docker – python design

October 18, 2021December 21, 2021

How to install Docker and pull Nagios image on RHEL 7

Step 1. remove old version and install latest Docker
sudo yum remove docker docker-common docker-selinux docker-engine
sudo yum-config-manager –add-repo https://download.docker.com/linux/centos/docker-ce.repo
sudo yum install docker-ce

If you got: Docker Error – Requires: container-selinux >= 2:2.74
Solution:
Go to http://mirror.centos.org/centos/7/extras/x86_64/Packages/
Find the latest version for container-selinux i.e. container-selinux-2.21-1.el7.noarch.rpm
Run the following command on your terminal: $
sudo yum install -y yum install http://mirror.centos.org/centos/7/extras/x86_64/Packages/container-selinux-2.107-1.el7_6.noarch.rpm
yum install -y yum install http://mirror.centos.org/centos/7/extras/x86_64/Packages/fuse3-libs-3.6.1-4.el7.x86_64.rpm
yum install -y yum install http://mirror.centos.org/centos/7/extras/x86_64/Packages/fuse-overlayfs-0.7.2-6.el7_8.x86_64.rpm

Step 2. enable docker service and start it
$ sudo systemctl enable docker.service
$ sudo systemctl start docker.service ## <-- Start docker ##
$ sudo systemctl stop docker.service ## <-- Stop docker ##
$ sudo systemctl restart docker.service ## <-- Restart docker ##
$ sudo systemctl status docker.service ## <-- Get status of docker ##
$ ip a list docker0
$ docker run hello-world ## <– test your docker installation

Step 3. Get Nagios from https://hub.docker.com/r/jasonrivers/nagios/
docker pull jasonrivers/nagios:latest
docker run –name nagios4 -p 0.0.0.0:8080:80 jasonrivers/nagios:latest
The default credentials for the web interface is nagiosadmin / nagios
alternatively you can use external Nagios configuration & log data with the following:

docker run --name nagios4  \
  -v /path-to-nagios/etc/:/opt/nagios/etc/ \
  -v /path-to-nagios/var:/opt/nagios/var/ \
  -v /path-to-custom-plugins:/opt/Custom-Nagios-Plugins \
  -v /path-to-nagiosgraph-var:/opt/nagiosgraph/var \
  -v /path-to-nagiosgraph-etc:/opt/nagiosgraph/etc \
  -p 0.0.0.0:8080:80 jasonrivers/nagios:latest

You can open it with http://your_server_ip:8080

Extra Plugins:
Nagios nrpe [http://exchange.nagios.org/directory/Addons/Monitoring-Agents/NRPE–2D-Nagios-Remote-Plugin-Executor/details]
Nagiosgraph [http://exchange.nagios.org/directory/Addons/Graphing-and-Trending/nagiosgraph/details]
JR-Nagios-Plugins – custom plugins I’ve created [https://github.com/JasonRivers/nagios-plugins]
WL-Nagios-Plugins – custom plugins from William Leibzon [https://github.com/willixix/WL-NagiosPlugins]
JE-Nagios-Plugins – custom plugins from Justin Ellison [https://github.com/justintime/nagios-plugins]

Step 4. How to edit file and restart nagios inside Docker
docker stop $(docker ps -a -q)
docker rm $(docker ps -a -q)
docker run –name nagios4 -v /root/nagios/etc/:/opt/nagios/etc/ -v /root/nagios/apache2/:/etc/apache2/ -p 0.0.0.0:8080:80 -it -d jasonrivers/nagios:latest

restart nagios inside Docker:
docker exec nagios4 rm etc/service/nagios
docker exec nagios4 ln -s /etc/sv/nagios /etc/service

July 10, 2020

push docker-compose images to Docker Hub

root@ubunu2004:~# docker-compose build
website uses an image, skipping
Building product-service
Step 1/3 : FROM python:3-onbuild
Executing 3 build triggers
—> Using cache
—> Using cache
—> b54600ebce6f
Step 2/3 : COPY . /usr/src/app
—> e49923648a44
Step 3/3 : CMD ["python", "api.py"]
—> Running in 3314ea5a2d0c
Removing intermediate container 3314ea5a2d0c
—> fc3e3c31fadc
Successfully built fc3e3c31fadc
Successfully tagged root_product-service:latest

root@ubunu2004:~# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
root_product-service latest fc3e3c31fadc 31 seconds ago 701MB
root@ubunu2004:~# docker tag root_product-service:latest zhuby1973/product-service:1
root@ubunu2004:~# docker push zhuby1973/product-service:1

