Build failed in Jenkins: Cassandra #1644

[Apache Jenkins Server]

See <https://builds.apache.org/job/Cassandra/1644/>

------------------------------------------
Started by an SCM change
Building remotely on ubuntu4 in workspace 
<https://builds.apache.org/job/Cassandra/ws/>
Checkout:Cassandra / <https://builds.apache.org/job/Cassandra/ws/> - 
hudson.remoting.Channel@539311ce:ubuntu4
Using strategy: Default
Last Built Revision: Revision 44f4cac62e33238461274b6aec6790d623b70484 
(origin/trunk)
Fetching changes from 1 remote Git repository
Fetching upstream changes from 
https://git-wip-us.apache.org/repos/asf/cassandra.git
Commencing build of Revision 45ad66895d0e5b99feaa74ec061b887c1a9688a3 
(origin/trunk)
Checking out Revision 45ad66895d0e5b99feaa74ec061b887c1a9688a3 (origin/trunk)
FATAL: Could not apply tag jenkins-Cassandra-1644
hudson.plugins.git.GitException: Could not apply tag jenkins-Cassandra-1644
        at hudson.plugins.git.GitAPI.tag(GitAPI.java:751)
        at hudson.plugins.git.GitSCM$4.invoke(GitSCM.java:1321)
        at hudson.plugins.git.GitSCM$4.invoke(GitSCM.java:1269)
        at hudson.FilePath$FileCallableWrapper.call(FilePath.java:2196)
        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:334)
        at java.util.concurrent.FutureTask.run(FutureTask.java:166)
        at 
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
        at 
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
        at java.lang.Thread.run(Thread.java:636)
Caused by: hudson.plugins.git.GitException: Command "git tag -a -f -m Jenkins 
Build #1644 jenkins-Cassandra-1644" returned status code 128:
stdout: 
stderr: 
*** Please tell me who you are.

Run

  git config --global user.email "y...@example.com"
  git config --global user.name "Your Name"

to set your account's default identity.
Omit --global to set the identity only in this repository.

fatal: empty ident  <jenk...@janus.apache.org
> not allowed

        at hudson.plugins.git.GitAPI.launchCommandIn(GitAPI.java:818)
        at hudson.plugins.git.GitAPI.launchCommand(GitAPI.java:780)
        at hudson.plugins.git.GitAPI.launchCommand(GitAPI.java:790)
        at hudson.plugins.git.GitAPI.tag(GitAPI.java:749)
        ... 12 more