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kubeadm: Set the kubelet --resolv-conf flag conditionally on init #64665

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Merged
k8s-github-robot merged 1 commit into from
Jun 4, 2018
Merged

kubeadm: Set the kubelet --resolv-conf flag conditionally on init #64665

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1 change: 1 addition & 0 deletions cmd/kubeadm/app/phases/kubelet/BUILD
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@ go_library(
"//pkg/apis/rbac/v1:go_default_library",
"//pkg/kubelet/apis/kubeletconfig/scheme:go_default_library",
"//pkg/kubelet/apis/kubeletconfig/v1beta1:go_default_library",
"//pkg/util/procfs:go_default_library",
"//pkg/util/version:go_default_library",
"//vendor/github.com/golang/glog:go_default_library",
"//vendor/k8s.io/api/core/v1:go_default_library",
Expand Down
7 changes: 6 additions & 1 deletion cmd/kubeadm/app/phases/kubelet/flags.go
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Expand Up @@ -28,6 +28,7 @@ import (
kubeadmapiv1alpha2 "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1alpha2"
"k8s.io/kubernetes/cmd/kubeadm/app/constants"
kubeadmutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
"k8s.io/kubernetes/pkg/util/procfs"
utilsexec "k8s.io/utils/exec"
)

Expand Down Expand Up @@ -72,8 +73,12 @@ func buildKubeletArgMap(nodeRegOpts *kubeadmapi.NodeRegistrationOptions, registe
kubeletFlags["register-with-taints"] = strings.Join(taintStrs, ",")
}

if pids, _ := procfs.PidOf("systemd-resolved"); len(pids) > 0 {
// procfs.PidOf only returns an error if the regex is empty or doesn't compile, so we can ignore it

@timothysc timothysc Jun 4, 2018

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IMO - we should still emit a message as a breadcrumb to the user in case anything happens.

kubeletFlags["resolv-conf"] = "/run/systemd/resolve/resolv.conf"
}

// TODO: Pass through --hostname-override if a custom name is used?
// TODO: Check if `systemd-resolved` is running, and set `--resolv-conf` based on that
// TODO: Conditionally set `--cgroup-driver` to either `systemd` or `cgroupfs` for CRI other than Docker

return kubeletFlags
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1 change: 0 additions & 1 deletion cmd/kubeadm/app/preflight/BUILD
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Expand Up @@ -57,7 +57,6 @@ go_library(
"//pkg/registry/core/service/ipallocator:go_default_library",
"//pkg/util/initsystem:go_default_library",
"//pkg/util/ipvs:go_default_library",
"//pkg/util/procfs:go_default_library",
"//pkg/util/version:go_default_library",
"//pkg/version:go_default_library",
"//test/e2e_node/system:go_default_library",
Expand Down
31 changes: 1 addition & 30 deletions cmd/kubeadm/app/preflight/checks.go
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Expand Up @@ -51,7 +51,6 @@ import (
"k8s.io/kubernetes/pkg/registry/core/service/ipallocator"
"k8s.io/kubernetes/pkg/util/initsystem"
ipvsutil "k8s.io/kubernetes/pkg/util/ipvs"
"k8s.io/kubernetes/pkg/util/procfs"
versionutil "k8s.io/kubernetes/pkg/util/version"
kubeadmversion "k8s.io/kubernetes/pkg/version"
"k8s.io/kubernetes/test/e2e_node/system"
Expand Down Expand Up @@ -830,33 +829,6 @@ func getEtcdVersionResponse(client *http.Client, url string, target interface{})
return err
}

// ResolveCheck tests for potential issues related to the system resolver configuration
type ResolveCheck struct{}

// Name returns label for ResolveCheck
func (ResolveCheck) Name() string {
return "Resolve"
}

// Check validates the system resolver configuration
func (ResolveCheck) Check() (warnings, errors []error) {
glog.V(1).Infoln("validating the system resolver configuration")

warnings = []error{}

// procfs.PidOf only returns an error if the string passed is empty
// or there is an issue compiling the regex, so we can ignore it here
pids, _ := procfs.PidOf("systemd-resolved")
if len(pids) > 0 {
warnings = append(warnings, fmt.Errorf(
"systemd-resolved was detected, for cluster dns resolution to work "+
"properly --resolv-conf=/run/systemd/resolve/resolv.conf must be set "+
"for the kubelet. (/etc/systemd/system/kubelet.service.d/10-kubeadm.conf should be edited for this purpose)\n"))
}

return warnings, errors
}

// ImagePullCheck will pull container images used by kubeadm
type ImagePullCheck struct {
Images images.Images
Expand Down Expand Up @@ -1011,8 +983,7 @@ func addCommonChecks(execer utilsexec.Interface, cfg kubeadmapi.CommonConfigurat
InPathCheck{executable: "ethtool", mandatory: false, exec: execer},
InPathCheck{executable: "socat", mandatory: false, exec: execer},
InPathCheck{executable: "tc", mandatory: false, exec: execer},
InPathCheck{executable: "touch", mandatory: false, exec: execer},
ResolveCheck{})
InPathCheck{executable: "touch", mandatory: false, exec: execer})
}
checks = append(checks,
SystemVerificationCheck{CRISocket: cfg.GetCRISocket()},
Expand Down