Docker Tasks
What I need before
I am using github codesapce as a server to implement docker tasks.
In this codespace I installed docker and python.
1.Dockerfile to run a Python Flask application inside a container.
mkdir app
sudo nano app.py
sudo nano requirementes.txt
sudo nano Dockerfile
Add port 5000 in your codespace and make it public
docker build -t flask-app . (to build dockerfile to create docker image)
docker images (to verify docker image is created or not)
docker run -d -p 5000:5000 flask-app (to run a container)
Now your application is running on 5000 port as a container in a browser.
2.Dockerfile for Node.js Application
Install nodejs on your codespace
sudo nano server.js
sudo nano package.json
sudo nano package-lock.json
sudo nano Dockerfile
Add port 3000 on your codespace and make it public
docker build -t node-app . (to build dockerfile to create docker image)
docker images (to verify docker image is created or not)
docker run -d -p 5000:5000 node-app (to run a container)
Now your application is running on 3000 port as a container in a browser.
3.Dockerfile for Nginx Web Server
mkdir website
sudo nano index.html
sudo nano Dockerfile
docker build -t nginx-app .
docker images
docker run -d -p 80:80 nginx-app
Add port 80 in a github codespace
Now your application is running on 80 port as a container in a browser.
4.Dockerfile for Java Spring Boot Application
make sure jdk and maven is installed in your codespace.
sudo nano app.java
sudo nano pom.xml
maven clean package (to build using maven to create .jar file)
ls (Now you can see .jar file is there in your current directory)
sudo nano Dockerfile
docker build -t java-app . (to build dockerfile to create docker image)
docker images (to verify docker image is created or not)
docker run -d -p 8080:8080 java-app (to run a container)
Add port 8080 in your codespace and make it public
Now your application is running on 8080 port as a container in a browser.
5.Dockerfile for MySQL Database
make sure you have installed docker compose on your codespace.
sudo nano docker-compose.yml
docker-compose up -d (to run mysql db as a container 3306 port)
Add port 3306 in your codesapce and make it public.
docker ps (you can see your mysql is running on 3306 port as a container)
docker exec -it 74c1 sh (to enter inside a container)
sudo mysql -u root -p (to login mysql as root. password:root)
SHOW DATABASES; (to view your databases)
docker-compose down (to remove container)
6.container backup and retreive
Create one container by pulling latest httpd form dockerhub
docker run -d -p 80:80 httpd
add 80 port visible on your codespace
docker ps (to check container in running)
check also in browser.
create image from above container
docker commit <container_id> <image_name>
docker images(to verify images is created)
take backup of above image
docker save -o backup.tar <image_name>
ls (to verify backup is created)
Now delete your running container
Now we want to retreive that container using backup file
docker load -i <backup file name>
create container using above image
docker run -d -p 80:80 ananth:v1.0
docker ps(to verify)
check git and nano are installed inside the container
docker exec -it <container_id> /bin/bash
7.Sync docker container with local folder
mkdir -p /opt/ananth (create one folder
in your local)
sudo chmod 777 /opt/ananth (give permissions so that
container canaccess)
docker run -d -p 80:80 -v "/root/ananth:/usr/local/apache2" httpd (mount your path while
run a container)
Add port 80 and check browser
docker exec -it <container_id> /bin/bash (go inside a container)
ls (now you are inside this directory by default-->/usr/local/apache2
touch file1 file2
exit
cd /opt/ananth
ls (now you can see both file1 and file2 are inside this directory also)
8.Create docker volume and mount inside a container
docker volume create ananth
docker volume ls (to check whether it is created or not)
docker run -d --mount source=ananth,target=/usr/local/apache2 -p 80:80 httpd
docker exec -it <container_id> /bin/bash
ls (now you are inside this directory by default-->/usr/local/apache2
touch file3 file4
exit
sudo su -
cd /var/lib/docker/volumes/ananth/_data
ls (Now you can view both files are in this )
docker volume rm <volume_name> (to delete volume)
docker inspect <volume_name>
8.Dockerfile form installing openssh inside a container and
access it directly using putty
sudo nano Dockerfile
docker build -t ssh-container . (build dockerfile to create image)
docker images
docker run -d --name my_ssh_container -p 2223:22 ssh-container
hostname -i (fetch your ip)
Now you can login putty using above ip, port 2222.
username and password: root passwd
9.give read-only access to a log file inside a Docker container
Mount the Log File as Read-Only
mkdir -p /opt/log/app.log
docker run -d -p 80:80 -v "/opt/ananth/app.log:/var/log/app.log:ro" httpd
docker exec -it <container_id> /bin/bash
cd /var/log/app.log
mkdir folder1 (try to create folder. you can't do that)
Change File Permissions Inside the Container
docker run -d -p 80:80 httpd
docker exec -it my_container /bin/sh
chmod 444 /var/log/app.log (file readable but not writable)
ls -l /var/log/app.log (to view the permiossons)
10.Docker networks
Docker networking allows containers to communicate with each other, the host, and the
internet.
1.bridge(default)- Containers can communicate on the same bridge network but are isolated
from others.
2.host-Removes network isolation; the container shares the host's network.
3.none-Completely disables networking for the container.
you can create custom network also.
Bydefault you can't ping other containers inside a container using hostname.
But in custom network you can able to ping other containers inside a container using hostname.
docker network create mynetwork
docker network ls
docker run -d --name mynginx --network mynetwork
docker run -d --name myapache --network mynetwork
docker ps
docker exec -it <container_id> /bin/bash
install ping using apt install -y inetutils-ping
ping <hostname>
