/devops-beginners-to-advanced-with-projects

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DevOps Beginners to Advanced with Projects

DevOps Beginners to Advanced with Projects

Table of Contents

What is DevOps?

DevOps is a set of practices that combines software development (Dev) and IT operations (Ops). It aims to shorten the systems development life cycle and provide continuous delivery with high software quality. DevOps is complementary with Agile software development; several DevOps aspects came from Agile methodology.

What is Continuous Integration?

Continuous Integration (CI) is a development practice that requires developers to integrate code into a shared repository several times a day. Each check-in is then verified by an automated build, allowing teams to detect problems early.

What is Continuous Deployment?

Continuous Deployment is a software release process that uses automated testing to validate if changes are correct and if they meet quality criteria. It is the natural extension of Continuous Integration: an approach in which teams ensure that every change to the system is releasable.

Virtualization

Virtualization is the process of creating a software-based, or virtual, representation of something, such as virtual applications, servers, storage, and networks. It is the single most effective way to reduce IT expenses while boosting efficiency and agility for all size businesses.

Linux

Linux is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged in a Linux distribution.

Linus Torvalds released the Linux kernel in 1991. He developed the Linux kernel on MINIX using the GNU C Compiler. He was inspired by MINIX, a Unix-like operating system based on a microkernel architecture.

Commands and File System

  • ls: List files and directories
  • pwd: Print working directory
  • cd: Change directory
  • touch: Create a file
  • mkdir: Create a directory
  • rm: Remove a file
  • rmdir: Remove a directory
  • cp: Copy files and directories
  • mv: Move and rename files and directories
  • cat: Concatenate files and print on the standard output
  • more: File perusal filter for crt viewing
  • less: Opposite of more
  • head: Output the first part of files
  • tail: Output the last part of files
  • grep: Print lines matching a pattern
  • find: Search for files in a directory hierarchy
  • chmod: Change file mode bits
  • chown: Change file owner and group
  • ps: Report a snapshot of the current processes
  • kill: Send a signal to a process
  • killall: Kill processes by name
  • ifconfig: Configure a network interface
  • ping: Send ICMP ECHO_REQUEST to network hosts

Where things live on the filesystem

  • /: The root directory
  • /bin: Essential command binaries
  • /boot: Static files of the boot loader
  • /dev: Device files
  • /etc: Host-specific system configuration
  • /home: Home directories
  • /lib: Essential shared libraries and kernel modules
  • /media: Mount point for removable media
  • /mnt: Mount point for mounting a filesystem temporarily
  • /opt: Add-on application software packages
  • /proc: Virtual filesystem providing process and kernel information

cat /etc/os-release # Display the operating system name and version

VIM Editor

  • i: Insert mode
  • Esc: Normal mode
  • :w: Save
  • :q: Quit
  • :wq: Save and quit
  • :q!: Quit without saving
  • dd: Delete a line
  • yy: Copy a line
  • p: Paste a line
  • u: Undo
  • Ctrl + r: Redo
  • :set number: Show line numbers
  • :set nonumber: Hide line numbers
  • :set autoindent: Enable auto-indent
  • :set noautoindent: Disable auto-indent
  • :set hlsearch: Highlight search results
  • :set nohlsearch: Disable highlight search results
  • :set ignorecase: Ignore case when searching
  • :set noignorecase: Do not ignore case when searching
  • :set incsearch: Show search results incrementally

Modes

  • Normal mode: The mode in which you can navigate through the file and perform actions like copying, pasting, and deleting text.
  • Insert mode: The mode in which you can insert text.
  • Visual mode: The mode in which you can select text.

Installing from a URL

Here is the command I ran wget -r -np -nH --cut-dirs=3 -R "index.html*" https://release.archboot.com/aarch64/latest/

  • -r: Turn on recursive retrieving
  • -np: Do not ever ascend to the parent directory
  • -nH: Disable generation of host-prefixed directories
  • --cut-dirs=3: Ignore 3 directory components
  • -R "index.html*": Reject files matching the pattern
  • https://release.archboot.com/aarch64/latest/: URL to download
  • wget: The non-interactive network downloader

In all honesty, I don't think I needed to download everything from the url, I needed the ISO. but its a start!

