Docker is a set of platform as a service (PaaS) products that use OS-level virtualization to deliver software in packages called containers.
Containers are isolated from one another and bundle their own software, libraries and configuration files; they can communicate with each other through well-defined channels. All containers are run by a single operating system kernel and therefore use fewer resources than virtual machines.
 

Docker Review

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25 Questions

1. Syntax to create an overlay network?

docker commit /docker image lsCMDd network create -d overlay --options encrypt FiggyOverlay1

2. Set what to run on start in dockerfile?

CMDdocker image lsd network create -d overlay --options encrypt FiggyOverlay1docker commit /

3. how to convert a container into an image?

docker image lsCMDdocker commit /d network create -d overlay --options encrypt FiggyOverlay1

4. list local images?

docker image lsd network create -d overlay --options encrypt FiggyOverlay1docker commit /CMD

5. list non running containers?

docker container ls --allCMDdocker commit /d network create -d overlay --options encrypt FiggyOverlay1

6. ratio of containers : hosts

CMDdocker commit /no contraints - can have several containers of same image running on same host, d works out networking (overlay)d network create -d overlay --options encrypt FiggyOverlay1

7. Idea of Overlay network?

docker commit /CMDAll hosts provide access to service on underlying swarm regardless of whether they are running the service (so use a HAProxy to spread load)d network create -d overlay --options encrypt FiggyOverlay1

8. dir structure of Dockerfile + bits?

CMDDir with Dockerfile and bits to copy indocker commit /d network create -d overlay --options encrypt FiggyOverlay1

9. Default config file?

d network create -d overlay --options encrypt FiggyOverlay1docker commit /docker-compose.ymlCMD

10. docker-swarm cmd to create 5 containers for a service?

d-s --replicas 5 -p ?:? --name websvc docker commit /CMDd network create -d overlay --options encrypt FiggyOverlay1

11. Kubernetes vs swarm?

docker commit /Similar, kuber does dynamic adding of containers, more complex, more usedCMDd network create -d overlay --options encrypt FiggyOverlay1

12. Syntax for ceating and running a new container?

d network create -d overlay --options encrypt FiggyOverlay1CMDdocker commit /d run

13. mandatory env variable to set on Mysql container?

docker commit /MYSQL_ROOT_PASSWORDCMDd network create -d overlay --options encrypt FiggyOverlay1

14. Root setions in compose file?

networks, services, volumes, containers, build,docker commit /d network create -d overlay --options encrypt FiggyOverlay1CMD

15. syntax to use a specific network?

d network create -d overlay --options encrypt FiggyOverlay1--net MyNetwork (can we use this when running?)CMDdocker commit /

16. cmd to up copies of image in swam?

docker commit /docker service scale web=8CMDd network create -d overlay --options encrypt FiggyOverlay1

17. Where does etcd come in?

docker commit /d network create -d overlay --options encrypt FiggyOverlay1KubernetesCMD

18. run up a new container from an image?

CMDdocker run d network create -d overlay --options encrypt FiggyOverlay1docker commit /

19. How to set up own docker hub?

d network create -d overlay --options encrypt FiggyOverlay1install a container based on docker registrydocker commit /CMD

20. Other useful cmds in Dockerfile?

EXPOSE (networking port - UPD + TCP?) ; HEALTHCHECK - cmd returns non null if there is a problemdocker commit /CMDd network create -d overlay --options encrypt FiggyOverlay1

21. concept of MacVLAN netowkring?

docker commit /containers are exposed through interfaces/subinterfaces (eg eth0.2 - on a vlan)d network create -d overlay --options encrypt FiggyOverlay1CMD

22. CMD and ENTRYPOINT in Dockerfile?

CMDdocker commit /d network create -d overlay --options encrypt FiggyOverlay1Entrypoint - the point of the container ; CMD - what to do when its started - eg EP=> "ls", CMD=>"/etc/" will list etc folder

23. Syntax to create a container on a swarm?

d network create -d overlay --options encrypt FiggyOverlay1CMDd service create docker commit /

24. How to use env vars in application.properties files?

d network create -d overlay --options encrypt FiggyOverlay1${host}docker commit /CMD

25. Scope of Overlay network driver?

CMDswarm widedocker commit /d network create -d overlay --options encrypt FiggyOverlay1