hamzazafar/docker-practice

The following steps create three services:
* app: contains the flask app 
* redis-master
* redis-slave

1- Clone the flask app.
   - git clone https://repo.simscale.com/tchaudhry/unstable-hasher-external

2- Create docker hub account and log into it!
   - docker login -u hamza100 -p <XXX>

3- Write the Dockerfile

------------------------------------
FROM ubuntu:14.04
MAINTAINER hamza zafar
RUN mkdir /home/code
RUN apt-get update \
    && apt-get install -y \
    python2.7 \
    curl \
    python-pip
WORKDIR /home/code
COPY main.py .
COPY requirements.txt .
RUN pip install -r requirements.txt
CMD ["python2", "main.py"]
------------------------------------

4- Build Image
   - sudo docker build -t simscale-app .

5- Tag the image
   - sudo docker tag <image-id> <docker-hub-username>/<image-name>:<version>

6- Push image to public repo
   - sudo docker push hamza100/simscale-app

   Remove Image from local repo:
   - sudo docker rmi -f 7041375abb84
 
   Pull Image from remote repo:
   - sudo docker pull hamza100/simscale-app

   Image is now available in local repo

7- Run container
   sudo docker run -it hamza100/simscale-app curl  (CREATE + START)

8- Use Redis Master/Slave image from bitnami/redis
   Create a Health Check script:
   ----------------------------------------------------------------------
   #!/bin/bash
   set -eo pipefail

   host="$(hostname --ip-address)"

   if ping="$(redis-cli -h "$host" ping)" && [ "$ping" = 'PONG' ]; then
        exit 0
   fi

   exit 1

   ----------------------------------------------------------------------

   Use the following dockerfile to create a new redis image and push to repo
 
   ----------------------------------------------------------------------
   FROM bitnami/redis:latest
   COPY redis-healthcheck.sh /usr/local/bin/
   ----------------------------------------------------------------------

9- Bring up a docker swarm, 1 manager, 2 workers
    First install virtualbox `sudo apt-get install virtualbox`

    - Steps for Manager
      - Create the machine
        sudo docker-machine create manager
      - Get IP of manager machine
        sudo docker-machine ip manager
        192.168.99.100
      - SSH into manager machine
        sudo docker-machine ssh manager
      - Set this machine as Swarm Manager 
        docker swarm init --advertise-addr 192.168.99.100
        ---------------------------------------------------------------------
        Swarm initialized: current node (iqmsn27xk928xdge8w0sv70xm) is now a 
        manager.

        To add a worker to this swarm, run the following command:

        docker swarm join \
        --token SWMTKN-1-5meloto93hiipt56eatbwchflnhqwlh9o1js1i9ls3qcmt2ztq-
        bpr9qjxz6htc7ctkgmsg0df7y \
        192.168.99.100:2377

        To add a manager to this swarm, run 'docker swarm join-token manager' 
        and follow the instructions.
        ---------------------------------------------------------------------


    - Steps for Worker machines
      - Create the machine
        sudo docker-machine create worker-0 
      - SSH into manager machine
        sudo docker-machine ssh worker-0
      - Run the join command provided by manager:
        docker swarm join --token SWMTKN-1-5meloto93hiipt56eatbwchflnhqwlh9o1j
        s1i9ls3qcmt2ztq-bpr9qjxz6htc7ctkgmsg0df7y  192.168.99.100:2377
        This node joined a swarm as a worker.
       
    - Login to the swarm manager and run docker node ls

ID                           HOSTNAME  STATUS  AVAILABILITY  MANAGER STATUS
7ivko97xbiqjleoo8v6br0nfb    worker-0  Ready   Active        
iqmsn27xk928xdge8w0sv70xm *  manager   Ready   Active        Leader

      The swarm nodes are verified now!

10- Writing docker compose:
    See the docker-compose.yml file

      sudo docker-machine scp docker-compose.yml manager:docker-compose.yml
    - Log into the manager machine
      sudo docker-machine ssh manager
    - Deploy the stack:
      sudo docker stack deploy --compose-file docker-compose.yml myStack
    - Check status of services
      sudo docker stack services myStack 

ID            NAME                  MODE        REPLICAS  IMAGE
5xzofx92vb67  myStack_app           replicated  0/4       hamza100/simscale-app:latest
qz3u34ibotbo  myStack_redis-master  replicated  0/1       hamza100/redis:latest
r8d6osak4q62  myStack_redis-slave   replicated  0/4       hamza100/redis:latest      

11- check on browser <manager-ip>:5000/hash?string=hello
12- Verify key is stored in Redis
    sudo docker exec -it <container-id> redis-cli get hello

13- Centralized Logging???

//remove all stopped containers
sudo docker rm $(sudo docker ps -aq)