Yeah now that I am looking at it, this could have been done with:

wget https://release.archboot.com/aarch64/latest/iso/archboot-2024.04.30-17.10-6.8.7-1-aarch64-ARCH-aarch64.iso.sig

Linux File Types

  • -: Regular file
  • d: Directory
  • l: Symbolic link
  • c: Character device file
  • b: Block device file
  • s: Socket file
  • p: Named pipe
  • D: Door
  • n: Network file
  • ?: Other file
  • !: Doors

you can use file command to determine the file type

[root@fedora-linux-38 /]# file /etc/passwd
/etc/passwd: ASCII text

Commands

  • grep: Print lines matching a pattern
    • grep -i: Ignore case
    • grep -v: Invert match
    • grep -r: Recursive search
  • find: Search for files in a directory hierarchy
    • find / -name file.txt: Search for a file
    • find / -type d: Search for a directory
    • find / -type f: Search for a file
    • find / -user user1: Search for files owned by a user
    • find / -size +1G: Search for files greater than 1GB
    • find / -size -1G: Search for files less than 1GB
    • find / -empty: Search for empty files and directories
    • find / -mtime -1: Search for files modified in the last 24 hours
    • find / -mtime +1: Search for files modified more than 24 hours ago
    • find / -exec command {} \;: Execute a command on the search results
  • chmod: Change file mode bits
    • chmod 777 file.txt: Give all permissions to everyone
    • chmod 755 file.txt: Give read, write, and execute permissions to the owner, and read and execute permissions to others
    • chmod 700 file.txt: Give all permissions to the owner, and no permissions to others
    • chmod u+x file.txt: Give execute permission to the owner
    • chmod g+w file.txt: Give write permission to the group
    • chmod o-r file.txt: Remove read permission from others
  • chown: Change file owner and group
    • chown user1 file.txt: Change the owner of a file
    • chown user1:group1 file.txt: Change the owner and group of a file

Users and Groups

  • Users and Groups are used to control access to the system and its resources.
  • Users login to the system and have unique usernames.
  • Every process has an owner and group affiliation.

Types of Users

User Type Description User ID (UID) Group ID (GID) Home Directory Shell
Root Superuser 0 0 /root /bin/bash
Regular Normal user 1000+ 1000+ /home/user1 /bin/bash
Service ftp, apache, mysql 1-999 1-999 /var/www, /var/lib/mysql /sbin/nologin

How to read /etc/passwd file

Here is a sample /etc/passwd file:

root:x:0:0:Super User:/root:/bin/bash
bin:x:1:1:bin:/bin:/usr/sbin/nologin
daemon:x:2:2:daemon:/sbin:/usr/sbin/nologin
adm:x:3:4:adm:/var/adm:/usr/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/usr/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/usr/sbin/nologin
  • root: Username
  • x: Password placeholder
  • 0: User ID (UID)
  • 0: Group ID (GID)
  • Super User: User description
  • /root: Home directory
  • /bin/bash: Shell

Here is the groups output from /etc/group file:

parallels:x:1000:
domhallan:x:1001:

The id command can be used to display the user and group information for the current user:

[root@fedora-linux-38 etc]# id domhallan
uid=1001(domhallan) gid=1001(domhallan) groups=1001(domhallan),10(wheel)

The useradd command can be used to add a new user:

[root@fedora-linux-38 etc]# useradd ansible

The groupadd command can be used to add a new group:

[root@fedora-linux-38 etc]# groupadd devops

We can run usermod to add a user to a group and the id command to verify the changes:

[root@fedora-linux-38 etc]# usermod -aG devops ansible
[root@fedora-linux-38 etc]# id ansible
uid=1002(ansible) gid=1002(ansible) groups=1002(ansible),1003(devops)

You can also add users in the /etc/group file manually, but it is not recommended.

You can use the passwd command to change the password for a user:

[root@fedora-linux-38 etc]# passwd ansible
Changing password for user ansible.
New password:
Retype new password:
passwd: all authentication tokens updated successfully.

lsof -u user1 command can be used to list all open files for a user:

[root@fedora-linux-38 etc]# lsof -u domhallan
COMMAND   PID USER   FD   TYPE DEVICE SIZE/OFF    NODE NAME
systemd     1 root  cwd    DIR    8,1     4096       2 /
systemd     1 root  rtd    DIR    8,1     4096       2 /

userdel and groupdel commands can be used to delete a user and group respectively:

[root@fedora-linux-38 etc]# userdel ansible
[root@fedora-linux-38 etc]# groupdel devops

File Permissions

  • r: Read
  • w: Write
  • x: Execute
  • -: No permission
  • d: Directory
  • l: Symbolic link
  • s: Setuid or Setgid
  • t: Sticky bit

Here is an example of file permissions:

