pause / containerd config: take advantage of no kubeadm preflight

also fix zfs

pkg/build/nodeimage/build_impl.go

@@ -114,28 +114,11 @@ func (c *buildContext) buildImage(bits kube.Bits) error {
 	}()
 
 	// pre-pull images that were not part of the build
-	images, err := c.prePullImages(bits, dir, containerID)
-	if err != nil {
+	if _, err = c.prePullImages(bits, dir, containerID); err != nil {
 		c.logger.Errorf("Image build Failed! Failed to pull Images: %v", err)
 		return err
 	}
 
-	// find the pause image and inject containerd config
-	pauseImage := findSandboxImage(images)
-	if pauseImage == "" {
-		return errors.New("failed to find imported pause image")
-	}
-	containerdConfig, err := getContainerdConfig(containerdConfigTemplateData{
-		SandboxImage: pauseImage,
-	})
-	if err != nil {
-		return err
-	}
-	const containerdConfigPath = "/etc/containerd/config.toml"
-	if err := createFile(cmder, containerdConfigPath, containerdConfig); err != nil {
-		return err
-	}
-
 	// Save the image changes to a new image
 	cmd := exec.Command(
 		"docker", "commit",
@@ -230,6 +213,24 @@ func (c *buildContext) prePullImages(bits kube.Bits, dir, containerID string) ([
 		return nil, err
 	}
 
+	// replace pause image with our own
+	config, err := exec.Output(cmder.Command("cat", "/etc/containerd/config.toml"))
+	if err != nil {
+		return nil, err
+	}
+	pauseImage, err := findSandboxImage(string(config))
+	if err != nil {
+		return nil, err
+	}
+	n := 0
+	for _, image := range requiredImages {
+		if !strings.Contains(image, "pause") {
+			requiredImages[n] = image
+			n++
+		}
+	}
+	requiredImages = append(requiredImages[:n], pauseImage)
+
 	// write the default CNI manifest
 	if err := createFile(cmder, defaultCNIManifestLocation, defaultCNIManifest); err != nil {
 		c.logger.Errorf("Image build Failed! Failed write default CNI Manifest: %v", err)

pkg/build/nodeimage/containerd_config.go

@@ -1,65 +0,0 @@
-/*
-Copyright 2020 The Kubernetes Authors.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-package nodeimage
-
-import (
-	"bytes"
-	"text/template"
-
-	"sigs.k8s.io/kind/pkg/errors"
-)
-
-type containerdConfigTemplateData struct {
-	SandboxImage string
-}
-
-const containerdConfigTemplate = `# explicitly use v2 config format
-version = 2
-
-# set default runtime handler to v2, which has a per-pod shim
-[plugins."io.containerd.grpc.v1.cri".containerd]
-  default_runtime_name = "runc"
-[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc]
-  runtime_type = "io.containerd.runc.v2"
-
-# Setup a runtime with the magic name ("test-handler") used for Kubernetes
-# runtime class tests ...
-[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.test-handler]
-  runtime_type = "io.containerd.runc.v2"
-
-[plugins."io.containerd.grpc.v1.cri"]
-  # ensure the sandbox image matches kubeadm
-  # TODO: probably we should instead just use the containerd default
-  # Implementing the pod sandbox is a CRI implementation detail ...
-  sandbox_image = "{{.SandboxImage}}"
-  # allow hugepages controller to be missing
-  # see https://github.com/containerd/cri/pull/1501
-  tolerate_missing_hugepages_controller = true
-`
-
-func getContainerdConfig(data containerdConfigTemplateData) (string, error) {
-	t, err := template.New("containerd-config").Parse(containerdConfigTemplate)
-	if err != nil {
-		return "", errors.Wrap(err, "failed to parse containerd config template")
-	}
-	var buff bytes.Buffer
-	err = t.Execute(&buff, data)
-	if err != nil {
-		return "", errors.Wrap(err, "error executing config template")
-	}
-	return buff.String(), nil
-}

pkg/build/nodeimage/helpers.go

@@ -18,8 +18,10 @@ package nodeimage
 
 import (
 	"path"
+	"regexp"
 	"strings"
 
+	"sigs.k8s.io/kind/pkg/errors"
 	"sigs.k8s.io/kind/pkg/exec"
 )
 
@@ -40,13 +42,10 @@ func createFile(containerCmder exec.Cmder, filePath, contents string) error {
 	).Run()
 }
 
-func findSandboxImage(images []string) string {
-	for _, image := range images {
-		// yep this seems legit
-		// https://github.com/kubernetes-sigs/kind/issues/1471#issuecomment-617579803
-		if strings.Contains(image, "pause") {
-			return image
-		}
+func findSandboxImage(config string) (string, error) {
+	match := regexp.MustCompile(`sandbox_image\s+=\s+"([^\n]+)"`).FindStringSubmatch(config)
+	if len(match) < 2 {
+		return "", errors.New("failed to parse sandbox_image from config")
 	}
-	return ""
+	return match[1], nil
 }