All knowledge base posts in Cloudera Community

Re: Cloudera Certification FAQ

cjervis — Mon, 07 May 2018 12:37:09 GMT

Thank you for asking . I did a quick check of each certification page and while I do see this on the CCP Data Engineer page:

What is the best way to prepare?

The CCP Data Engineer exam was created to identify talented data professionals looking to stand out and be recognized by employers looking for their skills. Outside of having hands-on experience in the field, it is recommended that professional looking to achieve this certification start by taking Cloudera's Spark and Hadoop Developer training course.

I also noticed on the main certifications page:

Cloudera Certified Associate (CCA)

CCA exams test foundational skills and sets forth the groundwork for a candidate to achieve mastery under the CCP program

For the CCA certifications, I do not see any recommendation on the order to take the exams or mention in prerequisites that one certification is required to take another exam.

Re: Cloudera Certification FAQ

nitmanit02 — Mon, 07 May 2018 01:26:04 GMT

Hi,
I have one queston:

Is there any particular order/sequence of giving the certifications out of these 4? Or can any of them be given in any order?

CCA Spark and Hadoop Developer

CCA Data Analyst

CCA Administrator

CCP Data Engineer

Thanks

Cloudera Altus Cluster Creation fails with INTERNAL_CM_CMD_FAIL on AWS

Anthony — Tue, 26 Jun 2018 15:31:01 GMT

Symptoms

When attempting to create a Cloudera Altus cluster in AWS, it fails with INTERNAL_CM_CMD_FAIL

Diagnosis

CM Deployment is failing at the creation / deployment of CM services due to incorrect or unexpected DNS hostnames of the AWS EC2 instances created for Cloudera Altus.
Cloudera Altus requires the options DNS hostnames and DNS resolution are enabled (set to yes) within the AWS VPC settings

Solution

Set and confirm DNS hostnames and DNS resolution are set to yes in the AWS VPC used for Cloudera Altus.
Details for configuring AWS VPCs with DNS is available here:
https://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/vpc-dns.html
Once the AWS VPC DNS settings of the Cloudera Altus Environment are enabled, ensure to delete the previous cluster creation attempt's EC2 instances, both within a Cloudera Altus console, as well as through the AWS EC2 interface
Retry creating a new Cloudera Altus cluster with the updated settings

Re: Unable to SSH to Cluster

EugeneF — Fri, 06 Apr 2018 21:49:28 GMT

The issue may also happen if SSH key supplied when at cluster creation time was generated using Pass Phrase. This option is not supported when trying to use SSH Proxy command and hence command can hang/timeout.

Re: Package Installation For Kafka

sds — Wed, 04 Apr 2018 10:37:09 GMT

Hi,

I am setting up kafka in Bluedata environment

I have created a topic “test” with 4 partitions with replication factor 1

Topic: test Partition: 0 Leader: 1 Replicas: 1 Isr: 1

Topic: test Partition: 1 Leader: 0 Replicas: 0 Isr: 0

Topic: test Partition: 2 Leader: 1 Replicas: 1 Isr: 1

Topic: test Partition: 3 Leader: 0 Replicas: 0 Isr: 0

When I run Console-Producer

(bin/kafka-console-producer.sh --broker-list localhost:9092 --topic test)

and enter some message, Its giving error like

WARN Error while fetching metadata with correlation id 0 : {test=LEADER_NOT_AVAILABLE}

WARN Error while fetching metadata with correlation id 1 : {test=LEADER_NOT_AVAILABLE}

WARN Error while fetching metadata with correlation id 2 : {test=LEADER_NOT_AVAILABLE}

So on…

Can any one help me in resolving this issue

Re: Getting "heartbeat" errors when trying to install CDH via Cloudera Manager

sharmaji — Tue, 20 Mar 2018 19:40:02 GMT

I could not figure out what the issue was so I use this workaround and add the host as "Currently Managed Hosts" instead of selcting a new one.