[root@fedora-linux-38 /]# ls -l
total 28
dr-xr-xr-x.   1 root root    0 Jan 23 19:00 afs
lrwxrwxrwx.   1 root root    7 Jan 23 19:00 bin -> usr/bin
dr-xr-xr-x.   9 root root 4096 May  7 14:51 boot
lrwxrwxrwx.   1 root root   37 May  7 15:40 cmds -> /opt/dev/ops/devops/test/commands.txt

In the first line of the output, the permissions are dr-xr-xr-x. Here is the breakdown:

  • d: Directory
  • r-x: Owner has read and execute permissions
  • r-x: Group has read and execute permissions
  • r-x: Others have read and execute permissions
  • 1: Number of links
  • root: Owner
  • root: Group
  • 0: Size
  • Jan 23 19:00: Last modified date
  • afs: File name

Permissions Breakdown

Octal Symbol Permission
0 --- No permissions
1 --x Execute
2 -w- Write
3 -wx Write and execute
4 r-- Read
5 r-x Read and execute
6 rw- Read and write
7 rwx Read, write and execute

Octal Notation

  • Octal (base-8) notation simplifies the setting of permissions by condensing the symbolic notation into a single digit per user/group/others classification. Each octal digit can represent a combination of read, write, and execute permissions.

Symbolic Notation

  • Symbolic notation represents permissions using characters: r for read, w for write, and x for execute. A dash (-) represents the absence of a permission.

Permission Categories

  1. 0 (---): No permissions. Neither the owner, nor the group, nor others can read, write, or execute the file.
  2. 1 (--x): Execute permission only. The file can be executed but not read or written.
  3. 2 (-w-): Write permission only. The file can be modified but not executed or read.
  4. 3 (-wx): Write and execute permissions. The file can be modified and executed but not read.
  5. 4 (r--): Read permission only. The file can be read but not written to or executed.
  6. 5 (r-x): Read and execute permissions. The file can be executed and read but not written to.
  7. 6 (rw-): Read and write permissions. The file can be modified and read but not executed.
  8. 7 (rwx): Full permissions. The file can be read, written to, and executed.

Practical Use

Permissions are typically set for three categories: owner, group, and others. An octal code for each category determines the permissions, typically shown as three digits. For example, 755 in Unix permissions would translate to rwx for the owner, and r-x for both the group and others. This setup is common for web servers where the owner needs full control over the files, but the files only need to be readable and executable by others.

These permissions are crucial for security and functionality in a Unix-like system, allowing fine-grained control over who can do what with a file or directory. Understanding and correctly setting these permissions is key to managing a secure and efficient system.

In Unix and Unix-like systems, file permissions are depicted in both symbolic notation (like dr-xr-xr-x) and can also be represented in octal notation, but they describe two different aspects of how permissions are stored and displayed.

Symbolic Notation (dr-xr-xr-x)

  • The first character (d in your example) indicates the type of file. Here, d stands for directory. Other common types include - for a regular file and l for a symlink.
  • The next nine characters represent the permissions for three different categories in three sets of three:
    • The first set (r-x) is for the owner (user) permissions.
    • The second set (r-x) is for the group permissions.
    • The third set (r-x) is for others (world) permissions.
  • Each set consists of three positions:
    • r (read)
    • w (write)
    • x (execute)
  • A dash (-) indicates the absence of a permission.

Octal Notation

  • The octal notation simplifies the symbolic notation into a three-digit number, each digit corresponding to one of the user categories (user, group, others).
  • Each digit is the sum of its constituent permissions, calculated as follows:
    • Read (r) has a value of 4.
    • Write (w) has a value of 2.
    • Execute (x) has a value of 1.

Converting dr-xr-xr-x to Octal

  • For each set of r-x:
    • r = 4
    • - = 0 (no write permission)
    • x = 1
  • So, r-x translates to 4 + 0 + 1 = 5.

Therefore, dr-xr-xr-x corresponds to the octal permissions 555. Each 5 represents r-x, which you can confirm by adding up the values for each permission in the sets (Read + Execute).

In summary, the octal notation comes from a method of summarizing the binary values of the permissions (where each permission is a binary flag) into more compact, base-8 digits, which is useful for quickly setting and understanding file permissions at a glance in command-line operations.

sudo Command

The sudo command allows users to run programs with the security privileges of another user (by default, the superuser). It is used to execute a command as another user, typically the superuser.

The sudo command is used to run a command with the security privileges of another user (by default, the superuser). It is typically used to perform administrative tasks that require root access.

