800+ Devops Engineer Interview Questions and Answers

To connect multiple VPCs, we can use VPC peering or VPN connections.

• Create a VPC peering connection between the VPCs

• Configure route tables to allow traffic between the VPCs

• Alternatively, create VPN connections between the VPCs

• Attach EC2 instances to the appropriate VPCs

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 Docker API.

• Send the desired Docker command to the remote se...read more

I use multiple programming languages depending on the task at hand.

• Python for automation and scripting

• Java for building applications

• Bash for shell scripting

• SQL for database management

• JavaScript for web development

• Go for microservices

• Perl for text processing

• C/C++ for system-level programming

To copy a commit from one branch to another, use the git cherry-pick command.

• Checkout the branch where you want to copy the commit

• Find the commit hash of the commit you want to copy

• Run 'git cherry-pick ' to apply the commit to the current branch

To create an EC2 instance using Terraform, define the necessary resources in a Terraform configuration file and run 'terraform apply'.

• Write a Terraform configuration file with the necessary resources, such as 'aws_instance' for EC2 instance.

• Specify the required parameters like 'ami', 'instance_type', 'subnet_id', etc.

• Run 'terraform init' to initialize the working directory.

• Run 'terraform plan' to see the execution plan.

• Run 'terraform apply' to create the EC2 instance.

• Verify t...read more

To troubleshoot issues with a running container service, follow these steps:

• Check the logs of the container to identify any errors or warnings

• Verify that the container is running on the correct port and IP address

• Check the network connectivity between the container and other services

• Verify that the container has access to the required resources and dependencies

• Restart the container or redeploy the service if necessary

Debugging errors involves identifying the root cause and using appropriate methods to resolve it.

• Start by reproducing the error and gathering relevant information

• Use debugging tools like logs, stack traces, and breakpoints to identify the root cause

• Once the root cause is identified, use appropriate methods like code changes or configuration updates to resolve the error

• Test the solution thoroughly to ensure it does not cause any new errors

Command to check httpd service status

• Use the command 'systemctl status httpd' to check the status of httpd service

• If httpd service is running, the output will show 'active (running)'

• If httpd service is not running, the output will show 'inactive (dead)'

Pipeline is a set of automated processes that build, test, and deploy code changes.

• Create a code repository

• Write code and commit changes to the repository

• Trigger a build process to compile and package the code

• Run automated tests to ensure code quality

• Deploy the code to a staging environment for further testing

• If tests pass, deploy the code to production environment

• Monitor the application for issues and repeat the process for new changes

To check logs for pods and containers in Kubernetes, you can use the kubectl command-line tool.

• Use the 'kubectl logs' command to view logs for a specific pod or container.

• Specify the pod or container name along with the appropriate flags.

• You can also use selectors to filter logs based on labels or namespaces.

• To follow logs in real-time, use the '-f' flag.

• To limit the number of lines displayed, use the '--tail' flag.

• To view logs from multiple containers in a pod, use the '--co...read more

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: Distributed nodes allow for better utilization of resources...read more

Third-party libraries can be downloaded from package managers or repositories.

• Package managers like npm, pip, and Maven can be used to download third-party libraries.

• Repositories like GitHub, GitLab, and Bitbucket can also be used to download libraries.

• Some cloud providers like AWS and Azure have their own repositories for third-party libraries.

• Libraries can also be downloaded from the official website of the library or the developer.

Restricting communication between Kubernetes pods can be achieved using network policies.

• Use Network Policies in Kubernetes to define rules for pod-to-pod communication

• Specify which pods are allowed to communicate with each other based on labels

• Deny all traffic by default and only allow specific traffic as needed

• Example: Define a network policy to allow communication only between pods with label 'app=frontend' and 'app=backend'

DNS in Linux is managed through configuration files and commands. DNS records contain information about domain names and IP addresses.

• DNS in Linux is managed through the /etc/resolv.conf file which contains the IP addresses of DNS servers.

• The 'nslookup' command can be used to query DNS records for a specific domain name.

• DNS records include A records (IP address), MX records (mail server), CNAME records (alias), and more.

• DNS caching can improve performance by storing frequentl...read more

Communication between pods in different namespaces is possible through services or network policies.

• Use services to allow communication between pods in different namespaces

• Create network policies to control traffic flow between pods in different namespaces

• Ensure proper DNS resolution for pods in different namespaces

I would follow the incident management process to identify the root cause and resolve the issue as quickly as possible.

• Notify the relevant stakeholders and initiate the incident management process

• Identify the root cause of the issue and take corrective actions

• Rollback to the previous stable version if necessary

• Communicate the status and progress of the incident to stakeholders

• Conduct a post-incident review to identify areas of improvement

Transit Gateway is a network transit hub that enables interconnectivity between virtual private clouds (VPCs) and on-premises networks.

• Transit Gateway simplifies network architecture by allowing multiple VPCs and VPN connections to connect to a single gateway.

• It provides a hub-and-spoke model for connecting VPCs and on-premises networks.

• Transit Gateway also supports routing between VPCs and on-premises networks, and can be used to consolidate VPC peering connections.

• It can al...read more

Testing is the process of evaluating a system or its component(s) with the intent to find whether it satisfies the specified requirements or not.

• Testing is done to ensure that the software meets the requirements and works as expected.

• It involves executing a system or its component(s) with the intent of finding errors or defects.

• Testing can be done at various stages of the software development life cycle such as unit testing, integration testing, system testing, and acceptance...read more

To secure and harden Tomcat, several precautions can be taken.

• Disable unused connectors and ports

• Use SSL/TLS encryption for secure communication

• Implement access control and authentication mechanisms

• Regularly update Tomcat and its dependencies

• Configure logging and monitoring for security events

Key elements in continuous testing tools include automation, integration with CI/CD pipelines, reporting and analytics, scalability, and support for various testing types.

• Automation of test cases to ensure quick feedback on code changes

• Integration with CI/CD pipelines for seamless testing in the software delivery process

• Reporting and analytics capabilities to track test results and identify issues

• Scalability to handle testing across different environments and configurations

• Su...read more

Various branching strategies in version control systems help manage code changes effectively.

• Mainline/Branch by Release: Each release has its own branch for bug fixes and maintenance.

• Feature Branching: Each new feature is developed in a separate branch and merged back to main branch after completion.

• Gitflow Workflow: Uses main, develop, feature, release, and hotfix branches for a structured workflow.

• Trunk-Based Development: All developers work on a single branch, promoting co...read more

To troubleshoot EC2 not having access to me, check security groups, network ACLs, and routing tables.

• Check if the EC2 instance is in the correct security group

• Verify that the security group allows inbound traffic from your IP address or CIDR block

• Check if there are any network ACLs that may be blocking traffic

• Verify that the routing table is correctly configured

• Check if there are any firewall rules on your local machine that may be blocking traffic

• Use tools like ping, tracero...read more