feat: add configurable Kerberos debug option

- Introduced a new `debug` configuration option for Kerberos.
- Updated container setup to include `KERBY_DEBUG` environment variable.
- Extended TOML and programmatic configurations to support `debug`.
- Enhanced documentation with guidance on enabling debug mode for troubleshooting.

Author: CoderYellow

core/src/main/kotlin/org/openprojectx/bigdata/test/core/BigDataTestKitOptions.kt

@@ -24,6 +24,7 @@ data class KerberosOptions(
     val materialTimeoutSeconds: Int = 30,
     val adminAttempts: Int = 30,
     val adminRetryDelaySeconds: Int = 1,
+    val debug: Boolean = false,
 )
 
 data class KerberosUserOptions(

core/src/main/kotlin/org/openprojectx/bigdata/test/core/container/BigDataContainerFactory.kt

@@ -94,6 +94,7 @@ internal class BigDataContainerFactory(
             .withEnv("KERBY_CLIENT_PASSWORD", kerberos.clientPassword)
             .withEnv("KERBY_KADMIN_ATTEMPTS", kerberos.adminAttempts.toString())
             .withEnv("KERBY_KADMIN_RETRY_DELAY_SECONDS", kerberos.adminRetryDelaySeconds.toString())
+            .withEnv("KERBY_DEBUG", kerberos.debug.toString())
             .waitingFor(
                 Wait.forLogMessage(".*Kerby KDC container ready\\..*", 1)
                     .withStartupTimeout(Duration.ofSeconds(kerberos.startupTimeoutSeconds.toLong())),

doc/user-guide.adoc

@@ -715,10 +715,13 @@ startupTimeoutSeconds = 180
 materialTimeoutSeconds = 120
 adminAttempts = 120
 adminRetryDelaySeconds = 1
+debug = true
 ----
 
 `startupTimeoutSeconds` controls how long Testcontainers waits for the KDC image to print its ready log. `materialTimeoutSeconds` controls the post-start wait for generated keytabs and client config to be readable. `adminAttempts` and `adminRetryDelaySeconds` are passed to the Kerby image as `KERBY_KADMIN_ATTEMPTS` and `KERBY_KADMIN_RETRY_DELAY_SECONDS`.
 
+Set `debug = true` when troubleshooting Kerberos startup in CI. It passes `KERBY_DEBUG=true` to the Kerby image, which enables JDK Kerberos debug output, Kerby DEBUG logs on container stdout, and dumps the generated `kdc.conf`, server `krb5.conf`, client `krb5.conf`, backend config, and admin server config into the container log.
+
 Programmatic setup exposes the same options:
 
 [source,kotlin]
@@ -730,6 +733,7 @@ BigDataTestKit.builder()
             startupTimeoutSeconds = 180,
             materialTimeoutSeconds = 120,
             adminAttempts = 120,
+            debug = true,
         ),
     )
 ----

example/spark/src/test/resources/spark-bigdata-test-apache-hms-kerberos.toml

@@ -8,6 +8,7 @@ startupTimeoutSeconds = 180
 materialTimeoutSeconds = 120
 adminAttempts = 120
 adminRetryDelaySeconds = 1
+debug = true
 
 [ports]
 kafka = 19092

example/spark/src/test/resources/spark-bigdata-test-cloudera-hms-kerberos.toml

@@ -8,6 +8,7 @@ startupTimeoutSeconds = 180
 materialTimeoutSeconds = 120
 adminAttempts = 120
 adminRetryDelaySeconds = 1
+debug = true
 
 [ports]
 kafka = 19092

junit5/src/main/kotlin/org/openprojectx/bigdata/test/junit5/BigDataTestConfig.kt

@@ -42,13 +42,15 @@ internal data class BigDataTestKerberosConfig(
     val materialTimeoutSeconds: Int? = null,
     val adminAttempts: Int? = null,
     val adminRetryDelaySeconds: Int? = null,
+    val debug: Boolean? = null,
 ) {
     fun merge(override: BigDataTestKerberosConfig): BigDataTestKerberosConfig =
         BigDataTestKerberosConfig(
             startupTimeoutSeconds = override.startupTimeoutSeconds ?: startupTimeoutSeconds,
             materialTimeoutSeconds = override.materialTimeoutSeconds ?: materialTimeoutSeconds,
             adminAttempts = override.adminAttempts ?: adminAttempts,
             adminRetryDelaySeconds = override.adminRetryDelaySeconds ?: adminRetryDelaySeconds,
+            debug = override.debug ?: debug,
         )
 }
 
@@ -249,6 +251,7 @@ internal class BigDataTestConfigLoader(
                 materialTimeoutSeconds = kerberos.int("materialTimeoutSeconds"),
                 adminAttempts = kerberos.int("adminAttempts"),
                 adminRetryDelaySeconds = kerberos.int("adminRetryDelaySeconds"),
+                debug = kerberos.boolean("debug"),
             ),
             tls = BigDataTestTlsConfig(
                 enabled = tls.boolean("enabled"),

junit5/src/main/kotlin/org/openprojectx/bigdata/test/junit5/BigDataTestExtension.kt

@@ -141,6 +141,7 @@ class BigDataTestExtension : BeforeAllCallback, AfterAllCallback, ParameterResol
                     materialTimeoutSeconds = kerberosConfig.materialTimeoutSeconds ?: defaultKerberos.materialTimeoutSeconds,
                     adminAttempts = kerberosConfig.adminAttempts ?: defaultKerberos.adminAttempts,
                     adminRetryDelaySeconds = kerberosConfig.adminRetryDelaySeconds ?: defaultKerberos.adminRetryDelaySeconds,
+                    debug = kerberosConfig.debug ?: defaultKerberos.debug,
                 ),
             )
         }