juicedata/juicefs · error

failed to execute command `%s`: %v

Error message

failed to execute command `%s`: %v

What it means

On Unix, `getCmdMount` locates the JuiceFS mount process by running `ps -f -p <pid>` or `ps -ef | grep ... mount | grep <mp>` through `/bin/sh`. If `exec.Command(...).CombinedOutput()` returns an error (shell or ps cannot run, or ps exits non-zero), the command and error are wrapped with this message.

Source

Thrown at cmd/debug_unix.go:61

		if err := json.Unmarshal(content, &cfg); err != nil {
			logger.Warnf("failed to unmarshal config file: %v", err)
		}
		if cfg.Pid != 0 {
			tmpPid = strconv.Itoa(cfg.Pid)
		}
		return nil
	}, 3*time.Second)

	var psArgs []string
	if tmpPid != "" {
		pid = tmpPid
		psArgs = []string{"/bin/sh", "-c", fmt.Sprintf("ps -f -p %s", pid)}
	} else {
		psArgs = []string{"/bin/sh", "-c", fmt.Sprintf("ps -ef | grep -v grep | grep mount | grep %s", mp)}
	}
	ret, err := exec.Command(psArgs[0], psArgs[1:]...).CombinedOutput()
	if err != nil {
		return "", "", "", fmt.Errorf("failed to execute command `%s`: %v", strings.Join(psArgs, " "), err)
	}
	var find bool
	var ppid string
	lines := strings.Split(string(ret), "\n")
	for i := len(lines) - 1; i >= 0; i-- {
		line := lines[i]
		fields := strings.Fields(line)
		if len(fields) <= 7 {
			continue
		}
		cmdFields := fields[7:]
		for _, arg := range cmdFields {
			if mp == arg {
				if find {
					newCmd := strings.Join(fields[7:], " ")
					newUid, newPid, newPpid := strings.TrimSpace(fields[0]), strings.TrimSpace(fields[1]), strings.TrimSpace(fields[2])
					if newPid == ppid {
						return uid, pid, cmd, nil

View on GitHub (pinned to c9a67b23e8)

Solutions

1. Install the `ps`/procps package in the container or debug from the host.
2. Ensure `/bin/sh` exists and is executable.
3. Re-run `juicefs debug`; a transient pid-exit race usually resolves on retry.
4. Check the wrapped `%v` error: 'executable file not found' means missing ps/sh; exit status 1 from `ps -f -p` means the pid no longer exists.

Example fix

// before (minimal container)
$ juicefs debug /jfs
failed to execute command `/bin/sh -c ps -ef ...`: exec: "ps": executable file not found
// after
$ apk add procps && juicefs debug /jfs

for _, bin := range []string{"/bin/sh", "ps"} {
  if _, err := exec.LookPath(bin); err != nil {
    return fmt.Errorf("%s missing; install procps", bin)
  }
}

null

err := runDebug(mp)
if err != nil && strings.Contains(err.Error(), "failed to execute command") {
  // 'executable file not found' -> install ps/sh; exit status -> retry (pid race)
}

When it happens

Trigger: Running `juicefs debug` on Unix when `/bin/sh` is missing, `ps` is not installed (e.g. minimal containers without procps), or `ps -f -p <pid>` fails because the pid vanished between listing and re-checking.

Common situations: Debugging inside a distroless/alpine container without `ps`; restricted seccomp blocking process exec; race where the mount process exits mid-debug.

Related errors

• failed to execute command `%s`: %v
• failed to get mount command: %v
• find more than one mount process for %s
• no mount command found for %s
• failed to run command line: %s, %v

AI-assisted analysis of juicedata/juicefs@c9a67b23e8 (2026-09-06). Data as JSON: /api/errors/62d7f056482189e8. Report an issue: GitHub.