This file is part of: PHP Development Template Stack Copyright (c) 2024 Nico Jan Eelhart This source code is licensed under the MIT License found in the ‘LICENSE.md’ file in the root directory of this source tree.

What

This describes how to create a Docker Swarm of this PHP container. These instructions are intended for developers who wants to experiment and learn how to deal with a Docker Swarm. To create and use a development container see the document: How to create a development container

1. Create Multipass docker VM infrastructure(X (5) VMs) and Initialize the Swarm.

We use Multipass for the different Virtual machines to hold the Docker Swarm.

1. Make sure Multipass is installed, see: Multipass
2. command: ./CreateDockerNodes.ps to create the, entered number of multipass Nodes (let’s assume 5)
3. Get the IP from one of the nodes (multipass ls)
4. mount and copy shared-container-files The docker compose_apache_php_swarm.yml need to have access to the shared files. For this reason we need to mount the whole service directory(ApachePHPWebService) on the host to: /mnt/host on the container. After that the /mnt/host file will be copied to /home/ubuntu/src/appname-service directory from where the docker compose file can read the files. Note that the compose file is unable to access the /mnt/host/ files and directories.
   For the described process we have another script which will do this for all our created Multipass VNode’s:
   command: ./mountcopy.ps1 # run this!
   Related and used command’ multipass mount "C:\path\to\your\folder" VNode1:/mnt/host. multipass set local.privileged-mounts=true # if needed, in case of no permission
   
5. Open the VM ‘VNode1’ in a shell
   command: multipass shell VNode1
6. Initialize the Swarm in the 1e Node.
   command: docker swarm init –advertise-addr IP(see 2)
7. Get manager and worker token
   command: docker swarm join-token manager.
   command: docker swarm join-token worker.
   Copy it.
8. exit VNode1 and
   command: multipass shell VNode2
9. Make the 2nd Node and 3rd also manager (and all other required) .
   command: Past the copied command.
   command: docker node ls (From admin node to check)
10. Do the same,as in step 8, but now for the nodes that must act as worker, in this case use the worker token(see step 7). worker nodes will actually run your application(s)

---

2. Make & Publish an Image

This step will create and image used for the service of the Swarm. We need to create it in the Docker registry so that it can be pulled later by the Swarm service.

2.1 Create Image

In this sample we use the Python image defined in the directory:”PythonWebService” but you can also use another directory with other files.

**Assuming your in the root directory: PythonWebService **

1. Make sure a (basic) (PHP) application is available in \app
2. a Dockerfile_Apache_PHP_cont file should be available
3. command: docker build -t [yourname]/apachephpweb -f Dockerfile_Apache_PHP_cont . Don’t forget the . option add the --no-cache option to force a rebuild command: docker build --no-cache -t eelhartn/apachephpweb -f Dockerfile_Apache_PHP_cont .
4. command: docker images # it should be there

2.2 Publish

You can skip this and use me image(eelhartn/apachephpweb) or continue, and create your own image to use that later on. First publish it to the Docker Hub, this must be done so we can pull the image in the Multipass VM manager node(s).

1. command: docker login with your docker login
2. command: docker image push [yourname]/apachephpweb Be aware the image is public by default, to make it private go to the web interface!

---

3. Use the Published Image to Deploy the Stack

Note: Stack is another term for compose in case of a Docker Swarm

To deploy the stack we need to have the PhpWebService\app directory and the PhpWebService\compose_apache_php_swarm.yml available on the Nultipass virtual machine MANAGER nodes! Make sure the script mountcopy.ps1 has run, this will make sure the app and shared files are available in:/home/ubuntu/src/ at the node.

