I have a spring boot oauth2 server that uses a JDBC implementation. It is configured as an authorization server with @EnableAuthorizationServer.

I'd like to scale that application horyzontally but it doesn't seem to work properly.

I can connect only if I have one instance (pods) of the server.

I use autorisation_code_client grant from another client service to get the token. So first the client service redirect the user to the oauth2 server form, then once the user is authenticated he is supposed to be redirect to the client-service with a code attached to the url, finally the client use that code to request the oauth2 server again and obtain the token.

Here the user is not redirected at all if I have several instance of the oauth2-server. With one instance it works well.

When I check the log of the two instances in real time, I can see that the authentication works on one of them. I don't have any specific error the user is just not redirected.

Is there a way to configure the oauth2-server to be stateless or other way to fix that issue ?

Here is my configuration, the AuthorizationServerConfigurerAdapter implementation.

@Configuration
public class AuthorizationServerConfiguration extends AuthorizationServerConfigurerAdapter {


    @Bean
    @ConfigurationProperties(prefix = "spring.datasource")
    public DataSource oauthDataSource() {
        return DataSourceBuilder.create().build();
    }

    @Autowired
    @Qualifier("authenticationManagerBean")
    private AuthenticationManager authenticationManager;

    @Bean
    public JdbcClientDetailsService clientDetailsSrv() {
        return new JdbcClientDetailsService(oauthDataSource());
    }

    @Bean
    public TokenStore tokenStore() {
        return new JdbcTokenStore(oauthDataSource());
    }

    @Bean
    public ApprovalStore approvalStore() {
        return new JdbcApprovalStore(oauthDataSource());
    }

    @Bean
    public AuthorizationCodeServices authorizationCodeServices() {
        return new JdbcAuthorizationCodeServices(oauthDataSource());
    }

    @Bean
    public TokenEnhancer tokenEnhancer() {

        return new CustomTokenEnhancer();
    }

    @Bean
    @Primary
    public AuthorizationServerTokenServices tokenServices() {


        DefaultTokenServices tokenServices = new DefaultTokenServices();

        tokenServices.setTokenStore(tokenStore());

        tokenServices.setTokenEnhancer(tokenEnhancer());

        return tokenServices;
    }

    @Override
    public void configure(ClientDetailsServiceConfigurer clients) throws Exception {

        clients.withClientDetails(clientDetailsSrv());
    }

    @Override
    public void configure(AuthorizationServerSecurityConfigurer oauthServer)  {

        oauthServer
                .tokenKeyAccess("permitAll()")
                .checkTokenAccess("isAuthenticated()")
                .allowFormAuthenticationForClients();

    }

    @Override
    public void configure(AuthorizationServerEndpointsConfigurer endpoints)  {
        endpoints
                .authenticationManager(authenticationManager)
                .approvalStore(approvalStore())
                //.approvalStoreDisabled()
                .authorizationCodeServices(authorizationCodeServices())
                .tokenStore(tokenStore())
                .tokenEnhancer(tokenEnhancer());
    }

}

The main class

@SpringBootApplication
@EnableResourceServer
@EnableAuthorizationServer
@EnableConfigurationProperties
@EnableFeignClients("com.oauth2.proxies")
public class AuthorizationServerApplication {


    public static void main(String[] args) {

        SpringApplication.run(AuthorizationServerApplication.class, args);

    }

}

The Web Security Configuration

@Configuration
@Order(1)
public class WebSecurityConfiguration extends WebSecurityConfigurerAdapter {


    @Bean
    @Override
    public UserDetailsService userDetailsServiceBean() throws Exception {
        return new JdbcUserDetails();
    }

    @Override
    @Bean
    public AuthenticationManager authenticationManagerBean() throws Exception {
        return super.authenticationManagerBean();
    }

    @Override
    protected void configure(HttpSecurity http) throws Exception { // @formatter:off

        http.requestMatchers()
                .antMatchers("/",
                        "/login",
                        "/login.do",
                        "/registration",
                        "/registration/confirm/**",
                        "/registration/resendToken",
                        "/password/forgot",
                        "/password/change",
                        "/password/change/**",
                        "/oauth/authorize**")
                .and()
                .authorizeRequests()//autorise les requetes
                .antMatchers(
                        "/",
                        "/login",
                        "/login.do",
                        "/registration",
                        "/registration/confirm/**",
                        "/registration/resendToken",
                        "/password/forgot",
                        "/password/change",
                        "/password/change/**")
                .permitAll()
                .and()
                .requiresChannel()
                .anyRequest()
                .requiresSecure()
                .and()
                .authorizeRequests()
                .anyRequest()
                .authenticated()
                .and()
                .formLogin()
                .loginPage("/login")
                .loginProcessingUrl("/login.do")
                .usernameParameter("username")
                .passwordParameter("password")
                .and()
                .userDetailsService(userDetailsServiceBean());


    } // @formatter:on


    @Override
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
        auth.userDetailsService(userDetailsServiceBean()).passwordEncoder(passwordEncoder());
    }


}

Client side the WebSecurityConfigurerAdapter

@EnableOAuth2Sso
@Configuration
public class UiSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    public void configure(HttpSecurity http) throws Exception {

        http.antMatcher("/**")
                .authorizeRequests()
                .antMatchers(
                        "/",
                        "/index.html",
                        "/login**",
                        "/logout**",
                        //resources
                        "/assets/**",
                        "/static/**",
                        "/*.ico",
                        "/*.js",
                        "/*.json").permitAll()
                .anyRequest()
                .authenticated()
                .and()
                .csrf().csrfTokenRepository(csrfTokenRepository())
                .and()
                .addFilterAfter(csrfHeaderFilter(), SessionManagementFilter.class);
    }

}

the oauth2 configuration properties

oauth2-server is the service name (load balancer) on kubernetes and also the server path that is why it appears twice.

security:
    oauth2:
        client:
            clientId: **********
            clientSecret: *******
            accessTokenUri: https://oauth2-server/oauth2-server/oauth/token
            userAuthorizationUri: https://oauth2.mydomain.com/oauth2-server/oauth/authorize
        resource:
            userInfoUri: https://oauth2-server/oauth2-server/me

Here an important detail, the value of userAuthorizationUri is the address to access the oauth2-server from the outside of the k8s cluster. The client-service send back that address into the response with a 302 http code if the user is not connected and tries to access to the /login path of the client-service. then the user is redirected to the /login path of the oauth2-server.
https://oauth2.mydomain.com target an Nginx Ingress controller that handle the redirection to the load balancer service.