DEV Community: Frank Promise Edah

terraform httpd_container

Frank Promise Edah — Mon, 25 Apr 2022 20:41:44 +0000

terraform {
  required_providers {
    docker = {
      source  = "kreuzwerker/docker"
      version = "~>2.12.0"
    }
  }
}

provider "docker" {}

resource "docker_image" "httpd_image" {
  name = "httpd:latest"
}

resource "random_string" "random" {
  count = 2
  length  = 4
  special = false
  upper   = false
}



resource "docker_container" "httpd_container" {
  count = 2
  name  = join("-", ["httpd", random_string.random[count.index].result])
  image = docker_image.httpd_image.latest
  ports {
    internal = 8080
    #external = 8080
  }
}



output "IPAddress" {
  value       = [for i in docker_container.httpd_container[*]: join(":", [i.ip_address], i.ports[*]["external"])]
  description = "The IP Address and port  of the container"
}


output "container_name" {
  value       = docker_container.httpd_container[*].name
  description = "The name of the container"
}

Using s3 commands with aws cli

Frank Promise Edah — Mon, 18 Apr 2022 19:51:27 +0000

This write up describes some of the commands you can use to manage your s3 buckets and objects using aws s3 command line interface.

create a bucket

To create an s3 bucket with the command line, we use s3 mb.
Note that the name given to an s3 bucket must be globally unique. It can contain letter or number, and cannot contain a period next to a hyphen or another period.

syntax
$ aws s3 mb [--options]

example
aws s3 mb s3://bucket-name

2. list buckets and objects

$ aws s3 ls
Using this command without an option attached list all buckets.

To list the object contained in specific folder(prefix)
$ aws ls s3://bucket-name/example/

3. Delete bucket

$ aws s3 rb s3://bucket-name

By default, AWS does not allow you delete a bucket that is not empty. In order to by pass that, you must add --force option. However, if versioning is enabled in the bucket, then even this option won't work.

4. Move objects

To move a folder in an s3 bucket to another s3 bucket, use:
$ aws s3 mv s3://bucket-name/example s3://my-bucket/

To move a local file from your current working directory to the Amazon S3 bucket:
aws s3 mv filename.txt s3://bucket-name

To move a file from your Amazon S3 bucket to your current working directory:
aws s3 mv s3://bucket-name/filename.txt ./

5. Copy objects
To copy objects in an s3 bucket to another:

$ aws s3 cp s3://bucket-name/example s3://my-bucket/

To copy a local file from your current working directory to the Amazon S3 bucket:
$ aws s3 cp filename.txt s3://bucket-name

How to create s3 bucket using infrastructure as code(terraform)

Frank Promise Edah — Sat, 16 Apr 2022 12:18:03 +0000

WHAT YOU WILL LEARN

In this tutorial, we are going to create an s3 bucket using terraform.

WHAT IS TERRAFORM?

Terraform is an infrastructure as code tool that allows you to develop, update, and version your infrastructure efficiently and keeping it secure.

PREREQUISITES

AWS IAM role with S3 permissions
Access key ID and secret access key of that account.

How to create an Access key and secret access key

login to your AWS account
select IAM
On the left side of the panel, select user
Select Add users and enter details

NOTE: you have to select programmatic access in access type to get access key ID and secret key.

Attach policy
Add tags(optional)
create user If your user is successfully created, you will see a message with your access key and secret key.

Steps to create an s3 bucket using Terraform

Create S3 bucket module Create a module that will have a basic s3 file configuration. And for that, i will create one folder name "S3" which will have two files namely : bucket.tf and var.tf.

2. Define bucket

Open bucket.tf and define your bucket in it.

resource "aws_s3_bucket" "practises3" { bucket = "${var.bucket_name}" acl = "${var.acl_value}" }

Explanation
There is a block with the key name resource with resource type aws_s3_bucket. It is a fixed value and since terraform is cloud agnostic, this value depends on the provider. In this case, the cloud provider is AWS and s3 is the resource and practises3 is the resource name used.

Bucket and ACL(access control list) are arguments types for our resources. Either we can provide value directly or use the var.tf file to declare the value of an argument.

3. Define variables

variable "bucket_name" {} variable "acl_value" { default = "private" }

Explanation

The block declares values of variables. We can either provide a default value to be used when needed or ask for value during execution.

4. Add configuration
Here, we will create a file named main.tf for keeping configuration in our working directory

provider "aws" { access_key = "${var.aws_access_key}" secret_key = "${var.aws_secret_key}" region = "${var.region}" } module "s3" { source = "<path-to-S3-folder>" bucket_name = "<Bucket-name>" }

Explanation

Here, details of our provider (AWS) access key, secret key, etc is provided. Since are using terraform modules to create s3, we use the keyword module and the name of the folder we created earlier. In argument, we provide a source to the s3 module and bucket name.

5. Add Access key, secret_key, and region

Now we will define variable.tf where we will enter our access key, secret key and region.

variable "aws_access_key" { default = “<your_access_key>” } variable "aws_secret_key" { default = “<your_secret_key>” } variable "region" { default = "region" }

Run Terraform script in your system

terraform init
It is used to initilize the working directory.
terraform plan
We will use this command for script verification to confirm that there is no error in our configuration.
terraform apply
we will use this command to create the s3 bucket.

