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1d032c40d3
systemd is the recommended driver as per the setup of running the kubelet using systemd as the init system. Add a preflight check that throws a warning if this isn't the case.
84 lines
2.4 KiB
Go
84 lines
2.4 KiB
Go
/*
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Copyright 2018 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package util
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import (
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"strings"
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"github.com/pkg/errors"
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utilsexec "k8s.io/utils/exec"
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)
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const (
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// CgroupDriverSystemd holds the systemd driver type
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CgroupDriverSystemd = "systemd"
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// CgroupDriverCgroupfs holds the cgroupfs driver type
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CgroupDriverCgroupfs = "cgroupfs"
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)
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// TODO: add support for detecting the cgroup driver for CRI other than
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// Docker. Currently only Docker driver detection is supported:
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// Discussion:
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// https://github.com/kubernetes/kubeadm/issues/844
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// GetCgroupDriverDocker runs 'docker info' to obtain the docker cgroup driver
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func GetCgroupDriverDocker(execer utilsexec.Interface) (string, error) {
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info, err := callDockerInfo(execer)
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if err != nil {
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return "", err
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}
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return getCgroupDriverFromDockerInfo(info)
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}
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func validateCgroupDriver(driver string) error {
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if driver != CgroupDriverCgroupfs && driver != CgroupDriverSystemd {
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return errors.Errorf("unknown cgroup driver %q", driver)
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}
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return nil
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}
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// TODO: Docker 1.13 has a new way to obatain the cgroup driver:
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// docker info -f "{{.CgroupDriver}}
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// If the minimum supported Docker version in K8s becomes 1.13, move to
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// this syntax.
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func callDockerInfo(execer utilsexec.Interface) (string, error) {
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out, err := execer.Command("docker", "info").Output()
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if err != nil {
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return "", errors.Wrap(err, "cannot execute 'docker info'")
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}
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return string(out), nil
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}
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func getCgroupDriverFromDockerInfo(info string) (string, error) {
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lineSeparator := ": "
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prefix := "Cgroup Driver"
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for _, line := range strings.Split(info, "\n") {
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if !strings.Contains(line, prefix+lineSeparator) {
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continue
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}
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lineSplit := strings.Split(line, lineSeparator)
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// At this point len(lineSplit) is always >= 2
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driver := lineSplit[1]
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if err := validateCgroupDriver(driver); err != nil {
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return "", err
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}
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return driver, nil
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}
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return "", errors.New("cgroup driver is not defined in 'docker info'")
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}
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