Merge pull request #6 from RadinPirouz/dev

Dev

Code Management/Git/Gitlab/Install/baremetal.md

@@ -0,0 +1,88 @@
+# Setting Up GitLab CE on Ubuntu
+
+Follow the steps below to install and configure GitLab Community Edition (CE) on your Ubuntu system.
+
+---
+
+## Step 1: Update the System
+Ensure your package lists are up-to-date:
+```bash
+sudo apt update
+```
+
+---
+
+## Step 2: Install Dependencies
+Install required packages for GitLab:
+```bash
+sudo apt install -y ca-certificates curl openssh-server postfix tzdata perl
+```
+
+- **ca-certificates**: Ensures proper SSL certificate handling.
+- **curl**: For downloading files.
+- **openssh-server**: For SSH-based Git operations.
+- **postfix**: Mail transport agent for email notifications.
+- **tzdata**: Time zone data.
+- **perl**: Required by GitLab scripts.
+
+During the installation, configure **Postfix** to match your mail setup. If unsure, select "Internet Site" and provide your domain.
+
+---
+
+## Step 3: Add GitLab's Repository
+Download and run the repository setup script:
+```bash
+curl -LO https://packages.gitlab.com/install/repositories/gitlab/gitlab-ce/script.deb.sh
+sudo bash script.deb.sh
+```
+
+---
+
+## Step 4: Install GitLab CE
+Install the GitLab CE package:
+```bash
+sudo apt install -y gitlab-ce
+```
+
+---
+
+## Step 5: Configure GitLab
+Edit the GitLab configuration file to match your environment:
+```bash
+sudo vim /etc/gitlab/gitlab.rb
+```
+
+- Modify the `external_url` setting to your desired domain or IP.
+
+Save and exit the editor.
+
+---
+
+## Step 6: Apply the Configuration
+Reconfigure GitLab to apply the changes:
+```bash
+sudo gitlab-ctl reconfigure
+```
+
+---
+
+## Step 7: Retrieve the Initial Root Password
+After configuration, retrieve the initial root password:
+```bash
+sudo cat /etc/gitlab/initial_root_password
+```
+
+---
+
+## Notes
+- The default admin username is `root`.
+- Save the password securely and change it after the first login.
+
+---
+
+## Troubleshooting
+- If you encounter issues, consult the [GitLab Documentation](https://docs.gitlab.com) or check logs in `/var/log/gitlab`.
+
+---
+
+Enjoy using GitLab CE!

Containerization & Orchestration/Kubernetes/3-Commands.md

@@ -1,65 +1,122 @@
-# Kubernetes
 
-## `kubectl` Command Reference
 
-### Get State of API Resources
+# Kubernetes Command Reference
-```bash
+
-kubectl api-resources
+This document provides a reference for common `kubectl` commands used for managing Kubernetes clusters. Use the examples and explanations below to help manage nodes, namespaces, pods, deployments, and more.
-```
+
+## Table of Contents
+
+- [Kubernetes Command Reference](#kubernetes-command-reference)
+  - [Table of Contents](#table-of-contents)
+  - [General Commands](#general-commands)
+  - [Node Management](#node-management)
+  - [Namespace Management](#namespace-management)
+  - [Pod Management](#pod-management)
+    - [Listing Pods](#listing-pods)
+    - [Running a Pod](#running-a-pod)
+    - [Deleting a Pod](#deleting-a-pod)
+  - [API Resources and Documentation](#api-resources-and-documentation)
+  - [Logs and Pod Information](#logs-and-pod-information)
+  - [Applying YAML Files](#applying-yaml-files)
+  - [Managing Nodes and Labels](#managing-nodes-and-labels)
+  - [Viewing Cluster Resources](#viewing-cluster-resources)
+  - [ReplicaSet and Deployment Management](#replicaset-and-deployment-management)
+  - [Additional Information](#additional-information)
+
+---
+
+## General Commands
+
+- **List API Resources**
+
+  ```bash
+  kubectl api-resources
+  ```
+
+---
+
+## Node Management
+
+- **Show all nodes**
 
-### Node Management
-- **Show all nodes:**
   ```bash
   kubectl get node
   ```
 
