In this article we are going to cover GitOps and ArgoCD Interview Questions and Answers | GitOps Interview Questions and Answers.
GitOps and ArgoCD Interview Questions and Answers
1. What is GitOps?
GitOps is a set of practices that uses Git as the single source of truth for infrastructure configuration. It automates the process of deploying and managing infrastructure by ensuring that the state of the infrastructure is always in sync with the desired state defined in Git, yeah you read it right, in a Git repository, enhances collaboration, promotes transparency, and reduces the chances of errors.
2. What is difference between DevOps and GitOps?
|It Focus on Automation and frequent deployments||It Focus on Correctness; doing DevOps correctly|
|DevOps main tool is CI/CD pipeline||GitOps main tool is Git|
|DevOps Supply chain management, Cloud Configuration as Code, etc.||GitOps Kubernetes, Controller (e.g., Operator), separate CI/CD pipelines, Infrastructure as a Code, etc.|
|DevOps Flexibility Less strict and more open||GitOps Flexibility Stricter and less open|
|Less focus on correctness||Designed with correctness|
3. What are benefits of GitOps?
Scalability: GitOps can be scaled to manage large and complex infrastructure environments.
Reliability: GitOps ensures that the infrastructure is always in a healthy state by continuously verifying the actual state against the desired state.
Security: GitOps can be used to enforce security policies by defining the desired state of the infrastructure in Git.
Collaboration: GitOps makes it easy for teams to collaborate on infrastructure management by using a single source of truth.
Auditability: GitOps provides a complete audit trail of all changes to the infrastructure, which can be used to troubleshoot problems or comply with regulations.
4. Why do we need GitOps?
GitOps came into existence to address the challenges of managing infrastructure in a complex and dynamic environment. Traditional approaches to infrastructure management, such as manual configuration and ad-hoc scripting, are not scalable or reliable. GitOps provides a more scalable, reliable, and secure way to manage infrastructure.
5. What are GitOps Tools?
a. Flux : Flux was created in 2016 by Weaveworks.
It is a GitOps operator for your Kubernetes cluster. It periodically pulls remote Git repository and looks for any new change in the manifest files. In case there is a change in the repository, it applies the changes to the cluster.
b. ArgoCD: ArgoCD is also a GitOps operator but with a web user interface. It simulated your GitOps pipeline with visuals and charts. You can also visualize your environment and application configurations using this tool.
c. Jenkins X: Jenkins X is a CICD solution for Kubernetes clusters but different than classic Jenkins. It is used as a GitOps tool for cluster creation, container deployment, automatic rollback, etc. When a change is pushed in a git repository, Jenkin X will read and update its configurations after a build is triggered.
d. WKSctl: WKSctl is a GitOps tool that uses Git commits to manage the Kubernetes cluster. GitOps running mode is where a cluster is configured based on the details present in cluster.yml and machines.yml files saved on Git.
e. Gitkube: Gitkube is ideal for development where it uses Git push to build and deploy docker images on a Kubernetes cluster. It is very easy to setup and requires simple public key-based authentication.
f. Quay: Quay is managed by Red-Hat and is used for image management/image registry. It provides security and reliability for image management. It doesn’t depend on GitHub; rather, it works with an on-premises image registry.
g. Helm Operator: Helm Operator is an open-source Kubernetes operator to manage helm chart releases declaratively. When combined with flux, it becomes a proper GitOps solution for automating the releases.
What is difference between Jenkins and ArgoCD?