The sudo command, which stands for "superuser do", is a powerful command in Unix and Linux-based systems that allows a permitted user to execute a command as the superuser or another user, as specified in the sudoers file.

Here are some important points about sudo:

  • It's often used for commands that require elevated permissions, such as installing software or changing system configurations.
  • The sudo command provides an audit trail of the commands run with superuser privileges. This can be useful for system administrators to track changes made to the system.
  • When you use sudo, you'll be prompted for your password, not the root password. This is a security feature.
  • The sudo command has a timeout feature. By default, once you've entered your password, you won't be asked for it again for a period of time (usually 15 minutes).
  • The sudo command can be configured to provide certain users with specific permissions to certain commands, providing fine-grained control over user permissions.

Here's an example of using sudo:

sudo apt-get update

We can add users to the sudo group to grant them sudo privileges:

usermod -aG sudo username

And we can also add them to the sudoers file:

echo "username ALL=(ALL) ALL" >> /etc/sudoers

This line of code is a command that is typically run in a Unix-like operating system's terminal. It's written in shell script, which is a scripting language used for system administration.

The echo command is used to output the strings that are passed to it. In this case, the string is "username ALL=(ALL) ALL".

The >> operator is used to append the output of the command on its left to the file on its right. If the file doesn't exist, it will be created.

The /etc/sudoers file is a configuration file for the sudo command. sudo stands for "superuser do", and it's used to run commands with the privileges of another user, typically the superuser (or root).

The string "username ALL=(ALL) ALL" is a rule that's being added to the sudoers file. This rule means that the user username is allowed to run any command as any user on any host.

username is the user this rule applies to. Replace this with the actual username. The first ALL is the hosts this rule applies to. In this case, it's all hosts. The =(ALL) part specifies the users the commands can be run as. Again, it's all users. The last ALL is the commands this rule applies to. Yet again, it's all commands. This is a very permissive rule. In a real-world scenario, you'd likely want to limit the commands a user can run with sudo, the users they can run commands as, or the hosts they can run commands on.

Please note that editing the sudoers file directly can be risky. If you make a mistake, you could lock yourself out of your system. It's generally recommended to use the visudo command to edit the sudoers file, as it includes syntax checking to prevent you from saving a file with errors.

Computer networking

ISO

  • ISO (International Organization for Standardization) is a worldwide federation of national standards bodies. The work of preparing International Standards is normally carried out through ISO technical committees.
  • ISO 27001 is a specification for an information security management system (ISMS). An ISMS is a framework of policies and procedures that includes all legal, physical, and technical controls involved in an organization's information risk management processes.
  • ISO 9001 is a standard that sets out the criteria for a quality management system. It can be used by any organization, large or small, regardless of its field of activity. In fact, there are over one million companies and organizations in over 170 countries certified to ISO 9001.
  • ISO 14001 is an internationally agreed standard that sets out the requirements for an environmental management system. It helps organizations improve their environmental performance through more efficient use of resources and reduction of waste, gaining a competitive advantage and the trust of stakeholders.
  • ISO 3166 is a standard published by the International Organization for Standardization (ISO) that defines codes for the names of countries, dependent territories, and special areas of geographical interest. The official name of the standard is Codes for the representation of names of countries and their subdivisions.

OSI Model

  • OSI (Open Systems Interconnection) is a conceptual framework that standardizes the functions of a telecommunication or computing system into seven abstraction layers.
  • OSI Model Layers:
    • Layer 1 (Physical): Deals with physical connections and transmission of signals.
    • Layer 2 (Data Link): Provides error detection and correction.
    • Layer 3 (Network): Handles routing and forwarding of data packets.
    • Layer 4 (Transport): Manages end-to-end connections and reliability.
    • Layer 5 (Session): Establishes, maintains, and terminates connections.
    • Layer 6 (Presentation): Translates data into a compatible format.
    • Layer 7 (Application): Provides user interfaces and network services.

TCP/IP

  • TCP/IP (Transmission Control Protocol/Internet Protocol) is a suite of communication protocols used to interconnect network devices on the internet.
  • TCP (Transmission Control Protocol): Provides reliable, ordered, and error-checked delivery of a stream of packets on the internet.
  • IP (Internet Protocol): Routes packets across multiple networks.
  • TCP/IP Model Layers:
    • Application Layer: Provides network services directly to end-users.
    • Transport Layer: Manages end-to-end communication and data reliability.
    • Internet Layer: Routes data packets to their destination.
    • Link Layer: Handles physical connections and data framing.

