKit, K8s, Docker and others can
use containerd without coordination. Through labels, one may use
namespaces as a tool for cleanly organizing the use of containerd
containers, including the metadata storage for higher level features,
such as ACLs.
Namespaces
Namespaces cross-cut all containerd operations and are communicated via
context, either within the Go context or via GRPC headers. As a general
rule, no features are tied to namespace, other than organization. This
will be maintained into the future. They are created as a side-effect of
operating on them or may be created manually. Namespaces can be labeled
for organization. They cannot be deleted unless the namespace is empty,
although we may want to make it so one can clean up the entirety of
containerd by deleting a namespace.
Most users will interface with namespaces by setting in the
context or via the `CONTAINERD_NAMESPACE` environment variable, but the
experience is mostly left to the client. For `ctr` and `dist`, we have
defined a "default" namespace that will be created up on use, but there
is nothing special about it. As part of this PR we have plumbed this
behavior through all commands, cleaning up context management along the
way.
Namespaces in Action
Namespaces can be managed with the `ctr namespaces` subcommand. They
can be created, labeled and destroyed.
A few commands can demonstrate the power of namespaces for use with
images. First, lets create a namespace:
```
$ ctr namespaces create foo mylabel=bar
$ ctr namespaces ls
NAME LABELS
foo mylabel=bar
```
We can see that we have a namespace `foo` and it has a label. Let's pull
an image:
```
$ dist pull docker.io/library/redis:latest
docker.io/library/redis:latest: resolved |++++++++++++++++++++++++++++++++++++++|
manifest-sha256:548a75066f3f280eb017a6ccda34c561ccf4f25459ef8e36d6ea582b6af1decf: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:d45bc46b48e45e8c72c41aedd2a173bcc7f1ea4084a8fcfc5251b1da2a09c0b6: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:5b690bc4eaa6434456ceaccf9b3e42229bd2691869ba439e515b28fe1a66c009: done |++++++++++++++++++++++++++++++++++++++|
config-sha256:a858478874d144f6bfc03ae2d4598e2942fc9994159f2872e39fae88d45bd847: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:4cdd94354d2a873333a205a02dbb853dd763c73600e0cf64f60b4bd7ab694875: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:10a267c67f423630f3afe5e04bbbc93d578861ddcc54283526222f3ad5e895b9: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:c54584150374aa94b9f7c3fbd743adcff5adead7a3cf7207b0e51551ac4a5517: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:d1f9221193a65eaf1b0afc4f1d4fbb7f0f209369d2696e1c07671668e150ed2b: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:71c1f30d820f0457df186531dc4478967d075ba449bd3168a3e82137a47daf03: done |++++++++++++++++++++++++++++++++++++++|
elapsed: 0.9 s total: 0.0 B (0.0 B/s)
INFO[0000] unpacking rootfs
INFO[0000] Unpacked chain id: sha256:41719840acf0f89e761f4a97c6074b6e2c6c25e3830fcb39301496b5d36f9b51
```
Now, let's list the image:
```
$ dist images ls
REF TYPE DIGEST SIZE
docker.io/library/redis:latest application/vnd.docker.distribution.manifest.v2+json sha256:548a75066f3f280eb017a6ccda34c561ccf4f25459ef8e36d6ea582b6af1decf 72.7 MiB
```
That looks normal. Let's list the images for the `foo` namespace and see
this in action:
```
$ CONTAINERD_NAMESPACE=foo dist images ls
REF TYPE DIGEST SIZE
```
Look at that! Nothing was pulled in the namespace `foo`. Let's do the
same pull:
```
$ CONTAINERD_NAMESPACE=foo dist pull docker.io/library/redis:latest
docker.io/library/redis:latest: resolved |++++++++++++++++++++++++++++++++++++++|
manifest-sha256:548a75066f3f280eb017a6ccda34c561ccf4f25459ef8e36d6ea582b6af1decf: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:d45bc46b48e45e8c72c41aedd2a173bcc7f1ea4084a8fcfc5251b1da2a09c0b6: done |++++++++++++++++++++++++++++++++++++++|
config-sha256:a858478874d144f6bfc03ae2d4598e2942fc9994159f2872e39fae88d45bd847: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:4cdd94354d2a873333a205a02dbb853dd763c73600e0cf64f60b4bd7ab694875: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:c54584150374aa94b9f7c3fbd743adcff5adead7a3cf7207b0e51551ac4a5517: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:71c1f30d820f0457df186531dc4478967d075ba449bd3168a3e82137a47daf03: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:d1f9221193a65eaf1b0afc4f1d4fbb7f0f209369d2696e1c07671668e150ed2b: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:10a267c67f423630f3afe5e04bbbc93d578861ddcc54283526222f3ad5e895b9: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:5b690bc4eaa6434456ceaccf9b3e42229bd2691869ba439e515b28fe1a66c009: done |++++++++++++++++++++++++++++++++++++++|
elapsed: 0.8 s total: 0.0 B (0.0 B/s)
INFO[0000] unpacking rootfs
INFO[0000] Unpacked chain id: sha256:41719840acf0f89e761f4a97c6074b6e2c6c25e3830fcb39301496b5d36f9b51
```
Wow, that was very snappy! Looks like we pulled that image into out
namespace but didn't have to download any new data because we are
sharing storage. Let's take a peak at the images we have in `foo`:
```
$ CONTAINERD_NAMESPACE=foo dist images ls
REF TYPE DIGEST SIZE
docker.io/library/redis:latest application/vnd.docker.distribution.manifest.v2+json sha256:548a75066f3f280eb017a6ccda34c561ccf4f25459ef8e36d6ea582b6af1decf 72.7 MiB
```
Now, let's remove that image from `foo`:
```
$ CONTAINERD_NAMESPACE=foo dist images rm
docker.io/library/redis:latest
```
Looks like it is gone:
```
$ CONTAINERD_NAMESPACE=foo dist images ls
REF TYPE DIGEST SIZE
```
But, as we can see, it is present in the `default` namespace:
```
$ dist images ls
REF TYPE DIGEST SIZE
docker.io/library/redis:latest application/vnd.docker.distribution.manifest.v2+json sha256:548a75066f3f280eb017a6ccda34c561ccf4f25459ef8e36d6ea582b6af1decf 72.7 MiB
```
What happened here? We can tell by listing the namespaces to get a
better understanding:
```
$ ctr namespaces ls
NAME LABELS
default
foo mylabel=bar
```
From the above, we can see that the `default` namespace was created with
the standard commands without the environment variable set. Isolating
the set of shared images while sharing the data that matters.
