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August 4, 2021 00:08
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| # Building Docker image with Packer and provisioning with Ansible | |
| ## Overview | |
| **Packer** | |
| * Packer is used to build image from a base image, perform provisions and store (commit) the final image. | |
| * We use provisioners and Packer templates to do the actual work to create the final image. | |
| * We use Ansible for provisioning. | |
| **Ansible** | |
| * Ansible runs playbooks on localhost (inside Docker container). | |
| * Ansible must be installed on the image you're provisioning. | |
| * Packer uploads the contents of the Ansible playbook to the Docker container instance, and runs it locally. | |
| # Install Packer | |
| * Follow instructions here: https://www.packer.io/docs/installation.html | |
| * Check Packer is installed: | |
| ``` | |
| packer | |
| usage: packer [--version] [--help] <command> [<args>] | |
| Available commands are: | |
| build build image(s) from template | |
| fix fixes templates from old versions of packer | |
| inspect see components of a template | |
| validate check that a template is valid | |
| ``` | |
| # Build image with Packer | |
| Files: | |
| ``` | |
| build.json - main file with configuration for packer | |
| playbook.yml - Ansible playbook for provisioning | |
| vars/prod.json - main config file for production environment | |
| vars/default.yml - default variables passed to Ansible | |
| vars/prod.yml - variables to pass to Ansible for production environment | |
| ``` | |
| ## Build workflow | |
| Build image for production environment specified by prod.json file: | |
| * run build process with packer build command: | |
| ``` | |
| sudo packer build -var-file=prod.json build.json | |
| ``` | |
| * packer start from the base image specified in build.json | |
| ``` | |
| # build.json | |
| { | |
| ... | |
| "builders":[ | |
| { | |
| "type": "docker", | |
| "image": "phusion/passenger-ruby22:0.9.18", | |
| "commit": true, | |
| ... | |
| } | |
| ], | |
| ... | |
| } | |
| ``` | |
| * packer runs provisioners specified in build.json | |
| * first, it installs Ansible in Docker container: | |
| ``` | |
| "provisioners":[ | |
| { | |
| "type": "shell", | |
| "inline": [ | |
| "apt-get -y update", | |
| "apt-get install -y software-properties-common", | |
| "apt-add-repository ppa:ansible/ansible", | |
| "apt-get -y update", | |
| "apt-get install -y ansible" | |
| ] | |
| }, | |
| ``` | |
| * packer uploads `vars/prod.yml` to the Docker container and saves it as `vars.yml` | |
| ``` | |
| { | |
| "type": "file", | |
| "source": "{{user `config_file`}}", | |
| "destination": "{{user `tmp_dir`}}/vars.yml" | |
| } | |
| ``` | |
| * packer uploads playbook.yml to the Docker container | |
| * packer runs Ansible playbook.yml locally in the Docker container | |
| ``` | |
| { | |
| "type": "ansible-local", | |
| "staging_directory": "{{user `tmp_dir`}}/ansible", | |
| "playbook_file": "playbook.yml", | |
| "extra_arguments": [ "--extra-vars \"tmp_dir={{user `tmp_dir`}} \"" ] | |
| } | |
| ``` | |
| * Ansible playbook uses variables defined in corresponding vars.yml file | |
| ``` | |
| - hosts: 127.0.0.1 | |
| user: root | |
| vars_files: | |
| - "{{tmp_dir}}/vars.yml" | |
| tasks: | |
| ``` | |
| * The final image is saved as "my-nginx:0.1" specified in build.json | |
| ``` | |
| "post-processors": [ | |
| [ | |
| { | |
| "type": "docker-tag", | |
| "repository": "my-nginx", | |
| "tag": "0.1" | |
| } | |
| ] | |
| ] | |
| ``` | |
| ## build configuration | |
| Create build.json file with configuration how to build Docker image. | |
| build.json: | |
| ``` | |
| { | |
| "variables": { | |
| "config_file": "vars/default.yml", | |
| "tmp_dir": "/tmp" | |
| }, | |
| "builders":[ | |
| { | |
| "type": "docker", | |
| "image": "nginx", | |
| "commit": true, | |
| "run_command": ["-d", "{{.Image}}", "nginx -g daemon off"] | |
| } | |
| ], | |
| "provisioners":[ | |
| { | |
| "type": "shell", | |
| "inline": [ | |
| "apt-get -y update", | |
| "apt-get install -y software-properties-common", | |
| "apt-add-repository ppa:ansible/ansible", | |
| "apt-get -y update", | |
| "apt-get install -y ansible" | |
| ] | |
| }, | |
| { | |
| "type": "shell", | |
| "inline": [ | |
| "mkdir -p {{user `tmp_dir`}}" | |
| ] | |
| } | |
| , | |
| { | |
| "type": "file", | |
| "source": "{{user `config_file`}}", | |
| "destination": "{{user `tmp_dir`}}/vars.yml" | |
| } | |
| , | |
| { | |
| "type": "ansible-local", | |
| "staging_directory": "{{user `tmp_dir`}}/ansible", | |
| "playbook_file": "playbook.yml", | |
| "extra_arguments": [ "--extra-vars \"tmp_dir={{user `tmp_dir`}} \"" ] | |
| } | |
| ], | |
| "post-processors": [ | |
| [ | |
| { | |
| "type": "docker-tag", | |
| "repository": "my-nginx", | |
| "tag": "0.1" | |
| } | |
| ] | |
| ] | |
| } | |
| ``` | |
| ## Configs | |
| ## Build image | |
| ``` | |
| sudo packer build -var-file=vars/prod.json build.json | |
| ``` | |
| ## Run Docker container | |
| ``` | |
| sudo docker run -d -p 8080:80 --name=my-server1 my-nginx:0.1 | |
| ``` |
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