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Just pulled it into a standalone project for easier building.\n\n\n# Orchestration with Swarm Computing\n\n> **Difficulty**: Beginner\n\n> **Time**: Approximately 40 minutes\n\nIn this lab you will deploy a Dockerized application to a single host and test the application. You will then configure Docker for Swarm Computing and deploy the same app across multiple hosts. You will then see how to scale the application and move the workload across different hosts\n\nYou will complete the following steps in this lab:\n\n- [Deploy a single host application](#deploy-application)\n- [Configure Docker for Swarm Computing](#start-cluster)\n- [Deploy the application across multiple hosts](#multi-application)\n- [Scale the application](#scale-application)\n- [Drain a node and reschedule the containers](#recover-application)\n\n## Pre-requisites\n\nYou will need all of the following in order to complete this lab:\n- Three nodes running Docker v1.12.x. Each VM will be referenced as **v112node0**, **v112node1**, and **v112node2**.\n- A Docker ID. Creating a Docker ID is free, and allows you to push and pull images from Docker Hub. [This link](https://docs.docker.com/mac/step_five/) describes how to create a Docker ID (you only need to complete the procedure up to step 2.3).\n\n\n## Step 1: Deploy a single host application\n\nIf you would like to skip using a Dockerfile and jump straight deploying on a cluster then go straight to Step 2.0.\n\nIn this step you will deploy a simple application that runs on a single Docker host. In order to do that, you will complete the following:\n\n- Clone the app's GitHub repo\n- Dockerize the app\n- Run the app\n- Push the image to Docker Hub\n\n\nThe application you will deploy is the `cats` application. It is a simple 1-container application that displays random pictures of cats, because why not!! It is a flask application written in Python that pulls the images from public URLs.\n\n### Step 1.1 - Log into VMs and verify that Docker is running\n\n1. SSH to your __v112node0__ with the username of `labuser`. You should have the hostnames in an email titled \"Docker Labs VMs Ready\"\n\n The command to SSH into **v112node0** will look something like the following:\n\n ```bash\n ssh labuser@\n ```\nYou will be asked for a password. The password is in the email with the DNS names of the lab VMs.\n\nAn example of the sign in ...\n```bash\nssh labuser@v112node0-9128f1906df54acda5044f56a1a86b07-2.cloudapp.net\nThe authenticity of host 'v112node0-9128f1906df54acda5044f56a1a86b07-2.cloudapp.net (40.112.136.129)' can't be established.\nECDSA key fingerprint is SHA256:3L9UZQTSCOUkzVuyO5z3H7jLedSp8/5AquUtSZ8ydEE.\nAre you sure you want to continue connecting (yes/no)? yes\nWarning: Permanently added 'v112node0-9128f1906df54acda5044f56a1a86b07-2.cloudapp.net,40.112.136.129' (ECDSA) to the list of known hosts.\nlabuser@v112node0-9128f1906df54acda5044f56a1a86b07-2.cloudapp.net's password:\nWelcome to Ubuntu 14.04.4 LTS (GNU/Linux 4.2.0-23-generic x86_64)\n```\n\n2. Verify that Docker is running. This lab is based on a pre-release version of Docker Engine 1.12 so that we can show you the latest Swarm features. We are running version `1.12.0-rc1` on these VMs.\n\n\t```bash\n\tlabuser@v112node0:~$ docker version\n\tClient:\n \tVersion: 1.12.0-rc1\n \tAPI version: 1.24\n \tGo version: go1.6.2\n \tGit commit: 1f136c1\n \tBuilt: Wed Jun 15 05:16:17 2016\n \tOS/Arch: linux/amd64\n\n\tServer:\n \tVersion: 1.12.0-rc1\n \tAPI version: 1.24\n \tGo version: go1.6.2\n \tGit commit: 1f136c1\n \tBuilt: Wed Jun 15 05:16:17 2016\n \tOS/Arch: linux/amd64\n \t```\n \n\n3. We are going to copy the contents of the application code to **v112node0**. Use `git` to clone the `cats` application from `https://github.com/mark-church/cats.git`\n\n \t```bash\n \tlabuser@v112node0:~$ git clone https://github.com/mark-church/cats.git\n\tCloning into 'cats'...\n\tremote: Counting objects: 10, done.