Most Asked DevOps Interview Questions
Here we have compiled the most probable DevOps interview questions asked in the industry. You will learn about software version control, Git repository, reverting a commit in Git, Vagrant, continuous testing elements, and the importance of continuous integration, testing, and deployment. These questions are curated after discussing with many interviewers and DevOps Training experts.
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Interview Questions
211. Where the docker volumes are stored?
In a linux machine Docker volumes are stored at this location:
/var/lib/docker/volumes
212. What are the states of Docker containers?
Important states of Docker container are as listed below:
1. Running
2. Paused
3. Restarting
4. Exit.
213. What is a Docker Swarm?
Docker Swarm is an orchestration tool for Docker containers. Docker Swarm is used to scale up/down nodes in a cluster. Even clusters can be created by Docker Swarm. It uses a network for internal communication among containers. Docker Swarm is native clustering for Docker. It turns a container pool of Docker hosts into a single Docker host. Docker Swarm manages the Docker API as well.
214. Do Docker support for IPV6?
Yes, but only if you modify /etc/docker/daemon.json and set the ipv6 key to "true". IPv6 networking is supported only on Docker daemons run on Linux hosts.
215. How does communication happen between Docker clients and the Docker Daemon?
Communication between Docker client and Docker Daemon happens with the combination of Rest API, socket.IO, and TCP.
216. What is a Dockerfile?
Docker can build images by reading the instructions given in a file called Dockerfile. A Dockerfile is a text document that contains all the commands in a sequence. This "docker build -t < Dockerfile/path > .", command will execute several instructions written in Dockerfile in a sequence to create Docker images. The common commands used in Dockerfile are: FROM, MAINTENANCE, COPY, RUN, and CMD.
217. How do you run multiple containers using a single service?
By using an orchestration tool like docker-compose, you can run multiple containers using a single service. All docker-compose files use yaml language.
218. What is Docker Compose?
Docker Compose contains information about the services, networks, and volumes for setting up the Docker application. So, you can use Docker Compose to create separate containers, and host them and get them to communicate with each other. Make sure that each container should expose a port for communicating with others. Docker Compose is written in YAML format.
219. Is it possible to use JSON instead of YAML in Docker Compose?
Yes, JSON can be used instead of YAML for a Docker Compose file. we have to specify the filename with the command:
"docker-compose -f docker-compose.json up".
220. What is a Docker Namespace?
The namespace is one of the features in linux and an important concept of containers. Namespace in Docker is a technique which offers isolated workspaces in Containers. In order to remain portable Docker provides various namespaces and does not affect the host system. Few Namespace types supported by Docker are as: – PID, IPC, NET, MNT, UTS, User accounts, Mount, Process Tree, Network etc.
