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healthcheck.go
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healthcheck.go
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//go:build !remote
package libpod
import (
"bufio"
"context"
"errors"
"fmt"
"io/fs"
"os"
"path/filepath"
"strings"
"time"
"github.com/containers/podman/v5/libpod/define"
"github.com/sirupsen/logrus"
"golang.org/x/sys/unix"
)
const (
// MaxHealthCheckNumberLogs is the maximum number of attempts we keep
// in the healthcheck history file
MaxHealthCheckNumberLogs int = 5
// MaxHealthCheckLogLength in characters
MaxHealthCheckLogLength = 500
)
// HealthCheck verifies the state and validity of the healthcheck configuration
// on the container and then executes the healthcheck
func (r *Runtime) HealthCheck(ctx context.Context, name string) (define.HealthCheckStatus, error) {
container, err := r.LookupContainer(name)
if err != nil {
return define.HealthCheckContainerNotFound, fmt.Errorf("unable to look up %s to perform a health check: %w", name, err)
}
hcStatus, err := checkHealthCheckCanBeRun(container)
if err != nil {
return hcStatus, err
}
isStartupHC := false
if container.config.StartupHealthCheckConfig != nil {
passed, err := container.StartupHCPassed()
if err != nil {
return define.HealthCheckInternalError, err
}
isStartupHC = !passed
}
hcStatus, logStatus, err := container.runHealthCheck(ctx, isStartupHC)
if !isStartupHC {
if err := container.processHealthCheckStatus(logStatus); err != nil {
return hcStatus, err
}
}
return hcStatus, err
}
func (c *Container) runHealthCheck(ctx context.Context, isStartup bool) (define.HealthCheckStatus, string, error) {
var (
newCommand []string
returnCode int
inStartPeriod bool
)
hcCommand := c.HealthCheckConfig().Test
if isStartup {
logrus.Debugf("Running startup healthcheck for container %s", c.ID())
hcCommand = c.config.StartupHealthCheckConfig.Test
}
if len(hcCommand) < 1 {
return define.HealthCheckNotDefined, "", fmt.Errorf("container %s has no defined healthcheck", c.ID())
}
switch hcCommand[0] {
case "", define.HealthConfigTestNone:
return define.HealthCheckNotDefined, "", fmt.Errorf("container %s has no defined healthcheck", c.ID())
case define.HealthConfigTestCmd:
newCommand = hcCommand[1:]
case define.HealthConfigTestCmdShell:
// TODO: SHELL command from image not available in Container - use Docker default
newCommand = []string{"/bin/sh", "-c", strings.Join(hcCommand[1:], " ")}
default:
// command supplied on command line - pass as-is
newCommand = hcCommand
}
if len(newCommand) < 1 || newCommand[0] == "" {
return define.HealthCheckNotDefined, "", fmt.Errorf("container %s has no defined healthcheck", c.ID())
}
rPipe, wPipe, err := os.Pipe()
if err != nil {
return define.HealthCheckInternalError, "", fmt.Errorf("unable to create pipe for healthcheck session: %w", err)
}
defer wPipe.Close()
defer rPipe.Close()
streams := new(define.AttachStreams)
streams.InputStream = bufio.NewReader(os.Stdin)
streams.OutputStream = wPipe
streams.ErrorStream = wPipe
streams.AttachOutput = true
streams.AttachError = true
streams.AttachInput = true
stdout := []string{}
go func() {
scanner := bufio.NewScanner(rPipe)
for scanner.Scan() {
stdout = append(stdout, scanner.Text())
}
}()
logrus.Debugf("executing health check command %s for %s", strings.Join(newCommand, " "), c.ID())
timeStart := time.Now()
hcResult := define.HealthCheckSuccess
config := new(ExecConfig)
config.Command = newCommand
exitCode, hcErr := c.exec(config, streams, nil, true)
if hcErr != nil {
hcResult = define.HealthCheckFailure