\n\tremote: Compressing objects: 100% (6/6), done.\n\tremote: Total 10 (delta 0), reused 7 (delta 0), pack-reused 0\n\tUnpacking objects: 100% (10/10), done.\n\tChecking connectivity... done.\n \t```\n \t\n \tThe repo contains all of the files and code that is required to create a container image of the application. The command above copies (clones) the repo into a new directory on your machine called `cats`.\n\n3. Change directory to `cats` and examine the list of files with 'tree'.\n\t```bash\n\tlabuser@v112node0:~/$ cd cats\n\n\tlabuser@v112node0:~/cats$ tree\n\t.\n\t├── app.py\n\t├── Dockerfile\n\t├── images\n\t│ ├── browser.png\n\t│ ├── cat.png\n\t│ └── food.png\n\t├── README.md\n\t└── templates\n \t└── index.html\n\n\t2 directories, 7 files\n \t```\n\n\nSome of the files worth knowing include the following:\n\n- __Dockerfile__: This file contains the recipe for the `cats` app image.\n\n- __app.py__: This is the main Python module that is our Flask application.\n \t\n- **/app/templates**: This folder includes the HTML web page that is called by the Python web server.\n\n Let's focus on the **Dockerfile** for a second. A **Dockerfile** is a text file that contains all the **instructions** required to build an application or service into a Docker image. This includes instructions to install packages, copy data, insert metadata, and anything else that should be included as part of the image. The Docker Engine uses Dockerfiles to create new images.\n\n### Step 1.2 - Dockerize the app\n\nYou **Dockerize** an application by describing it in a **Dockerfile** and using that **Dockerfile** to create a Docker image.\n\nThe following procedure will guide you through Dockerizing the the `cats` app. \n\nMake sure you're logged in to **v112node0** and in the `~/cats/` directory.\n\n\n1. Inspect the contents of the Dockerfile.\n\n\t```bash\n\n\tubuntu@v112node0:~/cats$ cat Dockerfile\n\tFROM ubuntu:14.04\n\n\tRUN sudo apt-get update && apt-get -y install python-pip\n\n\tRUN sudo pip install flask==0.10.1\n\n\tCOPY . /usr/bin\n\n\tWORKDIR /usr/bin\n\n\tEXPOSE 5000\n\n\tCMD [\"python\", \"./app.py\"]\n\t```\n\n Let's have a quick look at the contents of the Dockerfile.\n\n __FROM__: The FROM instruction sets the base image that all subsequent instructions will build on top of. The base image can be any valid Docker image including other peoples' images. In this exercise you are starting with the `ubuntu:14.04` image as your base image.\n\n __RUN__: The RUN instruction executes commands while the image is being built. Each RUN instruction creates a new image layer. The RUN instructions in this **Dockerfile** are updating the local `apt` package lists from source, and installing some packages that the Flask framework requires.\n\n __ADD__: The ADD instruction copies files or directories from the Docker host and adds them to the filesystem of the container. In this particular **Dockerfile** the `app` directory that was just cloned to **v112node0** form GitHub is copied to the image at `/usr/bin`.\n\n __EXPOSE__: The EXPOSE instruction lists the ports that the container will expose at runtime. This image will expose port 5000.\n\n __CMD__: The main purpose of CMD instruction is to provide defaults for an executing container. This CMD instruction will run `python` specifying `./app.py` as the argument.\n\n2. If you have not already signed up for a Docker Hub account please do so. Instructions are detailed in the preqresuites for this lab. Use the following `docker build` command to build an image from the Dockerfile.\n\n Be sure to substitute your own Docker ID in this example\n\n ```\n labuser@v112node0:~/cats$ docker build -t /cats .\n ```\n\n It will take between one and three minutes to build the image. This is because the `ubuntu:14.04` image has to be pulled locally and several packages have to be installed into the image.\n\n The `-t` flag lets you **tag** the image. The `/cats` will be the image tag - **Be sure to substitute your Docker ID**. Tagging the image lets you easily identify it as well as push to Docker Hub or other Docker Registries.