To have a more clear picture of the issue, we can have look at the below image:<\/p>\n\n\n\n Let us now go through an example of how the docker app works. I am going to deploy a dummy application Spring3hibernate<\/strong> from Opstree Github repository in QA env and later in PROD by making simple configuration changes.\n\n\n\n\n \nCreate a new directory in your home, we\u2019ll call it app home<\/em>:\n\n<\/p>\n\n\n\n \n\nNow, clone the app from Opstree Github repository. This app needs only mysql as a dependency.\n\n\n\n\n \nWe need to update database properties file and nginx config file with below contents respectively: \n\nReplace below content over there:\n\n\n\n \n\nFor nginx conf file: \n\n\n\n\n\n\nMove \n‘default.conf’ to ~\/spring3hibernate-app\/spring3hibernate\/nginx\/conf\/qa\/\n as we have different conf file for PROD which goes to \n~\/spring3hibernate-app\/spring3hibernate\/nginx\/conf\/prod\/ \n\n\nThis is the configuration for the nginx load balancer. Remember this, we\u2019ll use it later.\nLet\u2019s create our docker-app now, make sure you are in the app home directory \n\n\n\n\nThis will create a single file named s3h.dockerapp which will look like this: \n\n<\/p>\n\n\n\n \n\n\nAs you can see this file is divided into three parts, metadata, compose, and parameters. They are all in one file because we used –single-file switch. We can divide them up in multiple files by using docker-app split command in app home directory, docker-app merge will put them back in one file.\n\nNow, for QA, we have the following configuration for s3h.dockerapp file: \n\n\n\nAs mentioned before, first part contains app metadata, second part contains actual compose file with lots of variables, and last part contains values of those variables. Special mention here is x-enabled<\/em> variable, docker-app provides functionality to temporarily disable a service using this variable.\n\n\nNow, try a few commands:\n\n\n<\/p>\n\n\n\n \n\n\nIt will produce summary of whole app.\n\n\n\n<\/p>\n\n\n\n \n\nIt will replace all variables with their values and will produce a compose file\n\n<\/p>\n\n\n\n \n\n\nIt will remove nginx from docker-app compose as well as deploy\n\n\n\n\n<\/p>\n\n\n\n \n\n\n\nIt\n will spin up all the containers according to rendered compose file. We \ncan see the application running on port 81 of our machine.\n\n\n\n\n\n \n\n\nTo check out more commands and play around a bit.\n \n\nWe are going to loadbalance springapp1<\/em> and springapp2<\/em> in PROD environment, since we have enabled springapp2<\/em> using x-enabled parameter. We have also changed nginx conf bind path to the new conf file and host port for nginx to 80 (for Production). All so easily. Run command: \n \n\n\n\n\n\nThis command will produce a compose file ready for production deployment. Now run:\n\n\n<\/p>\n\n\n\n \n\n\n\n\nAnd production is deployed \u2026 Visit port 80 of your localhost to verify.\n\nWhat’s more exciting is that we can also share our docker-apps through docker hub, we can tag the app and push it to our remote registry as images after logging in:\n\n\n<\/p>\n\n\n\n \n\n\n\n\nProvide your username and password for docker hub, create an account if not yet created.\n<\/p>\n\n\n\n If we wish to upload additional files as well, we will have to split our project using docker-app split and put additional files in the directory before pushing. The additional files will go as attachments which can be accessed later. With the arrival of docker app, our large, composite, and containerized applications can also be shipped and re-used as images. That is cool. But there\u2019s something cooler which we haven\u2019t explored yet. Deploying our docker-apps on kubernetes with the goal of exploring how far in management, and how optimal in delivery, we can go with our applications. Let\u2019s keep this as a topic for the next blog. Until then, have a nice one. \ud83d\ude42<\/p>\n\n\n\n Image Source: https:\/\/reflectoring.io\/externalize-configuration\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":" When docker was released as a new containerization tool, it took the market by a storm. With its lightweight images, multi-os support, and ability to ship