daemon: allow shimv2 runtimes to be configured

Kubernetes only permits RuntimeClass values which are valid lowercase
RFC 1123 labels, which disallows the period character. This prevents
cri-dockerd from being able to support configuring alternative shimv2
runtimes for a pod as shimv2 runtime names must contain at least one
period character. Add support for configuring named shimv2 runtimes in
daemon.json so that runtime names can be aliased to
Kubernetes-compatible names.

Allow options to be set on shimv2 runtimes in daemon.json.

The names of the new daemon runtime config fields have been selected to
correspond with the equivalent field names in cri-containerd's
configuration so that users can more easily follow documentation from
the runtime vendor written for cri-containerd and apply it to
daemon.json.

Signed-off-by: Cory Snider <csnider@mirantis.com>

1 files changed, 38 insertions, 0 deletions

diff --git a/libcontainerd/shimopts/convert.go b/libcontainerd/shimopts/convert.go
new file mode 100644
index 0000000000..b5ef8f52a9
--- /dev/null
+++ b/libcontainerd/shimopts/convert.go
@@ -0,0 +1,38 @@
+package shimopts
+
+import (
+	runhcsoptions "github.com/Microsoft/hcsshim/cmd/containerd-shim-runhcs-v1/options"
+	runtimeoptions "github.com/containerd/containerd/pkg/runtimeoptions/v1"
+	"github.com/containerd/containerd/plugin"
+	runcoptions "github.com/containerd/containerd/runtime/v2/runc/options"
+	"github.com/pelletier/go-toml"
+)
+
+// Generate converts opts into a runtime options value for the runtimeType which
+// can be passed into containerd.
+func Generate(runtimeType string, opts map[string]interface{}) (interface{}, error) {
+	// This is horrible, but we have no other choice. The containerd client
+	// can only handle options values which can be marshaled into a
+	// typeurl.Any. And we're in good company: cri-containerd handles shim
+	// options in the same way.
+	var out interface{}
+	switch runtimeType {
+	case plugin.RuntimeRuncV1, plugin.RuntimeRuncV2:
+		out = &runcoptions.Options{}
+	case "io.containerd.runhcs.v1":
+		out = &runhcsoptions.Options{}
+	default:
+		out = &runtimeoptions.Options{}
+	}
+
+	// We can't use mergo.Map as it is too strict about type-assignability
+	// with numeric types.
+	tree, err := toml.TreeFromMap(opts)
+	if err != nil {
+		return nil, err
+	}
+	if err := tree.Unmarshal(out); err != nil {
+		return nil, err
+	}
+	return out, nil
+}