diff --git a/cmd/kubeadm/app/phases/kubelet/flags_test.go b/cmd/kubeadm/app/phases/kubelet/flags_test.go index 4c4b44f288d..fb838912b4e 100644 --- a/cmd/kubeadm/app/phases/kubelet/flags_test.go +++ b/cmd/kubeadm/app/phases/kubelet/flags_test.go @@ -66,23 +66,23 @@ func (f fakeExecer) LookPath(file string) (string, error) { return "", errors.Ne var ( systemdCgroupExecer = fakeExecer{ ioMap: map[string]fakeCmd{ - "docker info": { - b: []byte(`Cgroup Driver: systemd`), + "docker info -f {{.CgroupDriver}}": { + b: []byte(`systemd`), }, }, } cgroupfsCgroupExecer = fakeExecer{ ioMap: map[string]fakeCmd{ - "docker info": { - b: []byte(`Cgroup Driver: cgroupfs`), + "docker info -f {{.CgroupDriver}}": { + b: []byte(`cgroupfs`), }, }, } errCgroupExecer = fakeExecer{ ioMap: map[string]fakeCmd{ - "docker info": { + "docker info -f {{.CgroupDriver}}": { err: errors.New("no such binary: docker"), }, }, diff --git a/cmd/kubeadm/app/util/cgroupdriver.go b/cmd/kubeadm/app/util/cgroupdriver.go index 602f6c3f6f3..e183684da1b 100644 --- a/cmd/kubeadm/app/util/cgroupdriver.go +++ b/cmd/kubeadm/app/util/cgroupdriver.go @@ -36,13 +36,13 @@ const ( // Discussion: // https://github.com/kubernetes/kubeadm/issues/844 -// GetCgroupDriverDocker runs 'docker info' to obtain the docker cgroup driver +// GetCgroupDriverDocker runs 'docker info -f "{{.CgroupDriver}}"' to obtain the docker cgroup driver func GetCgroupDriverDocker(execer utilsexec.Interface) (string, error) { - info, err := callDockerInfo(execer) + driver, err := callDockerInfo(execer) if err != nil { return "", err } - return getCgroupDriverFromDockerInfo(info) + return strings.TrimSuffix(driver, "\n"), nil } func validateCgroupDriver(driver string) error { @@ -52,32 +52,10 @@ func validateCgroupDriver(driver string) error { return nil } -// TODO: Docker 1.13 has a new way to obatain the cgroup driver: -// docker info -f "{{.CgroupDriver}} -// If the minimum supported Docker version in K8s becomes 1.13, move to -// this syntax. func callDockerInfo(execer utilsexec.Interface) (string, error) { - out, err := execer.Command("docker", "info").Output() + out, err := execer.Command("docker", "info", "-f", "{{.CgroupDriver}}").Output() if err != nil { return "", errors.Wrap(err, "cannot execute 'docker info'") } return string(out), nil } - -func getCgroupDriverFromDockerInfo(info string) (string, error) { - lineSeparator := ": " - prefix := "Cgroup Driver" - for _, line := range strings.Split(info, "\n") { - if !strings.Contains(line, prefix+lineSeparator) { - continue - } - lineSplit := strings.Split(line, lineSeparator) - // At this point len(lineSplit) is always >= 2 - driver := lineSplit[1] - if err := validateCgroupDriver(driver); err != nil { - return "", err - } - return driver, nil - } - return "", errors.New("cgroup driver is not defined in 'docker info'") -} diff --git a/cmd/kubeadm/app/util/cgroupdriver_test.go b/cmd/kubeadm/app/util/cgroupdriver_test.go index ca1ba3a4545..3d6b66373d3 100644 --- a/cmd/kubeadm/app/util/cgroupdriver_test.go +++ b/cmd/kubeadm/app/util/cgroupdriver_test.go @@ -23,45 +23,36 @@ import ( func TestGetCgroupDriverDocker(t *testing.T) { testCases := []struct { name string - info string + driver string expectedError bool }{ { name: "valid: value is 'cgroupfs'", - info: `Cgroup Driver: cgroupfs`, + driver: `cgroupfs`, expectedError: false, }, { name: "valid: value is 'systemd'", - info: `Cgroup Driver: systemd`, + driver: `systemd`, expectedError: false, }, - { - name: "invalid: missing 'Cgroup Driver' key and value", - info: "", - expectedError: true, - }, - { - name: "invalid: only a 'Cgroup Driver' key is present", - info: `Cgroup Driver`, - expectedError: true, - }, { name: "invalid: empty 'Cgroup Driver' value", - info: `Cgroup Driver: `, + driver: ``, expectedError: true, }, { name: "invalid: unknown 'Cgroup Driver' value", - info: `Cgroup Driver: invalid-value`, + driver: `invalid-value`, expectedError: true, }, } for _, tc := range testCases { t.Run(tc.name, func(t *testing.T) { - if _, err := getCgroupDriverFromDockerInfo(tc.info); (err != nil) != tc.expectedError { - t.Fatalf("expected error: %v, saw: %v, error: %v", tc.expectedError, (err != nil), err) + result := tc.driver != CgroupDriverCgroupfs && tc.driver != CgroupDriverSystemd + if result != tc.expectedError { + t.Fatalf("expected error: %v, saw: %v", tc.expectedError, result) } }) }