DevOps Interview Questions and Answers
Question - 81 : - How do you create a Docker container?
Answer - 81 : -
Task: Create a MySQL Docker container
A user can either build a Docker image or pull an existing Docker image (like MySQL) from Docker Hub.
Now, Docker creates a new container MySQL from the existing Docker image. Simultaneously, the container layer of the read-write filesystem is also created on top of the image layer.
- Command to create a Docker container: Docker run -t –i MySQL
- Command to list down the running containers: Docker ps
Question - 82 : - What is the purpose of the expose and publish commands in Docker?
Answer - 82 : -
Expose
- Expose is an instruction used in Dockerfile.
- It is used to expose ports within a Docker network.
- It is a documenting instruction used at the time of building an image and running a container.
- Expose is the command used in Docker.
- Example: Expose 8080
Publish
- Publish is used in a Docker run command.
- It can be used outside a Docker environment.
- It is used to map a host port to a running container port.
- --publish or –p is the command used in Docker.
- Example: docker run –d –p 0.0.0.80:80
- Now, let's have a look at the DevOps interview questions for continuous monitoring.
Question - 83 : - How does Nagios help in the continuous monitoring of systems, applications, and services?
Answer - 83 : -
Nagios enables server monitoring and the ability to check if they are sufficiently utilized or if any task failures need to be addressed.
- Verifies the status of the servers and services
- Inspects the health of your infrastructure
- Checks if applications are working correctly and web servers are reachable
Question - 84 : - What do you mean by Nagios Remote Plugin Executor (NPRE) of Nagios?
Answer - 84 : -
Nagios Remote Plugin Executor (NPRE) enables you to execute Nagios plugins on Linux/Unix machines. You can monitor remote machine metrics (disk usage, CPU load, etc.)
- The check_npre plugin that resides on the local monitoring machine
- The NPRE daemon that runs on the remote Linux/Unix machine
Question - 85 : - What are active and passive checks in Nagios?
Answer - 85 : -
Nagios is capable of monitoring hosts and services in two ways:
Actively
- Active checks are initiated as a result of the Nagios process
- Active checks are regularly scheduled
Passively
- Passive checks are initiated and performed through external applications/processes
- Passive checks results are submitted to Nagios for processing
Question - 86 : - What is the Nagios Network Analyzer?
Answer - 86 : -
- It provides an in-depth look at all network traffic sources and security threats.
- It provides a central view of your network traffic and bandwidth data.
- It allows system admins to gather high-level information on the health of the network.
- It enables you to be proactive in resolving outages, abnormal behavior, and threats before they affect critical business processes.
Question - 87 : - What are the benefits of HTTP and SSL certificate monitoring with Nagios?
Answer - 87 : -
HTTP certificate monitoring
- Increased server, services, and application availability.
- Fast detection of network outages and protocol failures.
- Enables web transaction and web server performance monitoring.
SSL certificate monitoring
- Increased website availability.
- Frequent application availability.
- It provides increased security.
Question - 88 : - Explain what state stalking is in Nagios.
Answer - 88 : -
- State stalking is used for logging purposes in Nagios.
- When stalking is enabled for a particular host or service, Nagios will watch that host or service very carefully.
- It will log any changes it sees in the output of check results.
- This helps in the analysis of log files.