kubernetes/pkg/kubelet/prober/prober.go
2023-03-02 22:07:59 +00:00

256 lines
8.7 KiB
Go

/*
Copyright 2014 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 prober
import (
"context"
"fmt"
"io"
"time"
v1 "k8s.io/api/core/v1"
"k8s.io/client-go/tools/record"
kubecontainer "k8s.io/kubernetes/pkg/kubelet/container"
"k8s.io/kubernetes/pkg/kubelet/events"
"k8s.io/kubernetes/pkg/kubelet/prober/results"
"k8s.io/kubernetes/pkg/kubelet/util/format"
"k8s.io/kubernetes/pkg/probe"
execprobe "k8s.io/kubernetes/pkg/probe/exec"
grpcprobe "k8s.io/kubernetes/pkg/probe/grpc"
httpprobe "k8s.io/kubernetes/pkg/probe/http"
tcpprobe "k8s.io/kubernetes/pkg/probe/tcp"
"k8s.io/utils/exec"
"k8s.io/klog/v2"
)
const maxProbeRetries = 3
// Prober helps to check the liveness/readiness/startup of a container.
type prober struct {
exec execprobe.Prober
http httpprobe.Prober
tcp tcpprobe.Prober
grpc grpcprobe.Prober
runner kubecontainer.CommandRunner
recorder record.EventRecorder
}
// NewProber creates a Prober, it takes a command runner and
// several container info managers.
func newProber(
runner kubecontainer.CommandRunner,
recorder record.EventRecorder) *prober {
const followNonLocalRedirects = false
return &prober{
exec: execprobe.New(),
http: httpprobe.New(followNonLocalRedirects),
tcp: tcpprobe.New(),
grpc: grpcprobe.New(),
runner: runner,
recorder: recorder,
}
}
// recordContainerEvent should be used by the prober for all container related events.
func (pb *prober) recordContainerEvent(pod *v1.Pod, container *v1.Container, eventType, reason, message string, args ...interface{}) {
ref, err := kubecontainer.GenerateContainerRef(pod, container)
if err != nil {
klog.ErrorS(err, "Can't make a ref to pod and container", "pod", klog.KObj(pod), "containerName", container.Name)
return
}
pb.recorder.Eventf(ref, eventType, reason, message, args...)
}
// probe probes the container.
func (pb *prober) probe(ctx context.Context, probeType probeType, pod *v1.Pod, status v1.PodStatus, container v1.Container, containerID kubecontainer.ContainerID) (results.Result, error) {
var probeSpec *v1.Probe
switch probeType {
case readiness:
probeSpec = container.ReadinessProbe
case liveness:
probeSpec = container.LivenessProbe
case startup:
probeSpec = container.StartupProbe
default:
return results.Failure, fmt.Errorf("unknown probe type: %q", probeType)
}
if probeSpec == nil {
klog.InfoS("Probe is nil", "probeType", probeType, "pod", klog.KObj(pod), "podUID", pod.UID, "containerName", container.Name)
return results.Success, nil
}
result, output, err := pb.runProbeWithRetries(ctx, probeType, probeSpec, pod, status, container, containerID, maxProbeRetries)
if err != nil || (result != probe.Success && result != probe.Warning) {
// Probe failed in one way or another.
if err != nil {
klog.V(1).ErrorS(err, "Probe errored", "probeType", probeType, "pod", klog.KObj(pod), "podUID", pod.UID, "containerName", container.Name)
pb.recordContainerEvent(pod, &container, v1.EventTypeWarning, events.ContainerUnhealthy, "%s probe errored: %v", probeType, err)
} else { // result != probe.Success
klog.V(1).InfoS("Probe failed", "probeType", probeType, "pod", klog.KObj(pod), "podUID", pod.UID, "containerName", container.Name, "probeResult", result, "output", output)
pb.recordContainerEvent(pod, &container, v1.EventTypeWarning, events.ContainerUnhealthy, "%s probe failed: %s", probeType, output)
}
return results.Failure, err
}
if result == probe.Warning {
pb.recordContainerEvent(pod, &container, v1.EventTypeWarning, events.ContainerProbeWarning, "%s probe warning: %s", probeType, output)
klog.V(3).InfoS("Probe succeeded with a warning", "probeType", probeType, "pod", klog.KObj(pod), "podUID", pod.UID, "containerName", container.Name, "output", output)
} else {
klog.V(3).InfoS("Probe succeeded", "probeType", probeType, "pod", klog.KObj(pod), "podUID", pod.UID, "containerName", container.Name)
}
return results.Success, nil
}
// runProbeWithRetries tries to probe the container in a finite loop, it returns the last result
// if it never succeeds.
