Linux

Install InfluxDB on RHEL / Centos 7

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In this tutorial, How to install InfluxDB on RHEL / Centos 7. InfluxDB is an open-source time-series database. It is High availability storage and optimized for fast and metrics analysis.

To install InfluxDB on RHEL/CentOS 7, you can follow the steps below:

Install InfluxDB on RHEL / Centos 7

First, You add InfluxDB repository to your system using the command below

[vagrant@DevopsRoles ~]$ sudo vi  /etc/yum.repos.d/influxdb.repo

Add the content below:

[influxdb]
name = InfluxDB Repository
baseurl = https://repos.influxdata.com/rhel/7/x86_64/stable/
enabled = 1
gpgcheck = 1
gpgkey = https://repos.influxdata.com/influxdb.key

Install InfluxDB

[vagrant@DevopsRoles ~]$ sudo yum -y install influxdb

Enable the InfluxDB service to start on system boot:

[vagrant@DevopsRoles ~]$ sudo systemctl enable influxdb

Start InfluxDB services on RHEL / Centos 7

[vagrant@DevopsRoles ~]$ sudo systemctl start influxdb

To check the status of InfluxDB is running

[vagrant@DevopsRoles ~]$ sudo systemctl status influxdb

Configure InfluxDB Firewall on RHEL / Centos 7

The default, InfluxDB uses TCP port 8086 for client-server communication over HTTP API, and TCP port 8088 is used for backup and restore.

Open the port on the Firewall using the command below

[vagrant@DevopsRoles ~]$ sudo firewall-cmd --add-port=8086/tcp --permanent
[vagrant@DevopsRoles ~]$ sudo firewall-cmd --reload

Configure InfluxDB HTTP Authentication on RHEL / Centos 7

Enable HTTP authentication

[vagrant@DevopsRoles ~]$ sudo vi /etc/influxdb/influxdb.conf

Add the content below:

[http]
 auth-enabled = true

Restart the InfluxDB service.

[vagrant@DevopsRoles ~]$ sudo systemctl restart influxdb

Create a user with an Authentication password

[vagrant@DevopsRoles ~]$ curl -XPOST "http://localhost:8086/query" --data-urlencode "q=CREATE USER \
username WITH PASSWORD 'password' WITH ALL PRIVILEGES"

You need to run any Influxdb commands on the terminal with a specific username and password.

[vagrant@DevopsRoles ~]$ influx -username 'username' -password 'password'

For example, the curl command uses the -u option to specify a username and password.

[vagrant@DevopsRoles ~]$ curl -G http://localhost:8086/query -u username:password --data-urlencode "q=SHOW DATABASES"

Check Influxdb service is listening

[vagrant@DevopsRoles ~]$ sudo netstat -nplt | grep 8086
Install InfluxDB on RHEL / Centos 7

You have successfully installed InfluxDB on RHEL/CentOS 7. Thank you for reading the DevopsRoles page!

Linux

Install Netdata on RHEL 7 / CENTOS 7

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In this tutorial, How to install Netdata on RHEL 7 / CENTOS 7.

Netdata is performance and health monitoring for systems and applications. It is a monitoring agent you install on all your systems.

Why use Netdata

  • High-resolution metrics
  • Monitors everything
  • Install and get results immediately
  • Requires zero dedicated resources
  • Open-source, free and very easy
  • Auto-scaling of chart units
  • Time-series back-ends supported – it can archive its metrics on graphite, , Prometheus, JSON document DBs, in the same or lower detail

Install Netdata on RHEL 7 / CENTOS 7 from source

Install EPEL Repository

[vagrant@DevopsRoles ~]$ sudo yum install -y epel-release

Installing all dependencies for Netdata.

[vagrant@DevopsRoles ~]$ sudo yum install Judy-devel libuv cmake json-devel autoconf-archive autogen json-c-devel libmnl-devel libuv-devel lz4-devel nmap-ncat openssl-devel python3 git zlib-devel libuuid-devel libmnl gcc make git autoconf automake pkgconfig curl findutils

Clone Netdata from Github

[vagrant@DevopsRoles ~]$ git clone https://github.com/netdata/netdata.git --depth=100
[vagrant@DevopsRoles ~]$ cd netdata/

The build and installation Netdata on RHEL 7 / CENTOS 7

[vagrant@DevopsRoles ~]$ sudo ./netdata-installer.sh

The output terminal as the picture below

Netdata service will start auto after installation.

To stop netdata run

[vagrant@DevopsRoles ~]$ sudo systemctl stop netdata

To start netdata run

[vagrant@DevopsRoles ~]$ sudo systemctl start netdata

Accesing Netdata from Browser

The default listens on all IPs on port 19999. If you have firewalld, allow access to this port within LAN.