if errors.Is(hcErr, define.ErrOCIRuntimeNotFound) ||
errors.Is(hcErr, define.ErrOCIRuntimePermissionDenied) ||
errors.Is(hcErr, define.ErrOCIRuntime) {
returnCode = 1
hcErr = nil
} else {
returnCode = 125
}
} else if exitCode != 0 {
hcResult = define.HealthCheckFailure
returnCode = 1
}
// Handle startup HC
if isStartup {
inStartPeriod = true
if hcErr != nil || exitCode != 0 {
hcResult = define.HealthCheckStartup
c.incrementStartupHCFailureCounter(ctx)
} else {
c.incrementStartupHCSuccessCounter(ctx)
}
}
timeEnd := time.Now()
if c.HealthCheckConfig().StartPeriod > 0 {
// there is a start-period we need to honor; we add startPeriod to container start time
startPeriodTime := c.state.StartedTime.Add(c.HealthCheckConfig().StartPeriod)
if timeStart.Before(startPeriodTime) {
// we are still in the start period, flip the inStartPeriod bool
inStartPeriod = true
logrus.Debugf("healthcheck for %s being run in start-period", c.ID())
}
}
eventLog := strings.Join(stdout, "\n")
if len(eventLog) > MaxHealthCheckLogLength {
eventLog = eventLog[:MaxHealthCheckLogLength]
}
if timeEnd.Sub(timeStart) > c.HealthCheckConfig().Timeout {
returnCode = -1
hcResult = define.HealthCheckFailure
hcErr = fmt.Errorf("healthcheck command exceeded timeout of %s", c.HealthCheckConfig().Timeout.String())
}
hcl := newHealthCheckLog(timeStart, timeEnd, returnCode, eventLog)
logStatus, err := c.updateHealthCheckLog(hcl, inStartPeriod, isStartup)
if err != nil {
return hcResult, "", fmt.Errorf("unable to update health check log %s for %s: %w", c.healthCheckLogPath(), c.ID(), err)
}
// Write HC event with appropriate status as the last thing before we
// return.
if hcResult == define.HealthCheckNotDefined || hcResult == define.HealthCheckInternalError {
return hcResult, logStatus, hcErr
}
if c.runtime.config.Engine.HealthcheckEvents {
c.newContainerHealthCheckEvent(logStatus)
}
return hcResult, logStatus, hcErr
}
func (c *Container) processHealthCheckStatus(status string) error {
if status != define.HealthCheckUnhealthy {
return nil
}
switch c.config.HealthCheckOnFailureAction {
case define.HealthCheckOnFailureActionNone: // Nothing to do
case define.HealthCheckOnFailureActionKill:
if err := c.Kill(uint(unix.SIGKILL)); err != nil {
return fmt.Errorf("killing container health-check turned unhealthy: %w", err)
}
case define.HealthCheckOnFailureActionRestart:
// We let the cleanup process handle the restart. Otherwise
// the container would be restarted in the context of a
// transient systemd unit which may cause undesired side
// effects.
if err := c.Stop(); err != nil {
return fmt.Errorf("restarting/stopping container after health-check turned unhealthy: %w", err)
}
case define.HealthCheckOnFailureActionStop:
if err := c.Stop(); err != nil {
return fmt.Errorf("stopping container after health-check turned unhealthy: %w", err)
}
default: // Should not happen but better be safe than sorry
return fmt.Errorf("unsupported on-failure action %d", c.config.HealthCheckOnFailureAction)
}
return nil
}
func checkHealthCheckCanBeRun(c *Container) (define.HealthCheckStatus, error) {
cstate, err := c.State()
if err != nil {
return define.HealthCheckInternalError, err
}
if cstate != define.ContainerStateRunning {
return define.HealthCheckContainerStopped, fmt.Errorf("container %s is not running", c.ID())
}
if !c.HasHealthCheck() {
return define.HealthCheckNotDefined, fmt.Errorf("container %s has no defined healthcheck", c.ID())
}
return define.HealthCheckDefined, nil
}
// Increment the current startup healthcheck success counter.
