# Docker

### Basic Commands

```dockerfile
sudo docker images										# to know the docker image in current machine
sudo docker search httpd								# to get the list of available docker image in docker hub
sudo docker pull Imagepath		  						# latest tag will be pulled/download fron docker hub
sudo docker push Imagepath:version 						# to upload the image to dockerhub under username/appname:version 
sudo  docker run -d -it --name Myhttp -p 81:80 httpd  	# to run the images to get container
sudo docker build . -t myweb:v1							# to build image using alias tags
sudo docker exec it ubuntu1 /bin/bash					# to login container
sudo  docker ps -a   									# to check the image status
sudo docker inspect Imagepath 							# to check the port used in image for port forwarding 
grep -A 10 Config										# to filter results
sudo docker history										# to get history of commands
sudo docker save image Id > snapshot.tar				# backup or snapshot 
scp snapshot.tar username@remotemachine:path			# to pull image from other server


sudo docker images
sudo docker stop container_names						# to stop containers
sudo docker rm  container_name 							# to remove container  
sudo docker rmi	image_name								# to remove images ( container need to remove before remove images)
sudo docker commit docker Image_id Custom_name:tag		# to convert the container to image
sudo docker login 										# login dockerhub
sudo docker login sunil.aws.com							# Custom repository login
Sudo docker info										# to get information about docker
sudo docker logs										# to get logs
```

### Docker file Format (image file)

```dockerfile
FROM ubuntu:latest 
LABEL                                #( TO NAME AND alisa the environment ) 
EXPOSE 80 443                        # (define container port listen)
copy index.html /var/www/html/       # To copy index file to publish
```

Note : Command ADD (copy and extract tar file from source to destination), COPY (copy tar to destination location)

```dockerfile
RUN sudo apt-get update                                     # (RUN to run any command on top of image )
RUN sudo apt-get in-y apache2
RUN sudo apt-get update && sudo apt-get install -y apache2  # run in single layer will reduce size)
CMD apachectl -D FOREGROUND                                 # systemctl commad will not work here
CMD ping google.com
ENTRYPOINT ping google.com                                  # SAME HAS CMD but it cant be override during excution

VOLUME /PATH 	                                        	# MOUNT VOLUME
USER USERNAME		                                        # SELECT USER (DEFAULT WILL USE ROOT ) 
WORKDIR	/app		                                        # WORKING DIRECTORY 
ENV 			                                            # ENVIRONMENT VARIABLE COMPUTER
ARG			                                                # ENVIRONMENT VARIABLE USER DURING BUILD USED NOT IN CONTAINER
```

### Docker Orchestration - Docker Swarn

```dockerfile
sudo docker install swarm master
sudo docker init--advertise-addr Masternode_IP
sudo docker node ls 

docker service 																# Container called here has service
sudo docker service create --replicas 2 -p 80:8043 --name web1 imagename
sudo docker service ls  													# to list the service 
sudo docker service ps web1  												# to check the service running nodes
sudo docker service create --mode global -p 81:8044 --name testweb1 imagename  # to run the container with max replicas( max node available)
sudo docker service scale web1=5											# scale up to  5 replicate
sudo docker service scale web1=2  											# scale down to  2 replicate
sudo dcker network  create -d overlay newoverlay

sudo docker service update --image httpd:latest web1
sudo docker service rollback web1
sudo docker node update --availablity drain nodename 						# maintenanace mode
sudo docker node update --availablity pause nodename  						# drs will not migrate container to this node
sudo docker node update --availablity active nodename 

Docker compose  															# to run multi container
sudo apt-cache search docker-compose  										# to install  docker composr version
sudo docker-compose -f myapp.yaml config 									# to check the configuartion issue
sudo docker-compose -f myapp.yaml up -d 									# to run the compose
sudo docker-compose -f myapp.yaml images 									# to check images related to compose file 
```