@Kou_Bou    As we see the following message: WARNING 2019-11-06 09:46:39,683 NetUtil.py:93 - Failed to connect to https://localhost:8440/ca due to [Errno 111] Connection refused Which indicates that the Ambari Agent is trying to conect to the AmbariServer running in Localmachine "localhost". Ideally it should be using the FQDN of ambari server instead of "localhost:8440". So can you please try this: 1). please edit the "/etc/ambari-agent/conf/ambari-agent.ini" hostname to point to the FQDN (fully Qualified Hostname) of AmbariServer instead of localhost.  Please make sure to replace the "ambariserverhost.example.com" with the actual FQDN of your ambari server.    Example:   # grep -A1 '\[server\]' /etc/ambari-agent/conf/ambari-agent.ini [server] hostname=ambariserverhost.example.com   2. Then restart Ambari Agent.   # ambari-agent restart # cat /etc/hosts   3. Now verify iof you are able to connect to the mentioned AmbariServer FQDN and Port from the agent machine as following?   # telnet ambariserverhost.example.com 8440 (OR) # nc -v ambariserverhost.example.com 8440   4. Also please make sure that the iptables/firewall is disabled on AmbariServer host and port 8440 is listening Example:   # netstat -tnlpa | grep `cat /var/run/ambari-server/ambari-server.pid` tcp6 0 0 :::8080 :::* LISTEN 7463/java tcp6 0 0 :::8440 :::* LISTEN 7463/java     .   ... View more

@saivenkatg55  As we see the error indicates a Permission issue IOError: [Errno 13] Permission denied: '/var/log/ambari-metrics-monitor/ambari-metrics-monitor.log'   The permission on the file does not seems to be accurate as it does not have WRITE permission. -r--r--r-- 1 ams hadoop 3.1M Aug 22 13:43 ambari-metrics-monitor.log  . Please try the following command to change the permission and then try to restart metrics monitor again # chmod 644 /var/log/ambari-metrics-monitor/ambari-metrics-monitor.log . Can you try changing it to following and then try again:   ... View more

@ThanhP  In addition to my previous notes,  In order to further isolate the issue you can also try to start the NameNode (OR Hdfs services) manually using command line to see if it is starting fine?  See the doc: how to start HDFS services or individual components manually via command line: https://docs.cloudera.com/HDPDocuments/HDP3/HDP-3.1.0/administration/content/starting_hdp_services.html Example: # su -l hdfs -c "/usr/hdp/current/hadoop-hdfs-namenode/../hadoop/sbin/hadoop-daemon.sh start namenode" .   ... View more

@ThanhP  Are you sure that your NameNode is running fine and listening to Port 8020 ? Can you please verify if the port is actually listening or not?   # netstat -tnlpa | grep 8020 # netstat -tnlpa | grep 50070 # ps -ef | grep -i NameNode   . Most probably the NameNode may not be running healthy, Or there may be some errors  reported inside  the  "/var/log/hadoop/hdfs/hadoop-hdfs-namenode-*.log" Can you please check and share the NN log. Also as you are using Sandbox which runs many other services so some times due to less resource availability (like free memory/cpu..etc)  services does not run properly so please try to stop the services which you are not using currently like Spark/Zeppelin/Oozie ..etc to free some resources and then restart NameNode to see if it works fine? Just start the Selective Services first like HDFS/Yarn/MapReduce/Zookeeper ...etc and then later based on resource availability we can start other services which are needed else just stop other services and put them in Maintenance mode until you actually want to test them. ... View more

@hassaniraj  Looks like the error reported in this thread could be due to the same reason mentioned on another thread of yours: https://community.cloudera.com/t5/Support-Questions/Hortonworks-sandbox-2-5-yum-update-not-working/m-p/278491 . It will be great to follow the same instructions mentioned on that thread to see if that fixes this issue. Specially  if you see some "dev2.hortonworks.com.s3.amazonaws.com" repos base URLs inside your "/etc/yum.repos.d" repos then please refer to the other thread and try to disable them and try again. You should set the "enabled=0" (this will disable the sandbox.repo) which has issue. As that is just development repo and might not be available always. https://community.cloudera.com/t5/Support-Questions/yum-install-error-please-help-me-out/m-p/203121 After removing the problematic repos try to perform a clean at yum level and then try again: # yum clean all # yum install python-pip . ... View more

@hassaniraj  1. Please try restarting the VM once. 2. Inside the sandbox do SSH login and then try to see if you are able to make the following curl call .. this is just to verify the repo accessibility. If the following URL does not work then please share the HTTP Header section output of the following curl commands here so that we can verify if there are some special headers like Network proxy ..etc. # curl -iLvk <a href="http://public-repo-1.hortonworks.com/HDP-UTILS-1.1.0.21/repos/centos6/repodata/repomd.xml" target="_blank">http://public-repo-1.hortonworks.com/HDP-UTILS-1.1.0.21/repos/centos6/repodata/repomd.xml</a> AND   # curl -iLvk <a href="http://public-repo-1.hortonworks.com/HDP-UTILS-1.1.0.21/repos/centos6/repodata/7fcacadb44b1a860fb704795c187f549103e855a0a93ed31293a0b270a9022b4-primary.sqlite.bz2" target="_blank">http://public-repo-1.hortonworks.com/HDP-UTILS-1.1.0.21/repos/centos6/repodata/7fcacadb44b1a860fb704795c187f549103e855a0a93ed31293a0b270a9022b4-primary.sqlite.bz2</a>   3. If above works fine then we will have to look from the YUM side. Please try to perform the yum cache cleanup and then retry:   # yum clean all # yum update   4. It will be also good to verify if the "/etc/yum.repos.d/" directory has any problematic repo. Can you please list them?   # ls -lart /etc/yum.repos.d/   For temporarily you can move some of the repo files from "/etc/yum.repos.d/" file to outside and then retry... this will help in isolating if there are any corrupted repo issue. 5. Recently have you made any changes to the "/etc/yum.conf" file like enabling/disabling any proxy setting ..? # cat /etc/yum.conf   Also if you see some "dev2.hortonworks.com.s3.amazonaws.com" repos URLs inside your "/etc/yum.repos.d" repos then please refer to the other thread and try to disable them and try again: https://community.cloudera.com/t5/Support-Questions/yum-install-error-please-help-me-out/m-p/203121 Example:   # cat /etc/yum.repos.d/sandbox.repo [sandbox] baseurl=<a href="http://dev2.hortonworks.com.s3.amazonaws.com/repo/dev/master/utils/" target="_blank">http://dev2.hortonworks.com.s3.amazonaws.com/repo/dev/master/utils/</a> name=Sandbox repository (tutorials) gpgcheck=0 enabled=0       . . If your question is answered then, Please make sure to mark the answer as the accepted solution. If you find a reply useful, say thanks by clicking on the thumbs up button. ... View more