Category: Docker

Docker compose start container on boot

I have a docker container, that i need to start on server boot.

The docker-compose.yml file i used to create this docker container is

[root@cp03 serverok-rubycms]# cat docker-compose.yml 
version: '3'
services:
  web:
    image: serverok/rubycms:1.0
    command: bash -c "rm -f tmp/pids/server.pid && cd /myapp && source /etc/profile.d/rvm.sh && script/server -e production"
    volumes:
      - /home/naiwnyc/cms:/myapp
    ports:
      - "3000:3000"
[root@cp03 serverok-rubycms]#

With above docker-compose.yml file. i have to start docker container manually after server reboot.

To make it auto start, add the line

    restart: always

Here is the modified docker-compose.yml file.

[root@cp03 serverok-rubycms]# cat docker-compose.yml 
version: '3'
services:
  web:
    image: serverok/rubycms:1.0
    restart: always
    command: bash -c "rm -f tmp/pids/server.pid && cd /myapp && source /etc/profile.d/rvm.sh && script/server -e production"
    volumes:
      - /home/naiwnyc/cms:/myapp
    ports:
      - "3000:3000"
[root@cp03 serverok-rubycms]#

You need to rebuild docker container based on this docker-compose.yml file

Change to the folder where your docker-compse.yml file is, in my case it was

cd  ~/serverok-rubycms

Run

docker-compose down
docker-compose up -d

March 3, 2019

docker-compose: error while loading shared libraries

When running docker-compose on CentOS 7, i get following error

[root@cp03 serverok-rubycms]# docker-compose up 
docker-compose: error while loading shared libraries: libz.so.1: failed to map segment from shared object: Operation not permitted
[root@cp03 serverok-rubycms]#

To fix the error, do the following

mv /usr/local/bin/docker-compose /usr/local/bin/docker-compose-bin

Now create a new file

vi /usr/local/bin/docker-compose

Add following content

#!/bin/bash

export TMPDIR=/opt/compose-tmp
/usr/local/bin/docker-compose-bin "$@"

Make it executable

chmod 755 /usr/local/bin/docker-compose

Create temp folder

mkdir -p /opt/compose-tmp

Now docker-compose will work.

March 3, 2019

Dockerfile

Create Python Flask Docker Container

February 10, 2019
Create Python Flask Docker Container
Create a folder and change to the folder
```
mkdir python-flask
cd python-flask
```
Create file
```
vi Dockerfile
```
Add following content
```
FROM python:2.7-slim

WORKDIR /app
COPY . /app

RUN pip install -r requirements.txt

EXPOSE 8080

CMD ["python", "app.py"]
```
Create file requirements.txt, add “Flask” to it.
```
echo "Flask" > requirments.txt
```
Now lets create our Python Flask Application
```
vi app.py
```
Add following content
```
from flask import Flask
import os
import socket

app = Flask(__name__)

@app.route("/")
def hello():
	return  "Ok, World"

if __name__ == "__main__":
	app.run(host="0.0.0.0", port=8080)	
```
To test Flask application locally, install Flask using pip
```
sudo pip install Flask
```
Now run the application using
```
python app.py
```
Now you will be able to see web application at
```
http://localhost:8080
```
Press CTRL+C to stop the application.

To build Docker image, run
```
docker build -t python-flask-app .
```
-t specify tag.