Here’s a comparison of Jenkins and Argo CD in a table format, highlighting the key differences between these two tools:
|Purpose||Continuous Integration and Continuous Deployment (CI/CD) tool primarily for building, testing, and deploying applications.||Continuous Deployment tool for declarative, GitOps-style application delivery.|
|Use Case||Used for automating the entire software development process, from code integration and building to testing and deployment.||Focuses on automating application deployment and configuration management in a Kubernetes environment.|
|Workflow Automation||Provides a wide range of build and automation features, including plugins for various tasks.||Focuses on declarative, version-controlled application deployments.|
|Configuration||Uses pipeline definitions (Jenkinsfile) to define build and deployment processes.||Uses Kubernetes manifests and declarative configuration files to define application deployment and sync policies.|
|Integrations||Offers a large number of integrations through plugins, allowing you to connect to various tools and services.||Integrates with Kubernetes and Helm charts for application deployments and Git repositories for configuration.|
|Extensibility||Highly extensible through plugins and a vast plugin ecosystem.||Offers an extension mechanism using Kustomize overlays and Helm charts.|
|Deployment Method||Typically deploys applications to various environments using scripts, custom logic, and plugins.||Enforces GitOps principles by synchronizing applications with Git repositories.|
|Deployment Target||Can be used for various target platforms, including Kubernetes, but not limited to it.||Specifically designed for Kubernetes clusters, ideal for managing applications in a Kubernetes-native way.|
|UI and User Experience||Provides a web-based GUI for job configuration and monitoring.||Offers a web-based UI for managing application deployments and monitoring sync status.|
|Version Control Integration||Supports version control but does not enforce GitOps-style practices.||Relies on Git as the version control system and enforces GitOps practices for application deployments.|
|Rollback and Version Control||Rollback and version control are available but may require custom scripting or plugins.||Built-in support for declarative application rollback and version-controlled application definitions.|
|Complexity||Suitable for a wide range of automation needs, from simple to complex workflows.||Specialized for Kubernetes-based application deployment and may be less suitable for general-purpose CI/CD.|
|Learning Curve||Requires some learning to set up and configure pipelines, especially for beginners.||Designed with simplicity in mind, making it easier to get started with GitOps workflows.|
|Community and Ecosystem||Jenkins has a large and active community with a vast number of plugins and integrations.||Argo CD has a growing community focused on GitOps for Kubernetes.|
|Licensing||Jenkins is open-source and available under the MIT License.||Argo CD is also open-source and available under the Apache License 2.0.|
It’s important to note that Jenkins and Argo CD can complement each other in a CI/CD pipeline. Jenkins can be used for building and testing, while Argo CD can handle the GitOps-style continuous deployment and configuration management within a Kubernetes environment. The choice between them depends on your specific use case and requirements.
6. What is ArgoCD?
- Argo CD is an open-source, declarative, GitOps continuous delivery tool for Kubernetes. It is designed to help developers and DevOps teams automate the deployment and management of applications on Kubernetes clusters.
- Argo CD allows you to define the desired state of your applications and their resources in a Git repository, and it continuously monitors the cluster to ensure that the actual state matches the desired state.
- ArgoCD follows the principles of GitOps, where the desired state of the application is defined in a Git repository and a continuous delivery system automatically synchronizes the actual state with the desired state.
7. Explain ArgoCD Architecture and its components
ArgoCD Architecture Components
Argo CD Server: This is the core component of Argo CD. It runs as a Kubernetes deployment and acts as the control plane for managing the continuous delivery workflow. It handles the synchronization of the actual state with the desired state defined in Git.
API Server: The API server is a gRPC/REST server which exposes the API consumed by the Web UI, CLI, and CI/CD systems. It has the following responsibilities:
- application management and status reporting
- invoking of application operations (e.g. sync, rollback, user-defined actions)
- repository and cluster credential management (stored as K8s secrets)
- authentication and auth delegation to external identity providers
- RBAC enforcement
- listener/forwarder for Git webhook events
Repository Server: The repository server is an internal service which maintains a local cache of the Git repository holding the application manifests. It is responsible for generating and returning the Kubernetes manifests when provided the following inputs:
- repository URL
- revision (commit, tag, branch)
- application path
- template specific settings: parameters, helm values.yaml
Application Controller: The application controller is a Kubernetes controller which continuously monitors running applications and compares the current, live state against the desired target state (as specified in the repo). It detects OutOfSync application state and optionally takes corrective action. It is responsible for invoking any user-defined hooks for lifecycle events (PreSync, Sync, PostSync)
Reference: ArgoCD Official page
8. What are some Key Features of ArgoCD?
1. GitOps Workflow: Argo CD follows the principles of GitOps, where the desired state of the application is defined in a Git repository. It continuously monitors the repository for changes and ensures that the actual state of the applications matches the desired state.
2. Declarative Application Definition: Applications in Argo CD are defined using declarative manifests in YAML format or Helm charts. This allows for version-controlled and auditable application configuration.
3. Automated Deployment: Argo CD automates the application deployment process by continuously synchronizing the desired state defined in Git with the actual state in the Kubernetes cluster. It detects changes and updates the applications accordingly.
4. Rollback and Rollout: Argo CD provides rollback and rollout capabilities. It allows users to roll back to a previous known good state if issues occur during deployment. It also supports progressive deployments, such as canary and blue-green deployments.
5. Application Configuration Management: Argo CD manages application configuration using ConfigMaps, Secrets, and other Kubernetes resources. It tracks changes to the configuration and ensures that the deployed applications always use the correct configuration.
