Difference between revisions of "Docker Notes"
 
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> docker-compose -p challenge -f docker-compose-httpd.yml up -d --scale web=3 #it starts 3 instances
 
> docker-compose -p challenge -f docker-compose-httpd.yml up -d --scale web=3 #it starts 3 instances
 
> docker ps
 
> docker ps
 +
 +
 +
 +
=helpfull Docker-Compose Features=
 +
 +
> docker-compose pull #updates images defined in a docker-compose file.
 +
> docker-compose restart #..
 +
> docker-compose pause
 +
> docker-compose unpause
 +
> docker-compose start / stop
 +
 +
> docker-compose -h #shows available commands
 +
> docker -h #shows available commands
 +
 +
> docker-compose top
 +
> docker-compose logs -f
 +
> docker-compose logs -f httpd
 +
 +
> docker events
 +
> docker-compose events
 +
 +
> docker-compose rm
 +
> docker-compose ls
 +
 +
=docker hub / registry=
 +
Standard syntax : <registry>/<namespace>/<repo-name>:<tag>
 +
i.e.: docker.io/library/openjdk:8-jdk
 +
 +
> docker login docker.io #to login docker hub #picks up / pull images from dockerhub
 +
> docker tag alpine:edge rasimsen/alpine:5mb-linux #tag local images to push dockerhub
 +
> docker push rasimsen/alpine:5mb-linux # it has been sent to dockerhub, check from hub.docker.com
 +
 +
> docker logout #to logout
 +
 +
=docker hub registry alternatives =
 +
* self-hosted alternatives
 +
  ** Generic private docker registry
 +
  ** Portus
 +
* Other hosted alternatives
 +
  ** Quay.oi
 +
  ** Azure container registry
 +
  ** Amazon elastic container registry
 +
  ** Google container registry
 +
  ** Private docker registry
 +
  ** Artifactory
 +
 +
=Docker Swarm=
 +
Essentially it is a cluster of docker hosts that work together to deploy containers
 +
 +
The coordination involved  between the docker hosts is most often referred to as orchestration
 +
 +
  
 
=usefull containers=
 
=usefull containers=

Latest revision as of 09:38, 13 October 2018

Building && Running APP

docker-container

  > mkdir nginx-webapp
  > cd nginx-webapp
  > vi webapp.html
  > <html><body>...first app..</body></html>
  > vi nginx.conf #server conf file..
server{
   root /www;
}
  > vi Dockerfile  # dockerfile is blueprint of our image 
FROM nginx:latest #or version

ADD webapp.html /www/
ADD nginx.conf /etc/nginx/conf.d/default.conf

#EXPOSE 80
#EXPOSE 443

#CMD nginx -g "deamon off;" #to start nginx server

to start & test 

>docker build . -t webapp-oasis:latest
>docker run webapp-oasis
>docker ps #to see docker running images..

to run as a background process 

>docker run -d -p 84:80 webapp-oasis:latest #docker [deamon(background process)] [port] [hostport]:[containerport] [docker-image]:version

to test go to container ip address, and test: 

http://192.168.1.153:84/webapp.html

accessing to container shell 

> docker run -it ubuntu:latest /bin/bash (enter) 
> [ubuntu@shell] > 

> exit (to exit)

you can use all linux commands..

to remove interactive image: 

> docker run -it --rm ubuntu:latest /bin/bash (enter) 
> exit (to exit)

to see the running ubuntu process: 

> docker ps -a | grep ubuntu

accessing to container shell - 2 

> docker run -it ubuntu:latest /bin/sh (enter) 
> [ubuntu@shell] > whoami

> exit (to exit)

accessing to running container shell 

> docker ps #list process and pick up one 
> docker exec -it my_http /bin/bash
> docker ls

> exit (to exit)

to run php from docker image.. 

> docker run -it --rm php:latest /bin/bash #if exist, remove first..

run a php script mounted in the container using the volume option 

> docker run -it --rm -v "$(pwd)/challenge.php:/home/challenge.php" php:latest /bin/bash
> docker run -it --rm [mount] "$(pwd)/[source_file]:[target_address]" php:latest /bin/bash

installing software to a Docker Image... 