containers, it\u2019s popularity only roared. I have been using it for more than six months now, I can see why it is so. Hypervisors, another type of virtualizing tools,\u00a0 … Continue reading “Docker-Compose As A Bundled Application”<\/span><\/a><\/p>\n","protected":false},"author":155574231,"featured_media":29900,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_coblocks_attr":"","_coblocks_dimensions":"","_coblocks_responsive_height":"","_coblocks_accordion_ie_support":"","jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","enabled":false},"version":2}},"categories":[28070474,1],"tags":[27998418,182564,768739305,685617500,308799219,768739301,91482705,41395],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/opstree.com\/blog\/wp-content\/uploads\/2025\/11\/DevSecOps-1.jpg","jetpack_likes_enabled":true,"jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/pfDBOm-iy","jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/opstree.com\/blog\/wp-json\/wp\/v2\/posts\/1150"}],"collection":[{"href":"https:\/\/opstree.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/opstree.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/opstree.com\/blog\/wp-json\/wp\/v2\/users\/155574231"}],"replies":[{"embeddable":true,"href":"https:\/\/opstree.com\/blog\/wp-json\/wp\/v2\/comments?post=1150"}],"version-history":[{"count":12,"href":"https:\/\/opstree.com\/blog\/wp-json\/wp\/v2\/posts\/1150\/revisions"}],"predecessor-version":[{"id":1371,"href":"https:\/\/opstree.com\/blog\/wp-json\/wp\/v2\/posts\/1150\/revisions\/1371"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/opstree.com\/blog\/wp-json\/wp\/v2\/media\/29900"}],"wp:attachment":[{"href":"https:\/\/opstree.com\/blog\/wp-json\/wp\/v2\/media?parent=1150"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/opstree.com\/blog\/wp-json\/wp\/v2\/categories?post=1150"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/opstree.com\/blog\/wp-json\/wp\/v2\/tags?post=1150"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"\"](\"https:\/\/opstree.com\/blog\/\/wp-content\/uploads\/2019\/08\/31073-without_dockerapp.png\")
All of this points to the fact that there is no way to bundle the applications that use efficiently-bundled docker images. See the irony here? Well, there \u201cwas\u201d no way, until there was. Enter \u2018docker-app\u2019. This, relatively, new tool is the answer to packaging docker-compose applications. I came across it when I was, myself, struggling to re-use a docker-compose application I had written in another environment. As soon as I read about it, I had to try it, which I did and loved. It made the task much easier as it provided a template of compose file and a key-value store for environment dependent parameters. <\/p>\n\n\n\n
<\/p>\n\n\n\n![\"\"](\"https:\/\/opstree.com\/blog\/\/wp-content\/uploads\/2019\/08\/blog.png\")
\n\nInstalling docker-app is easy, though, there is one thing one should keep in mind: it can be installed as a plugin in docker-CLI or as standalone CLI tool itself. I will be installing it as a standalone CLI tool on linux. If you wish to install it as a plugin to docker-CLI and\/or on another OS, visit their Github page: https:\/\/github.com\/docker\/app<\/a> (Also, please visit github page for basics)\n\n\n
\n\n\nBefore continuing, please ensure you have docker-CLI and docker-compose installed.\n\n\n
\n\nPlease follow below steps to install docker-app:\n\n\n\n
<\/p>\n\n\n\n$ export OSTYPE=\"$(uname | tr A-Z a-z)\"\n$ curl -fsSL --output \"\/tmp\/docker-app-${OSTYPE}.tar.gz\" \\\n\"https:\/\/github.com\/docker\/app\/releases\/download\/v0.8.0\/docker-app-${OSTYPE}.tar.gz\"\n$ tar xf \"\/tmp\/docker-app-${OSTYPE}.tar.gz\" -C \/tmp\/\n$ install -b \"\/tmp\/docker-app-standalone-${OSTYPE}\" \/usr\/local\/bin\/docker-app<\/pre>\n\n\n\n$ cd ~\n$ mkdir spring3hibernate-app\n$ cd spring3hibernate-app\/<\/pre>\n\n\n\n
<\/p>\n\n\n\n$ git clone https:\/\/github.com\/opstree\/spring3hibernate.git<\/pre>\n\n\n\n
<\/p>\n\n\n\n$ vim ~\/spring3hibernate-app\/spring3hibernate\/src\/main\/resources\/database.properties<\/pre>\n\n\n\n