// Can stop the startup HC and start the regular HC if the startup HC has enough
// consecutive successes.
func (c *Container) incrementStartupHCSuccessCounter(ctx context.Context) {
if !c.batched {
c.lock.Lock()
defer c.lock.Unlock()
if err := c.syncContainer(); err != nil {
logrus.Errorf("Error syncing container %s state: %v", c.ID(), err)
return
}
}
// We don't have a startup HC, can't do anything
if c.config.StartupHealthCheckConfig == nil {
return
}
// Race: someone else got here first
if c.state.StartupHCPassed {
return
}
// Increment the success counter
c.state.StartupHCSuccessCount++
logrus.Debugf("Startup healthcheck for container %s succeeded, success counter now %d", c.ID(), c.state.StartupHCSuccessCount)
// Did we exceed threshold?
recreateTimer := false
if c.config.StartupHealthCheckConfig.Successes == 0 || c.state.StartupHCSuccessCount >= c.config.StartupHealthCheckConfig.Successes {
c.state.StartupHCPassed = true
c.state.StartupHCSuccessCount = 0
c.state.StartupHCFailureCount = 0
recreateTimer = true
}
if err := c.save(); err != nil {
logrus.Errorf("Error saving container %s state: %v", c.ID(), err)
return
}
if recreateTimer {
logrus.Infof("Startup healthcheck for container %s passed, recreating timer", c.ID())
// Create the new, standard healthcheck timer first.
if err := c.createTimer(c.HealthCheckConfig().Interval.String(), false); err != nil {
logrus.Errorf("Error recreating container %s healthcheck: %v", c.ID(), err)
return
}
if err := c.startTimer(false); err != nil {
logrus.Errorf("Error restarting container %s healthcheck timer: %v", c.ID(), err)
}
// This kills the process the healthcheck is running.
// Which happens to be us.
// So this has to be last - after this, systemd serves us a
// SIGTERM and we exit.
if err := c.removeTransientFiles(ctx, true); err != nil {
logrus.Errorf("Error removing container %s healthcheck: %v", c.ID(), err)
return
}
}
}
// Increment the current startup healthcheck failure counter.
// Can restart the container if the HC fails enough times consecutively.
func (c *Container) incrementStartupHCFailureCounter(ctx context.Context) {
if !c.batched {
c.lock.Lock()
defer c.lock.Unlock()
if err := c.syncContainer(); err != nil {
logrus.Errorf("Error syncing container %s state: %v", c.ID(), err)
return
}
}
// We don't have a startup HC, can't do anything
if c.config.StartupHealthCheckConfig == nil {
return
}
// Race: someone else got here first
if c.state.StartupHCPassed {
return
}
c.state.StartupHCFailureCount++
logrus.Debugf("Startup healthcheck for container %s failed, failure counter now %d", c.ID(), c.state.StartupHCFailureCount)
if c.config.StartupHealthCheckConfig.Retries != 0 && c.state.StartupHCFailureCount >= c.config.StartupHealthCheckConfig.Retries {
logrus.Infof("Restarting container %s as startup healthcheck failed", c.ID())
// Restart the container
if err := c.restartWithTimeout(ctx, c.config.StopTimeout); err != nil {
logrus.Errorf("Error restarting container %s after healthcheck failure: %v", c.ID(), err)
}
return
}
if err := c.save(); err != nil {
logrus.Errorf("Error saving container %s state: %v", c.ID(), err)
}
}
func newHealthCheckLog(start, end time.Time, exitCode int, log string) define.HealthCheckLog {
return define.HealthCheckLog{
Start: start.Format(time.RFC3339Nano),
End: end.Format(time.RFC3339Nano),
ExitCode: exitCode,
Output: log,
}
}
// updateHealthStatus updates the health status of the container
// in the healthcheck log
func (c *Container) updateHealthStatus(status string) error {
healthCheck, err := c.getHealthCheckLog()
if err != nil {
return err
}
healthCheck.Status = status
newResults, err := json.Marshal(healthCheck)
if err != nil {
return fmt.Errorf("unable to marshall healthchecks for writing status: %w", err)
}
return os.WriteFile(c.healthCheckLogPath(), newResults, 0700)
}
// isUnhealthy returns true if the current health check status is unhealthy.
