Ansible playbook for Java 11 Installation on Ubuntu | Ansible Java 11 Playbook Ubuntu

1. Login to Ansible management server/machine. Create SSH keys in Ansible host machine by executing the below command: (if you already have keys created, please skip this step)
ssh-keygen 

enter three times..now you will see keys successfully created.
2.  Execute the below command on Ansible management node and copy the public key content:
sudo cat ~/.ssh/id_rsa.pub

copy the above output.
3. Now login to target node, execute the below command to open the file
sudo vi /home/ubuntu/.ssh/authorized_keys
type shift A and then enter now 
    and paste the key in the above file. please do not delete any existing values in this file.

4. Now go back to Ansible mgmt node, do changes in /etc/ansible/hosts file to include the node you will be installing software. Make sure you add public IP address of target node as highlighted below in red color:
sudo vi /etc/ansible/hosts
[My_Group]  
xx.xx.xx.xx ansible_ssh_user=ubuntu ansible_ssh_private_key_file=~/.ssh/id_rsa  ansible_python_interpreter=/usr/bin/python3

5. make changes in playbooks as given below,
cd ~/playbooks

sudo vi installJava.yml

---
- hosts: My_Group
  tasks:
    - name: Update APT package manager repositories cache
      become: true
      apt:
        update_cache: yes
    - name: Install Java using Ansible
      become: yes
      apt:
        name: "{{ packages }}"
        state: present
      vars:
        packages:
           - openjdk-11-jdk
6. Execute Ansible playbook
ansible-playbook installJava.yml

How to Fix The following signatures couldn’t be verified Error in Ubuntu Linux | The following signatures couldn’t be verified Error in Ubuntu Linux | Jenkins Key Download Error

GPG error: https://pkg.jenkins.io/debian-stable binary/ Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY FEF32E745F2C3D5
E: The repository 'http://pkg.jenkins.io/debian-stable binary/ Release' is not signed.

This is a very common Jenkins install issue on Ubuntu/Debian. It happens because APT no longer trusts the old Jenkins GPG key method.

Fix (Recommended Solution)

Step 1: Remove old Jenkins repo (if exists)

sudo rm -f /etc/apt/sources.list.d/jenkins.list
sudo rm -f /etc/apt/sources.list.d/jenkins*.list

Step 2: Download and install Jenkins GPG key (new method)

curl -fsSL https://pkg.jenkins.io/debian-stable/jenkins.io-2023.key \
| sudo tee /usr/share/keyrings/jenkins-keyring.asc > /dev/null

✅ This stores the key in the recommended keyrings location

Step 3: Add Jenkins repository (signed-by)

echo deb [signed-by=/usr/share/keyrings/jenkins-keyring.asc] \
https://pkg.jenkins.io/debian-stable binary/ \
| sudo tee /etc/apt/sources.list.d/jenkins.list > /dev/null 

Step 4: Update & install Jenkins

sudo apt update
sudo apt install jenkins -y 

✅ Error should now be gone 

Slack Azure DevOps Integration | How to Integrate Slack with Azure DevOps | Send push notifications from Azure pipelines to Slack

Slack is popular collaboration tool used at work by many companies. Slack can be integrated with CI tools such as Jenkins, Azure DevOps(VSTS). We will see how to integrate with Azure Build pipelines. 

Pre-requisites:

1. Azure pipelines setup

2. Slack channel setup

 

Azure DevOps & Slack integration steps

 

1. Go to slack.com and sign in to workspace.
2. Go to channel where you would like to receive push notification from Azure DevOps. Click on more and Add apps

3. Add Visual Studio Team Services App

4. Add Configuration

5.  And then select channel to post notification and add the channel

6. In Azure DevOps Dashboard, click on Project settings.

7. Click on Service Hooks tab and then click create subscriptions button to add a new service hook.
 

8. Select Slack from the list of services, and press the Next button.

9. On the Trigger screen, choose the event that you’d like to trigger the notification, and add any filters. Press the Next button to continue.

10. On the Action screen, add the URL as the Slack Webhook URL and press Finish when you are done.

 

 

Now whenever Azure pipelines runs any builds, it will send push notifications to the Slack channel. Please watch the above steps in YouTube channel:

ERROR: Can't construct a java object for tag:yaml - Kubernetes Jenkins Deployment issue

ERROR: Can't construct a java object for tag:yaml.org,2002:io.kubernetes.client.openapi.models.V1Deployment; exception=Class not found: io.kubernetes.client.openapi.models.V1Deployment

 in 'reader', line 1, column 1:
    apiVersion: apps/v1

Caused by: hudson.remoting.ProxyException: org.yaml.snakeyaml.error.YAMLException: Class not found: io.kubernetes.client.openapi.models.V1Deployment at org.yaml.snakeyaml.constructor.Constructor.getClassForNode(Constructor.java:664) at org.yaml.snakeyaml.constructor.Constructor$ConstructYamlObject.getConstructor(Constructor.java:322) at org.yaml.snakeyaml.constructor.Constructor$ConstructYamlObject.construct(Constructor.java:331) ... 30 more

Fix/Workaround:

Try the deployment in Jenkins slave node instead of deploying from Jenkins Master.