\n\n The trailing period `.` tells the command to send your current working directory to the Docker daemon as the build context. The **build context** is a fancy way of saying the Dockerfile and other files required to build the image.\n\n The output of the `docker build` command will look similar to the following (many lines have been removed for brevity).\n\n >**Warning**: You will see text roll up the screen as packages are installed. \n\n \t```\n \tlabuser@v112node0:~/cats$ docker build -t markchurch/cats .\n\tSending build context to Docker daemon 65.54 kB\n\tStep 1 : FROM ubuntu:14.04\n\t---> 8f1bd21bd25c\n\tStep 2 : RUN sudo apt-get update && apt-get -y install \tpython-pip\n \t---> Using cache\n \t---> 50e52804ad74\n\tStep 3 : RUN sudo pip install flask==0.10.1\n \t---> Using cache\n \t---> 19103663e62b\n\tStep 4 : COPY . /usr/bin\n \t---> Using cache\n \t---> 3988eef3f4aa\n\tStep 5 : WORKDIR /usr/bin\n \t---> Using cache\n \t---> ed799e437260\n\tStep 6 : EXPOSE 5000\n \t---> Using cache\n \t---> 7121e0e1317d\n\tStep 7 : CMD python ./app.py\n \t---> Using cache\n \t---> 0968ec22c14f\n\tSuccessfully built 0968ec22c14f\n ```\n\n Your output will be a lot more verbose than this as it includes output from `apt-get` and `pip`. Each line in the Dockerfile is creating a new container, installing the packages inside that container, and then commiting that container to a new image. The final step gives us the final image for this application.\n\n3. Run a `docker images` command to confirm that the image is listed.\n\n ```\n \tlabuser@v112node0:~/cats$ docker images\n\tREPOSITORY TAG IMAGE ID CREATED SIZE\n\tmarkchurch/cats latest 6991f312ee28 7 seconds ago 363.5 MB\n\tubuntu 14.04 8f1bd21bd25c 3 weeks ago 188 MB\n ```\n\n The output of your command will show your Docker ID and not *markchurch*. Since we doewnloaded the `ubuntu:14.04` image as an intermediary step we can see that that image has been downloaded too.\n \n \n### Step 1.3 - Run the App\n\nNow that you've Dockerized the the `cats` app let's go ahead and run it.\ndocker \n\nPerform all of these steps from **v112node0**.\n\n1. Execute a `docker run` command to deploy a container with the `/cats` image.\n\n ```\n labuser@v112node0:~/cats$ docker run -d --name cats-app -p 8000:5000 markchurch/cats\n 0374e0c107b4e84d4201415d1ad5dd036787ea317c8baa2062615f1f9e0b334e\n ```\n\n This will create a container with the `cats` image. It will run in the background because of the `-d` flag. We are exposing the container on port `8000` of the host and mapping this to port `5000` inside the container. The container ID of the container is given as a message confirming that the container has been created from our image.\n \n \n\n\n2. Check that the container is running with `docker ps`.\n\n \t```\n \tlabuser@v112node0:~/cats$ docker ps\n\tCONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES\n\t0374e0c107b4 markchurch/cats \"python ./app.py\" 5 minutes ago Up 5 minutes 0.0.0.0:8000->5000/tcp cats-app\n \t```\n\tThis output shows us the container ID, the image used to build the container, the status of the container, and also the port-mapping between the container interface and the host interface. This confirms that our container is running.\n \t\n\n3. Point your web browser to the app.\n\n Paste the public DNS or public IP of **v112node0** into your web browser with port `8000`.\n

\n \n

\n \n\n You should see the following ...\n

\n \n