func (c *Container) isUnhealthy() (bool, error) {
if !c.HasHealthCheck() {
return false, nil
}
healthCheck, err := c.getHealthCheckLog()
if err != nil {
return false, err
}
return healthCheck.Status == define.HealthCheckUnhealthy, nil
}
// UpdateHealthCheckLog parses the health check results and writes the log
func (c *Container) updateHealthCheckLog(hcl define.HealthCheckLog, inStartPeriod, isStartup bool) (string, error) {
c.lock.Lock()
defer c.lock.Unlock()
// If we are playing a kube yaml then let's honor the start period time for
// both failing and succeeding cases to match kube behavior.
// So don't update the health check log till the start period is over
if _, ok := c.config.Spec.Annotations[define.KubeHealthCheckAnnotation]; ok && inStartPeriod && !isStartup {
return "", nil
}
healthCheck, err := c.getHealthCheckLog()
if err != nil {
return "", err
}
if hcl.ExitCode == 0 {
// set status to healthy, reset failing state to 0
healthCheck.Status = define.HealthCheckHealthy
healthCheck.FailingStreak = 0
} else {
if len(healthCheck.Status) < 1 {
healthCheck.Status = define.HealthCheckHealthy
}
if !inStartPeriod {
// increment failing streak
healthCheck.FailingStreak++
// if failing streak > retries, then status to unhealthy
if healthCheck.FailingStreak >= c.HealthCheckConfig().Retries {
healthCheck.Status = define.HealthCheckUnhealthy
}
}
}
healthCheck.Log = append(healthCheck.Log, hcl)
if len(healthCheck.Log) > MaxHealthCheckNumberLogs {
healthCheck.Log = healthCheck.Log[1:]
}
newResults, err := json.Marshal(healthCheck)
if err != nil {
return "", fmt.Errorf("unable to marshall healthchecks for writing: %w", err)
}
return healthCheck.Status, os.WriteFile(c.healthCheckLogPath(), newResults, 0700)
}
// HealthCheckLogPath returns the path for where the health check log is
func (c *Container) healthCheckLogPath() string {
return filepath.Join(filepath.Dir(c.state.RunDir), "healthcheck.log")
}
// getHealthCheckLog returns HealthCheck results by reading the container's
// health check log file. If the health check log file does not exist, then
// an empty healthcheck struct is returned
// The caller should lock the container before this function is called.
func (c *Container) getHealthCheckLog() (define.HealthCheckResults, error) {
var healthCheck define.HealthCheckResults
b, err := os.ReadFile(c.healthCheckLogPath())
if err != nil {
if errors.Is(err, fs.ErrNotExist) {
// If the file does not exists just return empty healthcheck and no error.
return healthCheck, nil
}
return healthCheck, fmt.Errorf("failed to read health check log file: %w", err)
}
if err := json.Unmarshal(b, &healthCheck); err != nil {
return healthCheck, fmt.Errorf("failed to unmarshal existing healthcheck results in %s: %w", c.healthCheckLogPath(), err)
}
return healthCheck, nil
}
// HealthCheckStatus returns the current state of a container with a healthcheck.
// Returns an empty string if no health check is defined for the container.
func (c *Container) HealthCheckStatus() (string, error) {
if !c.batched {
c.lock.Lock()
defer c.lock.Unlock()
}
return c.healthCheckStatus()
}
// Internal function to return the current state of a container with a healthcheck.
// This function does not lock the container.
func (c *Container) healthCheckStatus() (string, error) {
if !c.HasHealthCheck() {
return "", nil
}
if err := c.syncContainer(); err != nil {
return "", err
}
results, err := c.getHealthCheckLog()
if err != nil {
return "", fmt.Errorf("unable to get healthcheck log for %s: %w", c.ID(), err)
}
return results.Status, nil
}