How Do I Use Helm to Manage Releases of My Applications on Kubernetes?

Helm is a strong package manager made for managing applications on Kubernetes. It makes it easier to deploy and keep applications running. With Helm, we can define, install, and upgrade applications using a simple command line. This helps us manage Kubernetes better and makes fewer mistakes.

In this article, we will learn how to use Helm to manage our application releases on Kubernetes. We will talk about important ideas like what Helm is and why it matters for Kubernetes. We will also see how to install Helm on our local machines. Next, we will create Helm charts for our applications, deploy them using Helm, manage our releases, and do rollbacks. We will also look at Helm hooks. Plus, we will share real-life examples of using Helm, how to upgrade and uninstall releases, and answer common questions about Helm.

How Can We Use Helm to Manage Releases of Our Applications on Kubernetes?
What is Helm and Why Should We Use It for Kubernetes?
How to Install Helm on Our Local Machine?
How Do We Create a Helm Chart for Our Application?
How Can We Deploy Our Application Using Helm?
How Do We Manage Helm Releases and Rollbacks?
What Are Helm Hooks and How Can We Use Them?
What Are Real-Life Use Cases for Using Helm on Kubernetes?
How Do We Upgrade and Uninstall Releases with Helm?
Frequently Asked Questions

For more reading on Kubernetes, we can check these articles: What is Kubernetes and How Does It Simplify Container Management?, How Do We Use Helm to Deploy a Complex Application on Kubernetes?, and How Do We Create and Manage Helm Charts?.

What is Helm and Why Use It for Kubernetes?

Helm is a tool for managing packages on Kubernetes. It makes it easier to install and manage applications on Kubernetes clusters. With Helm, we can define, install, and upgrade complex Kubernetes apps using a simple command line. Helm helps us manage Kubernetes resources better. It makes it simpler for developers and operators to keep applications in the state we want.

Key Features of Helm:

Chart System: Helm uses a format called “charts.” Charts are groups of ready-made Kubernetes resources. They help us deploy apps easily and in the same way every time.
Release Management: Helm keeps track of the state of apps on Kubernetes in releases. We can upgrade, roll back, or delete each release. This gives us better control over app versions.
Dependency Management: Helm looks after the dependencies between charts. It makes sure all parts are installed and set up properly.
Parameterization: We can customize Helm charts using values files or command line options. This gives us flexible ways to set up our deployments.
Rollback Functionality: If an upgrade does not work or causes problems, Helm lets us go back to an older version easily. This helps reduce downtime and issues.

Why Use Helm for Kubernetes?

Simplicity and Efficiency: Helm hides the complicated parts of Kubernetes. We can deploy apps with just one command. This makes the deployment faster.
Standardization: Using Helm charts helps teams follow the same practices. Charts can be shared and reused, making deployments more consistent.
Community Support: Helm has a big and active community. They offer many ready-to-use charts for popular apps. This saves us time on common deployments.
Integration with CI/CD: Helm works well with continuous integration and delivery (CI/CD) systems. This allows us to automate deployments and rollbacks.

To start using Helm and manage our Kubernetes apps better, we can learn how to install Helm on your local machine.

How to Install Helm on Your Local Machine?

To install Helm on your local machine, we need to follow some steps based on your operating system.

For macOS

Using Homebrew:
```
brew install helm
```
Check Installation:
```
helm version
```

For Linux

Get the Helm Binary:

curl https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 | bash

Check Installation:
```
helm version
```

For Windows

Using Chocolatey:
```
choco install kubernetes-helm
```
Check Installation:
```
helm version
```

Manual Installation

Get the Latest Release: Go to the Helm Releases page. Download the right binary for your operating system.
Install the Binary:
- Move the binary to a folder that is in your PATH. For example:
```
sudo mv helm /usr/local/bin/
```
Check Installation:
```
helm version
```

Additional Setup

After we install Helm, we must initialize it by adding a repository:

helm repo add stable https://charts.helm.sh/stable

We should update the repository to make sure our Helm installation is ready:

helm repo update

Now we can use Helm to manage our Kubernetes applications well. For more tutorials, we can check out how to create and manage Helm charts.

How Do We Create a Helm Chart for Our Application?