How to Install Teamcity on AWS Ubuntu EC2 | How to setup TeamCity on Ubuntu 18.0.4 with PostgreSQL?

TeamCity is one of the CI tools, It is open source and Java based tool. It can be configured easily.

Please find below steps for installing TeamCity on Ubuntu:

Pre-requisites:
Make sure Ubuntu instance has at least 4 GB RAM
Open port 8111 in security firewall.

We need to setup database for storing all the build information. We will be using PostgreSQL.

PostgreSQL Installation

sudo sh -c 'echo "deb http://apt.postgresql.org/pub/repos/apt/ `lsb_release -cs`-pgdg main" >> /etc/apt/sources.list.d/pgdg.list'

 

sudo wget -q https://www.postgresql.org/media/keys/ACCC4CF8.asc -O - | sudo apt-key add -

sudo apt-get -y install postgresql postgresql-contrib

 

sudo systemctl start postgresql

sudo systemctl enable postgresql

Login as postgres user

sudo su - postgres

Now create a user below

createuser teamcity

Switch to sql shell by entering
psql

 

 

 

 

 

 

Execute the below three lines (one by one)

 

ALTER USER teamcity WITH ENCRYPTED password 'password';
CREATE DATABASE teamcity OWNER teamcity;
\q

type exit to come out of postgres user.

TeamCity Installation

Download Java

sudo apt-get update && sudo apt-get install default-jdk -y

Download TeamCity

wget https://download.jetbrains.com/teamcity/TeamCity-2020.1.5.tar.gz

Extract TeamCity
tar -xvf TeamCity-2020.1.5.tar.gz
sudo mkdir /opt/JetBrains
sudo mv TeamCity /opt/JetBrains/TeamCity
cd /opt/JetBrains/TeamCity
 

Create service file

sudo nano /etc/init.d/teamcity
(copy the whole text colored in green)
#!/bin/sh
### BEGIN INIT INFO
# Provides:          TeamCity autostart
# Required-Start:    $remote_fs $syslog
# Required-Stop:     $remote_fs $syslog
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: Start teamcity daemon at boot time
# Description:       Enable service provided by daemon.
# /etc/init.d/teamcity -  startup script for teamcity
### END INIT INFO

#  Ensure you enter the  right  user name that  TeamCity will run  under
USER="ubuntu"

export TEAMCITY_DATA_PATH="/opt/JetBrains/TeamCity/.BuildServer"

case $1 in

start)
  start-stop-daemon --start  -c $USER --exec /opt/JetBrains/TeamCity/bin/runAll.sh start
 ;;
stop)
  start-stop-daemon --start -c $USER  --exec  /opt/JetBrains/TeamCity/bin/runAll.sh stop
 ;;
 esac

exit 0

Ctrl + O enter
Ctrl + X enter
sudo chmod +x /etc/init.d/teamcity
sudo update-rc.d teamcity defaults
sudo /etc/init.d/teamcity start

Access logs files

cat /opt/JetBrains/TeamCity/buildAgent/logs/teamcity-agent.log

Now access Teamcity UI

Open browser and access team city url in the browser
http://public_dns_name:8111

Click on Proceed.
Select database type as jdbc driver as Postgres SQL from the dropdown and Click on Proceed.

now you need to download the jdbc driver at below location.
cd /opt/JetBrains/TeamCity/.BuildServer/lib/jdbc
sudo wget https://jdbc.postgresql.org/download/postgresql-9.4.1212.jar

Select database type as PostgreSQL
Refresh JDBC driver
You should see like this —> Loaded PostgreSQL JDBC driver version: 9.4

Now provide the below info
Enter database Host - localhost
Enter database name - teamcity
User name - teamcity
Password - password
Click on Proceed

please wait and watch..As It may take a few mins…

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Docker Installation on Red Hat Linux 8 | Install Docker on Linux

Find steps for installing Docker on Red Hat Enterprise Linux 8

Enable Docker Registry
sudo dnf config-manager --add-repo=https://download.docker.com/linux/centos/docker-ce.repo

Install Docker CE using dnf comman
sudo dnf list docker-ce
sudo dnf install docker-ce -y
sudo systemctl start docker

sudo systemctl enable docker

sudo systemctl status docker

docker --version

sudo docker run hello-world

Steps for installing Docker-compose

sudo curl -L "https://github.com/docker/compose/releases/download/1.23.2/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose

sudo chmod +x /usr/local/bin/docker-compose

docker-compose --version

Add the docker group to current user
sudo usermod -aG docker $USER

Logout and login again.