Disk Preparation and Configuration using Ansible

This guide will walk you through preparing, formatting, and mounting two disks (/dev/vdb and /dev/vdc) on a Linux system. Additionally, it covers enabling and configuring the firewall, as well as using Ansible for automation.

Preparing and Formatting Disks

Step 1: Prepare Disk /dev/vdb

To prepare the disk /dev/vdb, you need to create a partition table and a primary partition. The following command uses fdisk to achieve this:

echo -e "o\nn\np\n1\n\n\nw" | sudo fdisk /dev/vdb

Explanation:

• o: Create a new empty DOS partition table.
• n: Add a new partition.
• p: Primary partition.
• 1: Partition number 1.
• The three \n characters are for default values for first sector, last sector, and the next prompt.
• w: Write the changes and exit.

Step 2: Prepare Disk /dev/vdc

Similarly, prepare the disk /dev/vdc using the same command with the disk name changed:

echo -e "o\nn\np\n1\n\n\nw" | sudo fdisk /dev/vdc

Step 3: Format Both Disks

Format both disks with the ext4 filesystem using mkfs.ext4:

sudo mkfs.ext4 /dev/vdb
sudo mkfs.ext4 /dev/vdc

Step 4: Create Directories

Create mount points for the disks:

sudo mkdir /data1
sudo mkdir /data2

Step 5: Update /etc/fstab

Add the following entries to /etc/fstab to ensure the disks are mounted at boot:

/dev/vdb   /data1    ext4    defaults        0 0
/dev/vdc   /data2    ext4    defaults        0 0

Step 6: Mount All Filesystems

Mount all filesystems defined in /etc/fstab:

sudo mount -a

Firewall Configuration

Step 1: Enable and Start Firewalld

Enable and start the firewalld service:

sudo systemctl enable firewalld
sudo systemctl start firewalld

Step 2: Check Active Zones

Check the active zones in the firewall:

sudo firewall-cmd --get-active-zones

Step 3: List Services in Zones

List services for the public and internal zones:

sudo firewall-cmd --permanent --zone="public" --list-services
sudo firewall-cmd --permanent --zone="internal" --list-services

Step 4: Configure Interfaces and Ports

Assign eth1 to the internal zone and configure firewall rules:

sudo ip addr
sudo firewall-cmd --permanent --zone=internal --change-interface=eth1
sudo firewall-cmd --permanent --zone="internal" --add-source="192.168.100.0/24"
sudo firewall-cmd --permanent --zone="internal" --add-port=0-65535/tcp
sudo firewall-cmd --reload

Automation with Ansible

Step 1: Prepare Disks with Ansible

Use Ansible to create partitions on all servers:

ansible all-servers -i hosts -m parted -a "device=/dev/vdb number=1 state=present" --become
ansible all-servers -i hosts -m parted -a "device=/dev/vdc number=1 state=present" --become

Step 2: Format Disks with Ansible

Format the disks with ext4 filesystem:

ansible all-servers -i hosts -m filesystem -a "fstype=ext4 dev=/dev/vdb" --become
ansible all-servers -i hosts -m filesystem -a "fstype=ext4 dev=/dev/vdc" --become

Step 3: Mount Disks with Ansible

Mount the disks on all servers:

ansible all-servers -i hosts -m mount -a "fstype=ext4 src=/dev/vdb path=/data1 state=mounted" --become
ansible all-servers -i hosts -m mount -a "fstype=ext4 src=/dev/vdc path=/data2 state=mounted" --become

Step 4: Install Packages with Ansible

Install necessary packages:

ansible all-servers -i hosts -m yum -a "name=wget" --become
ansible all-servers -i hosts -m yum -a "name=telnet" --become
ansible all-servers -i hosts -m yum -a "name=java-1.8.0-openjdk-devel" --become

Step 5: Create Directories with Ansible

Create directories with specific permissions:

ansible all-servers -i hosts -m file -a "path=/data1/directory state=directory owner=admin group=admin mode=0755" --become
ansible all-servers -i hosts -m file -a "path=/data2/directory state=directory owner=admin group=admin mode=0755" --become

Step 6: Synchronize Data with Ansible

Synchronize data to the created directories:

ansible all-servers -i hosts -m synchronize -a "src=/home/training/ansible/data dest=/data1/directory" --become

Step 7: Update Bash Profile with Ansible

Add a line to the bash profile for setting the JAVA_HOME environment variable:

ansible all-servers -i hosts -m lineinfile -a "dest=/home/admin/.bash_profile state=present line='export JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.181-3.b13.el7_5.x86_64'"
ansible all-servers -i hosts -m command -a "cat /home/admin/.bash_profile"

Ansible Command Line Arguments

• -i: Specify inventory.
• -m: Specify module.
• -a: Module arguments.
• -u: User to connect to the remote host.
• --become: Run as root.
• --become-user: Perform tasks as a specific user.
• -f, --forks: Control the degree of parallelism.
• -h, --help: Display help.
• -C, --check: Predict changes that might occur.
• --syntax-check: Perform syntax check without executing.
• -v, --verbose: Enable verbose output.

This guide covers disk preparation, formatting, and mounting for /dev/vdb and /dev/vdc on a Linux system, enabling and configuring the firewall, and using Ansible for automation. Detailed explanations for each command and Ansible usage are provided for IT professionals.