How do you find the number of nodes in a hadoop cluster?

How do you find the number of nodes in a hadoop cluster?

1 Answer

1. Here is the simple formula to find the number of nodes in Hadoop Cluster?
2. N = H / D.
3. where N = Number of nodes.
4. H = HDFS storage size.
5. D = Disk space available per node.
6. Consider you have 400 TB of the file to keep in Hadoop Cluster and the disk size is 2TB per node.
7. Number of nodes required = 400/2 = 200.

How do I find my cluster ID?

Your hadoop cluster ID will be in this file /hadoop/hdfs/namenode/current/VERSION . Open the VERSION file in text editor and search for namespaceID . The namespaceID in the VERSION file is your hadoop cluster ID. You can also find your namespaceID in /hadoop/hdfs/namesecondary/current/VERSION file.

How do I get active NameNode?

If you want to get the active namenode hostname from hdfs-site. xml file, you can go through following python script in github – https://github.com/grakala/getActiveNN.

How do I find my hadoop cluster name?

Article Details

1. Log into the Ambari node as the user root.
2. Run the command curl –user username : password http : //localhost:8080/api/v1/clusters/ .
3. From the above output, we can see that the cluster name is “amb171hawq”.

How many nodes can a cluster have?

Every cluster has one master node, which is a unified endpoint within the cluster, and at least two worker nodes. All of these nodes communicate with each other through a shared network to perform operations. In essence, you can consider them to be a single system.

How do you calculate data nodes?

Formula to Calculate HDFS nodes storage 8

1. H = C*R*S/(1-i) * 120%
2. Example:
3. Number of data nodes (n): n = H/d = c*r*S/(1-i)/d.
4. RAM Considerations:

What is the cluster ID?

A cluster ID is a unique identifier of the cluster that is generated automatically when the cluster starts for the first time. A cluster tag is a user friendly name that you can assign to your cluster. You can use these values to identify your cluster in the monitoring system you use.

How do I find the cluster ID in Linux?

Using the Live UI

Select the “Clusters” tab along the top of the Admin page. For the specified cluster, hover over the ID column value next to your cluster’s name to display the full 36-character string.

What is ZKFC?

The ZKFailoverController (ZKFC) is a ZooKeeper client that monitors and manages the state of the NameNode. Each of the machines which run NameNode service also runs a ZKFC. ZKFC is responsible for: Health monitoring: ZKFC periodically pings its local NameNode with a health-check command.

What are active and passive nodes in Hadoop?

In HA (High Availability) architecture, we have two NameNodes – Active “NameNode” and Passive “NameNode”. Active “NameNode” is the “NameNode” which works and runs in the cluster. Passive “NameNode” is a standby “NameNode”, which has similar data as active “NameNode”.

What is HDFS DFS command?

In Hadoop, hdfs dfs -find or hadoop fs -find commands are used to get the size of a single file or size for all files specified in an expression or in a directory. By default, it points to the current directory when the path is not specified. $hadoop fs -find / -name test -print or $hdfs dfs -find / -name test -print.

How do you find IP address in hadoop?

Easiest way would be to quickly open the core-site. xml file under HADOOP_HOME/conf directory. The value of fs.default.name property will tell you the host and port where NN is running. The fs.default.name gives the Localhost of the DataNode Tarek.

What is difference between cluster and node?

In Hadoop distributed system, Node is a single system which is responsible to store and process data. Whereas Cluster is a collection of multiple nodes which communicates with each other to perform set of operation. Multiple nodes are configured to perform a set of operations we call it Cluster.

Why does node have 3 clusters?

Having a minimum of three nodes can ensure that a cluster always has a quorum of nodes to maintain a healthy active cluster. With two nodes, a quorum doesn’t exist. Without it, it is impossible to reliably determine a course of action that both maximizes availability and prevents data corruption.

What is your cluster size in Hadoop?

The default Hadoop configuration uses 64 MB blocks, while we suggest using 128 MB in your configuration for a medium data context as well and 256 MB for a very large data context. This means that a mapper task can process one data block (for example, 128 MB) by only opening one block.

How does Hadoop determine cluster size?

1 Answer

1. Bare minimum, depending on replication factor of 3, you need about 50TB (10×3=30TB 80% rule: 40TB usable, this give you 8TB to work with ) – So 5 Nodes at 10TB a piece for HDFS.
2. HDFS can only use a maximum of 80% of total cluster space.
3. More nodes = faster YARN jobs.

How do I change my cluster ID?

To change Cluster ID, it is recommended to do the changes in a maintenance window.
…
Change Cluster ID in CUCM:

1. Login to Cisco Unified Communications Manager Administration.
2. Navigate to System > Enterprise Parameters.
3. Change Cluster ID from StandAloneCluster to your desired clusterid.
4. Click Save.

Which command is used to display the cluster information?

The Display Cluster Information (DSPCLUINF) command is used to display or print information about a cluster. It must be invoked from a node in the cluster.

How many Namenodes can be there in a cluster?

You can have only a single name node in a cluster. Detail – In Yarn / Hadoop 2.0 they have come with a concept of active name node and standby name node. ( This is where most of the people get confused. They consider them to be 2 nodes in a cluster).

What is Qjm in Hadoop?

QJM is an HDFS implementation. It is designed to provide edit logs. It allows sharing these edit logs between the active namenode and standby namenode. For High Availability, standby namenode communicates and synchronizes with the active namenode. It happens through a group of nodes or daemons called “Journal nodes”.

What is active Name node?

Active Namenode is the primary Namenode which works and runs in the cluster. Passive Namenode is a standby Namenode, which has similar metadata as active Namenode. When the active Namenode goes down, the passive Namenode replaces the active Namenode in the cluster.

What is standby node in Hadoop?

The Standby NameNode maintains enough state to provide a fast failover. In order for the Standby node to keep its state synchronized with the Active node, both nodes communicate through a group of separate daemons called JournalNodes.

How do I list all files in HDFS?

Use the hdfs dfs -ls command to list files in Hadoop archives. Run the hdfs dfs -ls command by specifying the archive directory location. Note that the modified parent argument causes the files to be archived relative to /user/ .

How do I view data in HDFS?

Retrieving Data from HDFS

1. Initially, view the data from HDFS using cat command. $ $HADOOP_HOME/bin/hadoop fs -cat /user/output/outfile.
2. Get the file from HDFS to the local file system using get command. $ $HADOOP_HOME/bin/hadoop fs -get /user/output/ /home/hadoop_tp/

How do I find my hive IP address?

You can find your IP address by following the steps below.
Hadoop Hive Server.