Build failed in Jenkins: Knox-master-release #1

[Apache Jenkins Server]

See <https://builds.apache.org/job/Knox-master-release/1/>

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Started by user gmcdonald
Building remotely on ubuntu6 in workspace 
<https://builds.apache.org/job/Knox-master-release/ws/>
Checkout:Knox-master-release / 
<https://builds.apache.org/job/Knox-master-release/ws/> - 
hudson.remoting.Channel@7d5fc016:ubuntu6
Using strategy: Default
Cloning the remote Git repository
Cloning repository https://git-wip-us.apache.org/repos/asf/incubator-knox.git
git --version
git version 1.7.9.5
Fetching upstream changes from 
https://git-wip-us.apache.org/repos/asf/incubator-knox.git
Seen branch in repository origin/HEAD
Seen branch in repository origin/master
Seen branch in repository origin/v0.2.0
Commencing build of Revision 4865efb6400e18b3a5a20bb4bd49c23eaffcf0ea 
(origin/v0.2.0)
Checking out Revision 4865efb6400e18b3a5a20bb4bd49c23eaffcf0ea (origin/v0.2.0)
No change to record in branch origin/v0.2.0
[Knox-master-release] $ ant release
FATAL: command execution failed.
java.io.IOException: Cannot run program "ant" (in directory 
"<https://builds.apache.org/job/Knox-master-release/ws/";)>: 
java.io.IOException: error=2, No such file or directory
        at java.lang.ProcessBuilder.start(ProcessBuilder.java:459)
        at hudson.Proc$LocalProc.<init>(Proc.java:244)
        at hudson.Proc$LocalProc.<init>(Proc.java:216)
        at hudson.Launcher$LocalLauncher.launch(Launcher.java:763)
        at hudson.Launcher$ProcStarter.start(Launcher.java:353)
        at hudson.Launcher$RemoteLaunchCallable.call(Launcher.java:988)
        at hudson.Launcher$RemoteLaunchCallable.call(Launcher.java:955)
        at hudson.remoting.UserRequest.perform(UserRequest.java:118)
        at hudson.remoting.UserRequest.perform(UserRequest.java:48)
        at hudson.remoting.Request$2.run(Request.java:326)
        at 
hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:72)
        at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
        at java.util.concurrent.FutureTask.run(FutureTask.java:138)
        at 
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
        at 
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
        at java.lang.Thread.run(Thread.java:619)
Caused by: java.io.IOException: java.io.IOException: error=2, No such file or 
directory
        at java.lang.UNIXProcess.<init>(UNIXProcess.java:148)
        at java.lang.ProcessImpl.start(ProcessImpl.java:65)
        at java.lang.ProcessBuilder.start(ProcessBuilder.java:452)
        ... 15 more
Build step 'Invoke Ant' marked build as failure