FAILED to start HDFS Namenode

[#1]

Hi,
I have a problem when I'll start my HDFS Service. I have 3 nodes ( 1 Master, 2 Slaves).
All of Secondary Namenode, two Data Nodes is starting successfully, but the NameNode is failed to start.
there's the error messages a stderr 

Can't open /var/run/cloudera-scm-agent/process/117-hdfs-NAMENODE/supervisor.conf: Permission denied.
+ make_scripts_executable
+ find /var/run/cloudera-scm-agent/process/117-hdfs-NAMENODE -regex '.*\.\(py\|sh\)$' -exec chmod u+x '{}' ';'
+ '[' DATANODE_MAX_LOCKED_MEMORY '!=' '' ']'
+ ulimit -l
+ export HADOOP_IDENT_STRING=hdfs
+ HADOOP_IDENT_STRING=hdfs
+ '[' -n '' ']'
+ acquire_kerberos_tgt hdfs.keytab
+ '[' -z hdfs.keytab ']'
+ '[' -n '' ']'
+ '[' validate-writable-empty-dirs = namenode ']'
+ '[' file-operation = namenode ']'
+ '[' bootstrap = namenode ']'
+ '[' failover = namenode ']'
+ '[' transition-to-active = namenode ']'
+ '[' initializeSharedEdits = namenode ']'
+ '[' initialize-znode = namenode ']'
+ '[' format-namenode = namenode ']'
+ '[' monitor-decommission = namenode ']'
+ '[' jnSyncWait = namenode ']'
+ '[' nnRpcWait = namenode ']'
+ '[' -safemode = '' -a get = '' ']'
+ '[' monitor-upgrade = namenode ']'
+ '[' finalize-upgrade = namenode ']'
+ '[' rolling-upgrade-prepare = namenode ']'
+ '[' rolling-upgrade-finalize = namenode ']'
+ '[' nnDnLiveWait = namenode ']'
+ '[' refresh-datanode = namenode ']'
+ '[' mkdir = namenode ']'
+ '[' nfs3 = namenode ']'
+ '[' namenode = namenode -o secondarynamenode = namenode -o datanode = namenode ']'
+ HADOOP_OPTS='-Dsecurity.audit.logger=INFO,RFAS -Djava.net.preferIPv4Stack=true '
+ export 'HADOOP_OPTS=-Dhdfs.audit.logger=INFO,RFAAUDIT -Dsecurity.audit.logger=INFO,RFAS -Djava.net.preferIPv4Stack=true '
+ HADOOP_OPTS='-Dhdfs.audit.logger=INFO,RFAAUDIT -Dsecurity.audit.logger=INFO,RFAS -Djava.net.preferIPv4Stack=true '
+ '[' namenode = namenode -a rollingUpgrade = '' ']'
+ exec /usr/lib/hadoop-hdfs/bin/hdfs --config /var/run/cloudera-scm-agent/process/117-hdfs-NAMENODE namenode

and there is the message from stdout

can anybody tell why it's happen ?
Thank you.

[#2]

restart the cloudera-scm-agent service as root

[#3]

Namenode memory could sometimes be the problem, the Cloudera Quickstart set namenode memory to 50MB, I updated it to 1GB and have the issue resolved. (They recommend 4GB though).

[#4]

I've discovered by painful experience that this might be caused by having more than one oracle java installed, and even worse, any version of openjdk java. Namely, make sure you have added the ca you used for the ssl to the java keystore of the java version you are using (you can find that out in process list). Also, make sure that keytool you are using is belonging to this version of java - so it's best to have only one version installed, or (if that is unavoidable), use the full path to keytool. Hope it helps.