Here are the steps are use to add a new host ( some of them may not be applicabe to your setup)

Disable Firewall on node:

systemctl disable firewalld.service

Disable SELinux Set SELINUX=disabled in the /etc/selinux/config file and reboot

After reboot, run getenforce command to check that SELinux is disbaled

Update repository

yum-config-manager --add-repo https://archive.cloudera.com/cm5/redhat/7/x86_64/cm/cloudera-manager.repo

Install Java

$ sudo yum install –y oracle-j2sdk1.7

export JAVA_HOME=/usr/java/jdk1.7.0_67-cloudera

put it in .bashrc as well

echo "export JAVA_HOME=/usr/java/jdk1.7.0_67-cloudera" >>/root/.bashrc

Install cloudera daemons

sudo yum install -y cloudera-manager-agent cloudera-manager-daemons

On agent edit /etc/cloudera-scm-agent/config.ini to point to Cloudera manager (if nedded)

# Hostname of the CM server.

server_host=nodexxxx

Start Agent

# service cloudera-scm-agent start

# chkconfig cloudera-scm-agent on

Login to Cloudera manager and while adding host, insteading of selecting new host from the list, look for "Currently Managed Hosts(1)" link on the top of the screen. Click on the link and select the host from list.

Rest of the installation should go fine. Good luck

Re: Getting "heartbeat" errors when trying to install CDH via Cloudera Manager

Paul_ — Tue, 20 Mar 2018 16:55:05 GMT

I'm having the same issue's and need some help to get through this....

On a RHEL7.3 installed in a VM (VirtualBox) i'm trying to install a single node cluster using cloudera manager (Cloudera Express 5.14.1). I get stuck when adding a single agent node (on localhost that is).

Error message:

Installation failed. Failed to receive heartbeat from agent.

Ensure that the host's hostname is configured properly.
Ensure that port 7182 is accessible on the Cloudera Manager Server (check firewall rules).
Ensure that ports 9000 and 9001 are not in use on the host being added.
Check agent logs in /var/log/cloudera-scm-agent/ on the host being added. (Some of the logs can be found in the installation details).
If Use TLS Encryption for Agents is enabled in Cloudera Manager (Administration -> Settings -> Security), ensure that /etc/cloudera-scm-agent/config.ini has use_tls=1 on the host being added. Restart the corresponding agent and click the Retry link here.

I've checked, fixed, rechecked:

- no firewall is enabled

- selinux is disabled

- ipv6 is disabled

- ntp is setup

I have stopped, wiped, restarted the installation many times now but i always get stuck at this point.

I have extended my hosts files with:

10.0.2.15 my-host.local my-host

But i have found that when i try to aff my-host in the wizard it first seems to setup the agent at my-host.local @ 10.0.2.15, but then when i hit the error, if i open: http://localhost:7180/cmf/hardware/hosts it always shows up as localhost4.localdomain4. Then also the most odd thing is that in the hosts overview there is a Last Heartbeat column that actually shows that the heartbeat is working: it's like 4.26s, then when reloading it's 1,5s, etc....

I have checked both the cloudera-scm-server and cloudera-scm-agent logs but did not find any usefull things.

Anyone please; how do i setup a single node (test) cluster?

Notice i can't work with the quickstart because of Centos....

Paul

Re: Cloudera Certification FAQ

spk_cloud — Wed, 07 Mar 2018 16:41:25 GMT

Hi,

For the CCA175 prep, do we need just download and use the quick start VM as-is?

Or, should we install Cloudera Express that's offered free in the VM?

In case we are not using the Cloudera Manager, would we be able to install any service in the eco-system, start and stop them whenever necessary?

Thanks.

Re: Getting "heartbeat" errors when trying to install CDH via Cloudera Manager

Shelton — Sat, 20 Jan 2018 04:13:06 GMT

You shouldn't also forget setting up the SeLinux, passwordless connection and NTP! I have seen case where these have affected setup!

Re: How to setup Cloudera Quickstart Virtual Machine

cjervis — Fri, 19 Jan 2018 15:09:20 GMT

Hi dave. In this case I would suggest starting a new thread in the Hadoop 101 area. It may end up being a setting in VMWare but I'm not sure.

Re: How to setup Cloudera Quickstart Virtual Machine

DAve Milburn — Sun, 14 Jan 2018 22:17:13 GMT

I have just downloaded the Quickstart 5.12.0 and all appears to be working well except -

I cannot transfer files between my Windows Laptop and the VM.

