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
"cluster.initial_master_nodes",
                    "http.host"
                )
            );
            final Set<String> userAddedSettings = new HashSet<>(foundAutoConfigurationSettings.keySet());
            userAddedSettings.removeAll(expectedAutoConfigurationSettings);
            final List<String> newConfigurationLines = Arrays.stream(
                existingConfigurationAsString.replace(foundAutoConfigurationSettingsAsString, "").split(System.lineSeparator())
            ).collect(Collectors.toList());
            if (false == userAddedSettings.isEmpty()) {
                for (String key : userAddedSettings) {
                    newConfigurationLines.add(key + ": " + foundAutoConfigurationSettings.get(key));
                }
            }
            return newConfigurationLines;
        }
        return existingConfigLines;
    }
    private void removeAutoConfigurationFromKeystore(Environment env, Terminal terminal) throws UserException {
        if (Files.exists(KeyStoreWrapper.keystorePath(env.configFile()))) {
            try (
                KeyStoreWrapper existingKeystore = KeyStoreWrapper.load(env.configFile());
                SecureString keystorePassword = existingKeystore.hasPassword()
                    ? new SecureString(terminal.readSecret("Enter password for the elasticsearch keystore: "))
                    : new SecureString(new char[0]);
            ) {
                existingKeystore.decrypt(keystorePassword.getChars());
                List<String> secureSettingsToRemove = List.of(
                    "xpack.security.transport.ssl.keystore.secure_password",
                    "xpack.security.transport.ssl.truststore.secure_password",