\n\n\tNote that the container ID on the `cats-app` web page should match the container ID of the `docker ps` command. Try refreshing the browser a couple times. You will cycle through some fantastics cats!\n\n\n\n\n### Step 1.4 - Push the image to Docker Hub\n\nNow that we have verified that our application works we will push the newly created image to Docker Hub so that you can pull it form other nodes. \n\nPerform the following steps from **v112node0**.\n\n1. Login with your Docker ID.\n\n ```bash\n labuser@v112node0:~/cats$ docker login\n 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.\n Username: \n Password:\n Login Succeeded\n ```\n\n2. Push your image to Docker Hub. Later in the lab you will be pulling this image to different hosts.\n\n Remember to substitute your Docker ID.\n\n \t```bash\n \tlabuser@v112node0:~/cats$ docker push markchurch/cats\n\tThe push refers to a repository [docker.io/markchurch/cats]\n\teeba1e237f53: Pushed\n\tfaf8ac200bcd: Pushed\n\t2c00ae9664da: Pushed\n\t5f70bf18a086: Mounted from library/ubuntu\n\t6f8be37bd578: Mounted from library/ubuntu\n\t9f7ab087e6e6: Mounted from library/ubuntu\n\tdc109d4b4ccf: Mounted from library/ubuntu\n\ta7e1c363defb: Mounted from library/ubuntu\n\tlatest: digest: sha256:5fdee62784552531475c02afff4cdcc12f95a050dbdd4bce53da7ee3d589d582 size: 1992\n \t```\n\n This will push your newly built image to your own public repository on Docker Hub called `/cats`. The Docker Hub is the default Docker Registry and is hosted on the public internet. You can also push images to Docker Trusted Registry as well as third party registries.\n \n If you go to `hub.docker.com` and login then you will be able to see the repository and image tag that you just created.\n \n

\n \n

\n\nBefore proceeding to the next task, clear all of the containers on __v112node0__ by running the following command.\n\n\t\n\tlabuser@v112node0:~/cats$ docker rm -f $(docker ps -q)\n\t385f1c7a587c\n\t\n\nVerify that the command worked and there are no running or stopped containers on the host.\n\n\n\tlabuser@v112node0:~/cats$ docker ps\n\tCONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES\n\tlabuser@v112node0:~/cats$\n\t\n\t\nNow if you refresh your web browser with your application you will see that it is no longer running. \n\n## Step 2: Configure Swarm Mode\n\nSo far you have deployed an application to a single Docker host (node). However, real-world applications are typically deployed across multiple hosts. This improves application performance and availability, as well as allowing individual application components to scale independently. Docker has powerful native tools to help you do this.\n\nIn this step you will configure *Swarm Mode*. This is a new optional mode in which multiple Docker Engines form into a self-orchestrating group of engines called a *swarm*. Swarm mode enables new features such as *services* and *bundles* that help you deploy and manage multi-container apps across multiple Docker hosts.\n\nYou will complete the following:\n\n- Configure *Swarm mode*\n- Run the app\n- Scale the app\n- Drain nodes for maintenance and reschedule containers\n\nFor the remainder of this lab we will refer to *Docker native clustering* as ***Swarm mode***. The collection of Docker engines configured for Swarm mode will be referred to as the *swarm*.\n\nA swarm comprises one or more *Manager Nodes* and one or more *Worker Nodes*. The manager nodes maintain the state of swarm and schedule appication containers. The worker nodes run the application containers. As of Docker 1.12, no external backend, or 3rd party components, are required for a fully functioning swarm - everything is built-in!\n\nIn this part of the demo you will use all three of the nodes in your lab. __v112node0__ will be the Swarm manager, while __v112node1__ and __v112node2__ will be worker nodes. Swarm mode supports a highly available redundant manager nodes, but for the purposes of this lab you will only deploy a single manager node.\n\n*If you are just joining us on this step then feel free to use the `markchurch/cats` image from the Docker Hub for the rest of the lab*\n\n#### Step 2.1 - Create a Manager node\n\n1. If you haven't already done so, SSH in to **v112node0**.\n\n For example (remember to substitute your SSH key and **v112node0** for your lab):\n\n ```\n $ ssh labuser@v112node0-9a7b5b024cf247fb8d851bf173c72619-4.cloudapp.net\n ```\n\n2. Get the internal/private IP address of __v112node0__.