This adds a way for users to programatically install containerd binary
dependencies.
With runtime v2 and new shim's being built, it will be a challenge to
get those onto machines. Users would have to find the link, download,
place it in their path, yada yada yada.
With this functionality of a managed `/opt` directory, containerd can
use existing image and distribution infra. to get binarys, shims, etc
onto the system.
Configuration:
*default:* `/opt/containerd`
*containerd config:*
```toml
[plugins.opt]
path = "/opt/mypath"
```
Usage:
*code:*
```go
image, err := client.Pull(ctx, "docker.io/crosbymichael/runc:latest")
client.Install(ctx, image)
```
*ctr:*
```bash
ctr content fetch docker.io/crosbymichael/runc:latest
ctr install docker.io/crosbymichael/runc:latest
```
You can manage versions and see what is running via standard image
commands.
Images:
These images MUST be small and only contain binaries.
```Dockerfile
FROM scratch
Add runc /bin/runc
```
Containerd will only extract files in `/bin` of the image.
Later on, we can add support for `/lib`.
The code adds a service to manage an `/opt/containerd` directory and
provide that path to callers via the introspection service.
How to Test:
Delete runc from your system.
```bash
> sudo ctr run --rm docker.io/library/redis:alpine redis
ctr: OCI runtime create failed: unable to retrieve OCI runtime error (open /run/containerd/io.containerd.runtime.v1.linux/default/redis/log.json: no such file or directory): exec: "runc": executable file not found in $PATH: unknown
> sudo ctr content fetch docker.io/crosbymichael/runc:latest
> sudo ctr install docker.io/crosbymichael/runc:latest
> sudo ctr run --rm docker.io/library/redis:alpine redis
1:C 01 Aug 15:59:52.864 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
1:C 01 Aug 15:59:52.864 # Redis version=4.0.10, bits=64, commit=00000000, modified=0, pid=1, just started
1:C 01 Aug 15:59:52.864 # Warning: no config file specified, using the default config. In order to specify a config file use redis-server /path/to/redis.conf
1:M 01 Aug 15:59:52.866 # You requested maxclients of 10000 requiring at least 10032 max file descriptors.
1:M 01 Aug 15:59:52.866 # Server can't set maximum open files to 10032 because of OS error: Operation not permitted.
1:M 01 Aug 15:59:52.866 # Current maximum open files is 1024. maxclients has been reduced to 992 to compensate for low ulimit. If you need higher maxclients increase 'ulimit -n'.
1:M 01 Aug 15:59:52.870 * Running mode=standalone, port=6379.
1:M 01 Aug 15:59:52.870 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
1:M 01 Aug 15:59:52.870 # Server initialized
1:M 01 Aug 15:59:52.870 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect.
1:M 01 Aug 15:59:52.870 # WARNING you have Transparent Huge Pages (THP) support enabled in your kernel. This will create latency and memory usage issues with Redis. To fix this issue run the command 'echo never > /sys/kernel/mm/transparent_hugepage/enabled' as root, and add it to your /etc/rc.local in order to retain the setting after a reboot. Redis must be restarted after THP is disabled.
1:M 01 Aug 15:59:52.870 * Ready to accept connections
^C1:signal-handler (1533139193) Received SIGINT scheduling shutdown...
1:M 01 Aug 15:59:53.472 # User requested shutdown...
1:M 01 Aug 15:59:53.472 * Saving the final RDB snapshot before exiting.
1:M 01 Aug 15:59:53.484 * DB saved on disk
1:M 01 Aug 15:59:53.484 # Redis is now ready to exit, bye bye...
```
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Synchronous image delete provides an option image delete to wait
until the next garbage collection deletes after an image is removed
before returning success to the caller.
Signed-off-by: Derek McGowan <derek@mcgstyle.net>
Add garbage collection as a background process and policy
configuration for configuring when to run garbage collection.
By default garbage collection will run when deletion occurs
and no more than 20ms out of every second.
Signed-off-by: Derek McGowan <derek@mcgstyle.net>
Add differ options and package with interface.
Update optional values on diff interface to use options.
Signed-off-by: Derek McGowan <derek@mcgstyle.net>
With this change, we integrate all the plugin changes into the
introspection service.
All plugins can be listed with the following command:
```console
$ ctr plugins
TYPE ID PLATFORM STATUS
io.containerd.content.v1 content - ok
io.containerd.metadata.v1 bolt - ok
io.containerd.differ.v1 walking linux/amd64 ok
io.containerd.grpc.v1 containers - ok
io.containerd.grpc.v1 content - ok
io.containerd.grpc.v1 diff - ok
io.containerd.grpc.v1 events - ok
io.containerd.grpc.v1 healthcheck - ok
io.containerd.grpc.v1 images - ok
io.containerd.grpc.v1 namespaces - ok
io.containerd.snapshotter.v1 btrfs linux/amd64 error
io.containerd.snapshotter.v1 overlayfs linux/amd64 ok
io.containerd.grpc.v1 snapshots - ok
io.containerd.monitor.v1 cgroups linux/amd64 ok
io.containerd.runtime.v1 linux linux/amd64 ok
io.containerd.grpc.v1 tasks - ok
io.containerd.grpc.v1 version - ok
```
There are few things to note about this output. The first is that it is
printed in the order in which plugins are initialized. This useful for
debugging plugin initialization problems. Also note that even though the
introspection GPRC api is a itself a plugin, it is not listed. This is
because the plugin takes a snapshot of the initialization state at the
end of the plugin init process. This allows us to see errors from each
plugin, as they happen. If it is required to introspect the existence of
the introspection service, we can make modifications to include it in
the future.
The last thing to note is that the btrfs plugin is in an error state.
This is a common state for containerd because even though we load the
plugin, most installations aren't on top of btrfs and the plugin cannot
be used. We can actually view this error using the detailed view with a
filter:
```console
$ ctr plugins --detailed id==btrfs
Type: io.containerd.snapshotter.v1
ID: btrfs
Platforms: linux/amd64
Exports:
root /var/lib/containerd/io.containerd.snapshotter.v1.btrfs
Error:
Code: Unknown
Message: path /var/lib/containerd/io.containerd.snapshotter.v1.btrfs must be a btrfs filesystem to be used with the btrfs snapshotter
```
Along with several other values, this is a valuable tool for evaluating the
state of components in containerd.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: update events package to include emitter and use envelope proto
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: add events service
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: enable events service and update ctr events to use events service
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
event listeners
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: helper func for emitting in services
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: improved cli for containers and tasks
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
create event envelope with poster
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: introspect event data to use for type url
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: use pb encoding; add event types
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: instrument content and snapshot services with events
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: instrument image service with events
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: instrument namespace service with events
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: add namespace support
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: only send events from namespace requested from client
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: switch to go-events for broadcasting
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
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>
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>
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>
With this changeset, image store access is now moved to completely
accessible over GRPC. No clients manipulate the image store database
directly and the GRPC client is fully featured. The metadata database is
now managed by the daemon and access coordinated via services.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Because of the plugin findings and having the default runtime builtin
this makes it much better for development and testing.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
