6.9 to 6.10 upgrade: unable to read cipher data for 0

[luispabon]

I'm in the process of upgrading a working 6.9.2 installation to 6.10.

Once bamboo starts, it crashes with the following:

2020-02-10 13:44:29,000 INFO [localhost-startStop-1] [UpgradeLauncher] Upgrade completed. 171.6 ms
2020-02-10 13:44:29,000 INFO [localhost-startStop-1] [BambooContainer] Starting Bamboo...
2020-02-10 13:44:29,000 INFO [localhost-startStop-1] [BambooContainer] Reticulating splines...
2020-02-10 13:44:29,267 INFO [localhost-startStop-1] [ServerLifecycleManagerImpl] Server state changed to 'STARTING' from 'SETUP'
2020-02-10 13:44:29,270 INFO [localhost-startStop-1] [BambooContainer] Registered a default event listener: awsAccountBean
2020-02-10 13:44:29,297 INFO [AtlassianEvent::0-BAM::EVENTS:pool-1-thread-1] [InitialiseSmackOnStartup] Initialising IM servers...
2020-02-10 13:44:29,312 INFO [AtlassianEvent::0-BAM::EVENTS:pool-1-thread-1] [BambooSmackClient] No IM server specified. Bamboo Smack client not initialised.
2020-02-10 13:44:29,322 FATAL [localhost-startStop-1] [InstanceSecretStorage] Filesystem part of instance key is unavailable
2020-02-10 13:44:29,322 FATAL [localhost-startStop-1] [BambooContainer] Cannot start Bamboo
java.lang.IllegalArgumentException: Unable to read cipher data for 0

at com.atlassian.bamboo.crypto.instance.InstanceSecretStorage.readKeyAndIv(InstanceSecretStorage.java:59)
at com.atlassian.bamboo.crypto.instance.InstanceSecretStorage.loadCipherData(InstanceSecretStorage.java:121)
at com.atlassian.bamboo.crypto.instance.InstanceSecretStorage.getCipherData(InstanceSecretStorage.java:127)
at com.atlassian.bamboo.crypto.instance.InstanceSecretStorage.getOrCreateCipherData(InstanceSecretStorage.java:106)
at com.atlassian.bamboo.crypto.instance.InstanceSecretStorage.getCipherData(InstanceSecretStorage.java:99)
at com.atlassian.bamboo.crypto.instance.InstanceSecretStorage.getKeyAndIv(InstanceSecretStorage.java:84)
at com.atlassian.bamboo.crypto.instance.InstanceCipherProvider.getKeyAndIv(InstanceCipherProvider.java:64)
at com.atlassian.bamboo.crypto.instance.InstanceCipherProvider.getCipher(InstanceCipherProvider.java:50)
at com.atlassian.bamboo.crypto.instance.InstanceCipherProvider.getEncryptor(InstanceCipherProvider.java:37)
at com.atlassian.bamboo.crypto.instance.SecretEncryptionServiceInternalImpl.encrypt(SecretEncryptionServiceInternalImpl.java:121)
at com.atlassian.bamboo.crypto.instance.SecretEncryptionServiceInternalImpl.encrypt(SecretEncryptionServiceInternalImpl.java:110)
at com.atlassian.bamboo.container.BambooContainer.initializeEncryptionKeys(BambooContainer.java:351)
at com.atlassian.bamboo.container.BambooContainer.start(BambooContainer.java:254)
at com.atlassian.bamboo.upgrade.UpgradeLauncher.upgradeAndStartBamboo(UpgradeLauncher.java:142)
at com.atlassian.bamboo.upgrade.UpgradeLauncher.contextInitialized(UpgradeLauncher.java:50)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4770)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5236)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1423)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1413)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)

I have checked /opt/atlassian/bamboo-home/xml-data/configuration for the cipher folder and it does not exist. 6.9 however works fine without this folder. The bamboo user has full ownership of those file / folders.