IP Address

  • IP (Internet Protocol) address is a unique numerical label assigned to each device connected to a computer network that uses the IP for communication.
  • IPv4 (Internet Protocol version 4): Uses a 32-bit address scheme allowing for a total of 2^32 addresses.
  • IPv6 (Internet Protocol version 6): Uses a 128-bit address scheme allowing for a total of 2^128 addresses.
  • Public IP Address: Identifies a device on the internet.
  • Private IP Address: Identifies a device on a local network.
  • Static IP Address: Does not change and is manually configured.
  • Dynamic IP Address: Changes and is automatically assigned.

Protocols and Ports

  • HTTP (Hypertext Transfer Protocol): Used for transmitting web pages over the internet. Default port is 80.
  • HTTPS (Hypertext Transfer Protocol Secure): Secure version of HTTP. Default port is 443.
  • FTP (File Transfer Protocol): Used for transferring files between a client and server. Default ports are 20 (data) and 21 (control).
  • SSH (Secure Shell): Used for secure remote access to a computer. Default port is 22.
  • SMTP (Simple Mail Transfer Protocol): Used for sending email. Default port is 25.
  • POP3 (Post Office Protocol version 3): Used for retrieving email. Default port is 110.
  • IMAP (Internet Message Access Protocol): Used for retrieving email. Default port is 143.
  • DNS (Domain Name System): Used for translating domain names to IP addresses. Default port is 53.
  • DHCP (Dynamic Host Configuration Protocol): Used for automatically assigning IP addresses to devices. Default port is 67.
  • SNMP (Simple Network Management Protocol): Used for managing network devices. Default port is 161.
  • RDP (Remote Desktop Protocol): Used for remote desktop access. Default port is 3389.
  • NTP (Network Time Protocol): Used for synchronizing system clocks. Default port is 123.

Networking commands

  • ifconfig: Configure a network interface
  • ping: Send ICMP ECHO_REQUEST to network hosts
  • traceroute: Print the route packets take to network host
  • netstat: Print network connections, routing tables, interface statistics, masquerade connections, and multicast memberships
  • nslookup: Query Internet name servers interactively
  • dig: DNS lookup utility
  • host: DNS lookup utility
  • route: Show / manipulate the IP routing table
  • arp: Manipulate the system ARP cache
  • ss: Utility to investigate sockets
  • telnet: User interface to the TELNET protocol
  • ftp: Internet file transfer program
  • scp: Secure copy (remote file copy program)

Private IP Address Ranges

Class A: 10.0.0.0 - 10.255.255.255 Class B: 172.16.0.0 - 172.31.255.255 Class C: 192.168.0.0 - 192.168.255.255

These private IP address ranges fall into different classes based on their potential network size and distribution, designated as Class A, Class B, and Class C. Here’s a breakdown of each class as per your list:

Class A: 10.0.0.0 - 10.255.255.255

  • Range: 10.0.0.0 to 10.255.255.255
  • This Class A range allows for a very large number of addresses (16,777,216 addresses to be exact). It’s ideal for very large organizations with many devices that need IP addresses.
  • Typically, all devices within this range can communicate with each other within the same network without using the public internet.

Class B: 172.16.0.0 - 172.31.255.255

  • Range: 172.16.0.0 to 172.31.255.255
  • This Class B range includes 16 contiguous Class B networks, each of which can support up to 65,536 addresses (for a total of 1,048,576 addresses across all 16 networks).
  • It’s suitable for medium to large-sized networks.

Class C: 192.168.0.0 - 192.168.255.255

  • Range: 192.168.0.0 to 192.168.255.255
  • This Class C range encompasses 256 networks, each of which can handle up to 256 addresses (65,536 addresses in total across all networks).
  • It is commonly used in smaller networks, such as residential or small business networks.

Use of Private IP Addresses

These IP addresses are designed to be used in closed networks and are not routable on the public internet, meaning they can't directly send or receive data from internet devices without being translated to a public IP address via NAT. This setup helps alleviate the demand on the limited number of available public IP addresses and also adds an extra layer of security by isolating the internal network from external traffic.

Docker

  • Docker is a platform for developing, shipping, and running applications in containers. It enables developers to package applications with all dependencies into a standardized unit for software development.
  • Docker Containers are lightweight, standalone, and executable packages that include everything needed to run a piece of software, including the code, runtime, system tools, system libraries, and settings.
  • Docker Images are read-only templates used to create containers. They are built from a series of layers that include the base operating system, application code, and dependencies.
  • Docker Hub is a cloud-based registry service that allows you to link to code repositories, build your images, test them, and distribute them in both public and private repositories.
  • Docker Compose is a tool for defining and running multi-container Docker applications. It uses a YAML file to configure the application's services, networks, and volumes.