\n\n ```bash\n labuser@v112node0:~/$ ip a ls dev eth0 | sed -n \"s,.*inet *\$[^/]*\$/.*,\\1,p\"\n 10.0.0.11\n ```\n\n Make a note of this IP address as you will use it later when adding worker nodes to the swarm.\n\n3. Create a Manager node on __v112node0__ using its internal IP address and `docker swarm init --listen-addr :. This is the address the the swarm manager is advertising itself on to other nodes wishing to joing the swarm.\n\n Remember to substitute the IP address for the private IP of your **v112node0**.\n\n ```\n labuser@v112node0:~/$ docker swarm init --listen-addr 10.0.0.11:2377\n Swarm initialized: current node (0gohc21qtm7sp) is now a manager.\n ```\n\n `docker swarm init` is a new command in Docker 1.12. It is entirely optional, but is all that is needed to initialize a new *swarm* (native Docker cluster).\n\n Port `2377` is recommended but not mandatory. You can use a different port of your choosing.\n\n4. Run a `docker info` command to verify that **v112node0** was successfully configured as a swarm manager node.\n\n ```\n ubuntu@v112node0:~/FoodTrucks/$ docker info\n Containers: 0\n Running: 0\n \n\tSwarm:\n\t NodeID: 3vatl908ksmjk\n \tIsManager: YES\n\t\n ```\n\nThe swarm is now initialized with **v112node0** as the only Manager node. In the next section you will add **v112node1** and **v112node2** as *Worker nodes*.\n\n#### Step 2.2 - Join Worker nodes to the Swarm\n\nYou will perform the following procedure on **v112node1** and **v112node2**. Towards the end of the procedure you will switch back to **v112node0**.\n\n1. Open a new SSH session to __v112node1__ (Keep your SSH session to **v112node0** open in another tab or window).\n\n\n ```bash\n $ ssh labuser@v112node1-9128f1906df54acda5044f56a1a86b07-2.cloudapp.net\n ```\n\n2. Join the swarm using the *internal* IP of **v112node0** and the port specified when you created the Swarm.\n\n The format of the command is as follows:\n\n ```\n docker swarm join :\n ```\n\n The example below joins a new worker node to an existing swarm with a manager node with IP address of `10.0.0.11` on port `2377`.\n\n Be sure to substitute the internal IP address of your **v112node0** that you made a note of earlier.\n\n ```bash\n labuser@v112node1:~/$ docker swarm join 10.0.0.11:2377\n This node joined a Swarm as a worker.\n ```\n\n3. Repeat steps 1 and 2 for __v112node2__.\n\n4. Switch to **v112node0** and verify that the Swarm is up and running with **v112node0** as the Manager node and **v112node1** and **v112node2** both as Worker nodes.\n\n Run this command on **v112node0** (the Manager node).\n\n ```bash\n labuser@v112node0:~/$ docker node ls\n\tID NAME MEMBERSHIP STATUS AVAILABILITY MANAGER STATUS LEADER\n\t5zkcnyq6uqxv4sfpzsyvs8x3s v112node1-9128f1906df54acda5044f56a1a86b07-2 Accepted Ready Active\n\tacu262y2ight8uyn6fg8yvust * v112node0-9128f1906df54acda5044f56a1a86b07-2 Accepted Ready Active Reachable Yes\n\tbrr8ri58aa1ed9051drszoyh0 v112node2-9128f1906df54acda5044f56a1a86b07-2 Accepted Ready Active\n ```\n\n The `docker node ls` command shows you all of the nodes that are in the swarm as well as their roles in the swarm. The `*` identifies the node that you are issuing the command from.\n\nCongratulations. You have configured a swarm with one manager node and two worker nodes.\n\n## Step 3: Deploy a Multi-Host Application\n\nNow that you have a swarm up and running, it is time to deploy the app to it. To do this you will complete the following actions:\n\n- Create a new overlay network for the application\n- Deploy the application components as Docker *services*\n\nYou will perform the following procedure from **v112node0**.\n\n### Step 3.1 - Create a new overlay network for the application\n\n1. Create a new overlay network called `catnet`. `catnet` will be the overlay network that our application containers live on.