I am running Windows 10 with 16Gb RAM and VMWare Player 14 and associated Cloudera VM.

The image is not easily letting me do any configuration to support file transfers and always refuses a connection e.g. via WinSCP.

Can anyone advise of a solution please? I would of expected this to be default behaviour enabled with the VM.

Re: Getting "heartbeat" errors when trying to install CDH via Cloudera Manager

sharmaji — Mon, 08 Jan 2018 17:07:59 GMT

Correction : Port 7182, not 8182

[root@dsib2041 ~]# netstat -l

Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 0.0.0.0:mysql 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:7180 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:7182 0.0.0.0:* LISTEN

Re: Getting "heartbeat" errors when trying to install CDH via Cloudera Manager

sharmaji — Mon, 08 Jan 2018 17:05:10 GMT

I have the same issue and checked everything suggested by Clint. Firewall is disabled, Manager is listening on 8182. hostsa are able to resolve names to correct IP. Not sure what is missing. I am installling CDH-5.13.1-1.cdh5.13.1.p0.2 and I am trying to use "Single User Mode", could that be a problem ?

[08/Jan/2018 09:41:16 +0000] 4959 MainThread agent ERROR Heartbeating to dsib2041:None failed.
Traceback (most recent call last):
File "/usr/lib64/cmf/agent/build/env/lib/python2.7/site-packages/cmf-5.13.1-py2.7.egg/cmf/agent.py", line 1412, in _send_heartbeat
self.master_port)
File "/usr/lib64/cmf/agent/build/env/lib/python2.7/site-packages/avro-1.6.3-py2.7.egg/avro/ipc.py", line 469, in __init__
self.conn.connect()
File "/usr/lib64/python2.7/httplib.py", line 807, in connect
self.timeout, self.source_address)
File "/usr/lib64/python2.7/socket.py", line 571, in create_connection
raise err
error: [Errno 111] Connection refused
[08/Jan/2018 09:41:16 +0000] 4959 MainThread heartbeat_tracker INFO HB stats (seconds): num:1 LIFE_MIN:0.00 min:0.00 mean:0.00 max:0.00 LIFE_MAX:0.00
[08/Jan/2018 09:42:16 +0000] 4959 MainThread agent ERROR Heartbeating to dsib2041:None failed.
Traceback (most recent call last):
File "/usr/lib64/cmf/agent/build/env/lib/python2.7/site-packages/cmf-5.13.1-py2.7.egg/cmf/agent.py", line 1412, in _send_heartbeat
self.master_port)
File "/usr/lib64/cmf/agent/build/env/lib/python2.7/site-packages/avro-1.6.3-py2.7.egg/avro/ipc.py", line 469, in __init__
self.conn.connect()
File "/usr/lib64/python2.7/httplib.py", line 807, in connect
self.timeout, self.source_address)
File "/usr/lib64/python2.7/socket.py", line 571, in create_connection
raise err
error: [Errno 111] Connection refused

Re: Getting "heartbeat" errors when trying to install CDH via Cloudera Manager

OlegKhaykin — Thu, 07 Sep 2017 03:29:49 GMT

I have the same problem while installing of CDH-5.12 on a 3-node cluster:

1) PowerEdge - the main computer where cloudera-scm-server is running;

2) hadoop-1 - the 1st node where cloudera-scm-agent is running;

3) hadoop-2 - the 2nd node where cloudera-scm-agent is running;

This is what I see in /var/log/cloudera-scm-agent/cloudera-scm-agent.log on hadoop-1:

[06/Sep/2017 22:51:12 +0000] 18772 MainThread agent ERROR Heartbeating to computer.home:7182 failed.
Traceback (most recent call last):
File "/usr/lib64/cmf/agent/build/env/lib/python2.7/site-packages/cmf-5.12.0-py2.7.egg/cmf/agent.py", line 1401, in _send_heartbeat
self.master_port)
File "/usr/lib64/cmf/agent/build/env/lib/python2.7/site-packages/avro-1.6.3-py2.7.egg/avro/ipc.py", line 469, in __init__
self.conn.connect()
File "/usr/lib64/python2.7/httplib.py", line 807, in connect
self.timeout, self.source_address)
File "/usr/lib64/python2.7/socket.py", line 571, in create_connection
raise err
error: [Errno 111] Connection refused

BTW, this is what netstat is reporting:

> netstat -a | grep 7182

tcp 0 0 hadoop-1:47144 PowerEdge:7182 ESTABLISHED

What have I done wrong?