[vagrant@DevopsRoles ~]$ sudo firewall-cmd --permanent --add-rich-rule 'rule family="ipv4" \
source address="192.168.1.0/24" port protocol="tcp" port="19999" accept'

Reload Firewalld to apply changes

[vagrant@DevopsRoles ~]$ sudo firewall-cmd --reload

Access Netdata Web dashboard on server

Thank you for reading the DevopsRoles page!

Docker

Quick start install Elasticsearch and Kibana with Docker

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In this tutorial, How to Quickstart install Elasticsearch and Kibana with Docker.

  • Elasticssearch: localhost:9200
  • Kibana: localhost:5601

Docker-compose start with

docker-compose -f docker-compose.yml up -d

Docker-compose Stop

$ docker-compose -f docker-compose.yml down

Be careful with command docker-compose down. If you want Stop and remove containers, networks, images, and volumes as in the picture below

Install Elasticsearch with Kibana with Docker-compose

For example docker-compose.yml

version: '3'
services:
  elasticsearch:
    image: docker.elastic.co/elasticsearch/elasticsearch:6.3.2
    ports:
      - 9200:9200
    volumes:
      - ./share/elasticsearch/data:/usr/share/elasticsearch/data
      - ./share/elasticsearch/config/elasticsearch.yml:/usr/share/elasticsearch/config/elasticsearch.yml
    networks: [elastic]
    environment:
      - discovery.type=single-node
  kibana:
    image: docker.elastic.co/kibana/kibana-oss:6.3.2
    ports:
      - 5601:5601
    networks: [elastic]
networks:
  elastic:

Host OS ./share/elasticsearch/data and Guest OS /usr/share/elasticsearch/data are mounted for data persistence of Elasticsearch.

File configure single node “./share//config/elasticsearch.yml”

cluster.name: "docker-cluster"
network.host: 0.0.0.0
discovery.zen.minimum_master_nodes: 1

Steps install Elasticsearch and Kibana with Docker as the picture below

[vagrant@localhost ~]$ tree /home/vagrant/
/home/vagrant/
├── docker-compose.yml
└── share
    └── elasticsearch
        ├── config
        │   └── elasticsearch.yml
        └── data

4 directories, 2 files

Access the client browser as the picture below

Kibana: localhost:5601

Elasticsearch: localhost:9200

Conclusion

Thought the article, How to “Quickstart install Elasticsearch and Kibana with Docker” as above. I hope will this your helpful. Thank you for reading the DevopsRoles page!

Jenkins

Jenkins checkout Pipeline Multibranch

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In this tutorial, How to use Jenkins checkout Pipeline Multibranch. For example with Git, the reference a GitSCM Object. It is the same git pull command.

For example below, When you running job Jenkins then checkout source code from git takes 15 minutes. You running job Jenkins again then checkout the source code from git takes 4s. It is faster, as the picture below

Jenkins checkout Pipeline Multibranch code as below

stage('Checkout') {
      checkout([$class: 'GitSCM', branches: [[name: "${BRANCH}"]],
           doGenerateSubmoduleConfigurations: false,
            extensions: [[$class: 'CloneOption', depth: 0, noTags: false, reference: '', shallow: true, timeout: 30], 
[$class: 'LocalBranch', localBranch: '$BRANCH'], 
[$class: 'RelativeTargetDirectory', relativeTargetDir: 'devopsroles'], [$class: 'CleanBeforeCheckout'], 
[$class: 'CloneOption', depth: 0, honorRefspec: true, noTags: true, reference: '', shallow: false, timeout: 90]],
            submoduleCfg: [],
            userRemoteConfigs: [[credentialsId: '755f8df9-0g83-4b80-96d8-917eeb6b2fgg', url: 'https://gitlab.com/devopsroles.git']]
     ])
   }

Conclusion

You have use Jenkins checkout Pipeline Multibranch. I hope will this your helpful. Thank you for reading the DevopsRoles page!

Ansible

Ansible structure playbook

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In this tutorial, I wrote about the Ansible structure playbook. What does the Ansible structure playbook mean? Let’s begin!

