code: def make_cert_key(hostname, sign=False):
      print("creating cert for " + hostname)
      tempnames = []
      for _ in range(3):
          with tempfile.NamedTemporaryFile(delete=False) as f:
              tempnames.append(f.name)
      req_file, cert_file, key_file = tempnames
      try:
          req = req_template.format(hostname=hostname)
          with open(req_file, "w") as f:
              f.write(req)
          args = [
              "req",
              "-new",
              "-days",
              "365242",
              "-nodes",
              "-newkey",
              "rsa:2048",
              "-keyout",
              key_file,
              "-config",
              req_file,
          ]
          if sign:
              with tempfile.NamedTemporaryFile(delete=False) as f:
                  tempnames.append(f.name)
                  reqfile = f.name
              args += ["-out", reqfile]
  
          else:
              args += ["-x509", "-out", cert_file]
          subprocess.check_call(["openssl"] + args)
  
          if sign:
              args = [
                  "ca",
                  "-config",
                  req_file,
                  "-out",
                  cert_file,
                  "-outdir",
                  "cadir",
                  "-policy",
                  "policy_anything",
                  "-batch",
                  "-infiles",
                  reqfile,
              ]
              subprocess.check_call(["openssl"] + args)
  
          with open(cert_file) as f:
              cert = f.read()
          with open(key_file) as f:
              key = f.read()
          return cert, key
      finally:
          for name in tempnames:
              os.remove(name)
  
file_path: distributed/distributed/tests/make_tls_certs.py
imports: from __future__ import annotations
  import os
  import shutil
  import subprocess
  import tempfile
label_desc: Use image node_id 1 for calling a global function with example usage: make_cert_key(hostname, sign) and returns: cert,  key