The bit you are missing is
-Djava.security.auth.login.config=/opt/kairosdb/conf/auth/basicAuth.confPut that to the JVM_OPTS in kairosdb-env.sh
like this:
JAVA_OPTS="$JAVA_OPTS -Djava.security.auth.login.config=/opt/kairosdb/conf/auth/basicAuth.conf"
Assuming that is where your conf file is located. This was in the documentation that was linked but it looks like the links have moved. I now even remember having a conversation with the engineer that added this feature and he told me it was in the linked docs and it bothered me just a bit at the time. Obviously it should have bothered me more. I'll fix the docs in the kairosdb.conf file.
Brian