Building a Kubernetes 1.23 Cluster with Kubeadm

Frank Promise Edah — Wed, 06 Apr 2022 16:33:21 +0000

Log into the Control Plane Node (Note: The following steps must be performed on all

Create configuration file for containerd:

cat <<EOF | sudo tee /etc/modules-load.d/containerd.conf
overlay
br_netfilter
EOF

Load modules: sudo modprobe overlay sudo modprobe br_netfilter

Set system configurations for Kubernetes networking:
cat <<EOF | sudo tee /etc/sysctl.d/99-kubernetes-cri.conf
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
net.bridge.bridge-nf-call-ip6tables = 1
EOF

Apply new settings:

sudo sysctl --system

Install containerd:

sudo apt-get update && sudo apt-get install -y containerd

Create default configuration file for containerd:

sudo mkdir -p /etc/containerd

Generate default containerd configuration and save to the newly created default file:

sudo containerd config default | sudo tee /etc/containerd/config.toml

Restart containerd to ensure new configuration file usage:

sudo systemctl restart containerd

Verify that containerd is running.

sudo systemctl status containerd

Disable swap:

sudo swapoff -a

Disable swap on startup in /etc/fstab:

sudo sed -i '/ swap / s/^(.*)$/#\1/g' /etc/fstab

Install dependency packages:

sudo apt-get update && sudo apt-get install -y apt-transport-https curl

Download and add GPG key:

curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -

Add Kubernetes to repository list:

cat <<EOF | sudo tee /etc/apt/sources.list.d/kubernetes.list
deb https://apt.kubernetes.io/ kubernetes-xenial main
EOF

Update package listings:

sudo apt-get update

Install Kubernetes packages (Note: If you get a dpkg lock message, just wait a minute or two before trying the command again):

sudo apt-get install -y kubelet=1.23.0-00 kubeadm=1.23.0-00 kubectl=1.23.0-00

Turn off automatic updates:

sudo apt-mark hold kubelet kubeadm kubectl

Log into both Worker Nodes to perform previous steps.

Initialize the Cluster

Initialize the Kubernetes cluster on the control plane node using kubeadm (Note: This is only performed on the Control Plane Node):

sudo kubeadm init --pod-network-cidr 192.168.0.0/16 --kubernetes-version 1.23.0

Set kubectl access:

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

Test access to cluster:

kubectl get nodes

Install the Calico Network Add-On

On the Control Plane Node, install Calico Networking:
kubectl apply -f
https://docs.projectcalico.org/manifests/calico.yaml

Check status of the control plane node:

kubectl get nodes

Join the Worker Nodes to the Cluster In the Control Plane Node, create the token and copy the kubeadm join command (NOTE:The join command can also be found in the output from kubeadm init command): kubeadm token create --print-join-command

In both Worker Nodes, paste the kubeadm join command to join the cluster. Use sudo to run it as root:

sudo kubeadm join ...

In the Control Plane Node, view cluster status (Note: You may have to wait a few moments to allow all nodes to become ready):
kubectl get nodes
`

How to set up systemd targets in CENTOS

Frank Promise Edah — Mon, 28 Mar 2022 19:44:51 +0000

You have been handed a server that needs to be customized according to a specific standard. complete the following objectives

OBJECTIVES

carryout a check list on the default target in order to make sure the custom target you will create works.
Your custom target should be identical to your default target. Except that it should want httpd service.

Experience level
Basic

verify default target
To verify default target: systemctl get-default
To set it to multi user target: systemctl set-default multiuser.target_
To isolate the target: systemctl isolate multiuser.target
CREATE custom.target
a) Change directory: cd/etc/systemd/system

b) create a file by copying multi-user.target into custom.target: __/usr/lib/systemd/system/multi-user.target ./custom.target

c) open the file: nano custom.target
d) Edit the [unit] section:
[Unit]
Description=Custom Target
Documentation=man:systemd.special(7)
Requires=basic.target
Wants=httpd.service
Conflicts=rescue.service rescue.target
After=basic.target rescue.service rescue.target
AllowIsolate=yes
e) use the ctrl X option to save and quit
check if httpd is already installed in the server: rpm -q httpd_
if not installed, do yum install httpd -y

f) isolate custom.target
g) check status of httpd: systemctl status httpd

If we try to isolate into multi-user.target, we will see that httpd is dead because it is not set up to want Apache service.

python code for a treasure hunt game

Frank Promise Edah — Sun, 27 Mar 2022 16:49:14 +0000

Learning python has made me realize the importance of repetition. Especially if one is new to it.