\n\n ```\n labuser@v112node0:~/$ docker network create -d overlay catnet\n 81pjggkd57fbbl7zmheasc6m8\n ```\n\n The network ID will be output to signal the succesful creation of a Docker network. The `-d` flag let's you specify which network driver to use. In this example you are telling Docker to create a new network using the **overlay** driver. In *Swarm Mode* the overlay network does not require an external key-value store. It is integrated into the engine. The overlay provides reachability between the hosts across the underlay network. Out of the box containers on the same overlay network will be able to ping eachother without any other special configuration.\n\n2. Confirm that the network was created. We can see that there are several other default networks that already exist in a Docker host.\n\n ```\n labuser@v112node0:~/$ docker network ls\n\tNETWORK ID NAME DRIVER SCOPE\n\t09b78531f1d5 bridge bridge local\n\te7cf5b545252 docker_gwbridge bridge local\n\t9311e4b9e4e1 host host local\n\tbhpf10k7w3gt ingress overlay swarm\n\t26b729bf0d65 none null local\n\n\t```\n\nNow that the container network is created you are ready to deploy the application to the swarm.\n\n#### Step 3.2 - Deploy the application components as Docker services\n\nYour `cats` application is becoming very popular on the internet. People just love pictures of cats. You are going to have to scale your application to meet peak demand. You will have to do this across multiple hosts for high availability. We will use the concept of *Services* to scale our application easily and manage many containers as a single entity.\n\n*Services* are a new concept in Docker 1.12. They work with swarms and are intended for long-running containers.\n\n\nYou will perform this procedure from **v112node0**.\n\n1. Deploy `cats` as a *Service*. Remember to use your `` instead of `markchurch`. However, if you did not complete Part 1 of this lab you are welcome to use `markchurch/cats` as the application image as that will work as well.\n\n ```bash\n labuser@v112node0:~/$ docker service create --name cat-app --network catnet -p 8000:5000 markchurch/cats\n5qwkfpdpsm72opbxvzgzk9s5q\n ```\n\n\n2. Verify that the `service create` has been received by the Swarm manager.\n\n ```\n labuser@v112node0:~/$ docker service ls\n\tID NAME SCALE IMAGE COMMAND\n\t5qwkfpdpsm72 cat-app 1 markchurch/cats\n ```\n\n3. We can insepct the progress of our individual service containers by using the `docker service tasks` command. It may take a minute or two until the `LAST STATE` column is in the `Running` status.\n\n\t```\n\tlabuser@v112node0:~/$ docker service tasks cat-app\n\tID NAME SERVICE IMAGE LAST STATE DESIRED STATE NODE\n\tehfg9vq9m8bgyrxyv0abrex8c cat-app.1 cat-app markchurch/cats Running 5 minutes Running v112node0-9128f1906df54acda5044f56a1a86b07-2\n\t```\n\t\n\tThe state of the service may change a couple times until it is running. The image is being downloaded from your Docker Hub repository directly to the other engines in the Swarm. Once the image is downloaded the container goes into a running state on one of the three nodes.\n\n\tAt this point it may not seem that we have done anything very differently than in part 1. We have again deployed a single container on a host and mapped it to port `8000`. The difference here is that the container has been scheduled on a swarm cluster. The application is available on port `8000` on any of the hosts in the cluster even though the `cat-app` container is just running on a single host. The Swarm intelligently routes routes requests to the `cat-app`.\n\n4. Check that the app is running in your browser. You can use any of the node URLs. The Swarm will advertise the published port on every host in the cluster.\n\n Point your web browser to `http://:8000`. Now try pointing it to `http://:8000`. You should see the same `cat-app` being served by the same container ID in both cases. Your request is being routed by the Docker engine from any Swarm node to the correct node. 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htrease/cats

Tags for htrease/cats