[docker-up] Set same MTU than ceth0

Author: aledbf

components/docker-up/BUILD.yaml

@@ -40,8 +40,8 @@ packages:
         - ["rm", "-r", "components-docker-up--bin-docker-up"]
         - ["mv", "components-docker-up--bin-runc-facade/docker-up", "runc-facade"]
         - ["rm", "-r", "components-docker-up--bin-runc-facade"]
-        # Override docker-compose with custom version https://github.com/aledbf/compose/pull/1
-        - ["curl", "-sSL", "https://github.com/aledbf/compose/releases/download/v2.4.1.1-gitpod/docker-compose-linux-x86_64", "-o", "docker-compose"]
+        # Override docker-compose with custom version https://github.com/gitpod-io/compose/pull/1
+        - ["curl", "-sSL", "https://github.com/aledbf/compose/releases/download/v2.4.1.2-gitpod/docker-compose-linux-x86_64", "-o", "docker-compose"]
         - ["chmod", "+x", "docker-compose"]
   - name: docker
     type: docker

components/docker-up/docker-up/main.go

@@ -29,6 +29,7 @@ import (
 	sigproxysignal "github.com/rootless-containers/rootlesskit/pkg/sigproxy/signal"
 	"github.com/sirupsen/logrus"
 	"github.com/spf13/pflag"
+	"github.com/vishvananda/netlink"
 	"golang.org/x/sys/unix"
 	"golang.org/x/xerrors"
 )
@@ -122,6 +123,14 @@ func runWithinNetns() (err error) {
 	}
 	args = append(args, userArgs...)
 
+	containerIf := "ceth0"
+	netIface, err := netlink.LinkByName(containerIf)
+	if err != nil {
+		return xerrors.Errorf("cannot get container network device %s: %w", containerIf, err)
+	}
+
+	args = append(args, fmt.Sprintf("--mtu=%v", netIface.Attrs().MTU))
+
 	if listenFDs > 0 {
 		os.Setenv("LISTEN_PID", strconv.Itoa(os.Getpid()))
 		args = append(args, "-H", "fd://")