July 10, 2020July 10, 2020

Docker compose tutorial

install docker-compose
apt install docker-compose

create two dir: Product and website and files as below:
root@ubunu2004:~/tmp# tree
.
├── docker-compose.yml
├── Product
│   ├── api.py
│   ├── Dockerfile
│   └── requirements.txt
└── website
└── index.php

root@ubunu2004:~/Product# cat api.py
from flask import Flask
from flask_restful import Resource, Api
app = Flask(__name__)
api = Api(app)
class Product(Resource):
def get(self):
    return {
        'products': ['Ice cream',
                    'Chocolate',
                    'Eggs',
                    'Fruit']
    }
api.add_resource(Product, '/')
if __name__ == '__main__':
app.run(host='0.0.0.0', port=80, debug=True)
root@ubunu2004:~/Product# cat requirements.txt
Flask==0.12
flask-restful==0.3.5
root@ubunu2004:~/Product# cat Dockerfile
FROM python:3-onbuild
COPY . /usr/src/app
CMD ["python", "api.py"]

root@ubunu2004:~/tmp/website# cat index.php
<html>
<head>
    <title>My Shop</title>
</head>

<body>
    <h1>Welcome to my shop</h1>
    <ul>
        <?php
            $json = file_get_contents('http://product-service');
            $obj = json_decode($json);
            $products = $obj->products;
            foreach ($products as $product) {
                echo "<li>$product</li>";
            }
        ?>
    </ul>
</body>
</html>

create docker-compose.yml:

version: '3'
services:
product-service:
build: ./Product
volumes:
  - ./Product:/usr/src/app
ports:
  - 5001:80
website:
image: php:apache
volumes:
  - ./website:/var/www/html
ports:
  - 5000:80
depends_on:
  - product-service

then we can start it:
docker-compose up
or start/stop as daemon:
root@ubunu2004:~# docker-compose up -d
Starting root_product-service_1 … done
Starting root_website_1 … done
root@ubunu2004:~# docker-compose stop
Stopping root_website_1 … done
Stopping root_product-service_1 … done

verify the app on http://192.168.0.43:5000/

July 10, 2020July 10, 2020

Docker images and container cleanup

Stop and remove all containers:
docker stop $(docker ps -a -q)
docker rm $(docker ps -a -q)
Remove containers according to a pattern:
docker ps -a | grep "pattern" | awk ‘{print $3}’ | xargs docker rmi
Remove one or more specific images:
docker rmi Image Image
Purging All Unused or Dangling Images, Containers, Volumes, and Networks
docker system prune -a
REF:
https://www.digitalocean.com/community/tutorials/how-to-remove-docker-images-containers-and-volumes

pull and start an image:
docker pull zhuby1973/php:1
docker run -p 82:80 zhuby1973/php:1
you can run it as daemon with -d option:
docker run -d -p 82:80 zhuby1973/php:1

July 10, 2020July 10, 2020

build a container with php/apache

we can search php and apache image on Docker Hub, we will use php:7.0-apache for this demo.

create Dockerfile and src/index.php as below

root@ubunu2004:~/docker_sample# tree
.
├── Dockerfile
└── src
└── index.php
1 directory, 2 files
root@ubunu2004:~/docker_sample# cat  Dockerfile
FROM php:7.0-apache
COPY src/ /var/www/html
EXPOSE 80
root@ubunu2004:~/docker_sample# cat src/index.php
<?php
echo "Hello World!";

build the container
docker build -t hello_world .
run the container
docker run -p 82:80 hello_world
then you can verify it on http://192.168.0.43:82/
if you want mapping the index.php to container, you can start it with
docker run -p 82:80 -v /root/docker_sample/src/:/var/www/html/ hello_world
now if you update index.php, you will get the change immediately on http://192.168.0.43:82/
you can push this image to Docker Hub
root@ubunu2004:~/docker_sample# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
hello_world latest dc8c649d4e8b 19 minutes ago 368MB
root@ubunu2004:~/docker_sample# docker run -it -d hello_world:latest
root@ubunu2004:~/docker_sample# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
d2963444e718 hello_world:latest "docker-php-entrypoi…" 10 seconds ago Up 6 seconds 80/tcp laughing_williamson
root@ubunu2004:~/docker_sample# docker commit d2963444e718 zhuby1973/php:1
sha256:1f2007f4786c344c8007b574af6f71b7604431c6d6cce0e2091e6adf1a8c8621
root@ubunu2004:~/docker_sample# docker push zhuby1973/php:1

