web.xml

<web-app xmlns="http://java.sun.com/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
         version="3.0">
    <display-name>Multi Tenant Example</display-name>

    <context-param>
        <param-name>keycloak.config.resolver</param-name>
        <param-value>org.keycloak.example.multitenant.control.PathBasedKeycloakConfigResolver</param-value>
    </context-param>

    <security-constraint>
        <web-resource-collection>
            <web-resource-name>REST endpoints</web-resource-name>
            <url-pattern>/*</url-pattern>
        </web-resource-collection>
        <auth-constraint>
            <role-name>*</role-name>
        </auth-constraint>
    </security-constraint>

    <login-config>
        <auth-method>KEYCLOAK</auth-method>
        <realm-name>not-important</realm-name>
    </login-config>
    <security-role>
        <role-name>user</role-name>
    </security-role>
</web-app>