A sample Ansible Directory Layout for staging development as below

[huupv2@server-deployment huupv2]$ tree myproject			
myproject			
├── group_vars			
│   └── nginx-server-var.yml			
├── host_vars			
│   └── server-web01.yml			
├── inventory			
│   └── my_hosts			
├── nginx-server.yml			
├── requirements			
│   └── web-server.yml			
├── roles			
└── vars			
    └── nginx_instance.yml			
			
6 directories, 6 files

Create a structured folder for the Ansible playbook

[huupv2@server-deployment huupv2]$ mkdir myproject									
[huupv2@server-deployment huupv2]$ mkdir -p myproject/{inventory,host_vars,group_vars,vars,requirements,roles}

Create structure files for the Ansible playbook

[huupv2@server-deployment huupv2]$ touch myproject/requirements/web-server.yml							
[huupv2@server-deployment huupv2]$ touch myproject/vars/nginx_instance.yml							
[huupv2@server-deployment huupv2]$ touch myproject/group_vars/nginx-server-var.yml							
[huupv2@server-deployment huupv2]$ touch myproject/inventory/my_hosts							
[huupv2@server-deployment huupv2]$ touch myproject/host_vars/server-web01.yml							
[huupv2@server-deployment huupv2]$ touch myproject/nginx-server.yml

For Ansible structure playbook

Server “server-deployment” installed Ansible and you want to deploy Nginx for server “server-web01” etc as in the picture below:

Working with inventory

[huupv2@server-deployment myproject]$ cat inventory/my_hosts
					
[dev-develop:children]					
tomcat-server					
nginx-server					
db-server					
					
[tomcat-server]					
					
[nginx-server]					
server-web01					
					
[db-server]					
server-db01

Working with host_vars

set variables for individual hosts in the generated inventory file. For example, The content host_vars/nginx-server.yml file as below

nginx_instances:					
 - env_id: "dev"					
   instance_name:					
     - "DEVOPSROLES"

Working with group_vars

set variables to particular groups. For example, The content group_vars/nginx-server-var.yml as below

nginx_version:  1.14.2					
nginx_package:					
  fullname: nginx-1.14.2-1.el6.ngx

Working with requirements

Automatically install Ansible Galaxy roles with requirements/web-server.yml. For example, The content requirements/web-server.yml as below

## tag					
## version: v1.0.0					
## develop specify develop branch					
# version: remotes/origin/develop					
					
- src: git+https://huupv2:123456789@gitlab.com/tomcat/role-tomcat.git					
  version: v2.2					
					
- src: git+https://huupv2:123456789@gitlab.com/nginx/role-nginx.git					
  version: feature/dev-nginx

Use ansible-galaxy to install all roles required by your playbook.

ansible-galaxy install -r requirements/web-server.yml -p roles

Working with vars

For example, The content file myproject/vars/nginx_instance.yml as below

# For devopsroles / role-nginx		
nginx_instance:		
# templates/conf/common.conf.j2		
  common_settings:		
    client_body_buffer_size: 16k		
    client_body_timeout: 60s		
    client_header_buffer_size: 1k		
    client_header_timeout: 60s		
    client_max_body_size: 1m		
    default_type: text/html		
    keepalive_timeout: 60s		
    large_client_header_buffers:		
      count: 4		
      size: 8k		
# templates/conf/nginx_site_instance.conf Used by		
  instance_indexes:		
  - index.html		
  - index.htm		
  instance_name: DEVOPSROLES							  		
# templates/conf/http[s].virtual_host.conf Used by		
  virtual_host_settings:				
    indexes:		
    - index.html		
    - index.htm		
    listen_port:		
      http: '8080'		
      https: '8443'					
    locations:				
    name: devopsroles.com		
    root: /app/DEVOPSROLES/nginx/htdocs		
    server_names:		
    - devopsroles.com

Working with nginx-server.yml

- hosts: nginx-server		
  user: huupv		
  become: yes		
  roles:		
    - role-nginx

Ansible run playbook

sudo ansible-playbook -i inventory/my_hosts nginx-server.yml -vvv --limit "server-web01"

Conclusion

Through the article, you can create a structured Ansible playbook simple. I hope will this your helpful. For more details, Ansible refers to Ansible tutorial.

Linux

create user and group in Linux

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In this tutorial, I will quickly guide create user and group in Linux. How to add a user to a group in Linux. How to create users has permission or user no has permission.

Using command to create the and command to create the in Linux system.

How to create user and group in Linux

create group new in Linux

use groupadd command as below

$ sudo groupadd -g 2000 common # group common no has sudo permission
$ sudo groupadd -g 2001 dev # group dev has sudo permission
$ sudo groupadd -g 1100 IT

Create user new in Linux

For example, user user01 no has permission and user has permission

# useradd -m -d /home/user01 -s  /bin/bash   -g common -u 5000  user01; echo -e "user01\nuser01\n"  |  passwd  user01
# useradd -m -d /home/huupv  -s  /bin/bash   -g IT  -G dev    -u 5001  huupv; echo -e "huupv\nhuupv\n"  |  passwd  huupv

Add group to sudoers file

use visudo to open and edit the /etc/sudoers file and add group dev as follow below

%dev ALL=(root) ALL

Option

Create a user with sudo without password Linux.