July 10, 2020July 10, 2020

commit and push a docker image to Docker Hub

sign up on Docker Hub to get your user id and password
pull a image from Docker Hub
docker pull ubuntu

make a dir on ubuntu image and commit/push image

docker images
docker run -it -d ubuntu
docker ps -a
root@ubunu2004:~# docker exec -it 6e08ac7cc702 bash
root@6e08ac7cc702:/# mkdir /test_dir
root@6e08ac7cc702:/# exit
exit
docker commit 6e08ac7cc702 zhuby1973/ubuntu:1
root@ubunu2004:~# docker login
Login with your Docker ID to push and pull images from Docker Hub. If you don't have a Docker ID, head over to https://hub.docker.com to create one.
Username: zhuby1973
Password:
WARNING! Your password will be stored unencrypted in /root/.docker/config.json.
Configure a credential helper to remove this warning. See
https://docs.docker.com/engine/reference/commandline/login/#credentials-store
Login Succeeded
root@ubunu2004:~# docker push zhuby1973/ubuntu:1
The push refers to repository [docker.io/zhuby1973/ubuntu]
d3d28de77691: Pushed
544a70a875fc: Mounted from library/ubuntu
cf0f3facc4a3: Mounted from library/ubuntu
132bcd1e0eb5: Mounted from library/ubuntu
d22cfd6a8b16: Mounted from library/ubuntu
2: digest: sha256:4c50ab7b0f8cadd72f5d37a569795a4ba697be892fca1b36a96eb9aa49a59d2e size: 1359

logon https://hub.docker.com/repositories you will find zhuby1973/ubuntu already there!

you can start this container to verify


root@ubunu2004:~# docker run -it -d zhuby1973/ubuntu:1
e5477e45b6b2bfe330e9f37a6f74e90964ef887f0f0a37ae23bbae4319a465a1
root@ubunu2004:~# docker ps
CONTAINER ID        IMAGE                COMMAND             CREATED             STATUS              PORTS               NAMES
e5477e45b6b2        zhuby1973/ubuntu:1   "/bin/bash"         26 seconds ago      Up 24 seconds                           vigilant_satoshi
df78087a8ef1        zhuby1973/test:2     "/bin/bash"         17 minutes ago      Up 17 minutes                           charming_wiles
6e08ac7cc702        ubuntu               "/bin/bash"         32 minutes ago      Up 32 minutes                           charming_goodall
root@ubunu2004:~# docker exec -it e5477e45b6b2 bash
root@e5477e45b6b2:/# ls -ltr /test-dir
total 0

July 9, 2020July 10, 2020

install Docker on Ubuntu and setup CONTAINER openspug/spug

install Docker on Ubuntu
sudo apt-get update
sudo apt install docker.io
sudo systemctl start docker
sudo systemctl enable docker
docker –version
setup openspug/spug container
openspug/spug is a small server manage tool developed with python!
https://github.com/openspug/spug
sudo docker pull openspug/spug
sudo docker run -d -p 80:80 openspug/spug
if port 80 already in use, you can find the process by:
sudo lsof -i:80
in our case it’s apache, stop it with:
sudo systemctl stop apache2

sudo docker ps to get running container details:

(base) ubuntu@ubunu2004:/$ sudo docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS                NAMES
c493cbf6aceb        openspug/spug       "/entrypoint.sh"    4 minutes ago       Up 4 minutes        0.0.0.0:80->80/tcp   determined_allen

initial and restart the spug:
export CONTAINER_ID=c493cbf6aceb
sudo docker exec $CONTAINER_ID init_spug admin spug.dev
sudo docker restart $CONTAINER_ID

then you can login http://192.168.0.43/ with:
user: admin
password: spug.dev