Pushing your app with Cloud Foundry CLI (cf push)

The cf CLI command cf push pushes apps to TAS for VMs. There are two main ways to run the cf push command:

• Run cf push APP-NAME to push an app the easiest way, using default settings. For more information, see Push with Defaults below.

• Run the cf push command with flags and helper files to customize:

  • How the pushed app runs, including its route, instance count, disk size limits, memory limits, and log rate limits.
  • How the push process works: whether it’s configured with a manifest, runs a startup script, or limits files uploaded to the Cloud Controller.

For more information about custom settings, see Push with Custom Settings below.

For an explanation of what TAS for VMs does when you run cf push, see How Apps are Staged.

For information about the lifecycle of an app, see App Container Lifecycle.

Prerequisites

Before you push your app to TAS for VMs, ensure the following:

• Your app is cloud-ready. TAS for VMs behaviors related to file storage, HTTP sessions, and port usage may require modifications to your app. To prepare an app to be pushed to TAS for VMs, see:

  • Considerations for Designing and Running an App in the Cloud
  • Any Buildpacks guides specific to your app language or framework, such as Getting Started Deploying Ruby on Rails Apps

• Your TAS for VMs deployment supports the type of app you are going to push, or you have the URL of an externally-available buildpack that can stage the app.

• All required app resources are uploaded. For example, you may need to include a database driver.

• You have your target and credentials:

  • The API endpoint for your TAS for VMs deployment. Also known as the target URL, this is the URL of the Cloud Controller in your TAS for VMs instance.
  • Your username and password for your TAS for VMs deployment.

• You are logged into your app’s target org and space.

  1. Decide the org and space where you want to push your app. You may have access to one or more org and space.
  2. Log into this target org and space with cf login.

• Your app can access every service that it uses, because an instance of the service runs in, or is shared with, the app’s space.

  • For information about sharing service instances across spaces, see Sharing Service Instances.
  • Typical services that cloud apps use include databases, message queues, and key-value stores.

Push with defaults

To push an app with default settings:

1. Choose a name for the app. The app name must consist of alphanumeric characters and be unique to your TAS for VMs deployment.

   • To use an app name that is not unique, customize the app’s route as described in Customize the Route below.
   • Apps running at their default routes require unique names because default routes are based on app names, and all routes must be globally unique.

2. Run:

   cf push APP-NAME
   

   Where APP-NAME is the name of the app.

Default route

An app’s route is the URL at which it runs. TAS for VMs assembles the route for a pushed app from a hostname and a domain.

By default, TAS for VMs sets the hostname and domain as follows:

• Hostname: The name of the app, as specified in the cf push command. If the app name contains underscores, TAS for VMs converts them to hyphens when creating the app’s route.

• Domain: The default apps domain for your TAS for VMs deployment.

For example, an app named example-app running on TAS for VMs with an apps domain apps.example.com would run at the URL https://example-app.apps.example.com by default.

For more information about routes and domains, see Routes and Domains.

Example session

The following example terminal output for cf push example-app demonstrates how TAS for VMs assigns default values to an app you push:

Creating app example-app in org example-org / space development as [email protected]...
OK

Creating route example-app.shared-domain.example.com...
OK

Binding example-app.shared-domain.example.com to example-app...
OK

Uploading example-app...
Uploading app: 560.1K, 9 files
OK

Starting app example-app in org example-org / space development as [email protected]...
-----> Downloaded app package (552K)
OK
-----> Using Ruby version: ruby-1.9.3
-----> Installing dependencies using Bundler version 1.3.2
       Running: bundle install --without development:test --path
         vendor/bundle --binstubs vendor/bundle/bin --deployment
       Installing rack (1.5.1)
       Installing rack-protection (1.3.2)
       Installing tilt (1.3.3)
       Installing sinatra (1.3.4)
       Using bundler (1.3.2)
       Updating files in vendor/cache
       Your bundle is complete! It was installed into ./vendor/bundle
       Cleaning up the bundler cache.
-----> Uploading droplet (23M)

1 of 1 instances running

App started

Showing health and status for app example-app in org example-org / space development as [email protected]...
OK

requested state: started
instances: 1/1
usage: 1G x 1 instances
urls: example-app.shared-domain.example.com

     state     since                    cpu    memory        disk          logging
#0   running   2022-09-14 05:07:18 PM   0.0%   18.5M of 1G   52.5M of 1G   3B/s of 1M/s

Push with custom cettings

Pushing an app with with custom settings typically proceeds as follows:

1. (Optional) Customize Basic App Settings

2. (Optional) Customize the Route

3. (Optional) Limit the Upload Files

4. (Optional) Configure App Initialization

5. Custom Push the App

6. (Optional) Configure App Services

The sections below detail these steps.

Customize basic app settings (optional)

Basic settings to customize when pushing an app include:

• Name: You can use any series of alphanumeric characters as the name of your app.