# useradd -d /home/devops -u 8888 -s /bin/bash						
# echo -e "devops\ndevops\n" |  passwd devops						
# echo "devops ALL = (root) NOPASSWD:ALL" | tee /etc/sudoers.d/devops						
# chmod 0440 /etc/sudoers.d/devops

Conclusion

Through the article, You can create user and group in Linux as above. I hope will this your helpful. Thank you for reading the DevopsRoles page!

Bash Script

Shell script execute SQL file

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In this tutorial, How do I use shell script execute SQL file on DB? On the server running the shell script, you use a sqlplus command on the server.

You need to install Oracle client on server-run shell script. Example picture below

Oracle Client is free, easy to install client software for connecting to Oracle databases.

For example shell script execute SQL file as below

#!/bin/bash

CONNT=dbuser/password@connect_identifier #your env
SQL_FILE=/home/huupv/create_user.sql
sqlplus -s ${CONNT} <<EOF
  @${SQL_FILE}
EOF

RSTATUS=$?
if [ "${RSTATUS}" != "0" ]
then
  echo "Error"
  exit 100
else
  echo "success"
  exit 0
fi

Thank you for reading DevOpsRoles.com page.

Bash Script

How to extract substring in Bash Shell

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In this tutorial, How to extract substring in Bash Shell on Linux. You can use a select substring from the string. The awk command has a few useful functions. It is function.

Function substr mean Returns a substring.

The syntax extract substring in Bash Shell

substr(S,P,N)
  • P: starting at position
  • N: it N number of from string S.

For example, I will use a string “HuuPV2123456789” with a length is 15 and starting position is 10.

$ echo "HuuPV2123456789" | awk '{ printf "%s", substr($0, 10, (length($0)-9)) }'

The result is below

456789

man page function substr here. Thank you for reading the DevopsRoles page!

Linux

Change timezone in Linux

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In this tutorial, I will change timezone in Linux by command line. How to change the to your current time zone.

  • The location of the local time file in Linux is /etc/localtime.
  • Timezone files are located in /usr/share/zoninfo/

To change the timezone in the Linux command line, you can use the methods below, which are available on most modern Linux distributions. Here’s how you can do it:

How to Change Timezone in Linux with Two Methods.

Method 1: I will copy from /usr/share/zoneinfo/Asia/Ho_Chi_Minh to /etc/localtime

$ sudo cp /usr/share/zoneinfo/Asia/Ho_Chi_Minh /etc/localtime

Method 2: I will delete and make a symbolic Linux from //share//Asia/Ho_Chi_Minh to /etc/ as following below

$ sudo rm -f /etc/localtime
$ sudo ln -s /usr/share/zoneinfo/Asia/Ho_Chi_Minh /etc/localtime

Verify the new timezone:

Conclusion

After changing the timezone, you may need to restart services or applications that rely on the system time to ensure they reflect the new timezone.

You changed your current timezone You can type date command to verify and you’re done. I hope this is helpful you.

Jenkins

Jenkins pipeline error timeout after 10 minutes

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How to fix Error fetching remote repository ‘origin’ from Jenkins build jobs. In this tutorial, I will be fixing the Jenkins pipeline error timeout after 10 minutes.

Jenkins build job error code as below

ERROR: Timeout after 10 minutes
ERROR: Error fetching remote repo 'origin'
Caused by: hudson.plugins.git.GitException: Command "/usr/local/git/bin/git fetch --tags --progress https://gitlab.com/devopsroles.git +refs/heads/*:refs/remotes/origin/*" returned status code 143:

Cause by

  1. incorrect credentials were provided with the Jenkins job definition.
  2. The repository is so large that it takes more than 10 minutes to clone.
  3. Bandwidth to the git server is slow enough that it takes more than 10 minutes to clone.

Jenkins pipeline error timeout after 10 minutes fixed

stage('Getsource') { // for display purposes
    // Get some code from a GitHub repository
    checkout([$class: 'GitSCM',
        branches: [[name: "${TARGET_BRANCH}"]],
        extensions: [[$class: 'CloneOption', timeout: 120]],
        gitTool: 'Default', 
        userRemoteConfigs: [[credentialsId: 'w55f8df9-0183-4b80-96d8-917ccccccccccc', url: 'https://gitlab.com/devopsroles.git']]
    ])
}

In my example, I will Increase the timeout is 120 minutes for the Git checkout source from the repository.

Conclusion

Through the article, you have solved the problem of Jenkins pipeline error timeout after 10 minutes as above. I hope will this your helpful.

Thank you for reading the DevopsRoles page!

Devops Tutorial

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