AWS, Docker, Kubernetes & DevOps Concepts Explained with Easy Tricks
1. What is a Route Table & How Does Traffic Flow?
A route table in AWS defines how network traffic is directed within a Virtual Private Cloud (VPC). It contains a set of rules (routes) that determine where network traffic should be forwarded.
How Traffic Flows:
1. A request originates from an instance within a VPC.
2. The packet is checked against the route table.
3. The rule in the route table determines if the request should be forwarded to another subnet, an internet gateway, or remain internal.
4. If no matching rule is found, the packet is dropped.
Trick to Remember:
Think of a route table as Google Maps for your AWS network. It helps traffic find the shortest route to its destination.
2. Difference Between Internet Gateway (IGW) & NAT Gateway
• Internet Gateway (IGW): Provides a direct connection between your VPC and the internet. Required for public-facing instances.
• NAT Gateway: Allows private instances to access the internet while preventing inbound connections.
Use Case:
• IGW is used when you need an internet-accessible instance (e.g., web servers).
• NAT Gateway is used when internal servers need to download updates but should not be publicly accessible.
Trick to Remember:
IGW = Two-way traffic (IN & OUT), NAT Gateway = One-way traffic (OUT only).
3. Default Protocol Used in Route Table
The default protocol used in route tables is IPv4 (Internet Protocol version 4), but AWS also supports IPv6.
Trick to Remember:
IPv4 is like the traditional mailing address for your AWS instances.
4. Disaster Recovery in AWS
AWS provides various disaster recovery strategies, including:
• Backup & Restore: Regular backups to AWS S3 or Glacier.
• Pilot Light: A minimal but running version of your system.
• Warm Standby: A scaled-down but fully functional copy of your environment.
• Multi-site (Active-Active): A full-scale, redundant system running in another region.
Trick to Remember:
“BPWM” – Backup Power With Minimum downtime!
5. High Availability vs Disaster Recovery
• High Availability (HA): Ensures minimal downtime using redundant systems.
• Disaster Recovery (DR): Focuses on restoring services after a major failure.
Example:
• HA: Deploying multiple instances across different Availability Zones.
• DR: Keeping database backups in a different region.
Trick to Remember:
HA = No downtime, DR = Quick recovery!
6. Difference Between Snapshot & Image
• Snapshot: Copy of a disk at a specific time (used to restore volumes).
• Image (AMI): A full OS image used to launch new instances.
Trick to Remember:
Snapshot = Partial backup, Image = Full system backup.
7. Connecting to Private EC2 Without a Private Key
• Use EC2 Instance Connect (if using Amazon Linux 2 or Ubuntu).
• Create a new key pair, then manually update the authorized_keys file.
• Use Systems Manager Session Manager (if enabled beforehand).
Trick to Remember:
“EC2 Connect is your emergency door when the private key is lost.”
8. Types of Networks in Docker
1. Bridge – Default network for containers.
2. Host – Shares the host’s networking.
3. Overlay – Used in Swarm mode.
4. Macvlan – Assigns MAC addresses.
5. None – No networking.
Trick to Remember:
“BHOMN” – Be Happy On My Network!
9. CMD vs ENTRYPOINT in Docker
• CMD: Default command but can be overridden.
• ENTRYPOINT: Cannot be overridden.
Trick to Remember:
CMD = Default, ENTRYPOINT = Fixed.
10. Docker Architecture
Docker follows a client-server architecture with:
• Docker Client: Sends commands.
• Docker Daemon: Executes commands.
• Docker Registry: Stores images.
Trick to Remember:
“Client asks, Daemon works, Registry stores!”
11. Prerequisites for Jenkins
• Java
• Git
• Server with proper access
Trick to Remember:
“Jenkins needs JGS – Java, Git, Server.”
12. Git Clone vs Git Fork
• Clone: Creates a local copy.
• Fork: Copies the repository under your account.
Trick to Remember:
“Fork to own it, Clone to use it!”
13. Maximum VPCs in AWS
AWS allows up to 5 VPCs per region by default, but you can request an increase.
14. Transit Gateway vs Peering Connection
• Transit Gateway: Connects multiple VPCs and on-premises networks.
• Peering Connection: Connects only two VPCs.
Trick to Remember:
Peering = Two-way road, Transit Gateway = Highway!
15. What is Runtime?
Runtime is the environment where code is executed, such as JVM for Java or Node.js for JavaScript.
Trick to Remember:
“Runtime is the kitchen where your code is cooked!”
16. Load Balancer in Kubernetes
Kubernetes uses LoadBalancer service to expose applications externally.
Trick to Remember:
“LoadBalancer spreads traffic evenly like a traffic cop!”
17. Default Network in Docker
The bridge network is the default in Docker.
Trick to Remember:
“Bridge helps connect containers!”
18. Default Folder Permission in Linux
755 (rwxr-xr-x)
Trick to Remember:
“7 for owner, 5 for group, 5 for others!”
19. Kubernetes Node Architecture
Yes, Kubernetes follows a node-based architecture with:
• Master Node
• Worker Nodes
Trick to Remember:
“Master commands, Workers execute!”
20. Why is Replication Needed?
Replication ensures data availability and redundancy.
Trick to Remember:
“Replication is like making photocopies – just in case you lose one!”
Selenium Interview Question and Answers
https://corporatedidi.blogspot.com/2025/03/selenium-interview-question-answers.html
WIPRO DEVOPS HIRING: https://corporatedidi.blogspot.com/2025/03/wipro-is-hiring-devops-engineer-role.html
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Conclusion
AWS, Docker, and Kubernetes are essential technologies for cloud and DevOps engineers. Understanding these concepts and using tricks to remember them makes learning easier. Keep practicing and implementing these technologies to build expertise!
By mastering these topics, you can confidently handle cloud architecture, containerization, and automation tasks efficiently.