-### Namespace Management
+- **Set a label on a node**
-- **List all namespaces:**
+
+  ```bash
+  kubectl label nodes <node-name> kubernetes.io/<label-key>=<label-value>
+  ```
+
+---
+
+## Namespace Management
+
+- **List all namespaces**
+
   ```bash
   kubectl get namespaces
-  ```
+  # or the abbreviated version:
-  ```bash
   kubectl get ns
   ```
-- **Create a custom namespace:**
+
+- **Create a custom namespace**
+
   ```bash
   kubectl create ns <namespace-name>
   ```
 
-### Pod Management
+---
-- **Get the list of pods in the default namespace:**
+
+## Pod Management
+
+### Listing Pods
+
+- **List pods in the default namespace**
+
   ```bash
   kubectl get pod
   ```
-- **Get the list of pods in the default namespace with full information:**
+
+- **List pods with detailed information (wide output) in the default namespace**
+
   ```bash
   kubectl get pod -o wide
   ```
-- **Get the list of pods in a custom namespace with full information:**
+
+- **List pods with detailed information in a specific namespace**
+
   ```bash
-  kubectl get pod -o wide -n <name-space>
+  kubectl get pod -o wide -n <namespace-name>
   ```
 
 ### Running a Pod
-- **Run a new pod:**
+
+- **Run a new pod**
+
+  Use the following command structure to run a pod with various options:
+
   ```bash
   kubectl run <pod-name> <switch> {
-    --image=<image-name>,                # Specifies the container image to use
+    --image=<image-name>,                # Container image to use
-    --port=<portnumber>,                 # Specifies the port that the container exposes
+    --port=<port-number>,                # Port that the container exposes
-    -n <namespace-name>,                 # Specifies the namespace
+    -n <namespace-name>,                 # Namespace in which to run the pod
-    --env="KEY=VALUE",                   # Sets environment variables in the container
+    --env="KEY=VALUE",                   # Environment variables for the container
-    --command,                           # Treats the rest of the arguments as the command to run in the container
+    --command,                           # Treat the following arguments as the command
-    --replicas=<number>,                 # Specifies the number of replicas for the deployment
+    --replicas=<number>,                 # Number of pod replicas to create
-    --labels="key=value,key2=value2",    # Adds labels to the pod(s)
+    --labels="key=value,key2=value2",    # Labels to assign to the pod(s)
-    --dry-run=client,                    # Prints the object that would be sent, without creating it
+    --dry-run=client,                    # Print the object without creating it
-    --restart=<Always|OnFailure|Never>,  # Determines the restart policy for the pod
+    --restart=<Always|OnFailure|Never>,  # Pod restart policy
-    --overrides='<json>',                # Provides a JSON override for the generated object
+    --overrides='<json>',                # JSON override for the generated object
-    --image-pull-policy=<policy>,        # Specifies the image pull policy (Always, IfNotPresent, Never)
+    --image-pull-policy=<policy>,        # Image pull policy (Always, IfNotPresent, Never)
-    --limits=cpu=<cpu>,memory=<memory>,  # Specifies resource limits for the container
+    --limits=cpu=<cpu>,memory=<memory>,   # Resource limits for the container
-    --requests=cpu=<cpu>,memory=<memory> # Specifies resource requests for the container
+    --requests=cpu=<cpu>,memory=<memory>  # Resource requests for the container
   }
   ```
-  - *Example:*
+
+  - **Example:**
+
     ```bash
     kubectl run mypod --image=nginx --port=80 -n mynamespace \
       --env="ENV_VAR_NAME=VALUE" --command -- nginx -g "daemon off;" \
@@ -69,34 +126,118 @@ kubectl api-resources
       --requests=cpu=50m,memory=128Mi
     ```
 
-
 ### Deleting a Pod
-- **Delete a pod in a custom namespace:**
+
+- **Delete a pod in a custom namespace**
+
   ```bash
   kubectl delete pod -n <namespace-name> <pod-name>
   ```
 
-### API Resource Documentation
+---
-- **Get documentation of an API resource:**
+
+## API Resources and Documentation
+
+- **Get documentation for an API resource**
+
   ```bash
   kubectl explain <api-resource-name>
   ```
+
   - *Example:*
+
     ```bash
     kubectl explain pod
     ```
 