If all worked properly, you will see

You can see the container image listed
```
docker images
```
Now your docker image is ready. To build a container using this image, run
```
docker container run -d --name my-flask-app -p 8080:8080 python-flask-app
```
You can access your python application running inside docker container on URL
```
http://localhost:8080
```
To stop the application, run
```
docker stop my-flask-app
```
To start it, run
```
docker start my-flask-app
```
February 10, 2019
Create Kubernetes cluser using gcloud
Login to gcloud with
```
gcloud auth login
```
Set default region
```
gcloud config set compute/zone us-central1-a
```
To create a cluser, run
```
gcloud container clusters create CLUSTER-NAME
```
To create a cluster with 2 nodes, run
```
gcloud container clusters create CLUSTER-NAME --num-nodes 2
```
To specify compute engine type during cluster creation, run
```
gcloud container clusters create CLUSTER-NAME --num-nodes 2 --machine-type n1-standard-2
```
You can also specify scopes, this allow you to give the cluster permission to access other google cloud resources. For example to allow cluster access Cloud Source Repositories and Google Container Registry. run
```
gcloud container clusters create CLUSTER-NAME --num-nodes 2 --machine-type n1-standard-2 --scopes "https://www.googleapis.com/auth/projecthosting,cloud-platform"
```
To list your container, run
```
gcloud container clusters list
```
Before you can use cluser, you need to get authentication credentials with command
```
gcloud container clusters get-credentials CLUSTER-NAME
```
To interact with Kubernetes, you need kubectl, on Ubuntu, yu can install it with
```
sudo snap install kubectl --classic
```
To deploy a container, run
```
kubectl run hello-server --image=gcr.io/google-samples/hello-app:1.0 --port 8080
```
This will deploy google provided hello-app container to the cluser.

To make the application available to public, create a loadbalancer service.
```
kubectl expose deployment hello-server --type="LoadBalancer"
```
Now find IP of the LoadBalacner service with command
```
kubectl get services
```
From the result, we found EXTERNAL-IP for LoadBalancer is 35.232.226.216. To access the application, go to url

http://35.232.226.216:8080

See Kubernetes
February 10, 2019
Docker container start on boot
To set a docker container to start on system reboot, run
```
docker update --restart=unless-stopped CONTAINER_ID
```
Replace CONTAINER_ID with actual ID of your container.

You can specify
```
--restart=unless-stopped
```
On creating docker container, for example
```
docker run -d -p 80:80 --restart=unless-stopped nginx
```
January 2, 2019
Docker Nginx Proxy
Docker Nginx Proxy allow you to run multiple docker containers on same server behind nginx proxy. This is done using

https://github.com/jwilder/nginx-proxy

To do this, you need a server with port 80 and 443 unused.

To setup nginx proxy, run following
```
cd /root/
git clone https://github.com/evertramos/docker-compose-letsencrypt-nginx-proxy-companion.git
cd docker-compose-letsencrypt-nginx-proxy-companion
cp .env.sample .env
./start.sh
```
This will start nginx proxy. You can modify .env file if you want.

Starting a Docker Web App Behind Proxy

To start a web app, all you need is to start docker container on same network as nginx proxy. By default it is “webproxy”.

Here is an example command to start a web server.
```
docker run -d 
    -e VIRTUAL_HOST=test.serverok.in \
    -e LETSENCRYPT_HOST=test.serverok.in \
    -e LETSENCRYPT_EMAIL=admin@serverok.in \
    --network=webproxy \
    --name my_app \
    httpd:alpine
```
This will start a test web server. You need to point the domain specified to this servers IP, then only nginx proxy can get LetsEncrypt SSL installed.

Replace test.serverok.in with your actual domain.

If you don’t want LetsEncrypt SSL installed, you can remove following 2 options
```
    -e LETSENCRYPT_HOST=test.serverok.in \
    -e LETSENCRYPT_EMAIL=admin@serverok.in \
```
December 23, 2018
Docker Build
Build a docker container with Apache

docker build command is used to create a docker image from Dockerfile.

To create an image, first lets create a working directory and change to the directory.
```
mkdir ~/my-docker-image
cd ~/my-docker-image
```
Create a file with name Dockerfile
```
vi Dockerfile
```
Put following content in it
```
FROM ubuntu:18.04

RUN apt update && apt upgrade -y

CMD ["/bin/bash"]
```
Now build the docker image with
```
docker build -t my-ubuntu .
```
This will create a docker image with name “my-ubuntu”.

To run this, we need to create a container using this image, this can be done with command
```
docker run -ti my-ubuntu
```
Here i used -ti as we need to run interactively using terminal, this is because our the command we set to start is “/bin/bash” in the Dockerfile.

