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###### DOCKER ###########
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MONOLITHIC: Deploying monolithic applications is more straightforward than
deploying microservices. Developers install the entire application code base and
dependencies in a single environment.
MICRO SERVICES: Microservices are deployed using VM or Containers. Containers are
the preferred deployment route for microservices as containers are lighter,
portable, and modular. The microservice code is packaged into a container image and
deployed as a container service.
multiple services are deployed on multiple servers with multiple databases.
note: if number of application are more will go with microservices concept (docker
and kubernetes)
BASED ON USERS AND APP COMPLEXITY WE NEED TO SELECT THE ARCHITECTURE.
FACTORS AFFECTIONG FOR USING MICRO SERVICES:
FLEXIBLE
COST
MAINTAINANCE
EASY CONTROL
## ----- Docker overview ----------##
Docker is an open platform for developing, shipping, and running applications.
Docker enables you to separate your applications from your infrastructure so you
can deliver software quickly. With Docker, you can manage your infrastructure in
the same ways you manage your applications. By taking advantage of Docker's
methodologies for shipping, testing, and deploying code, you can significantly
reduce the delay between writing code and running it in production.
DOCKER IMAGE:
Docker images are read-only templates that contain instructions for creating a
container. A Docker image is a snapshot or blueprint of the libraries and
dependencies required inside a container for an application to run
CONTAINERS:
A Docker container image is a lightweight, standalone, executable package of
software that includes everything needed to run an application: code, runtime
its same as a server/vm.
operating system independent
(Ec2 server=AMI, CONTAINER=IMAGE)
os will be managed in image
-----docker install process -------
----root------
sudo yum install docker -y # If linux 20203
sudo systemctl start docker
sudo systemctl status docker
Note : By default Docker works with the root user and other users can only access
to Docker with sudo commands. However, we can bypass the sudo commands by creating
a new group with the name docker and add ec2_user.
#First let’s create the docker group
if you install on ec2-user
sudo groupadd docker (optional if group is not created)
#Now let’s add ec2-user to docker group
sudo usermod -a -G docker ec2-user
#In order to enable the changes, run the following command
newgrp docker
sudo chmod 666 /var/run/docker.sock # to give access docker demon to run docker
server
docker --version to check docker version
#If you want to see an extended version of the version details, such as the API
version, Go version, and Engine Version, use the version command without dashes.
give below command
docker version
# ----commands:---- #
---to pull base images from public docker repository
docker pull image <imagename>
docker pull nginx or ubuntu
docker inspect image nginx ### to check images details
docker images # to check list of images
docker run -it imagename /bin/bash --will enter into the container interact
terminal
docker run -dt imagename -we are not enter into the container detach terminal
docker run -dt --name <name> <imagename>
(to give csutome name --name)
docker ps ## to check running containers
docker ps -a ## to check both running and stopped containers
docker ps -a | grep 'Exited' #to check only stopped container
Condition-1----- running container login
## To login container ##
docker exec -it <continername or continerid> /bin/bash # to login running container
1.if you want to come out from container without stop give "ctrl p+q" or exit
(container already running while login time so no impact)
condition-2-------create container from image and login
## To login container ##
docker run -it <imagename> /bin/bash # to create container from image and also
interactive (login mode)
1.if you want to come out from container without stop give "ctrl p+q"
2.if you give "exit" container also will stop
Condition-3-------run container detach mode
docker run -dt <imagename> (detach mode not going to be interacted with container)
After if we want login "docker exec -it <continername or continerid> /bin/bash"
ps -ef --to know how many processors running if it is in vm many process we can
see but it is in container onle few becuase its light weight
ps -ef | wc -l #to know number of processors request running backend
#### how to start container#####
docker start <containerid>
or
docker start <container name>
#### how to stop container#####
docker stop <containerid>
or
docker stop <container name>
## docker kill comeplete terminated
docker kill <containername>
docker pause cont_name : to pause container
docker unpause cont_name: to unpause container
docker inspect cont_name: to get complete info of a container
docker logs <containerid>: to check the logs
## danger commands##
#### deleting process ######
## Images -----
docker rmi <imagename> ##to delete image if image is not tagging to any container
weather it is running or stopped
docker rmi <imageID> -f #forcrfully delete image even respective container weather
it is running or stopped
docker system prune -a to remove all images (if images are tag to stopped
containers)
## container ------
docker rm <containername or containerid> ### to remover stopped container
docker rm -f <container id> delete running and stopped container
docker container prune -- delete all stopped containers
docker rm -f $(docker ps -aq) ---delete all running containers
# --Enabeling port-- #
docker run -p <HOST_PORT>:<CONTAINER:PORT> IMAGE_NAME
docker run -dt -p 3000:3000 --name project-2 ubuntu #along port expose
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-------- pull jenkins----------
docker pull jenkins/jenkins
docker run -dt -p <local host port>:<container run port> --name <name of the
container> <name of the image>
docker run -dt -p 8081:8080 --name jenkins container jenkins/jenkin
access the jenkins with public ip and port number (8081)
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