-### Logging and Pod Information
+---
-- **Get and follow logs of a pod (pod must be created and running):**
+
+## Logs and Pod Information
+
+- **Stream logs for a running pod**
+
   ```bash
-  kubectl logs -f -n <namespace-name> <podname>
+  kubectl logs -f -n <namespace-name> <pod-name>
-  ```
-- **Get logs and state information of a pod (works at any time):**
-  ```bash
-  kubectl describe pod -n <namespace-name> <podname>
   ```
 
-### Apply Yaml File
+- **Get detailed state and log information for a pod**
-```bash
+
-kubectl apply -f <yaml-file> -n <namespace-name>
+  ```bash
-```
+  kubectl describe pod -n <namespace-name> <pod-name>
+  ```
+
+---
+
+## Applying YAML Files
+
+- **Apply configuration from a YAML file to a specific namespace**
+
+  ```bash
+  kubectl apply -f <yaml-file> -n <namespace-name>
+  ```
+
+---
+
+## Managing Nodes and Labels
+
+- **Label a node with a custom key-value pair**
+
+  ```bash
+  kubectl label nodes <node-name> kubernetes.io/<label-key>=<label-value>
+  ```
+
+---
+
+## Viewing Cluster Resources
+
+- **Display all resources loaded in a namespace**
+
+  ```bash
+  kubectl get all -n <namespace-name>
+  ```
+
+- **Display replica sets, pods, and deployments in a specific namespace**
+
+  ```bash
+  kubectl get rs,pod,deployment -n <namespace-name>
+  ```
+
+---
+
+## ReplicaSet and Deployment Management
+
+- **Scale a ReplicaSet**
+
+  ```bash
+  kubectl scale rs <replicaset-name> -n <namespace-name> --replicas=<count>
+  ```
+
+- **View rollout history of a deployment**
+
+  ```bash
+  kubectl rollout history deployment -n <namespace-name> <deployment-name>
+  ```
+
+- **View details of a specific revision in a deployment's rollout history**
+
+  ```bash
+  kubectl rollout history deployment -n <namespace-name> <deployment-name> --revision <number>
+  ```
+
+- **Roll back a deployment to a specific revision**
+
+  ```bash
+  kubectl rollout undo deployment -n <namespace-name> <deployment-name> --to-revision=<number>
+  ```
+
+  > **Note:** The command for rolling back to a specific revision is `kubectl rollout undo` rather than using `--to-revision` with `kubectl rollout history`.
+
+---
+
+## Additional Information
+
+- **Static Manifest Files**
+
+  All YAML files located under `/etc/kubernetes/manifests/` are automatically loaded after a server reboot.
+
+---

Databases/Postgresql/install.md

@@ -0,0 +1,56 @@
+# PostgreSQL Installation and Configuration Guide
+
+Follow these steps to install and configure PostgreSQL on your system:
+
+## Step 1: Update System Packages
+Ensure your system's package list is up-to-date:
+
+```bash
+sudo apt update
+```
+
+## Step 2: Install PostgreSQL
+Install PostgreSQL and its additional utilities:
+
+```bash
+sudo apt install postgresql postgresql-contrib
+```
+
+## Step 3: Start PostgreSQL Service
+Start the PostgreSQL service:
+
+```bash
+sudo systemctl start postgresql.service
+```
+
+## Step 4: Enable PostgreSQL to Start on Boot
+Enable the PostgreSQL service to start automatically on system boot:
+
+```bash
+sudo systemctl enable postgresql.service
+```
+
+## Step 5: Switch to the PostgreSQL User
+Switch to the `postgres` system user to perform database administration tasks:
+
+```bash
+sudo -i -u postgres
+```
+
+## Step 6: Access the PostgreSQL Command-Line Interface
+Start the `psql` command-line interface:
+
+```bash
+psql
+```
+
+## Step 7: Configure PostgreSQL
+Edit the PostgreSQL configuration file:
+
+```bash
+vim /etc/postgresql/14/main/postgresql.conf
+```
+
+---
+
+**Note:** Replace `14` in the file path above with your PostgreSQL version number, if it's different.