To create a Helm chart for our application, we can follow these steps:

Install Helm (if we do not have it yet):

curl https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 | bash

Create a New Chart: We can use the helm create command to start a new chart.
```
helm create my-application
```

Understand the Chart Structure: The chart we create will have this structure:

my-application/
├── Chart.yaml         # Info about the chart
├── values.yaml        # Default values for templates
├── charts/            # Dependency charts
├── templates/         # Template files
│   ├── deployment.yaml # Kubernetes deployment file
│   ├── service.yaml    # Kubernetes service file
│   ├── _helpers.tpl     # Helper templates
│   └── ...

Edit Chart.yaml: We should change the Chart.yaml file to set info like name, version, and description.
```
apiVersion: v2
name: my-application
description: A Helm chart for Kubernetes
version: 1.0.0
```

Configure Values in values.yaml: We need to update values.yaml to set default values for our application settings.

replicaCount: 2
image:
  repository: my-repo/my-image
  tag: "latest"
service:
  type: ClusterIP
  port: 80

Modify Deployment Template: We can edit templates/deployment.yaml to change our deployment. Example:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ include "my-application.fullname" . }}
  labels:
    {{- include "my-application.labels" . | nindent 4 }}
spec:
  replicas: {{ .Values.replicaCount }}
  selector:
    matchLabels:
      app: {{ include "my-application.name" . }}
  template:
    metadata:
      labels:
        app: {{ include "my-application.name" . }}
    spec:
      containers:
        - name: {{ .Chart.Name }}
          image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
          ports:
            - containerPort: 80

Add Additional Templates: We can create other Kubernetes files as we need in the templates/ folder, like ConfigMaps, Secrets, Ingress, and more.
Package the Chart: To package our Helm chart for sharing, we run:
```
helm package my-application
```
Test the Chart: We can use the helm install command to deploy our chart in a Kubernetes cluster.
```
helm install my-release ./my-application
```

These steps will help us create a Helm chart for our application. This way, we can manage its deployment and settings well on Kubernetes. For more details, we can check this detailed guide on creating and managing Helm charts.

How Can We Deploy Our Application Using Helm?

To deploy our application using Helm on Kubernetes, we need to follow some steps. We will initialize Helm, create a Helm chart if we don’t have one, and then deploy the chart. Here is how we can do it:

Step 1: Initialize Helm

If we have not initialized Helm yet, we can run this command:

helm init

Step 2: Create a Helm Chart

If we need to create a new Helm chart for our application, we can use this command:

helm create my-app

This command will make a folder called my-app with the files and structure we need.

Step 3: Configure Our Chart

Next, we edit the values.yaml file inside our chart folder. We need to set the values for our application like image repository, tag, replicas, and service type:

replicaCount: 2

image:
  repository: my-app-image
  tag: "1.0"
  pullPolicy: IfNotPresent

service:
  type: ClusterIP
  port: 80

Step 4: Deploy the Chart

Now we can deploy the Helm chart to our Kubernetes cluster by running this command:

helm install my-app ./my-app

This command will deploy our application with the name my-app.

Step 5: Verify the Deployment

To check how our deployment is doing, we can use:

helm list

We can also check the status of the application with:

kubectl get all -l app=my-app

Step 6: Access Our Application

If our application has a service, we can access it based on the service type we set (ClusterIP, NodePort, or LoadBalancer). For example, if we used NodePort, we can find the port number by running:

kubectl get service my-app

Then we can access our application using the Node’s IP and the port we got.

By following these steps, we can deploy our applications using Helm on Kubernetes. For more details on Helm charts and how to deploy, we can check this article on creating and managing Helm charts.

How Do We Manage Helm Releases and Rollbacks?

Managing releases and rollbacks in Helm is very important for keeping our applications on Kubernetes running well. Helm gives us a simple command-line tool to manage deployments, upgrades, and rollbacks of our applications.

