// java.lang.NullPointerException
  at hudson.plugins.ec2.EC2Computer.getState(EC2Computer.java:188)
  at hudson.plugins.ec2.EC2RetentionStrategy.start(EC2RetentionStrategy.java:279)
  at hudson.plugins.ec2.EC2RetentionStrategy.start(EC2RetentionStrategy.java:53)
  at hudson.model.AbstractCIBase.createNewComputerForNode(AbstractCIBase.java:192)
  at hudson.model.AbstractCIBase.updateComputer(AbstractCIBase.java:153)
  at hudson.model.AbstractCIBase$1.run(AbstractCIBase.java:255)
  at hudson.model.Queue._withLock(Queue.java:1395)
  at hudson.model.Queue.withLock(Queue.java:1269)
  at hudson.model.AbstractCIBase.updateComputerList(AbstractCIBase.java:238)
  at jenkins.model.Jenkins.updateComputerList(Jenkins.java:1683)
  at jenkins.model.Nodes$6.run(Nodes.java:351)
  at hudson.model.Queue._withLock(Queue.java:1395)
  at hudson.model.Queue.withLock(Queue.java:1269)
  at jenkins.model.Nodes.load(Nodes.java:346)
  at jenkins.model.Jenkins$12.run(Jenkins.java:3429)
  at org.jvnet.hudson.reactor.TaskGraphBuilder$TaskImpl.run(TaskGraphBuilder.java:177)
  at org.jvnet.hudson.reactor.Reactor.runTask(Reactor.java:305)
  at jenkins.model.Jenkins$5.runTask(Jenkins.java:1164)
  at org.jvnet.hudson.reactor.Reactor$2.run(Reactor.java:221)
  at org.jvnet.hudson.reactor.Reactor$Node.run(Reactor.java:120)
  at jenkins.security.ImpersonatingExecutorService$1.run(ImpersonatingExecutorService.java:68)
  at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
  at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
  at java.base/java.lang.Thread.run(Thread.java:829)
Caused: org.jvnet.hudson.reactor.ReactorException
  at org.jvnet.hudson.reactor.Reactor.execute(Reactor.java:290)
  at jenkins.InitReactorRunner.run(InitReactorRunner.java:49)
  at jenkins.model.Jenkins.executeReactor(Jenkins.java:1199)
  at jenkins.model.Jenkins.<init>(Jenkins.java:987)
  at hudson.model.Hudson.<init>(Hudson.java:86)
  at hudson.model.Hudson.<init>(Hudson.java:82)
  at hudson.WebAppMain$3.run(WebAppMain.java:247)
Caused: hudson.util.HudsonFailedToLoad
  at hudson.WebAppMain$3.run(WebAppMain.java:264)