Microservices

  • Microservices is an architectural style that structures an application as a collection of small, autonomous services modeled around a business domain. Each service is self-contained and can be deployed independently.
  • Benefits of Microservices:
    • Scalability: Services can be scaled independently.
    • Flexibility: Easier to update and maintain.
    • Resilience: Failure in one service doesn't affect the entire application.
    • Technology Diversity: Different services can use different technologies.
    • Team Autonomy: Teams can work independently on services.
  • Challenges of Microservices:
    • Complexity: Managing multiple services can be complex.
    • Data Management: Data consistency and transactions can be challenging.
    • Testing: Testing distributed systems can be difficult.
    • Deployment: Managing deployments across multiple services.
    • Monitoring: Monitoring and debugging services can be complex.
    • Security: Securing microservices architecture.
    • Communication: Services need to communicate effectively.

AWS Part 1

  • AWS (Amazon Web Services) is a cloud computing platform that offers a wide range of services, including computing power, storage, databases, machine learning, and more.
  • EC2 (Elastic Compute Cloud): Provides scalable computing capacity in the cloud.
  • S3 (Simple Storage Service): Object storage service for storing and retrieving data.
  • RDS (Relational Database Service): Managed relational database service.
  • IAM (Identity and Access Management): Service for managing user access to AWS resources.
  • VPC (Virtual Private Cloud): Service for creating isolated virtual networks.
  • Route 53: DNS web service.
  • CloudWatch: Monitoring and observability service.
  • Elastic Beanstalk: Platform as a service (PaaS) for deploying and managing applications.
  • Lambda: Serverless computing service.
  • SNS (Simple Notification Service): Pub/sub messaging service.
  • SQS (Simple Queue Service): Message queuing service.
  • DynamoDB: NoSQL database service.
  • EKS (Elastic Kubernetes Service): Managed Kubernetes service.
  • EFS (Elastic File System): Scalable file storage service.

EC2

  • EC2 (Elastic Compute Cloud) is a web service that provides resizable compute capacity in the cloud. It allows users to launch virtual servers, known as instances, and scale capacity up or down as needed.
  • Instance Types: EC2 instances come in various types optimized for different use cases, such as general-purpose, compute-optimized, memory-optimized, storage-optimized, and more.
  • AMI (Amazon Machine Image): An AMI is a template that contains the software configuration (operating system, application server, and applications) required to launch an EC2 instance.
  • Security Groups: Security groups act as a virtual firewall that controls inbound and outbound traffic to an EC2 instance.
  • Key Pairs: Key pairs are used to securely connect to an EC2 instance using SSH. The private key is used to log in to the instance, while the public key is stored on the instance.
  • EBS (Elastic Block Store): EBS provides persistent block storage volumes for EC2 instances. It allows you to create volumes that can be attached to instances for data storage.
  • Elastic IP: An Elastic IP is a static IPv4 address that can be associated with an EC2 instance. It allows you to mask the failure of an instance by rapidly remapping the address to another instance in your account.
  • Instance Metadata: Instance metadata is data about your instance that you can use to configure or manage the running instance. It includes information such as the instance type, public IP address, security groups, and more.
  • Instance Store: Instance store volumes are temporary block storage volumes that are physically attached to the host computer. They provide temporary storage for data that is deleted when the instance is stopped or terminated.
  • Placement Groups: Placement groups are logical groupings of instances within a single Availability Zone. They are used to influence the placement of instances to meet specific requirements, such as low latency or high network throughput.
  • Spot Instances: Spot instances allow you to bid on unused EC2 capacity at a discounted price. They are ideal for workloads that are flexible in terms of when they run and can be interrupted.
  • Reserved Instances: Reserved instances provide a significant discount (up to 75%) compared to on-demand instances in exchange for a commitment to use the instance for a one- or three-year term.
  • Load Balancers: Load balancers distribute incoming application traffic across multiple targets, such as EC2 instances, to ensure optimal performance and availability.
  • Auto Scaling: Auto Scaling automatically adjusts the number of EC2 instances in a group based on demand or a predefined schedule. It helps maintain application availability and reduce costs.
  • CloudWatch: CloudWatch is a monitoring and observability service that provides data and insights to monitor your applications, respond to system-wide performance changes, optimize resource utilization, and get a unified view of operational health.