1. Check that the key differences(required for a Swarm) in the compose_apache_php_swarm.yml are made, which are (should already be done):
   • Most importantly there is NO build property but instead a image property that point to our image stored in the Docker hub
   • Check also other non-Swarm required properties, so that those make sense: service name, command(start-up app), ports…
     
     
2. When you did not skip ‘Create image’ you will need to change the image property in the file: compose_apache_php_swarm.yml so that it refers to your image!
3. Login to docker Hub and make sure that the referenced image (compose_apache_python_swarm.yml) is public!
4. Execute the following commandos from the directory:
   command: cd /home/ubuntu/src/appname-service/ from a manager VNode
   command: docker stack deploy -c compose_apache_php_swarm.yml MyWebApp
   This will use the compose_apache_php_swarm.yml file to retrieve the deployed image from the docker Hub and create a service MyWebApp
   
   Checks:
   command: docker stack ls
   command: docker stack ps MyWebApp
   command: docker stack services MyWebApp
   command: docker service logs [service name previous CMD] # In case of errors
   
   To Open a docker shell in the stack use command: docker ps # Get the Container ID of (NOT from Master VNode! ?? use another admin node) command: docker exec -it [container ID] bash # shell
   
   Now try if your lucky
   
   • command: multipass ls # look for the IP addresses
     Then in your host browser enter:
     – [a VM IP address]:8071\index.html
     – [a VM IP address]:8071\index.php
     – [a VM IP address]:8071\phpinfo.php
     

Warning!
In my experience when you get ‘the forbidden’ return page there are problems with the network between the host and the VM’s, anyway proceed with ‘4. Test the installation’ in case of problems

---

4. Test the installation

Because our Swarm has some layers of complexity(host machine, VM’s in the host, and a docker image in each VM, networking and others) we have to test the result in different stages

4.1 Inside a docker image contained in a VM, check running state

Enter the docker Container

• Open a shell to a manager VM (but not the master\leader!)
• command: docker ps # get the container ID
• command: docker exec -it [container ID] bash # inside the docker running Apache and PHP Now you can use the following command to check the state:
• command: netstat -tuln | grep ':80' # when returns listing Apache 2 is working
• command: php --version # Okay when returns version
• command: /run/php/php8.2-fpm.sock # if returns it own location PHP-FPM is successfully installed
• command: tail -f /var/log/apache2/access.log # Check access errors
• command: apt-get update
• command: apt-get install curl # needed for next
• command: curl -f http://localhost:80/index.html # should return page, note internal it’s port 80 external 8071
• command: curl -f http://localhost:80/phpinfo.php # should return page, note internal it’s port 80 external 8071. if so INSTALLATION OKAY

  4.2 In any docker image, tests

  Here we first need to install curl:

• command: curl -f http://localhost:8071/index.html || exit 1 if the above command returns the html page Apache2 is working for HTML
• command: curl -f http://localhost:8071/phpinfo.php || exit 1 If it returns value, PHP is INSTALLATION OKAY and reachable from the VM host
• command: curl -f http://localhost:8071/index.php || exit 1 if the above command returns the PHP page Apache2 is working for PHP. When this is the case the installation is okay, the only thing what can go wrong is the network connection between the VM and host +++if the phpinfo.php work, and this not, there is an error in the PHP app or app setup+++
• command: ping [IP host] If this fails the install is ok but you can not reach the host so web page will not be displayed on the host. While this is irritating I consider this outside the scope of this project

  4.3 In the host, test accessibility

  When a command like: [a VM IP address]:8071\index.html is not working in the host, the last ping command probably also failed. Again, while this is irritating I consider this outside the scope of this project. But any way here are some checks you could begin with:

• command: Start a (host) browser and type any VNode * IP-address:8071/index.html* # this fails I guess otherwise you would not be here (for completeness it’s here)
• command: ping a [VM IP addr]
• Try the following Power-Shell script, make sure to enter a VM IP address:

  try {
        $response = Invoke-WebRequest -Uri http://72.28.207.1:8071/index.html
        Write-Output $response.Content
    } catch {
        Write-Output "Failed to connect"
    }
  

  4.4 Errors

• The error ‘Rejected’ means most of the time that the image could not be found(misspell or private?? not logged in docker?) But be aware that the command: ‘docker stack ps MyWebApp’ could return old info, so also check if the Website runs!
• Restart a Multipass VM node will reassign a new IP and break the swarm! (use Fixed IP, but how?)
  

---

Note:
This installation method use the declarative method to create the Swarm. this means

• No Dockerfile is used
• The compose file has a few changes(because the dockerfile is not used)
• More information see my personal WIKI