We generate certificates that are intended to be used for server authentication in a couple of places:

- `bin/elasticsearch-certutil http` command  ( See `CertGenUtils.generateSignedCertificate` in `HttpCertificateCommand` )
- TLS auto-configuraion for node startup ( see [`AutoConfigureNode`](https://github.com/elastic/elasticsearch/blob/814f7f9f52cb8c05db6465b9bfc818ea5d76c575/x-pack/plugin/security/cli/src/main/java/org/elasticsearch/xpack/security/cli/AutoConfigureNode.java#L454) )

In these cases we know that the certificate is meant to be used for server authentication, so we can set Extended Key Usage extension to `1.3.6.1.5.5.7.3.1`
x-pack/plugin/security/cli/src/main/java/org/elasticsearch/xpack/security/cli/AutoConfigureNode.java
throw new UserException(ExitCodes.USAGE, "enrollment-token is a mandatory parameter when reconfiguring the node");
            }
            env = possiblyReconfigureNode(env, terminal, options, processInfo);
        }
        
        
        checkExistingConfiguration(env.settings(), inEnrollmentMode, terminal);
        final ZonedDateTime autoConfigDate = ZonedDateTime.now(ZoneOffset.UTC);
        final Path tempGeneratedTlsCertsDir = env.configFile()
            .resolve(String.format(Locale.ROOT, TLS_GENERATED_CERTS_DIR_NAME + ".%d.tmp", autoConfigDate.toInstant().getEpochSecond()));
        try {
            
            Files.createDirectory(tempGeneratedTlsCertsDir);
            
            
            PosixFileAttributeView view = Files.getFileAttributeView(tempGeneratedTlsCertsDir, PosixFileAttributeView.class);
            if (view != null) {
                view.setPermissions(PosixFilePermissions.fromString("rwxr-x---"));
            }
        } catch (Throwable t) {
            try {
                deleteDirectory(tempGeneratedTlsCertsDir);
            } catch (Exception ex) {
                t.addSuppressed(ex);
            }
            
            
            
            
            throw new UserException(ExitCodes.CANT_CREATE, "Could not create auto-configuration directory", t);