Setting Up Hadoop Pre-requisites and Security Hardening



Hadoop Cluster Constructing is a step-by-step course of the place the method begins from buying the required servers, mounting into the rack, cabling, and so on. and putting in Datacentre. Then we have to set up the OS, it may be carried out utilizing kickstart within the real-time setting if the cluster measurement is massive. As soon as OS put in, then we have to put together the server for Hadoop Set up and we have to put together the servers in line with the Group’s safety insurance policies.


On this article, we are going to undergo OS-level pre-requisites really useful by Cloudera. Additionally, now we have highlighted some essential Safety Hardening ideas in line with the CIS Benchmark for Manufacturing servers. These safety Hardening could be completely different in line with the necessities.

Setting Up Cloudera Hadoop Pre-requisites

Right here, we are going to talk about the OS-level pre-requisites really useful by Cloudera.

1. Disable Clear Large Web page

By default, Clear Large Web page (THP) is enabled in Linux machines which poorly work together with Hadoop workloads and it degrades the general efficiency of Cluster. So we have to disable this in an effort to obtain optimum efficiency utilizing the next echo command.

# echo by no means > /sys/kernel/mm/transparent_hugepage/enabled
# echo by no means > /sys/kernel/mm/transparent_hugepage/defrag

Setting Up Hadoop Pre-requisites and Security HardeningDisable Clear Large Web page

2. Change VM Swappiness

By default, the vm.swappiness worth is 30 or 60 for a lot of the Linux machines.

# sysctl vm.swappiness

Setting Up Hadoop Pre-requisites and Security HardeningExamine VM Swappiness

Having the next worth of swappiness is just not really useful for Hadoop servers as a result of it could trigger prolonged Rubbish assortment pauses. And, with the upper swappiness worth, knowledge could be cached to swap reminiscence even when now we have sufficient reminiscence. Decrease the swappiness worth could make bodily reminiscence to comprise extra reminiscence pages.

# sysctl vm.swappiness=1

Or, you possibly can open the file /and so on/sysctl.conf and add “vm.swappiness=1” on the finish.


3. Disable Firewall

Every Hadoop server shall be having its personal accountability with a number of companies (daemons) operating on that. All of the servers shall be speaking with one another in a frequent method for varied functions.

For Instance, Datanode will ship a heartbeat to Namenode for each Three seconds in order that Namenode will guarantee that the Datanode is alive.

If all of the communication occurs between the daemons throughout completely different servers through the Firewall, it is going to be an additional burden to Hadoop. So it’s finest follow to disable the firewall within the particular person servers in Cluster.

# iptables-save > ~/firewall.guidelines
# systemctl cease firewalld
# systemctl disable firewall

Setting Up Hadoop Pre-requisites and Security HardeningDisable Firewall

4. Disable SELinux

If we hold the SELinux enabled, it can trigger points whereas putting in Hadoop. As Hadoop is a cluster computing, Cloudera Supervisor will attain all of the servers within the cluster to put in Hadoop and its companies and it’ll create essential service directories wherever required.

If SELinux enabled, it won’t let Cloudera Supervisor to rule the set up because it needs. So, enabling SELinux shall be an impediment to Hadoop and it’ll trigger efficiency points.

You possibly can examine the standing of SELinux by utilizing the beneath command.

# sestatus

Setting Up Hadoop Pre-requisites and Security HardeningExamine SELinux Standing

Now, open the /and so on/selinux/config file and disable SELINUX as proven.


Setting Up Hadoop Pre-requisites and Security HardeningDisable SELinux

After disabling SELinux, it is advisable to reboot the system to make it energetic.

# reboot

5. Set up NTP Providers

In Hadoop Cluster, all of the servers ought to be Time Synchronised to keep away from clock offset errors. The RHEL/CentOS 7 is having chronyd inbuilt for community clock/time synchronization, however Cloudera recommends to make use of NTP.

We have to set up NTP and configure it. As soon as put in, cease ‘chronyd‘ and disable. As a result of, if a server having each ntpd and chronyd operating, Cloudera Supervisor will think about chronyd for time synchronization, then it can throw an error even when now we have time synchronized by ntp.

# yum -y set up ntp
# systemctl begin ntpd
# systemctl allow ntpd
# systemctl standing ntpd

Setting Up Hadoop Pre-requisites and Security HardeningExamine NTP Standing

6. Disable Chronyd

As we talked about above, we don’t want chronyd energetic as we’re utilizing ntpd. Examine the standing of chronyd, whether it is operating cease and disable. By default, chronyd is stopped until till we begin it after OS set up, simply we have to disable for safer aspect.

# systemctl standing chronyd
# systemctl disable chronyd

Setting Up Hadoop Pre-requisites and Security HardeningDisable Chronyd

7. Set FQDN (Absolutely Certified Area Title)

We’ve got to set the hostname with FQDN (Absolutely Certified Area Title). Every server ought to be having a singular Canonical identify. To resolve the hostname, both we have to configure the DNS or /and so on/hosts. Right here, we’re going to configure /and so on/hosts.