> vi Dockerfile
FROM ubuntu:latest

# apt-get update : checks program updates
# apt-get install -y : ask yes/no for installation for new update
# --no-install-recommends vim : don't install lib update for vim
RUN apt-get update && apt-get install -y --no-install-recommends vim &&  apt-get clean

(save & exit)
> docker built . -t ubuntu-vim # it updates ubuntu and install vim.. 
> docker images
> docker run -it --rm ubuntu-vim /bin/bash  # run

access container console logs .. 

> docker logs -h # shows log options
> docker logs -f --tail 10 readmine

to see apache logs.. 

> docker run -d -p httpd
> docker ps
> docker logs -f xxxxxxx_images

docker container healthcheck 

> CURL -I "http://localhost:8080" # it show header info about address
> CURL -I -f "http://localhost:8080"
> CURL -I "http://localhost:8080" || exit 1

#how to check in docker image
> vi Dockerfile
FROM httpd:latest

RUN apt-get update && apt-get install -y --no-install-recommends curl &&  apt-get clean

EXPOSE 80

# --interval=15s : every 15s check
# --retries=5 : if fail, 5 times retry
# --start-period=30s : when server run, 30s later start to check
# CMD : run that commands after CMD
HEALTHCHECK --interval=15s --retries=5 --timeout=30s --start-period=30s CMD curl -I -f "http://localhost:80" || exit 1

(save & exit)

> docker built . -t httpd-oasis

#docker run -d -p --name [new-image-alias] [docker-image] 
> docker run -d -p --name http-my-oasis http-oasis 

> docker ps #we will see healtcheck..

> docker logs -f httpd-my-oasis #to see the logs..


linking docker containers... 

> docker run -d --name resuse-httpd httpd

# docker run -it --link "[container-name or id]:[alias]" php-apache-wget /bin/bash
> docker run -it --link "reuse-httpd:web" php-apache-wget /bin/bash

> wget "http://web:80"
> cat index.html

create a MySql(mysql) container linked to a phpMyAdmin(adminer) container 

> docker run --name our-mysql -e MYSQL_ROOT_PASSWORD=password -d mysql:latest # for details, go to docker mysql pages..

> docker run --link "our-mysql:db" -p 8080:8080 adminer

# goto browser
http://192.168.1.34:8080


docker-compose

docker compose :

install docker compose .. > docker-compose -v > ls

> vi docker-compose.yml version '3.1'

  1. services: containers

services : 

 tomcat1:
   #dockercomp_tomcat1
   image:tomcat:lates
   ports:
     - 1002:80
     - 1003:8080
     - 1013:8080

 tomcat2:
   #dockercomp_tomcat2
       image:tomcat:lates
       ports:
         - 1002:80
         - 1003:8080
         - 1013:8080

environment: 

 TEST_ENV_VAR: test1234
  1. save & exit

> docker-compose up (enter) > docker ps #you see all images up

> docker exec -it dockercomp_tomcat2_1 /bin/bash

  1. to test environmentvariable

> echo $TEST_ENV_VAR #you'll see result

mysql && phpmyadmin with docker-compose.yml

> vi docker-compose.yml version '3.1' services: 

 db:
   image:mysql:latest
   restart:always
   environment:
     MYSQL_ROOT_PASSWORD:password
 adminer:
   image:adminer:latest
   restart:always
   ports:
     -8080:8080

(save&&exit)

> docker-compose up -d #background process > docker ps

check it via browser ..

docker networks : - all of the containers easily communicate with each other - networks communicate with IP's

> docker network ls # to see networks , bridge means : isolated networks

> docker network create --help

> \docker network create oasis_test_network > docker network ls > docker network prune #to remove unused networks > docker ps

lets create a network

> docker run -d nginx > docker-machine ssh default > vi docker-compose.yml db: 

 image:mysql:latest
 restart:always
 environment:
   MYSQL_ROOT_PASSWORD:password
 networks:
     -backend

adminer: 

 image:adminer:latest
 restart:always
 ports:
   -8080:8080
 networks:
   -frontend

networks: 

 frontend: #ıf you dont give anything, it will be bridge
   driver:bridge
 backend:
   driver:bridge

 default:
   name:oasis_test_network1

(save&exit)