Managing Helm Releases

List Releases: To see the current releases, we can use this command:
```
helm list
```
Get Release Details: To get details about a specific release, we run:
```
helm get all <release-name>
```
Upgrade a Release: If we want to upgrade a release with a new chart version or configuration, we use:
```
helm upgrade <release-name> <chart-name> [flags]
```
For example:
```
helm upgrade my-app my-app-chart --set image.tag=2.0
```
Rollback a Release: If the upgrade does not work or we need to go back to an old version, we can do a rollback:
```
helm rollback <release-name> [revision]
```
For example:
```
helm rollback my-app 1
```
Delete a Release: To remove a release from our cluster, we use:
```
helm uninstall <release-name>
```

Rollback Specifics

Identifying Revisions: To see the history of a release and its revisions, we can use: bash helm history <release-name>
Rollback to a Specific Revision: If we want to go back to a specific revision, we need to choose the revision number like we show above.

By using these commands, we can manage Helm releases easily. This helps our applications run smoothly on Kubernetes. We can also quickly fix problems by rolling back to stable versions. If we want to learn more about Helm and its features, we can check this article on Helm and Kubernetes.

What Are Helm Hooks and How to Use Them?

Helm hooks are special tags. They help us run actions at certain points in the Helm release process. We can run scripts or jobs before or after events like installing, upgrading, or deleting Helm releases. Hooks help us do tasks like database migrations, sending alerts, or cleaning up.

Common Helm Hook Types

pre-install: Runs before we install a release.
post-install: Runs after we install a release.
pre-upgrade: Runs before we upgrade a release.
post-upgrade: Runs after we upgrade a release.
pre-delete: Runs before we delete a release.
post-delete: Runs after we delete a release.
test: Runs tests for the release.

Example of a Helm Hook

To make a hook in your Helm chart, we can add a tag to our Kubernetes resource YAML file. Here is an example of a job that runs a migration before we install the application:

apiVersion: batch/v1
kind: Job
metadata:
  name: my-migration-job
  annotations:
    "helm.sh/hook": pre-install
    "helm.sh/hook-delete-policy": before-hook-creation
spec:
  template:
    spec:
      containers:
        - name: migrate
          image: my-database-migration-image
          command: ["sh", "-c", "run-migration.sh"]
      restartPolicy: Never

Hook Delete Policies

We can set how Helm handles hooks after they run using the helm.sh/hook-delete-policy tag. The policies include:

before-hook-creation: Delete the old hook before making a new one.
hook-succeeded: Keep the hook if it worked.
hook-failed: Keep the hook if it did not work.

Running Helm Hooks

To use hooks, we just deploy our Helm chart like normal with the helm install or helm upgrade commands. The hooks we made will trigger at the right times.

Best Practices

Make hooks idempotent. This means running them many times should not cause problems.
Use hooks for actions that need to happen at certain times during deployment.
Watch how hooks run. If they fail, it can cause problems with deployments.

For more information on using Helm in our Kubernetes setups, check this article on how to create and manage Helm charts.

What Are Real-Life Use Cases for Using Helm on Kubernetes?

Helm is a great tool for managing applications on Kubernetes. Here are some real-life examples of how we can use Helm in a Kubernetes space:

Microservices Deployment
Helm helps us deploy complex microservices applications with charts. Each microservice gets its own chart. This makes it easier to manage and update them. For example, if we have an e-commerce app, we can create separate charts for the user service, product service, and order service.
Continuous Integration and Continuous Deployment (CI/CD)
We can use Helm with CI/CD pipelines to make deployments better. With Helm charts, teams can automate app deployments to different environments like development, staging, and production. This needs less manual work. For instance, a CI/CD pipeline can run a Helm upgrade command to release a new app version after testing.
```
helm upgrade my-release my-chart --install --set image.tag=latest
```
Version Management
Helm is good at managing app versions. Each release can have a version number. This way, we can roll back to an earlier version if something goes wrong. This is very helpful in production where we need stability.
```
helm rollback my-release 1
```
Configuration Management
Helm charts make it easy to manage configurations using values files. We can keep different settings for different environments. For example, a values file can have different database connection strings for development and production.
```
# values.yaml
database:
  host: db.prod.example.com
  user: prod_user
  password: prod_password
```
Managing Dependencies
Helm helps us manage dependencies between charts. If a web app needs a Redis cache, we can add this dependency in the Helm chart. This way, we make sure that the Redis service gets installed before the web app.
```
dependencies:
  - name: redis
    version: 14.0.0
    repository: https://charts.bitnami.com/bitnami
```
Multi-Environment Deployments
With Helm, we can deploy the same app in many environments with different settings. This makes it easier to manage different Kubernetes manifests.
Application Upgrades and Rollbacks
Helm makes upgrading apps simple. When we have new features or fixes, we can use a Helm upgrade command to apply changes. If something goes wrong, it is easy to roll back.
```
helm upgrade my-release my-chart
```
Custom Resource Definitions (CRDs)
Helm can manage CRDs. These are important for deploying Kubernetes apps that need custom resources. This is useful for operators and apps that expand Kubernetes abilities.
Ecosystem Standardization
Using Helm helps us standardize how we package and deploy apps in Kubernetes. This encourages best practices and helps new team members learn faster.
Community Charts Usage
Helm gives us access to many community charts. This helps us quickly deploy popular apps. For example, we can deploy a WordPress site or a Prometheus monitoring stack with just a few commands.
```
helm repo add stable https://charts.helm.sh/stable
helm install my-wordpress stable/wordpress
```