Jars Built for EMR Failed to Run on Cloudera Altus

dice — Tue, 26 Jun 2018 15:45:46 GMT

Symptoms

A Spark job fails with INTERNAL_FAILURE. In the WA (Workload Analytics) page of the job that failed, the following message is reported:

org.apache.spark.SparkException: Application application_1503474791091_0002 finished with failed status

Diagnosis

As the Telemetry Publisher didn't retrieve the application log due to a known bug, we have to diagnose the application logs (application_1503474791091_0002) directly, which are stored in the user's S3 bucket.

If the following exception is found, it indicates that the application failed to resolve a dependency in the Hadoop class path:

17/08/24 13:13:33 INFO ApplicationMaster: Preparing Local resources
Exception in thread "main" java.lang.NoSuchMethodError: org.apache.hadoop.tracing.TraceUtils.wrapHadoopConf(Ljava/lang/String;Lorg/apache/hadoop/conf/Configuration;)Lorg/apache/htrace/core/HTraceConfiguration;
 at org.apache.hadoop.fs.FsTracer.get(FsTracer.java:42)
 at org.apache.hadoop.hdfs.DFSClient.<init>(DFSClient.java:687)
 at org.apache.hadoop.hdfs.DFSClient.<init>(DFSClient.java:671)
 at org.apache.hadoop.hdfs.DistributedFileSystem.initialize(DistributedFileSystem.java:155)
 at org.apache.hadoop.fs.FileSystem.createFileSystem(FileSystem.java:2653)

This most likely occurred because the jar may have been built using the another Hadoop distribution's repository, for example EMR (Amazon Elastic MapReduce)

Solution

To resolve the issue, rebuild the application using the CDH repository, https://repository.cloudera.com/artifactory/cloudera-repos/, using Maven or sbt. The example of using Maven is as follows.

https://www.cloudera.com/documentation/enterprise/release-notes/topics/cdh_vd_cdh5_maven_repo.html

Re: HBase FAQ: Sizing a Cluster

Electronics — Mon, 04 Sep 2017 11:31:20 GMT

nice information sir :)

Re: Adding cluster failed - how to troubleshoot?

giladwolff — Tue, 29 Aug 2017 17:15:56 GMT

One typo correction to Anthony's reply above, the CLI command to retrieve information about a cluster is as 'describe-cluster' and not 'describe-clusters'.

Re: Adding cluster failed - how to troubleshoot?

Robert Justice — Tue, 29 Aug 2017 13:56:02 GMT

Great to hear! Thanks for getting back and letting us know.

Re: Re: Adding cluster failed - how to troubleshoot?

uzubair — Tue, 29 Aug 2017 13:06:03 GMT

I was able to resolve the issue...was able to run Spark jobs in Altus using Talend Big Data.

The issue had to do with the VPC setup in my Amazon environment. It wasn't setup properly. I picked a different region where the VPC is setup correctly and I was able to launch the cluster.

Re: Re: Adding cluster failed - how to troubleshoot?

Anthony — Tue, 29 Aug 2017 12:54:12 GMT

Hi @uzubair,

Thanks for raising this to our attention.

You may be able to check the S3 bucket (if configured) for log output that may help with determining why the described symptoms occurred.

Given the nature of this issue, are you able to create a support case through the Altus Web UI (Altus Web UI -> Support -> Support Center -> Technical Support; Component = Altus Data Engineering; Sub-Component = Clusters)?

Would you be able to provide some additional details within the support case as well, in particular:

The output of the following command as well (if you have the Altus CLI installed):

$ altus dataeng describe-clusters --cluster-name <cluster_name>
Cluster Creation time
# of Workers and Computer workers created, and if spot instances were used
Was there an Instance Bootstrap Script used? If so can you attach that to the Support Case as well?
Has any other Cluster creations failed in this same manner recently, or has this only been a single manifestation?

Kind Regards,

Anthony