alibaba/arthas · critical · IllegalStateException

Arthas server did not start after attach (no listener on {ip

Error message

Arthas server did not start after attach (no listener on {ip}:{telnetPort}), see errors above and the target's arthas.log

What it means

Thrown by Arthas.main attach path: the attach handshake to the target JVM succeeded, but the in-target Arthas server never opened a listener on the expected ip:telnetPort (probe failed). The message is a deliberately loud, actionable failure for the cross mount-namespace attach scenario where resources copied into the target (/proc/<pid>/root/.../arthas-<pid>) may be incomplete or the server bind failed inside the target.

Source

Thrown at core/src/main/java/com/taobao/arthas/core/Arthas.java:477

                try {
                    Thread.sleep(300);
                } catch (InterruptedException ie) {
                    Thread.currentThread().interrupt();
                    break;
                }
            }
        }

        // 失败：大声报错，并给出可操作的排查路径
        String copiedHome = "/proc/" + targetPid + "/root" + detectTargetTmpDir(targetPid) + "/arthas-" + targetPid;
        AnsiLog.error("Arthas server did NOT start on {}:{} after attach. The attach handshake succeeded, but the "
                + "in-target server failed to bind.", ip, telnetPort);
        AnsiLog.error("Common cause under cross mount-namespace: incomplete resources copied into the target, or a "
                + "bind failure inside the target JVM.");
        AnsiLog.error("Copied arthas home in target: {}", copiedHome);
        AnsiLog.error("Check the target's arthas.log for the real cause, e.g.: find /proc/{}/root -name arthas.log",
                targetPid);
        throw new IllegalStateException("Arthas server did not start after attach (no listener on " + ip + ":"
                + telnetPort + "), see errors above and the target's arthas.log");
    }

    private static String encodeArg(String arg) {
        try {
            return URLEncoder.encode(arg, "utf-8");
        } catch (UnsupportedEncodingException e) {
            return arg;
        }
    }

    public static void main(String[] args) {
        try {
            new Arthas(args);
        } catch (Throwable t) {
            AnsiLog.error("Start arthas failed, exception stack trace: ");
            t.printStackTrace();
            System.exit(-1);

View on GitHub (pinned to 21cf2e9ba5)

Solutions

1. Read the target's arthas.log: find /proc/<pid>/root -name arthas.log — the real cause (class not found, bind refused, missing jar) is logged there.
2. Verify the copied home in the target is complete: ls -la /proc/<pid>/root<tmp>/arthas-<pid>.
3. Run arthas from inside the target's namespace (exec into the container, or use -h/--target-ip pointing at the right interface).
4. Ensure the target's telnetPort is free inside that namespace and reachable from where you connect.
5. Clean a stale in-target arthas dir and re-attach.

Example fix

// before
java -jar arthas-boot.jar <pid>  // from host, target in container

// after
# exec into the target container and attach from inside
kubectl exec -it <pod> -- sh -c 'cd /tmp && java -jar arthas-boot.jar 1'

try {
    arthasAttach(pid, ip, telnetPort);
} catch (IllegalStateException e) {
    // read /proc/<pid>/root/.../arthas.log, clean stale home, then attach from inside the target namespace
}

When it happens

Trigger: Cross-mount-namespace attach (e.g. arthas running in a sidecar/host attaching to a target JVM in a container) where the attach succeeds but the telnet/http server does not bind; incomplete copy of the Arthas home into the target's mount namespace; a bind failure (port conflict, permission) inside the target JVM after attach.

Common situations: Attaching arthas from outside a container to a JVM inside it; targeting a process in a different PID/mount namespace; stale arthas home in the target blocking re-copy; the requested ip/telnetPort cannot be bound in the target namespace.

Related errors

• 元数据获取失败
• 火焰图获取失败
• Failed to create directory within ${TEMP_DIR_ATTEMPTS} attem
• Could not find an available tcp port in the range [%d, %d] a
• Arthas failed to bind telnet or http port! Telnet port: ${co

AI-assisted analysis of alibaba/arthas@21cf2e9ba5 (2026-08-14). Data as JSON: /api/errors/b61485ecb12df2c5. Report an issue: GitHub.