In conclusion, Helm is very important for making app management on Kubernetes easier. It becomes a key tool for DevOps teams. For more details on how to deploy apps with Helm, we can check out this article on Helm and Kubernetes deployments.

How Do We Upgrade and Uninstall Releases with Helm?

To upgrade and uninstall releases with Helm, we use the helm upgrade and helm uninstall commands. Here is how we can do each step.

Upgrading a Release

Prepare the new chart or updated values: We can change the existing Helm chart or give a new set of values.
Use the helm upgrade command:
```
helm upgrade <release-name> <chart-name> [flags]
```
- <release-name>: This is the name of the release we want to upgrade.
- <chart-name>: This is the path to the updated chart or the name from the repository.
- We can also add a values file with -f like this:
```
helm upgrade <release-name> <chart-name> -f values.yaml
```

Example Command:

helm upgrade my-app ./my-app-chart -f values-production.yaml

Uninstalling a Release

Use the helm uninstall command:
```
helm uninstall <release-name> [flags]
```
- <release-name>: This is the name of the release we want to uninstall.
Example Command:
```
helm uninstall my-app
```
Additional Options:
- We can use the --dry-run flag with both commands to see what will happen without making any changes.
- If we want to keep the release history after uninstalling, we can use the --keep-history flag like this:
```
helm uninstall my-app --keep-history
```

With these commands, we can manage upgrades and uninstall our apps on Kubernetes using Helm. For more details on managing Helm releases, we can check this article on Helm.

Frequently Asked Questions

What is Helm in Kubernetes?

We can say Helm is a helpful package manager for Kubernetes. It makes it easier to deploy and manage applications. With Helm, we can define, install, and manage Kubernetes applications using Helm charts. These charts are sets of ready-made Kubernetes resources. Using Helm helps us deploy complex applications and manage their lifecycle. So, it is an important tool for people who use Kubernetes.

How do I install Helm on my local machine?

To install Helm on our local machine, we first need to download the latest Helm release from the Helm GitHub repository. Then, we extract the downloaded file and move the helm binary to a folder in our PATH, like /usr/local/bin. After we install it, we can check if it works by typing helm version in the terminal.

How do I create a Helm chart for my application?

Creating a Helm chart is easy with the Helm CLI. We start by running helm create <chart-name>. This command makes a folder structure for our chart. Next, we can change the values.yaml file to set the configuration values for our application. After that, we add Kubernetes templates in the templates/ folder. These templates describe the resources our application needs.

How can I upgrade and uninstall releases using Helm?

To upgrade a release, we use the command helm upgrade <release-name> <chart-name>. This command updates the existing release with the changes in our Helm chart. If we want to uninstall a release, we just run helm uninstall <release-name>. This command removes all resources linked to that release from our Kubernetes cluster.

What are Helm hooks and how do I use them?

Helm hooks are special scripts. They let us do actions at certain points in the release lifecycle. For example, we can set a hook to run before or after an install, upgrade, or delete action. To use a hook, we add annotations in our Kubernetes resource definitions in the Helm chart. This way, we can automate tasks like database migration or cleanup during deployments.

For more information on Kubernetes and Helm, we can check these articles: What is Kubernetes and How Does It Simplify Container Management? and How Do I Use Helm to Deploy a Complex Application on Kubernetes?.