Since runtimes can now just be containerd shims, we need to check if the
reference is possibly a containerd shim.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Contrary to popular belief, the OCI Runtime specification does not
specify the command-line API for runtimes. Looking at containerd's
architecture from the lens of the OCI Runtime spec, the _shim_ is the
OCI Runtime and runC is "just" an implementation detail of the
io.containerd.runc.v2 runtime. When one configures a non-default runtime
in Docker, what they're really doing is instructing Docker to create
containers using the io.containerd.runc.v2 runtime with a configuration
option telling the runtime that the runC binary is at some non-default
path. Consequently, only OCI runtimes which are compatible with the
io.containerd.runc.v2 shim, such as crun, can be used in this manner.
Other OCI runtimes, including kata-containers v2, come with their own
containerd shim and are not compatible with io.containerd.runc.v2.
As Docker has not historically provided a way to select a non-default
runtime which requires its own shim, runtimes such as kata-containers v2
could not be used with Docker.
Allow other containerd shims to be used with Docker; no daemon
configuration required. If the daemon is instructed to create a
container with a runtime name which does not match any of the configured
or stock runtimes, it passes the name along to containerd verbatim. A
user can start a container with the kata-containers runtime, for
example, simply by calling
docker run --runtime io.containerd.kata.v2
Runtime names which containerd would interpret as a path to an arbitrary
binary are disallowed. While handy for development and testing it is not
strictly necessary and would allow anyone with Engine API access to
trivially execute any binary on the host as root, so we have decided it
would be safest for our users if it was not allowed.
It is not yet possible to set an alternative containerd shim as the
default runtime; it can only be configured per-container.
Signed-off-by: Cory Snider <csnider@mirantis.com>
The io/ioutil package has been deprecated in Go 1.16. This commit
replaces the existing io/ioutil functions with their new definitions in
io and os packages.
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>
This fixes a panic when an admin specifies a custom default runtime,
when a plugin is started the shim config is nil.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
The previous default runtime `io.containerd.runtime.v1.linux` is being deprecated (https://github.com/containerd/containerd/issues/4365)
`io.containerd.runc.v2` is available since containerd v1.3.0.
Using v1.3.5 or later is recommended. v1.3.0-v1.3.4 doesn't pass `TestContainerStartOnDaemonRestart`.
Fix#41107
Replace #41115
Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
In dockerd we already have a concept of a "runtime", which specifies the
OCI runtime to use (e.g. runc).
This PR extends that config to add containerd shim configuration.
This option is only exposed within the daemon itself (cannot be
configured in daemon.json).
This is due to issues in supporting unknown shims which will require
more design work.
What this change allows us to do is keep all the runtime config in one
place.
So the default "runc" runtime will just have it's already existing shim
config codified within the runtime config alone.
I've also added 2 more "stock" runtimes which are basically runc+shimv1
and runc+shimv2.
These new runtime configurations are:
- io.containerd.runtime.v1.linux - runc + v1 shim using the V1 shim API
- io.containerd.runc.v2 - runc + shim v2
These names coincide with the actual names of the containerd shims.
This allows the user to essentially control what shim is going to be
used by either specifying these as a `--runtime` on container create or
by setting `--default-runtime` on the daemon.
For custom/user-specified runtimes, the default shim config (currently
shim v1) is used.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
