The basic concepts of Object-oriented programming concepts are: Class Object Inheritance Constructor Destructor Polymorphism CLASS A class is a template which represents a real-world entity, and it defines properties and methods of the entity. It is only structure of operations , it comes in action when object is being created You could think of class properties as variables that are used to hold information about the object. Object Objects are an instance of a class. A variable holds the data

What is the benefit of using CMD? CMD instruction can be used to set default command to execute when we run docker container. It allows the user to execute some particular command while running docker container. What is the benefit of using ENTRYPOINT? ENTRYPOINT instruction allows you to configure a container that will run as an executable. It has two forms – exec and shell Exec form allows to set commands and parameters and then use either form of CMD

Title – Complete referenece of dockerfile cmd and entrypoint What is the benefit of using CMD? What is the benefit of using ENTRYPOINT? Compare CMD vs Entrypoint with 5 Bullets points in tablular format What happens When i specify 2 CMD in one dockerfile? What happens When i specify 2 ENTRYPOINT in one dockerfile? What happens When i specify 1 ENTRYPOINT & 1 CMD in one dockerfile? What is the differenece between exec mode and shell mode? Run these 5

Docker image image is the collection of file systems.Each file system in image is known as layer.Docker image can contain either single layer or multiple layers.In case of multiple layes one layer is originated from prev layer.Base file system(root) is the mandatory layer of the image.One copy of image can mounted into each container.All layers are meged into one layer before mounted to container.Highest layered file gets priority to avoid conflicts at the time of merging.Repo name can always same

It’s a collection of filesystems, namely => rootfs, user fs, application fs These filesystems are represented as layers. Therefore each docker image has multiple filesystems, that is, each docker image has multiple layers Each layer is identified by a uuid, which is sha256 encoded. The lowest layer is the root filesystem. That is, it contains files under root directory The upper most layer is the only layer which is writeable, rest all layers are readonly Whenever you create any new

Define a docker image in points Docker Image has many layers which holds the information required for the configuration. Base image + parent image + layers+ container layer + docker manifest. Each of the files that make up a Docker image is known as a layer. These layers form a series of intermediate images, built one on top of the other in stages, where each layer is dependent on the layer immediately below it. Thus, you should organize layers that change most often

Docker image is template used to build the docker containers Docker image contains application code, tools, dependencies and other files needed to make an application run Docker images are store in docker registry Docker images have multiple layers(base image, parent image, Layers), each one originates from the previous layer but is different from it The layered file systems are identified using UUID which are created using SHA256 algorithm. When we create a container – all layers are merged into 1

Docker image is a collection of filesystems. Each image has a unique UUID assigned via sha-256 algorithm.Each image and a container has storage device assocaited with it.Each file system represents a layer in the image.The base layer for any image is the rootFS.Every layer comes bundled with it’s parent layer.All the layers of an image are read only.At the time of container start, a merged layer is created including all the layers of corresponding image and made writable for custimization.

It is a record of a Docker container at a specific point in time. A Docker image has many layers, and each image includes everything needed to configure a container environment — system libraries, tools, dependencies and other files. Docker images also act as the starting point when using Docker

Docker Image is a collection of file system rootfs (base) + ufs + appfs 2. 1 COPY of image of get mounted to each container. 3. Image name is the same as repo name 4. repo can be stored in registry (dockerhub etc) 5. Docker images contains multiple file system and each file system is referred to as layer. 6. Base layer is always — root file system 7. When we create a container – all layers are merged into

is a layer of filesystem. like rootfs +userfs+ apps+ apps all layers are read only. layer wise we can create container. when we pull the image then in var/lib/docker folder images is downloaded when we create the container then in var/lib/docker folder merged layer is created with RW file system conflict in layers then top layer is given priority. when we stop the container then merged layer is removed image is assigned to a user then a container is created

Docker image contains collection of file systems (root,user,application) Docker image can contain one or many layers. rootfs layer is always present. In case of file system conflict, the top layer takes precedence. The layered file systems are identified using UUID which are created using SHA256 algorithm. tagging is used to identify specific UUID with user friendly name docker inspect command can show the UUID of various layers used in the image. docker inspect command can be used to view docker

Docker is a tool /platform to manage containersFast, consistent delivery of your applicationsfaster deployment and good performanceDocker is light weightuses less resourcescost savingtime savingeffective infra management

Docker images are basically a collection of filesystems One copy of an image of gets mounted to each container Images can be stored in a repository for use by other orgs Docker images can contain one or more filesystems Each filesystem in a docker image is called a layer The base layer is always the root filesystem When multiple layers exist in a docker image, the top layer will get priority When we create a container, all layers get merged

docker logs 219444e11a87 > output.log

Update: On go we can change the settings of the container using Update command Before updating the memory-swap After updating the memory-swap and memory Wait: Docker wait command waits for 1 or more container to exit and provides the return status of the docker exit.Once docker wait is used the control will go inside the container and waits there until its get exited.

Docker update is used for updating container configurations for cpu or kernel related things. Docker wait is used for waiting for other container. And prints their return code.

blocks container and when container is stop ,it prints their exit code [root@ip-172-31-4-255 centos]# docker run -dit –name=my_container ubuntu bashdcd196da19b9c9b356597efa55b442fe0479f7c4f66d6dcf6745fab0995a64eb[root@ip-172-31-4-255 centos]# docker wait my_container in duplicated terminal [root@ip-172-31-4-255 centos]# docker stop my_containermy_container in previous terminal [root@ip-172-31-4-255 centos]# docker wait my_container0

Docker Update command Docker update command is used to change the configurations of one or more docker container dynamically. [root@ip-172-31-7-40 centos]# docker ps -aCONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES15c695103fd0 jenkins/jenkins “/sbin/tini — /usr/…” 19 hours ago Exited (137) 7 minutes ago sharp_albattanie91a38a225ad ubuntu “bash” 20 hours ago Up 16 minutes practical_shirley[root@ip-172-31-7-40 centos]#[root@ip-172-31-7-40 centos]# docker inspect 15c695103fd0 | grep -i cpu“CpuShares”: 100,“NanoCpus”: 1000000000,“CpuPeriod”: 0,“CpuQuota”: 0,“CpuRealtimePeriod”: 0,“CpuRealtimeRuntime”: 0,“CpusetCpus”: “”,“CpusetMems”: “”,“CpuCount”: 0,“CpuPercent”: 0,[root@ip-172-31-7-40 centos]# The current CpuShares value for this container

update : Update configuration of one or more containers [root@ip-172-31-14-110 centos]# docker update –cpu-shares 512 d28b65c987d8 ecstatic_shawd28b65c987d8ecstatic_shaw[root@ip-172-31-14-110 centos]# docker diff d28b65c987d8C /tmpA /tmp/jetty-0_0_0_0-8080-war-_-any-8581425030792705993A /tmp/winstone6787664488571520537.jarA /tmp/hsperfdata_jenkinsA /tmp/hsperfdata_jenkins/7 wait Block until one or more containers stop, then print their exit codes in 1st terminal [root@ip-172-31-14-110 centos]# docker wait 465d9c332e130[root@ip-172-31-14-110 centos]# [root@ip-172-31-14-110 centos] in 2nd terminal: [root@ip-172-31-14-110 centos]# docker stop 465d9c332e13465d9c332e13