Since we removed the images for namespace `foo`, we can remove it now:
```
$ ctr namespaces rm foo
foo
```
However, when we try to remove the `default` namespace, we get an error:
```
$ ctr namespaces rm default
ctr: unable to delete default: rpc error: code = FailedPrecondition desc = namespace default must be empty
```
This is because we require that namespaces be empty when removed.
Caveats
- While most metadata objects are namespaced, containers and tasks may
exhibit some issues. We still need to move runtimes to namespaces and
the container metadata storage may not be fully worked out.
- Still need to migrate content store to metadata storage and namespace
the content store such that some data storage (ie images).
- Specifics of snapshot driver's relation to namespace needs to be
worked out in detail.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
This avoids issues with the various deferred error handlers in the event that
`err` is shadowed or named differently, which this function currently avoids
but which is an easy trap to fall into.
Since named return values are all or nothing we need to name the waitGroup too
and adjust the code to suite.
Thanks to Aaron Lehmann for the suggestion, see also
https://github.com/docker/swarmkit/pull/1965#discussion_r118137410
Signed-off-by: Ian Campbell <ian.campbell@docker.com>
Working from feedback on the existing implementation, we have now
introduced a central metadata object to represent the lifecycle and pin
the resources required to implement what people today know as
containers. This includes the runtime specification and the root
filesystem snapshots. We also allow arbitrary labeling of the container.
Such provisions will bring the containerd definition of container closer
to what is expected by users.
The objects that encompass today's ContainerService, centered around the
runtime, will be known as tasks. These tasks take on the existing
lifecycle behavior of containerd's containers, which means that they are
deleted when they exit. Largely, there are no other changes except for
naming.
The `Container` object will operate purely as a metadata object. No
runtime state will be held on `Container`. It only informs the execution
service on what is required for creating tasks and the resources in use
by that container. The resources referenced by that container will be
deleted when the container is deleted, if not in use. In this sense,
users can create, list, label and delete containers in a similar way as
they do with docker today, without the complexity of runtime locks that
plagues current implementations.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
This moves both the Mount type and mountinfo into a single mount
package.
This also opens up the root of the repo to hold the containerd client
implementation.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Update go-runc to 49b2a02ec1ed3e4ae52d30b54a291b75
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Add shim to restore creation
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Keep checkpoint path in service
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Add C/R to non-shim build
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Checkpoint rw and image
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Pause container on bind checkpoints
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Return dump.log in error on checkpoint failure
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Pause container for checkpoint
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Update runc to 639454475cb9c8b861cc599f8bcd5c8c790ae402
For checkpoint into to work you need runc version
639454475cb9c8b861cc599f8bcd5c8c790ae402 + and criu 3.0 as this is what
I have been testing with.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Move restore behind create calls
This remove the restore RPCs in favor of providing the checkpoint
information to the `Create` calls of a container. If provided, the
container will be created/restored from the checkpoint instead of an
existing container.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Regen protos after rebase
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
This adds support for signalling a container process by pid.
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
make Ps more extensible
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
ps: windows support
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
Remove rootfs service in place of snapshot service. Adds
diff service for extracting and creating diffs. Diff
creation is not yet implemented. This service allows
pulling or creating images without needing root access to
mount. Additionally in the future this will allow containerd
to ensure extractions happen safely in a chroot if needed.
Signed-off-by: Derek McGowan <derek@mcgstyle.net>
The split between provider and ingester was a long standing division
reflecting the client-side use cases. For the most part, we were
differentiating these for the algorithms that operate them, but it made
instantation and use of the types challenging. On the server-side, this
distinction is generally less important. This change unifies these types
and in the process we get a few benefits.
The first is that we now completely access the content store over GRPC.
This was the initial intent and we have now satisfied this goal
completely. There are a few issues around listing content and getting
status, but we resolve these with simple streaming and regexp filters.
More can probably be done to polish this but the result is clean.
Several other content-oriented methods were polished in the process of
unification. We have now properly seperated out the `Abort` method to
cancel ongoing or stalled ingest processes. We have also replaced the
`Active` method with a single status method.
The transition went extremely smoothly. Once the clients were updated to
use the new methods, every thing worked as expected on the first
compile.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
This updates containerd to use the latest versions of cgroups, fifo,
console, and go-runc from the containerd org.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
This adds pause and unpause to containerd's execution service and the
same commands to the `ctr` client.
Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com>
This mainly fixes Linux vs generic Unix differences, with some
differences between Darwin and Freebsd (which are close bit not
identical). Should make fixing for other Unix platforms easier.
Note there are not yet `runc` equivalents for these platforms;
my current use case is image manipulation for the `moby` tool.
However there is interest in OCI runtime ports for both platforms.
Current status is that MacOS can build and run `ctr`, `dist`
and `containerd` and some operations are supported. FreeBSD 11
still needs some more fixes to continuity for extended attributes.
Signed-off-by: Justin Cormack <justin.cormack@docker.com>
