containerd: add socket forwarding to host (#1017)

* Added containerd socket port forward when using containerd runtime

* Added comment to "HostSocketFile" function in containerd.go

environment/container/containerd/containerd.go

@@ -3,15 +3,20 @@ package containerd
 import (
 	"context"
 	_ "embed"
+	"path/filepath"
 	"time"
 
 	"github.com/abiosoft/colima/cli"
+	"github.com/abiosoft/colima/config"
 	"github.com/abiosoft/colima/environment"
 )
 
 // Name is container runtime name
 const Name = "containerd"
 
+// HostSocketFile returns the path to the containerd socket on host.
+func HostSocketFile() string { return filepath.Join(config.Dir(), "containerd.sock") }
+
 // This is written with assumption that Lima is the VM,
 // which provides nerdctl/containerd support out of the box.
 // There may be need to make this flexible for non-Lima VMs.

environment/vm/lima/yaml.go

@@ -13,6 +13,7 @@ import (
 
 	"github.com/abiosoft/colima/config"
 	"github.com/abiosoft/colima/environment"
+	"github.com/abiosoft/colima/environment/container/containerd"
 	"github.com/abiosoft/colima/environment/container/docker"
 	"github.com/abiosoft/colima/util"
 	"github.com/sirupsen/logrus"
@@ -198,6 +199,16 @@ func newConf(ctx context.Context, conf config.Config) (l Config, err error) {
 			}
 		}
 
+		// containerd socket
+		if conf.Runtime == containerd.Name {
+			l.PortForwards = append(l.PortForwards,
+				PortForward{
+					GuestSocket: "/var/run/containerd.sock",
+					HostSocket:  containerd.HostSocketFile(),
+					Proto:       TCP,
+				})
+		}
+
 		// handle port forwarding to allow listening on 0.0.0.0
 		// bind 0.0.0.0
 		l.PortForwards = append(l.PortForwards,