Docker
May 4, 2018
Installing Docker on Ubuntu 16.04
To install docker on Ubuntu 16.04, run
```
wget -qO- https://get.docker.com/ | sh
```
To run docker commands as your user, run
```
usermod -aG docker your-user
```
Docker
March 10, 2018

docker search

docker search command allows you to search for images in docker hub.

Example

root@ok:~# docker search nginx
NAME                                                   DESCRIPTION                                     STARS               OFFICIAL            AUTOMATED
nginx                                                  Official build of Nginx.                        8043                [OK]                
jwilder/nginx-proxy                                    Automated Nginx reverse proxy for docker con…   1284                                    [OK]
richarvey/nginx-php-fpm                                Container running Nginx + PHP-FPM capable of…   526                                     [OK]
jrcs/letsencrypt-nginx-proxy-companion                 LetsEncrypt container to use with nginx as p…   320                                     [OK]
kong                                                   Open-source Microservice & API Management la…   160                 [OK]                
webdevops/php-nginx                                    Nginx with PHP-FPM                              97                                      [OK]
kitematic/hello-world-nginx                            A light-weight nginx container that demonstr…   95                                      
bitnami/nginx                                          Bitnami nginx Docker Image                      44                                      [OK]
linuxserver/nginx                                      An Nginx container, brought to you by LinuxS…   33                                      
1and1internet/ubuntu-16-nginx-php-phpmyadmin-mysql-5   ubuntu-16-nginx-php-phpmyadmin-mysql-5          26                                      [OK]
tobi312/rpi-nginx                                      NGINX on Raspberry Pi / armhf                   18                                      [OK]
wodby/drupal-nginx                                     Nginx for Drupal container image                9                                       [OK]
webdevops/nginx                                        Nginx container                                 8                                       [OK]
blacklabelops/nginx                                    Dockerized Nginx Reverse Proxy Server.          8                                       [OK]
nginxdemos/nginx-ingress                               NGINX Ingress Controller for Kubernetes         8                                       
centos/nginx-18-centos7                                Platform for running nginx 1.8 or building n…   6                                       
nginxdemos/hello                                       NGINX webserver that serves a simple page co…   4                                       [OK]
1science/nginx                                         Nginx Docker images that include Consul Temp…   4                                       [OK]
behance/docker-nginx                                   Provides base OS, patches and stable nginx f…   2                                       [OK]
pebbletech/nginx-proxy                                 nginx-proxy sets up a container running ngin…   2                                       [OK]
toccoag/openshift-nginx                                Nginx reverse proxy for Nice running on same…   1                                       [OK]
travix/nginx                                           NGinx reverse proxy                             1                                       [OK]
mailu/nginx                                            Mailu nginx frontend                            0                                       [OK]
goodguide/nginx-application-proxy                      No-configuration Nginx reverse proxy for a R…   0                                       [OK]
ppc64le/nginx                                          Official build of Nginx.                        0                                       
root@ok:~#

To see results with 4 or more stars, use

docker search --filter stars=4

docker

March 3, 2018

Docker Login

docker login command allows you to login to docker.com. You need to login to docker before you can upload your own images to docker hub. This is also needed if you need to pull down a private image.

root@ok:~# 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: serverok
Password: 
Login Succeeded
root@ok:~#

if you need to login to a different docker registery, for example your company docker registery, use

docker login IP_OR_HOST_OF_DOCKER_REGISTRY:PORT

To log off, use

docker logout

docker logout IP_OR_HOST_OF_DOCKER_REGISTRY:PORT

docker

March 3, 2018

portainer – Web based UI for Docker
Portainer is a web based UI for managing docker.

https://portainer.io/

You can run it with command
```
docker volume create portainer_data
docker run -d -p 8000:8000 -p 9000:9000 --name=portainer --restart=always -v /var/run/docker.sock:/var/run/docker.sock -v portainer_data:/data portainer/portainer-ce
```
Now login to portainer with url

http://YOUR_SERVER_IP:9000

docker
February 27, 2018

Category: Docker

Ok, World