2a63ba1db6
Add a new utility file - util/cgroupdriver.go. Currently it only contains the public function GetCgroupDriverDocker(). The function uses 'docker info' to obtain the cgroup driver for Docker. On a later stage this file can contain more methods for different CRI. Use GetCgroupDriverDocker() in phases/kubelet/flags.go to conditionally set the 'cgroup-driver' argument. On error print a warning and don't set the argument value. Add unit tests in cgroupdriver_test.go.
95 lines
3.7 KiB
Go
95 lines
3.7 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 kubelet
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import (
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"fmt"
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"io/ioutil"
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"os"
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"path/filepath"
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"strings"
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"github.com/golang/glog"
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kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
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kubeadmapiv1alpha2 "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1alpha2"
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"k8s.io/kubernetes/cmd/kubeadm/app/constants"
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kubeadmutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
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utilsexec "k8s.io/utils/exec"
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)
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// WriteKubeletDynamicEnvFile writes a environment file with dynamic flags to the kubelet.
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// Used at "kubeadm init" and "kubeadm join" time.
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func WriteKubeletDynamicEnvFile(nodeRegOpts *kubeadmapi.NodeRegistrationOptions, registerTaintsUsingFlags bool) error {
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argList := kubeadmutil.BuildArgumentListFromMap(buildKubeletArgMap(nodeRegOpts, registerTaintsUsingFlags), nodeRegOpts.ExtraArgs)
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envFileContent := fmt.Sprintf("%s=%s\n", constants.KubeletEnvFileVariableName, strings.Join(argList, " "))
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return writeKubeletFlagBytesToDisk([]byte(envFileContent))
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}
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// buildKubeletArgMap takes a MasterConfiguration object and builds based on that a string-string map with flags
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// that should be given to the local kubelet daemon.
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func buildKubeletArgMap(nodeRegOpts *kubeadmapi.NodeRegistrationOptions, registerTaintsUsingFlags bool) map[string]string {
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kubeletFlags := map[string]string{}
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if nodeRegOpts.CRISocket == kubeadmapiv1alpha2.DefaultCRISocket {
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// These flags should only be set when running docker
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kubeletFlags["network-plugin"] = "cni"
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kubeletFlags["cni-conf-dir"] = "/etc/cni/net.d"
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kubeletFlags["cni-bin-dir"] = "/opt/cni/bin"
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execer := utilsexec.New()
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driver, err := kubeadmutil.GetCgroupDriverDocker(execer)
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if err != nil {
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glog.Warningf("cannot automatically assign a '--cgroup-driver' value when starting the Kubelet: %v\n", err)
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} else {
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kubeletFlags["cgroup-driver"] = driver
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}
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} else {
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kubeletFlags["container-runtime"] = "remote"
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kubeletFlags["container-runtime-endpoint"] = nodeRegOpts.CRISocket
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}
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if registerTaintsUsingFlags && nodeRegOpts.Taints != nil && len(nodeRegOpts.Taints) > 0 {
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taintStrs := []string{}
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for _, taint := range nodeRegOpts.Taints {
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taintStrs = append(taintStrs, taint.ToString())
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}
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kubeletFlags["register-with-taints"] = strings.Join(taintStrs, ",")
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}
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// TODO: Pass through --hostname-override if a custom name is used?
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// TODO: Check if `systemd-resolved` is running, and set `--resolv-conf` based on that
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// TODO: Conditionally set `--cgroup-driver` to either `systemd` or `cgroupfs` for CRI other than Docker
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return kubeletFlags
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}
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// writeKubeletFlagBytesToDisk writes a byte slice down to disk at the specific location of the kubelet flag overrides file
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func writeKubeletFlagBytesToDisk(b []byte) error {
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fmt.Printf("[kubelet] Writing kubelet environment file with flags to file %q\n", constants.KubeletEnvFile)
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// creates target folder if not already exists
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if err := os.MkdirAll(filepath.Dir(constants.KubeletEnvFile), 0700); err != nil {
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return fmt.Errorf("failed to create directory %q: %v", filepath.Dir(constants.KubeletEnvFile), err)
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}
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if err := ioutil.WriteFile(constants.KubeletEnvFile, b, 0644); err != nil {
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return fmt.Errorf("failed to write kubelet configuration to the file %q: %v", constants.KubeletEnvFile, err)
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}
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return nil
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}
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