> docker-compose down #stop first >docker-compose up

to use specific network

> docker network connect -h #for help > docker network connect [network_name] [docker_image] > docker network connect dockercompnetworks_frontend oasis_new_image

to inspect

> docker network inspect dockercompnetworks_frontend # you can see attached container as well

>docker-compose up -d #as a background process

Docker Compose Scaling Healing

> docker-compose up -d --scale nginx_4 (enter)

for loadbalance .. > docker run --rm -it --network scalevol_default ubuntu-dev bash

test > curl nginx/hostname #(enter) > curl nginx/hostname #(enter) > curl nginx/hostname #(enter)

it will show always different id..(load loadbalance) with auto healing

monitoring healty container : willfarrell/autoheal ..

> docker ps -f health=healthy > docker ps -f health=unhealthy -q #to list unhealthy images id.. > docker restart $(docker ps -f health=unhealthy -q) #to restart unhealthy process

..

deploy an apache web server(httpd) using compose, then scale it to 3

> vi docker-compose-httpd.yml version: '3.1'

services: 

web:
 image: httpd:latest
 restart: always

(save&exit)

  1. notes: don't forget to put space after ": "!!
  1. > docker-compose -p [project-name] [file-save:-f] [filename]

> docker-compose -p challenge -f docker-compose-httpd.yml up -d #to deploy single instance

> docker-compose -p challenge -f docker-compose-httpd.yml up -d --scale web=3 #it starts 3 instances > docker ps


helpfull Docker-Compose Features

> docker-compose pull #updates images defined in a docker-compose file. > docker-compose restart #.. > docker-compose pause > docker-compose unpause > docker-compose start / stop

> docker-compose -h #shows available commands > docker -h #shows available commands

> docker-compose top > docker-compose logs -f > docker-compose logs -f httpd

> docker events > docker-compose events

> docker-compose rm > docker-compose ls

docker hub / registry

Standard syntax : <registry>/<namespace>/<repo-name>:<tag> i.e.: docker.io/library/openjdk:8-jdk

> docker login docker.io #to login docker hub #picks up / pull images from dockerhub > docker tag alpine:edge rasimsen/alpine:5mb-linux #tag local images to push dockerhub > docker push rasimsen/alpine:5mb-linux # it has been sent to dockerhub, check from hub.docker.com

> docker logout #to logout

docker hub registry alternatives

  • self-hosted alternatives
 ** Generic private docker registry
 ** Portus
  • Other hosted alternatives
 ** Quay.oi
 ** Azure container registry
 ** Amazon elastic container registry
 ** Google container registry
 ** Private docker registry
 ** Artifactory

Docker Swarm

Essentially it is a cluster of docker hosts that work together to deploy containers

The coordination involved between the docker hosts is most often referred to as orchestration


usefull containers

Alpine Linux

Alpine Linux is a Linux distribution built around musl libc and BusyBox. The image is only 5 MB in size and has access to a package repository that is much more complete than other BusyBox based images. This makes Alpine Linux a great image base for utilities and even production applications. Read more about Alpine Linux here and you can see how their mantra fits in right at home with Docker images.

https://hub.docker.com/_/alpine/

You need to keep in mind that Docker is still running inside a VM. The system paths are still relative to the VM, and not to your Mac. Only some folders are already mounted from your Mac into the VM. You can get an overview by running this command:

$ docker run --rm -it -v /:/vm-root alpine:edge ls -l /vm-root

How to use this image

Use like you would any other base image: 

FROM alpine:3.7
RUN apk add --no-cache mysql-client
ENTRYPOINT ["mysql"]

This example has a virtual image size of only 36.8MB. Compare that to our good friend Ubuntu: 

FROM ubuntu:18.04
RUN apt-get update \
    && apt-get install -y --no-install-recommends mysql-client \
    && rm -rf /var/lib/apt/lists/*
ENTRYPOINT ["mysql"]

This yields us a virtual image size of about 145MB image.

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