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How to install Elasticsearch on CentOS / Red Hat

By webmaster • May 28, 2023

Install the latest Java Runtime Environment.
```
# yum install -y java-1.8.0-openjdk
```

Add Elasticsearch repository to yum.

Download and install the public signing key.

# rpm --import https://artifacts.elastic.co/GPG-KEY-elasticsearch

Add the following lines to /etc/yum.repos.d/elasticsearch.repo.

[elasticsearch-6.x]
name=Elasticsearch repository for 6.x packages
baseurl=https://artifacts.elastic.co/packages/6.x/yum
gpgcheck=1
gpgkey=https://artifacts.elastic.co/GPG-KEY-elasticsearch
enabled=1
autorefresh=1
type=rpm-md

Install Elasticsearch package along with dependencies.
```
# yum install -y elasticsearch
```
Configure Elasticsearch if necessary by editing /etc/elasticsearch/elasticsearch.yml.
Configure firewall for Elasticsearch service.
1. Enable network access to port 9200and 9300.
```
# firewall-cmd --permanent --add-port=9200/tcp
# firewall-cmd --permanent --add-port=9300/tcp
```
2. Reload firewall rules and keep state information.
```
# firewall-cmd --reload
```
Configure Elasticsearch service to automatically start during boot.
```
# systemctl enable elasticsearch
```
Start Elasticsearch service.
```
# systemctl start elasticsearch
```
The service will take a while to start

Test if installation is successful.

$ curl 127.0.0.1:9200
{
  "name" : "8v4rGQI",
  "cluster_name" : "elasticsearch",
  "cluster_uuid" : "nkZIqfkpSyCdh_jg3nqWfw",
  "version" : {
    "number" : "6.2.2",
    "build_hash" : "10b1edd",
    "build_date" : "2018-02-16T19:01:30.685723Z",
    "build_snapshot" : false,
    "lucene_version" : "7.2.1",
    "minimum_wire_compatibility_version" : "5.6.0",
    "minimum_index_compatibility_version" : "5.0.0"
  },
  "tagline" : "You Know, for Search"
}

How to change Apache user and group

By webmaster • May 28, 2023

Apache normally runs as an unprivileged user without shell access in most platforms. This is for security reason as a poorly written script or configuration if exploited will not escalate and cause much harm to the system.

If you’re running a development environment and know exactly what you’re doing, you can change the user and group that the Apache process runs as with these simple steps;

Find User and Group directives in Apache‘s configuration file.

Apache configuration files
Set the user and group that you want Apache process to run as. The following example is to run it as root.
```
User root
Group root
```
This could be a big security risk, especially to run it as root.

Make sure the user and group has appropriate permission to DocumentRoot and related files and folders.
Restart Apache.

How to restart Apache service

Check if the changes was successful

$ ps aux | grep apache2
root      1188  0.0  0.1 162184  6664 ?        Ss   Mar29   0:02 /usr/sbin/apache2 -k start
root  1197  0.0  0.1 162184  5668 ?        S    Mar29   0:00 /usr/sbin/apache2 -k start
root  1198  0.0  0.1 162184  5916 ?        S    Mar29   0:00 /usr/sbin/apache2 -k start
root  1200  0.0  0.1 162184  5684 ?        S    Mar29   0:00 /usr/sbin/apache2 -k start
root  1201  0.0  0.1 162184  5684 ?        S    Mar29   0:00 /usr/sbin/apache2 -k start
root  1202  0.0  0.1 162184  5684 ?        S    Mar29   0:00 /usr/sbin/apache2 -k start

In some distributions the Apache binary could be named httpd instead of apache2.

How to check hard-drive’s health status in Linux

By webmaster • May 28, 2023

SMART or Self-Monitoring, Analysis, and Reporting Technology is used to monitor the hard drives for reliability. Hard drive’s failure can be anticipated and appropriate action can be taken before the hard drive fail completely.

To check your hard drive’s health status in Linux, the tool smartctl can be used. It is available in the smartmontools package, and in Ubuntu running the command at the terminal will install the package

sudo apt-get install smartmontools

Assuming your hard drive is /dev/sda, running the following command will return the SMART’s health status of your hard drive

sudo smartctl -H /dev/sda

A healthy hard drive will return the following output

smartctl 5.40 2010-03-16 r3077 [x86_64-unknown-linux-gnu] (local build)
Copyright (C) 2002-10 by Bruce Allen, http://smartmontools.sourceforge.net

=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED

The following is an example output of a problematic hard drive

smartctl 5.40 2010-03-16 r3077 [x86_64-unknown-linux-gnu] (local build)
Copyright (C) 2002-10 by Bruce Allen, http://smartmontools.sourceforge.net

Log Sense failed, IE page [scsi response fails sanity test]

Sample Page

By admin • May 27, 2023

This is an example page. It’s different from a blog post because it will stay in one place and will show up in your site navigation (in most themes). Most …
Read More

Hello world!

By admin • May 27, 2023

Welcome to dirrtyremix.es. This is your first post. Edit or delete it, then start blogging!

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