diff --git a/src/main/kotlin/org/domaindrivenarchitecture/provs/framework/core/Prov.kt b/src/main/kotlin/org/domaindrivenarchitecture/provs/framework/core/Prov.kt
index f13fbc4..343642e 100644
--- a/src/main/kotlin/org/domaindrivenarchitecture/provs/framework/core/Prov.kt
+++ b/src/main/kotlin/org/domaindrivenarchitecture/provs/framework/core/Prov.kt
@@ -374,8 +374,9 @@ open class Prov protected constructor(
                 successPerLevel.add(successOfCurrentLevel)
             }
 
-            val successOfLevelAbove = if (currentLevel == 0) successOfCurrentLevel else successPerLevel[currentLevel - 1]
-            println(result.toString().escapeControlChars().formattedAsResultLine(successOfLevelAbove))
+            // check success levels above; if a level above succeeded then a failure in this level will be considered optional (i.e. marked yellow instead of red)
+            val successOfLevelsAbove = levelsAboveContainsSuccess(successPerLevel, currentLevel)
+            println(result.toString().escapeControlChars().formattedAsResultLine(successOfLevelsAbove))
         }
         if (internalResults.size > 1) {
             println("----------------------------------------------------------------------------------------------------- ")
@@ -384,6 +385,14 @@ open class Prov protected constructor(
         println("============================================ SUMMARY END ============================================ " + newline())
     }
 
+    private fun levelsAboveContainsSuccess(successPerLevel: ArrayList<Boolean>, currentLevel: Int): Boolean {
+        var success = false
+        for (i in 0..currentLevel - 1) {
+            success = success || successPerLevel[i]
+        }
+        return success
+    }
+
     private fun String.formattedAsResultLine(showFailedInYellow: Boolean = false): String {
         val failedColor = if (showFailedInYellow) ANSI_BRIGHT_YELLOW else ANSI_BRIGHT_RED
         return this
diff --git a/src/test/kotlin/org/domaindrivenarchitecture/provs/framework/core/ProvTest.kt b/src/test/kotlin/org/domaindrivenarchitecture/provs/framework/core/ProvTest.kt
index c72e93d..10e056b 100644
--- a/src/test/kotlin/org/domaindrivenarchitecture/provs/framework/core/ProvTest.kt
+++ b/src/test/kotlin/org/domaindrivenarchitecture/provs/framework/core/ProvTest.kt
@@ -355,7 +355,7 @@ internal class ProvTest {
 
     @Test
     @NonCi
-    fun prov_prints_correct_output_for_failure_that_is_not_taken_into_account() {
+    fun prov_marks_failed_output_yellow_if_optional() {
 
         // given
         setRootLoggingLevel(Level.OFF)
@@ -369,11 +369,14 @@ internal class ProvTest {
         System.setErr(PrintStream(errContent))
 
         // when
-        Prov.newInstance(name = "test instance with no progress info", progressType = ProgressType.NONE).requireLast {
-            checkPrereq_evaluateToFailure()
-            task("returns success") {
-                ProvResult(true)
-            }
+        Prov.newInstance(name = "test instance with no progress info", progressType = ProgressType.NONE).task("taskA") {
+                    optional {
+                        taskWithResult("taskB") {
+                            taskWithResult("taskC") {
+                                ProvResult(false)
+                            }
+                        }
+                    }
         }
 
         // then
@@ -384,9 +387,10 @@ internal class ProvTest {
 
         val expectedOutput =
             "============================================== SUMMARY (test instance with no progress info) ============================================== \n" +
-                    ">  \u001B[92mSuccess\u001B[0m -- prov_prints_correct_output_for_failure_that_is_not_taken_into_account (requireLast) \n" +
-                    "--->  \u001B[93mFAILED\u001B[0m  -- checkPrereq_evaluateToFailure (requireLast)  -- Error: This is a test error.\n" +
-                    "--->  \u001B[92mSuccess\u001B[0m -- returns success \n" +
+                    ">  \u001B[92mSuccess\u001B[0m -- taskA \n" +
+                    "--->  \u001B[92mSuccess\u001B[0m -- prov_marks_failed_output_yellow_if_optional (optional) \n" +
+                    "------>  \u001B[93mFAILED\u001B[0m  -- taskB \n" +
+                    "--------->  \u001B[93mFAILED\u001B[0m  -- taskC \n" +
                     "----------------------------------------------------------------------------------------------------- \n" +
                     "Overall >  \u001B[92mSuccess\u001B[0m\n" +
                     "============================================ SUMMARY END ============================================ \n" +
diff --git a/src/test/kotlin/org/domaindrivenarchitecture/provs/framework/ubuntu/keys/ProvisionKeysTest.kt b/src/test/kotlin/org/domaindrivenarchitecture/provs/framework/ubuntu/keys/ProvisionKeysTest.kt
index e81257e..612b0f5 100644
--- a/src/test/kotlin/org/domaindrivenarchitecture/provs/framework/ubuntu/keys/ProvisionKeysTest.kt
+++ b/src/test/kotlin/org/domaindrivenarchitecture/provs/framework/ubuntu/keys/ProvisionKeysTest.kt
@@ -2,13 +2,13 @@ package org.domaindrivenarchitecture.provs.framework.ubuntu.keys
 
 import org.domaindrivenarchitecture.provs.framework.core.Secret
 import org.domaindrivenarchitecture.provs.test.defaultTestContainer
+import org.domaindrivenarchitecture.provs.test.tags.ContainerTest
 import org.domaindrivenarchitecture.provs.test.tags.NonCi
 import org.junit.jupiter.api.Assertions.assertTrue
-import org.junit.jupiter.api.Test
 
 internal class ProvisionKeysTest {
 
-    @Test
+    @ContainerTest
     @NonCi
     fun provisionKeys() {
         // given