Vision IAS Devops Engineer Interview Questions and Answers

The VPN port used for UDP is typically 500.

• The VPN port used for UDP is usually port 500.

• UDP is a protocol that allows for faster transmission of data but does not guarantee delivery or order of packets.

• Port 500 is commonly used for IPsec VPNs, which provide secure communication over the internet.

• Other VPN protocols may use different ports for UDP, so it's important to check the specific configuration.

Syntax for grep command and regex

• grep [options] pattern [file]

• Regular expression (regex) is used to define the pattern

• Examples: grep 'hello' file.txt

• grep -i 'hello' file.txt

• grep -r 'hello' /path/to/directory

You can use the Docker API to remotely run Docker commands on a Linux server without taking a separate SSH session.

• Use the Docker API to interact with the Docker daemon on the remote Linux server.

• Make sure Docker is installed and running on both your laptop and the remote server.

• Authenticate with the remote server using appropriate credentials.

• Establish a connection to the Docker daemon on the remote server using the D...read more

Terraform modules are reusable components that allow you to define and manage infrastructure as code.

• Modules are collections of resources that can be used across multiple Terraform configurations

• They can be shared and reused by other teams or projects

• Modules can be published to the Terraform Registry for easy discovery and use

• They help to reduce duplication of code and simplify infrastructure management

Debugging Apache Nginx issues involves checking logs, configuration files, and server status.

• Check error logs for any relevant error messages

• Verify the configuration files for syntax errors

• Check server status and resource usage

• Use tools like curl or telnet to test connectivity and response times

• Check firewall rules and network settings

• Consider load balancing and caching configurations

Prevent DDoS attack by implementing various measures

• Implementing firewalls and intrusion detection systems

• Using load balancers to distribute traffic

• Blocking traffic from suspicious IP addresses

• Using content delivery networks (CDNs)

• Limiting the number of requests per IP address

• Using anti-DDoS services provided by cloud providers

• Regularly monitoring network traffic for unusual patterns

Yes, AWS provides various methods to blacklist IPs.

• Use AWS WAF to create rules to block specific IP addresses

• Configure security groups to deny traffic from specific IP addresses

• Utilize AWS Network ACLs to block traffic from specific IP addresses

Average load in Linux refers to the amount of work being done by the system at a given time.

• Average load is measured as a decimal number, with 1.00 representing a fully loaded system.

• It takes into account both running processes and processes waiting for resources.

• High average load can indicate a need for more resources or optimization of processes.

• Command 'uptime' can be used to check the average load on a Linux system

Inodes are data structures that store information about files on a Unix/Linux file system. File descriptors are unique identifiers for open files. Swap is a space on a hard disk used as virtual memory.

• Inodes contain metadata about files such as ownership, permissions, and timestamps.

• File descriptors are used by the operating system to keep track of open files and to perform I/O operations on them.

• Swap is used when the ...read more

Load balancer routes traffic to other healthy instances

• Load balancer detects the unhealthy instance

• Stops sending traffic to that instance

• Routes traffic to other healthy instances

• Maintains high availability and scalability of the application

To debug a progressively slowing down website, I would analyze the server logs, check for memory leaks, and optimize the code.

• Analyze server logs to identify any errors or bottlenecks

• Check for memory leaks in the code

• Optimize the code by removing unnecessary scripts and optimizing images

• Use tools like Chrome DevTools to identify performance issues

• Consider implementing a content delivery network (CDN) to improve website

Docker save and Docker load commands can be used to transfer an image from one machine to another without using a Docker registry.

• Use the 'docker save' command to save the image as a tar file on the source machine

• Transfer the tar file to the destination machine using any file transfer method (e.g., scp)

• On the destination machine, use the 'docker load' command to load the image from the tar file

A program to reverse a string in Python

• Use the slicing technique to reverse the string

• Start with the last character and move backwards

• Store the reversed string in a new variable

Ansible playbook to install Apache

• Create a playbook file with .yml extension

• Define hosts and remote user

• Add tasks to install Apache package

• Start Apache service

• Save and run the playbook using ansible-playbook command

Distributed Jenkins nodes are used to handle large-scale builds and improve performance.

• Large-scale builds: When there are a large number of builds to be executed simultaneously, distributed Jenkins nodes can handle the load by distributing the builds across multiple nodes.

• Improved performance: By distributing the workload, the overall build time can be reduced, resulting in improved performance.

• Resource utilization: D...read more