<\/p>\n\n\n\ndatabase.driver=com.mysql.jdbc.Driver\ndatabase.url=jdbc:mysql:\/\/mysql:3306\/employeedb\ndatabase.user=admin\ndatabase.password=password\nhibernate.dialect=org.hibernate.dialect.MySQLDialect\nhibernate.show_sql=true\nhibernate.hbm2ddl.auto=update\nupload.dir=c:\/uploads<\/pre>\n\n\n\n
<\/p>\n\n\n\n$ vim ~\/spring3hibernate-app\/spring3hibernate\/nginx\/default.conf\n<\/pre>\n\n\n\n
server {\n listen 80;\n server_name localhost;\n\n location \/ {\n stub_status on;\n proxy_pass http:\/\/springapp1:8080\/;\n\n }\n# redirect server error pages to the static page \/50x.html\n error_page 500 502 503 504 \/50x.html;\n location = \/50x.html {\n root \/usr\/share\/nginx\/html;\n }\n\n}<\/pre>\n\n\n\n
<\/p>\n\n\n\nupstream s3hbackend {\n server springapp1:8080;\n server springapp2:8080;\n}\nserver {\n listen 80;\n location \/ {\n stub_status on;\n proxy_pass http:\/\/s3hbackend;\n }\n \n # redirect server error pages to the static page \/50x.html\n error_page 500 502 503 504 \/50x.html;\n location = \/50x.html {\n root \/usr\/share\/nginx\/html;\n }\n\n}<\/pre>\n\n\n\n
\nwhen executing this command:\n
<\/p>\n\n\n\n$ docker-app init --single-file s3h<\/pre>\n\n\n\n
# This section contains your application metadata.\n# Version of the application\nversion: 0.1.0\n# Name of the application\nname: s3h\n# A short description of the application\ndescription:\n# List of application maintainers with name and email for each\nmaintainers:\n - name: ubuntu\n email:\n\u2028\n---\n# This section contains the Compose file that describes your application services.\nversion: \"3.6\"\nservices: {}\n\u2028\n---\n# This section contains the default values for your application parameters.\n\n{}<\/pre>\n\n\n\n
<\/p>\n\n\n\nversion: 0.1.0\nname: s3h\ndescription:\nmaintainers:\n - name: atbk5\n email: adeel.ahmad@opstree.com\n\u2028\n---\nversion: \"3.7\"\nservices:\n mysql:\n image: mysql:5.7\n container_name: mysql\n environment:\n MYSQL_ROOT_PASSWORD: ${mysql.env.rootpass}\n MYSQL_DATABASE: ${mysql.env.database}\n MYSQL_USER: ${mysql.env.user}\n MYSQL_PASSWORD: ${mysql.env.userpass}\n restart: always\n networks:\n - backend\n volumes:\n - db_data:\/var\/lib\/mysql\n\u2028\n spring1:\n depends_on:\n - mysql\n build:\n context: .\/spring3hibernate\/\n dockerfile: Dockerfile\n container_name: springapp1\n restart: always\n networks:\n - backend\n - frontend\n\u2028\n spring2:\n depends_on:\n - mysql\n build:\n context: .\/spring3hibernate\/\n dockerfile: Dockerfile\n container_name: springapp2\n restart: always\n networks:\n - backend\n - frontend\n x-enabled: ${spring.app2}\n\u2028\n nginx:\n depends_on:\n - spring1\n image: nginx:alpine\n container_name: proxy\n restart: always\n networks:\n - frontend\n volumes:\n - ${nginx.conf}:\/etc\/nginx\/conf.d\n ports:\n - ${nginx.port}:80\n x-enabled: ${nginx.status}\n\u2028\nnetworks:\n frontend:\n backend:\n\u2028\nvolumes:\n db_data:\n\u2028\n---\nmysql:\n env:\n rootpass: password\n database: employeedb\n user: admin\n userpass: password\nnginx:\n conf: \/home\/ubuntu\/dockerApp\/spring3hibernate\/nginx\/conf\/qa\n port: 81\n status: true\nspring:\n app2: false<\/pre>\n\n\n\n$ docker-app inspect<\/pre>\n\n\n\n
$ docker-app render<\/pre>\n\n\n\n
$ docker-app render --set nginx.status=\u201dfalse\u201d<\/pre>\n\n\n\n
$ docker-app render | docker-compose -f - up<\/pre>\n\n\n\n
<\/p>\n\n\n\n$ docker-app --help<\/pre>\n\n\n\n
\n\nAt this point, it will be better to create two directories in app home<\/em>: qa and prod. Create a file in qa: qa-params.yml. Another file in prod: prod-params.yml. Copy all parameters from above s3h.dockerapp file to qa-params.yaml (or not). More importantly, copy below changes in parameters to prod-params.yml\n\n\n\n<\/p>\n\n\n\nmysql:\n env:\n rootpass: password\n database: employeedb\n user: admin\n userpass: password\nnginx:\n conf: \/home\/ubuntu\/dockerApp\/spring3hibernate\/nginx\/conf\/prod\n port: 80\n status: true\nspring:\n app2: true<\/pre>\n\n\n\n
<\/p>\n\n\n\n$ docker-app render --parameters-file .\/prod\/prod-params.yaml<\/pre>\n\n\n\n
$ docker-app render --parameters-file .\/prod\/prod-params.yml | docker-compose -f - up<\/pre>\n\n\n\n
$ docker login<\/pre>\n\n\n\n
$ docker-app push --tag atbk5\/s3h.dockerapp:latest<\/pre>\n\n\n\n
<\/p>\n\n\n\n\nConclusion<\/strong>\n<\/h4>\n\n\n\n