func (pb *prober) runProbeWithRetries(ctx context.Context, probeType probeType, p *v1.Probe, pod *v1.Pod, status v1.PodStatus, container v1.Container, containerID kubecontainer.ContainerID, retries int) (probe.Result, string, error) {
var err error
var result probe.Result
var output string
for i := 0; i < retries; i++ {
result, output, err = pb.runProbe(ctx, probeType, p, pod, status, container, containerID)
if err == nil {
return result, output, nil
}
}
return result, output, err
}
func (pb *prober) runProbe(ctx context.Context, probeType probeType, p *v1.Probe, pod *v1.Pod, status v1.PodStatus, container v1.Container, containerID kubecontainer.ContainerID) (probe.Result, string, error) {
timeout := time.Duration(p.TimeoutSeconds) * time.Second
if p.Exec != nil {
klog.V(4).InfoS("Exec-Probe runProbe", "pod", klog.KObj(pod), "containerName", container.Name, "execCommand", p.Exec.Command)
command := kubecontainer.ExpandContainerCommandOnlyStatic(p.Exec.Command, container.Env)
return pb.exec.Probe(pb.newExecInContainer(ctx, container, containerID, command, timeout))
}
if p.HTTPGet != nil {
req, err := httpprobe.NewRequestForHTTPGetAction(p.HTTPGet, &container, status.PodIP, "probe")
if err != nil {
return probe.Unknown, "", err
}
if klogV4 := klog.V(4); klogV4.Enabled() {
port := req.URL.Port()
host := req.URL.Hostname()
path := req.URL.Path
scheme := req.URL.Scheme
headers := p.HTTPGet.HTTPHeaders
klogV4.InfoS("HTTP-Probe", "scheme", scheme, "host", host, "port", port, "path", path, "timeout", timeout, "headers", headers)
}
return pb.http.Probe(req, timeout)
}
if p.TCPSocket != nil {
port, err := probe.ResolveContainerPort(p.TCPSocket.Port, &container)
if err != nil {
return probe.Unknown, "", err
}
host := p.TCPSocket.Host
if host == "" {
host = status.PodIP
}
klog.V(4).InfoS("TCP-Probe", "host", host, "port", port, "timeout", timeout)
return pb.tcp.Probe(host, port, timeout)
}
if p.GRPC != nil {
host := status.PodIP
service := ""
if p.GRPC.Service != nil {
service = *p.GRPC.Service
}
klog.V(4).InfoS("GRPC-Probe", "host", host, "service", service, "port", p.GRPC.Port, "timeout", timeout)
return pb.grpc.Probe(host, service, int(p.GRPC.Port), timeout)
}
klog.InfoS("Failed to find probe builder for container", "containerName", container.Name)
return probe.Unknown, "", fmt.Errorf("missing probe handler for %s:%s", format.Pod(pod), container.Name)
}
type execInContainer struct {
// run executes a command in a container. Combined stdout and stderr output is always returned. An
// error is returned if one occurred.
run func() ([]byte, error)
writer io.Writer
}
func (pb *prober) newExecInContainer(ctx context.Context, container v1.Container, containerID kubecontainer.ContainerID, cmd []string, timeout time.Duration) exec.Cmd {
return &execInContainer{run: func() ([]byte, error) {
return pb.runner.RunInContainer(ctx, containerID, cmd, timeout)
}}
}
func (eic *execInContainer) Run() error {
return nil
}
func (eic *execInContainer) CombinedOutput() ([]byte, error) {
return eic.run()
}
func (eic *execInContainer) Output() ([]byte, error) {
return nil, fmt.Errorf("unimplemented")
}
func (eic *execInContainer) SetDir(dir string) {
// unimplemented
}
func (eic *execInContainer) SetStdin(in io.Reader) {
// unimplemented
}
func (eic *execInContainer) SetStdout(out io.Writer) {
eic.writer = out
}
func (eic *execInContainer) SetStderr(out io.Writer) {
eic.writer = out
}
func (eic *execInContainer) SetEnv(env []string) {
// unimplemented
}
func (eic *execInContainer) Stop() {
// unimplemented
}
func (eic *execInContainer) Start() error {
data, err := eic.run()
if eic.writer != nil {
// only record the write error, do not cover the command run error
if p, err := eic.writer.Write(data); err != nil {
klog.ErrorS(err, "Unable to write all bytes from execInContainer", "expectedBytes", len(data), "actualBytes", p)
}
}
return err
}
func (eic *execInContainer) Wait() error {
return nil
}
func (eic *execInContainer) StdoutPipe() (io.ReadCloser, error) {
return nil, fmt.Errorf("unimplemented")
}
func (eic *execInContainer) StderrPipe() (io.ReadCloser, error) {
return nil, fmt.Errorf("unimplemented")
}