1993 docker run -itd –name=sjt ubuntu1995 docker ps |grep sjt1998 docker attach sjt apt-get update apt-get install git apt-get install ntp apt-get install apache2 1999 docker commit -a”Sujith Sunny” -m”ub-up-git-ap2″ sjt ub-up-git-ap22000 docker images

Ideally, very little data is written to a container’s writable layer, and you use Docker volumes to write data. However, some workloads require you to be able to write to the container’s writable layer. This is where storage drivers come in.

All layers in a docker image is Read only. All layers in an image is merged to one layer while creating the container.. Docker image is a collection of files systems. A docker image is a template for docker container. One docker image can be used to create multiple containers File systems are layered over each other Layer 0 have the root filesystem Each layer in image will have 40 character length UUID generated by SHA 256 algorithm.

What is Docker Images and Explain in 10 bullet lines? Collection of file systems One copy of docker image get attached to each container. From one image multiple containers can be created Layered structure Each layer is each File system Layer 0 should be base image or Root FS Once image is attached to container, these layers will be attached to the container as a single layer The layers in image will be on read only format, and to have

Steps docker run –name aji_4 -itd centosattach to ityum install gityum install httpd yum install epel-releaseyum install -y ntp

Docker image is a collection of file system (Root FS, USER FS and APP FS) One copy of Docker image get attached to each container created from the image We can create multiple containers from same image docker image made up of file system layered over each other i.e Layer-n(image n)….. –> Layer1(image 1) –> Layer 0 (image 0) Layer 0 in the docker image is base image and requires root file system Higher layers always win when there is

Docker uses storage drivers to store image layers, and to store data in the writable layer of a container. The container’s writable layer does not persist after the container is deleted, but is suitable for storing ephemeral data that is generated at runtime. Storage drivers are optimized for space efficiency, but (depending on the storage driver) write speeds are lower than native file system performance, especially for storage drivers that a use copy-on-write filesystem

Docker image is a collection of files systems. A docker image is a template for docker container. One docker image can be used to create multiple containers File systems are layered over each other Layer 0 have the root filesystem Each layer in image will have 40 character length UUID generated by SHA 256 algorithm. All layers in a docker image is Read only. All layers in an image is merged to one layer while creating the container..

Docker uses the storage driver to store image layers

docker run –name vin1 -itd ubuntu:latestdocker psdocker attach e80fd4a69088docker commit –helpdocker commit -a”VIneesh” -m”Added apache” e80fd4a69088 vineesh_ubuntudocker imagesdocker psdocker exec e80fd4a69088 gitdocker imagesdocker run -itd vineesh_ubuntudocker psdocker exec acdda25da2d2 git

Docker image consists of RootFS + UserFS + AppFS

Storage drivers are used to store image layers, and to store data in the writable layer of a container. Types are overlay,overlay2,fuse-overlayfs,btrfs,zfs,vfs,aufs and devicemapper. overlay2 is the default storage driver.

The storage driver controls how images and containers are stored and managed on your Docker host.

The images and containers in Docker host are stored, managed and mapped using some pluggable architecture. This plugins are known as Docker Storage Drivers. Types: Driver Description overlay2 overlay2 is the preferred storage driver for all currently supported Linux distributions, and requires no extra configuration. fuse-overlayfs fuse-overlayfsis preferred only for running Rootless Docker on a host that does not provide support for rootless overlay2. On Ubuntu and Debian 10, the fuse-overlayfs driver does not need to be used, and overlay2 works even in rootless mode. Refer

Steps used to create the docker image create a docker containerattach to itapt updateapt install gitapt install ntpapt install apache2docker commit -a”Aji Raphel” -m”created a docker image with ubuntu+git+ntp+apache2″ b3bab63b207d aji_ubuntu

Create one Image which have base as centos and with git – ntp – httpd.

Create one Image which have base as ubuntu and with git – ntp – apache2

docker run –name akilan_centos_container -itd centosdocker attach 47ff211e687b8a499d1a213132c9141cfd8e4eb8d167618c941de3ad8bf59ddadocker psdocker ps|grep akilan2010 docker commit -a “akilan” -m “centos-git-httpd-akilan” \d 47ff211e687b8a499d1a213132c9141cfd8e4eb8d167618c941de3ad8bf59dda centos-git-httpd-akilandocker images