Application Groups

Introduction

Application groups in Devtron streamline the deployment of microservices by enabling you to build and deploy multiple applications simultaneously. This feature is particularly beneficial when your microservices are interdependent, as a change in one service often triggers the need to redeploy others.

Accessing Application Groups

1. From the left sidebar, go to Application Groups

   
2. You will see a list of environments. Select the environment to view the application group.

   
3. The application group would contain the applications meant for deployment in the chosen environment.

   

As you can see, it has similar options as available under Applications:

• Overview

• Build & Deploy

• Build history

• Deployment history

• Configurations

First, we will walk you through the key features of Application Groups, followed by additional features that will help you perform bulk actions.

Key Features

Building Application Images

The Build & Deploy tab of your application group enables you to trigger the CI builds of one or more applications in bulk.

1. Select the applications using the checkboxes and click the Build Image button present at the bottom.

   
2. The Build image screen opens. Select the application and the commit for which you want to trigger the CI build.

   

1. Similar to application, you can also pass build parameters in application groups before triggering the build.

• Go to the Parameters tab.

  
• Click + Add parameter.

  
• Enter your key-value pair as shown below.

  
• You may follow the above steps for other applications too, and then click Start Build.

  

  

1. The builds will initiate, following which, you can close the Build image screen.

   

Changing Configurations

The Configurations tab of your application group allows you to configure the following:

• Deployment template

• ConfigMaps

• Secrets

As shown below, you can handle the configurations of more than one application from a single screen.

Deploying Applications

The Build & Deploy tab of your application group helps you deploy one or more applications in bulk.

1. Select the applications using the checkboxes and click the Deploy button present at the bottom.

   
2. Select the desired container image that you want to deploy for respective application.

   

   Repeat the step for other applications too.

   
3. If you wish, you can deploy all applications in an Application Group using a single deployment strategy; select the preferred deployment strategy for all the applications and click Deploy. By default, all applications will be deployed using their respective default strategies.

   

• Deployment feasibility page will open; in case for any application, the selected deployment strategy is not configured, you can select one of the configured strategies for that application. If you do not select a configured deployment strategy, deployment will be skipped for that particular application.

  

1. The deployment will be initiated, following which, you can close the screen as shown below.

   

Once the deployment is successful, the pipelines will show Succeeded.

Managing Traffic

While deployment, Devtron allows you to manage your Canary and Blue-Green deployments by providing visibility and easy controls to manage how new versions (releases) are shared with users.

To do so, follow the below steps:

1. Go to Overview and Click on Manage Traffic.

   
2. Select the required applications, a side window will appear displaying all the eligible rollouts.

3. You can take the following actions based on the deployment strategy of the application

• For Canary Deployments, you can either choose to initiate the next step or to initiate the full rollout.

  
• For Blue Green deployments, you can either choose to Swap Traffic, or you can choose Skip & Promote Full.

  • Swap Traffic: This will swap the traffic from the current deployment to the application latest deployment.

    
  • Skip & Promote Full: While deploying, this will directly deploy the whole traffic to application latest deployment.

    

1. Click Initiate Eligible Rollouts to implement the actions.

   

   

Additional Features

Clone Pipelines

This feature aims at helping the user clone existing CI/CD pipelines for new target environments in multiple applications. The configurations present in the given CI/CD pipeline also get copied to the cloned pipelines (refer the below table).

Use Case: Let's say you have 'n' number of apps deployed to a development environment named dev-env. Later, a few testers joined your team, thus necessitating the addition of a testing environment (test-env) with those same apps deployed. Manually creating the pipelines and configuring them for test-env environment in each app might be impractical. Therefore, we recommend you to use the cloning feature.

Methods of Cloning

This feature gives you two methods of cloning:

1. New Workflow: Creates a new workflow and clones the source CI and CD pipeline. Gives you the flexibility to tweak the cloned CI (e.g., changing code branch for build) too.

   
2. Source Workflow: Uses the same workflow and clones only the source CD pipeline, thus keeping the original CI pipeline unchanged.

   

Steps to Clone Pipelines

1. Go to Application Groups and click the source environment from the list.

   
2. Select the applications whose pipelines you wish to clone and click Clone Pipeline Config.

   
3. From the dropdown, select the target environment for which pipelines should be created for selected applications.

   
4. Select the workflow where you wish to create deployment pipeline: New Workflow or Workflow as source environment. Refer Methods of Cloning to know which option will fulfill your requirement.

   
5. Click Clone in new workflow or Clone in source workflow (depending on the option you selected in the previous step).

   

Hibernating and Unhibernating Apps

Since every application comes with an option to hibernate, the same is true for application groups. Using application group, you can hibernate one or more applications belonging to the same environment if you do not want them to consume resources (replica count will be set to 0).

In other words, you can hibernate running applications or unhibernate hibernated applications as per your requirement.

Hibernation Process

1. In the Overview page of your application group, use the checkboxes to choose the applications you wish to hibernate, and click the Hibernate button.

   
2. Confirm the hibernation.

   
3. Hibernation will initiate as shown below. You may close the window.

   

Your applications pods would be scaled down and would stop incurring costs.

Unhibernation Process

1. In the same Overview page, you can use the checkboxes to choose the hibernated applications you wish to unhibernate, and click the Unhibernate button.

   
2. Confirm the unhibernation.

   
3. Unhibernation will initiate as shown below. You may close the window.

   

Your applications would be up and running in some time.

Restart Workloads

Restarting workloads might be necessary if you want your new code or configuration to come into effect, or you are experiencing issues like crashing of pods.

Using application group, you can select the workloads (i.e., Pod, Deployment, ReplicaSet, etc.) of specific applications and restart them.

1. Use the checkboxes to choose the applications whose workloads you wish to restart, and click the Restart Workload button.

   
2. Next to the application, click the workload dropdown to view all the individual workloads of an application. Choose only the ones you wish to restart.

   

   Moreover, you can easily select, deselect, or choose multiple workloads as shown below.

   
3. Click Restart Workloads.

   

Restarting workloads might take time depending on the number of applications.

Filtering Applications

Assume you have multiple applications (maybe 10, 50, 100, or more) showing up in an application group. If you want to limit your operations (build/deploy/other) to a specific set of applications, the filter feature will help you narrow down the list. Thus, you will see only those applications you select from the filter (be it on the Overview page, Build & Deploy page, and so on.)

1. Click the filter next to the application group as shown below.

   
2. The filter will show all the applications present in the group. Click to select the relevant ones.

   
3. The filter narrows down the list of applications as shown below.

   
4. (Optional) If required, you can save the filter for future use by clicking Save selection as filter.

   
5. Add a name and description to the filter to help you know its purpose, and click Save.

   

Now when you access the application group, your saved filter will be visible on top.

Changing Branch

Assume you have a few applications whose build pipelines fetch from the main branch of your code repository. However, you decided to maintain a master branch, and you want all the upcoming CI builds to consider the master branch as the source. Devtron provides you the option to change the branch at both levels—individual application as well as application group.

1. In the Build & Deploy tab of your application group, select the intended applications and click the Change Branch button present at the bottom.

   
2. Enter the new branch name. If your build pipeline has Branch Regex as the Source Type, you must ensure your new branch name matches the regex (regular expression) provided in that build pipeline. Once done, click Update Branch.