Today, i was able to write a basic code for a treasure hunt game without guidiance

print("Welcome to Treasure Island.")
print("Your mission is to find the treasure.") 



first_choice = input('You\re on a crossroad, where do you want to go? Left or right\n').lower()


if first_choice == 'left':
  second_choice = input('You\ve come to a lake. There is an island in the middle of the lake. Do you wait or swim?\n"').lower()


  if second_choice == 'wait':

    third_choice = input('You have arrived the island unharmed. There is a house with 3 doors. One red, one yellow and one blue. Which colour do you choose?\n').lower()


    if third_choice == 'blue':
      print('Eaten by beasts. Game over')
    elif third_choice == 'red':
      print('burned by fire. Game over')
    elif third_choice == 'yellow':
      print('You win')
    else:
      print('Game over.')


  else:
    print('swallowed by a shark. Game over')

else:
  print('oops! wrong choice. Game over')

privelege escalation

Frank Promise Edah — Thu, 24 Mar 2022 09:44:59 +0000

As part of your onboarding, you've been tasked with setting a server up so that bob is a superuser. Set bob up so no password is required when he uses the sudo command and he can run any command. In addition, set up adam to be able to run the journalctl command as root without being prompted for a password.

STEP 1__ Add bob to sudo files
In order to add bob to sudo files, we have to first make bob a root user by user the sudo -i command and then run the visudo command.

STEP 2
inside the editor, press i on the keyboard to insert the folllowing:
bob ALL= (ALL) NOPASSWD: ALL
adam ALL=(root) NOPASSWD: /bin/journalctl

To exit, press the _esc key which makes insert to disappear, thereafter enter __:wq: to quit and save.

To check if your changes works properly, try:
sudo -adam
Try to install php as this user, and you will notice it doesnt allow you to because adam is only set to run /bin/journalctl.

WORKING WITH FILES IN CENTOS8

Frank Promise Edah — Wed, 23 Mar 2022 00:15:19 +0000

Let's assume you are a junior sysadmin in a company and as part of your on board process, you have been asked to perform some basic tasks in order to check your knowledge of the operating system. You have been asked to perform the following tasks:

Find out how many CPU's are in the system and what type.
Gather the logs
Find out how many users are on the system.

At first, this might look quite challenging, but knowing what commands to use at the right time makes it easier! We are going to walk through each steps together and arrive at the right end!

Find out how many CPU's are in the system and what type.

Log into the server using the credentials given. You can temporary assume root privilege using the sudo i command.

2.To know how many cpu's are on the system, use the cat command to print out the content of /proc/cpuinfo. This directory is where you can find all informations related to the CPU.

In order to get the relevant information, use the head -5 command. This command shows you the first five lines of the /proc/cpuinfo.

Alternatively, if there are more than 1 CPU, you can use the grep command like this grep A 4 processor /proc/cpuinfo. Adding 'A', tells grep to print four lines after it matches the word 'Processor'.

Summary of task

cat /proc/cpuinfo
head -5 > /tmp/cpu
OR
grep A processor /proc/cpuinfo > /tmp/cpu
'>' tells the system to redirect the result into the file stated instead of printing it out.

Gather the logs containing today's information

Let's assume we want information on today's date, we can use the tail command to print out the recent logs from /var/log/messages. Run the following command:
tail /var/log/messages
__grep "Mar 3 " /var/log/messages > /tmp/logs

Find out how many users are on the system

To do this, we can use the wc command. This command is use to the lines in a line. To know how many users are on the system, run the following command:
wc -l /etc/passwd > /tmp/usernum

Now you see it is not as challenging as it seems from the beginning!

Suggestions on other ways this can be done will be highly welcomed

Creating an Amazon RDS DB Instance (MS SQL Server)

Frank Promise Edah — Mon, 21 Mar 2022 21:59:26 +0000

STEP1
Create a relational database.

To create a relational database, go the aws console, search for RDS. Make sure the engine options is set to Mysqlserver. As soon as the DB is up and running, the security group settings can be changed. For instance, the inbound rules can be edited to allow traffic from any where if there isn't any known IP addresses. same with the outbound rules.

STEP2
In order to connect to the local server, copy the endpoint of the RDS. On the local engine, paste the endpoint on the space for 'server name', chose the mysql engine for authentication, enter the username and password generated during the RDS creation stage.

How to build AWS SERVERLESS AURORA

Frank Promise Edah — Sun, 20 Mar 2022 19:31:16 +0000

step 1
Create an rds database and choose the serverless option. Make sure the API button is clicked.

step 2
connect the query editor to the database

How to host a website on an ec2 server

Frank Promise Edah — Sat, 19 Mar 2022 14:39:33 +0000

**STEP 1:
Create an s3 bucket and upload the zip folder or file containing the index.html. Note that all objects in an s3 bucket are private by default. Hence, it is important to make the file publicly accessible using the the bucket ACL.
Two choice is available: Either create the bucket policy manually or use the AWS policy generator.

**STEP 2:
Launch an ec2 instance allowing internet access over port 80. SSH into the instance using PUTTY( for windows user). copy the ipv4 address of the instance and under the part labelled 'session' on PUTTY, insert 'ec2-user@theipyoucopied'.

**STEP 3:
Install Apache by typing in 'yum install httpd -y' in the command line. change directory to the \var\www\html, the copy website on the s3 bucket into the ec2 instance. To do that, type in the command line 'wget 'add the object url'. Move the file to the var html directory.

**STEP 4:
start http using the command 'service httpd start'.

yehhhh!!!! website hosting successful!!
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