• Instances: Generally speaking, the more app instances you run, the less downtime your app will experience. If your app is still in development, running a single instance can simplify troubleshooting. For any production app, VMware recommends a minimum of two instances.

• Memory limit: The maximum amount of memory that each instance of your app can consume. If an app instance exceeds this limit, TAS for VMs restarts the instance. If an app instance exceeds its memory limit repeatedly in a short period of time, TAS for VMs delays restarting the app instance.

• Disk space limit: The maximum amount of disk space that each instance of your app can consume. If an app instance exceeds this limit, TAS for VMs restarts the instance. If an app instance exceeds its disk space limit repeatedly in a short period of time, TAS for VMs delays restarting the app instance.

• Log rate limit: The maximum number of logs that each instance of your app can send to Loggregator. If an app instance exceeds this limit, TAS for VMs drops the excess logs and reports doing so.

• Start command: This is the command that TAS for VMs uses to start each instance of your app. This start command differs by app framework.

Limit the upload files (optional)

By default, TAS for VMs uploads all app files except version control files and folders with names such as .svn, .git, and _darcs.

VMware recommends that you explicitly exclude extraneous files residing within your app directory, particularly if your app is large. For example, if you build your app locally and push it as a binary, you can save resources by not uploading any of the app’s source code.

To exclude files from upload:

1. Create a .cfignore file that lists the files to exclude.

2. Save the .cfignore file to the directory where you run the cf push command.

For more information, see Ignore Unnecessary Files When Pushing in Considerations for Designing and Running an App in the Cloud.

Configure app initialization (optional)

You can configure cf push to run custom initialization tasks for an app.

These tasks run after TAS for VMs loads the app droplet but before it launches the app itself to let the initialization script access the app language runtime environment. For example, your script can map values from $VCAP_SERVICES into other environment variables or a config file that the app uses.

Additional notes for including important information about configuring app initialization when you use certain buildpacks:

• Java: Initialization scripts for the Java buildpack require additional configuration.For more information, see How to Modify the Application Container Environment prior to Application Execution in the VMware Tanzu Knowledge Base.

• PHP: TAS for VMs does not support initialization scripts for the PHP buildpack versions prior to v4.3.18. If you use one of these buildpack versions, your app hosts the .profile script’s contents. This means that any app staged using the affected buildpack versions can leak credentials placed in the .profile script.

To run initialization tasks:

1. Create a .profile script that contains the initialization tasks.

2. Save the .profile script to the directory where you run the cf push command.

The following example .profile file uses bash to set a value for the environment variable LANG:

# Set the default LANG for your apps
export LANG=en_US.UTF-8

Setting this value at the operating system level allows the app to determine which language to use for error messages and instructions, collating sequences, and date formats.

Your app root directory may also include a .profile.d directory that contains bash scripts that perform initialization tasks for the buildpack. Developers should not edit these scripts unless they are using a custom buildpack. For more information about custom buildpacks, see Custom Buildpacks.

Initialization tasks as described here are also called pre-runtime hooks and .profile tasks.

Custom push the app

To specify custom options when pushing an app with cf push, you can include them in one or both of the following:

• The cf push command itself.

• A manifest file.

  • The manifest file must be named manifest.yml and reside in the directory where you run cf push.
  • The manifest can include the app name, which lets you run cf push with no arguments.
  • The manifest can also include a services block that lists service instances for the app to bind to automatically. For more information, see Services in App Manifest Attribute Reference.

For information about how app settings change from push to push, including how command-line options, manifests, and commands like cf scale interact, see Deploying with App Manifests.

For a full list of cf push options, see the Cloud Foundry CLI Reference Guide.

Configure app services (optional)

If a newly-pushed app has the same name and route as an older app version, the new app retains the service bindings and service configuration of the previously-pushed version.

For apps that are not already set up for the services that they use:

1. Bind the services to the app. For more information about services, see Services Overview.

2. (Optional) Configure the app with the service URL and credentials, if needed. For more information, see Configuring Service Connections.

Build custom push workflows (optional)

The CF CLI includes composible push sub-step commands that empower you to build your own push. These are useful if the default behavior of cf push does not match your needs, or if you want to implement more complicated app build, promotion, and run workflows.

App updates and downtime

By default, when you push an app that is already running, TAS for VMs stops all existing instances of that app. Users who try to access the app see a 404 Not Found message while cf push runs.

When old and new versions of your app can run simultaneously, you can avoid app downtime by using Rolling deployments. Alternatively, you can use the blue-green deployment method to swap routes between app versions running in parallel. For more information, see Using blue-green deployment to reduce downtime and risk.

With some app updates, old and new versions of your code should never run at the same time. A worst-case example is if your app update migrates a database schema, causing old app instances to fail and lose user data. To prevent this, you must stop all running instances of your app before you push the new version.

Troubleshoot app push problems

If your app does not start on TAS for VMs, first ensure that the app can run locally.

To troubleshoot your app in the cloud using the cf CLI, see Troubleshoot App Deployment and Health.