This blog post covers a brief overview of the topics covered and some common questions asked on Day 3 and Day 4 Live Interactive training on Docker and Kubernetes Certification i.e. CKA / CKAD and CKS.
This will help you to learn Docker & Kubernetes and prepare you for these certifications and get a better-paid job in the field of Microservices, Containers and Kubernetes.
In the Day 1 and Day 2 CKA Live session we covered an overview of Monolithic V/S Microservice, Introduction to Container, Docker Installation, Docker Architecture and Working with Containers. And in this week, Day 3 and Day 4 we covered Container Lifecycle, Docker Storage and Docker Networking.
we also performed labs.
Here are some of the FAQ’s asked during the Live session:
Container Lifecycle
When a container is created it will go through various life stages that are called as Container lifecycle. We discussed each stage in Container Lifecycle in detail.
If you want to know more about Docker Lifecycle
FAQ’s asked in the session are:
Q1) What does pause mean in Docker container Lifecycle?
Ans: docker pause is used to pause the running container. The command used for pausing a container is docker pause container-id or name. It can be unpaused using the command docker unpause container-id or name.
Q2) What is the average size of a Docker image?
Ans: The average size of any image is between 300MB to 600MB.
Read more about Docker Image here.
Q3) What is the use of -it flags in a docker container?
Ans: -it stands for the interactive terminal. It is used for opening a docker container instance in interactive mode.
Q4) What is iputils?
Ans: The iputils package is a set of small useful utilities for Linux networking
Q5) What is the Containerd shim process?
Ans: Containerd-shim is a child process of containerd that serves a single container and takes care of the container lifecycle and exposes its functions to containerd through containerd-shim API.
Know more: about what is a container?
Q6) What is the difference between docker start & docker exec?
Ans: Docker exec is used to execute a command on running containers and docker run is used to creates a temporary container, executes the command in it.
Also Check: Our blog post on Docker Tutorial. Click here
Docker Storage
In traditional bare-metal application, storage is just a device that is attached to an image. But docker containers handle storage in different ways. The docker image usually contains a writable layer, which is only useful for stateless, non-persistent data and is insufficient for data storage or stateful persistent device data needs. The following are the types of docker Storage Volume mount, Bind mount and tmpfs mount.
To know more about Docker Storage.
FAQ’s asked in the session are:
Q7) What is OverlayFs?
Ans: OverlayFS is a union mount filesystem implementation for Linux. It is a new file system similar to AUFS. It uses a simpler implementation and it is faster. Docker provides two storage drivers for OverlayFS that are overlay and overlay2.
Q8) What is curl?
Ans: curl is a command-line tool to transfer data to or from a server. It uses any of the following protocols HTTP, FTP, IMAP, POP3, SCP, SFTP, SMTP, TFTP, TELNET, LDAP or FILE.
Q9)what are the different types of mount available in docker?
Ans:
- Volume mounts are stored as a part of the host filesystem and it is managed by docker. It cannot be modified by a Non-Docker process. volumes are used to persist data in Docker.
- Bind mounts can be stored anywhere in the host system. Bind mounts are used to store important system files and directories. Bind mount can be modified by any process.
- tmpfs mounts are stored in the host system memory and it is temporary storage.
Also Check: Our blog post on Vulnerable Docker Images. Click here
Docker Network
Networking environments are crucial in Docker architecture. which network driver should I use? This is a common question in Docker Network. Each driver has its pros and cons. We have built-in network drivers in docker and various plugins are also available. The most commonly used built-in network drivers are bridge, overlay and macvlan.
Read our Blog: Docker Network: An Introduction to Docker Networking
FAQ’s asked in the session are:
Q10) What is the difference between docker network prune and docker network rm?
Ans: Docker network prune is used to remove all unused networks and docker network rm is used to remove one or more networks.
Q11) What is iptable?
Ans: iptables is a firewall program that is used in containers. It will monitor traffic from and to your server using tables.
Q12) Can containers have multiple networks?
Ans: Docker allows you to build different networks and connect containers to one or more of them. Containers can interact with one another across networks but not through networks. A container with network attachments can communicate with any of the containers on any of those networks.
Q13) what is the use of the netstat command.
Ans: It is used to display the network status .using netstat we can display the status of TCP and UDP endpoints in a table format, routing table information, and interface information.
Also Read: Our blog post on Kubernetes Dashboard. Click here
Quiz Time (Sample Exam Questions):
With CKA training program, we are going to cover 100+ sample exam questions to help you prepare for CKA certification.
Check out one of the questions and see if you can solve this.
Q1) Containers running on a single machine all share the same operating system kernel, so they start instantly and make more efficient use of RAM.
A: True
B: False
Q2) Identify the lifecycle of the Docker Container?
A: Create a container
B: Run the Docker container
C: Pause the Container
D: All of the above
Comment your answer in the comment box.
Related Post
- Kubernetes for Beginners
- How To Setup A Three Node Kubernetes Cluster For CKA: Step By Step
- Check out and Subscribe to our YouTube channel on “Docker & Kubernetes.”
- Certified Kubernetes Administrator (CKA) Certification Exam
- Certified Kubernetes Administrator (CKA) Certification: Step By Step Activity Guides/Hands-On Lab Exercise
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