When starting Hadoop using start-all.sh I kept seeing the following in my log file
"Unable to load realm info from SCDynamicStore"
A workaround is suggested on the Hadoop Jira under
HADOOP-7489
which is to specify kerberos config on the command line:
-Djava.security.krb5.realm=OX.AC.UK -Djava.security.krb5.kdc=kdc0.ox.ac.uk:kdc1.ox.ac.uk
This works perfectly but is easier if you add it into the HADOOP_OPTS environment variable in $HADOOP_HOME/conf/hadoop-env.sh
Mine looks like this:
export HADOOP_OPTS="-server -Djava.security.krb5.realm=OX.AC.UK -Djava.security.krb5.kdc=kdc0.ox.ac.uk:kdc1.ox.ac.uk"