I have Cloudera quickstart CDH 5.15 cluster is very slow
when i run a simple hadoop command like "hadoop fs -ls" it takes almost 20 seconds
but when i try runnnig local commands like "ls" it is very fast please help me with this.
The quickstart VM requires 6-8 GB of RAM to work reliably.
But the JVM startup process for any hadoop command is going to be much much slower compared to other built-in shell commands that operate similarly. There's no way around that fact.
If you want the Hadoop ls command to be quicker, it would be beneficial to setup an actual distributed cluster with adequate memory for the Namenode process, which is what ls contacts
Related
I'm trying to install Hadoop in a virtual machine, I found a tutorial explaining how to do that in a multi-node cluster .
So my question is what's the difference between a single-node and a multi-node cluster ?
Thanks in advance :)
Single node cluster : By default, Hadoop is configured to run in a non-distributed or standalone mode, as a single Java process. There are no daemons running and everything runs in a single JVM instance. HDFS is not used.
Pseudo-distributed or multi-node cluster: The Hadoop daemons run on a local machine, thus simulating a cluster on a small scale. Different Hadoop daemons run in different JVM instances, but on a single machine. HDFS is used instead of local FS
And you can have your work environment set up as follow
Step 1 - Download VMware player latest version and install on your laptop/desktop. You can also install VMware tools, which will be very useful for your working with guest OS.
Step 2 - Once you Step 1 is completed then Download Cloudera Quick Start VM from
http://www.cloudera.com/content/support/en/downloads/download-components/download-products.html?productID=F6mO278Rvo
Step 3 - Open VMPlayer program and click on “Open a virtual Machine”. and go to directory “cloudera-quickstart-vm-4.4.0-1-vmware”. Select cloudera-quickstart-vm-4.4.0-1-vmware. This will create a virtual machine instance in VM Player.
Step 4 - Start the Cloudera VM by Clicking on power on to start the Cloudera Demo VM.
You are good to go
Good luck
I'm trying to automate stopping, formatting and starting HDFS and MapReduce services on a Cloudera Hadoop 4.4 cluster, using a bash script.
It's easy to kill HDFS and MapReduce processes using "pkill -U hdfs && pkill -U mapred", but how can I start those processes again, without using the Cloudera Manager GUI?
Well, apparently CM has a pretty sweet API
Check it out here
http://cloudera.github.io/cm_api/
I have 3 operations from Mahout and I want them to run over Multi-Node Hadoop cluster.
Does these operations could run?
seq2sparse, trainnb, testnb
I try to run it, but it seems that all executes over one machine(master).
I am wondering if we can setup a cloudera cluster on amazon and kick off a hadoop job from my local linux without ssh into amazon's node.
Is there anything like a client to do this communication?
The tips from the following tutorial really work. You should be able to put a working Hadoop Cluster in under 20 minutes, from cold iron to production ready, using just his guidance:
Hadoop Quickstart: Build a Cluster In The Cloud In 20 Minutes
Really worth checking it.
You can install an Hadoop client in your local linux and use the "hadoop jar" command with your own jar. Specify the option mapred.job.tracker in the command line and the client will push your jar to the jobtracker and duplicate it in all the tasktrackers that will be used for this job.
I'm deploying Hadoop CDH3 in pseudo-distributed mode on a VPS.
So i have installed CDH3, then i have executed
sudo apt-get install hadoop-0.20-conf-pseudo
but if i try to start all daemons with
for service in /etc/init.d/hadoop-0.20-*; do sudo $service start; done
it throws
ERROR. Could not start Hadoop datanode daemon
The same installation and starting commands works on my notebook.
I don't understand the cause. In fact the log file is empty. The available RAM is about 900MB, with 98G of available disk space.
Which can be the cause or how can i discover it? I'm excluding that the error is from the configuration files.
Consider using Cloudera Manager, it could save you some time (especially if you use multiple nodes). There is a nice video on Youtube which shows deployment process