IP tackle and FQDN of every server ought to be entered in /and so on/hosts of all of the servers. Then solely Cloudera Supervisor can talk all of the servers with its hostname.

# hostnamectl set-hostname

Subsequent, configure /and so on/hosts file. For Instance: – If now we have 5 node cluster with 2 masters and three employees, we are able to configure the /and so on/hosts as beneath.

Setting Up Hadoop Pre-requisites and Security HardeningConfigure Hostnames

8. Putting in a Java Growth Equipment (JDK)

As Hadoop is made up of Java, all of the hosts ought to be having Java put in with the suitable model. Right here we’re going to have OpenJDK. By default, Cloudera Supervisor will set up OracleJDK however, Cloudera recommends having OpenJDK.

# yum -y set up java-1.8.0-openjdk-devel
# java -version

Setting Up Hadoop Pre-requisites and Security HardeningExamine Java Model

Hadoop Safety and Hardening

On this part, we shall be going to Harden Hadoop setting safety…

1. Disable Automounting

Automounting ‘autofs‘ permits computerized mounting of bodily gadgets like USB, CD/DVD. Person with bodily entry can connect their USB or any Storage medium to entry of insert knowledge. Use the beneath instructions to confirm whether or not it’s disabled or not, if not disable it.

# systemctl disable autofs
# systemctl is-enabled autofs

Setting Up Hadoop Pre-requisites and Security HardeningDisable Automounting

2. Safe Boot Settings

The grub configuration file comprises crucial data of boot settings and credentials to unlock boot choices. The grub config file ‘grub.cfg‘ positioned at /boot/grub2 and it’s been linked as /and so on/grub2.conf and guarantee grub.cfg is owned by root person.

# cd /boot/grub2

Setting Up Hadoop Pre-requisites and Security HardeningExamine Grub Information

Use the beneath command to examine Uid and Gid are each 0/root and ‘group’ or ‘different’ shouldn’t have any permission.

# stat /boot/grub2/grub.cfg

Setting Up Hadoop Pre-requisites and Security HardeningExamine Grub File Stat

Use the beneath command to take away permissions from different and group.

# chmod og-rwx /boot/grub2/grub.cfg

Setting Up Hadoop Pre-requisites and Security HardeningTake away Permission of Grub File

3. Set the Bootloader Password

This setting avoids different un-authorized rebooting of the server. ie, It requires a password to reboot the server. If it’s not set, unauthorized customers can boot the server and might make modifications to the boot partitions.

Use the beneath command to set the password.

# grub2-mkpasswd-pbkdf2

Setting Up Hadoop Pre-requisites and Security HardeningCreate a Bootloader Password

Add the above-created password in to /and so on/grub.d/01_users file.

Setting Up Hadoop Pre-requisites and Security HardeningAdd Grub Password to File

Subsequent, re-generate the grub configuration file.

# grub2-mkconfig > /boot/grub2/grub.cfg

Setting Up Hadoop Pre-requisites and Security HardeningGenerate Grub Configuration

4. Take away Prelink Software

Prelink is a software program program that may improve vulnerability in a server if malicious customers can compromise frequent libraries corresponding to libc.

Use the beneath command to take away it.

# yum take away prelink

5. Disable Undesirable Providers

We should always think about disabling some companies/protocols to keep away from potential assaults.

# systemctl disable

  • Disable Community Providers – Make sure the community companies – costs, daytime, discard, echo, time aren’t enabled. These Community companies are for debugging and testing, it’s really useful to disable which might reduce the distant assault.
  • Disable TFTP & FTP – Each the protocol won’t help the confidentiality of the info or credentials. It’s best follow to not have within the server until it’s required explicitly. Principally these protocols are put in and enabled on Fileservers.
  • Disable DHCP – DHCP is the protocol that may dynamically allocate the IP tackle. It’s really useful to disable until it’s a DHCP server to keep away from potential assaults.
  • Disable HTTP – HTTP is the protocol that can be utilized to host internet content material. Other than Grasp/Administration servers(the place WebUI of companies are to be configured like CM, Hue, and so on), we are able to disable HTTP on different employee nodes which might keep away from the potential assaults.


We’ve got gone by the server preparation which consists of Cloudera Hadoop Pre-requisites and a few safety hardening. OS degree pre-requisites outlined by Cloudera are obligatory for the graceful set up of Hadoop. Normally, a hardening script shall be ready with the usage of the CIS Benchmark and used to audit and remediate non-compliance in real-time.

In a minimal set up of CentOS/RHEL 7, solely fundamental functionalities/software program are put in, this may keep away from undesirable danger and vulnerabilities. Despite the fact that it’s Minimal Set up a number of iterations of safety auditing shall be carried out earlier than putting in Hadoop, even after constructing the cluster, earlier than transferring the Cluster into Operation/Manufacturing.

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