6. Multi-Environment Support: Argo CD supports deploying applications to multiple environments, such as development, staging, and production
9. Explain How does ArgoCD Works | Explain GitOps Pipeline
Lets understand above GitOps Pipeline Workflow Diagram
- The code is pushed to the code repository like GitHub, GitLab, BitBucket etc
- The code is built and tested in the CI platform like Jenkins, GitLab CI, GitHub Actions
- The code is shipped to artifactory and Docker image is built and pushed to a registry.
- The CI pipeline commits and pushes a new version into to the Deployment repository.
- GitOps Repo which consists of deployment config,sync policy of one or more multiple Kubernetes clusters, Supports for multiple config management (kustomize, Helm, Jsonnet, plain-YAML)
- This push triggers a synchronization: the new code is automatically deployed to the target Kubernetes Clusters
- The Kubernetes clusters Monitored and alerting by tools like Prometheus, Grafana, Cloudwatch, etc.,
10. Explain What ArgoCD Not
Argo CD is not a programming language, a development framework, or a runtime environment for applications. It is a specific tool used for continuous delivery and GitOps practices. Here’s what Argo CD is not:
- Programming Language: Argo CD is not a programming language itself. It doesn’t define how applications or infrastructure are written or developed. It manages and deploys existing application configurations defined in Git repositories.
- Development Framework: It is not a development framework like Django or Ruby on Rails. It is not used for building applications from scratch but for deploying and managing them after they have been developed.
- Runtime Environment: Argo CD is not a runtime environment for applications. It doesn’t host or run your applications; it deploys them to Kubernetes or other infrastructure where they can be executed.
- Infrastructure as Code (IaC) Tool: While Argo CD can manage Kubernetes manifests and Helm charts, it is not an infrastructure as code tool like Terraform or AWS CloudFormation. It doesn’t provision infrastructure resources, but it deploys and manages applications on existing infrastructure.
- Version Control System (VCS): Argo CD relies on a version control system (typically Git) to manage application configurations, but it is not a replacement for a VCS. It doesn’t provide branching, code collaboration, or other features of a VCS.
- Monitoring and Observability Tool: Argo CD primarily focuses on application deployment and synchronization with Git repositories. It does not provide monitoring, logging, or observability features for your applications. You would typically use separate tools for that purpose, like Prometheus, Grafana, or Elasticsearch.
In summary, Argo CD is a tool specifically designed for continuous delivery and GitOps, which involves automatically deploying and managing applications based on Git repository contents. It complements other tools and processes in the software development and deployment pipeline.
11. How ArgoCD is different from other CD Tools?
ArgoCD is a continuous delivery (CD) tool that is designed specifically for deploying applications and services in Kubernetes environments. It differs from other CD tools in several ways:
- Native Kubernetes Integration: ArgoCD is built with native Kubernetes integration in mind. It uses Custom Resource Definitions (CRDs) to represent applications and their desired states, making it well-suited for deploying and managing applications in Kubernetes clusters. Many other CD tools are more generic and may require additional plugins or configuration to work effectively in Kubernetes environments.
- Declarative Configuration: ArgoCD operates on a declarative model. You define the desired state of your applications in Git repositories using manifests (YAML files), and ArgoCD ensures that your actual cluster state matches the desired state. This approach simplifies the management of application configurations and promotes Infrastructure as Code (IaC) practices.
- GitOps Approach: ArgoCD follows the GitOps methodology, which means that your entire application configuration, including version control, is stored in a Git repository. ArgoCD continuously monitors the repository and automatically synchronizes the cluster with the repository’s content. This approach helps in versioning, auditing, and collaboration on application configurations.
- App-Centric Model: ArgoCD focuses on managing applications rather than just Kubernetes resources. It allows you to group related Kubernetes resources into applications and enables you to define dependencies between them. This makes it easier to manage complex applications with multiple components.
- Rollback Capabilities: ArgoCD provides a straightforward mechanism for rolling back to a previous version of an application if issues arise during deployment. This can be essential for ensuring stability and reliability in your CD process.
- Observability: ArgoCD offers built-in monitoring and observability features, such as an intuitive web-based user interface and Prometheus metrics. You can visualize the state of your applications and get insights into deployment history and synchronization status.
- Extensibility: ArgoCD is designed to be extensible. You can create custom tools, plugins, or scripts to integrate with ArgoCD to suit your specific CD needs. It also supports Helm charts and Kustomize overlays for advanced configuration management.
- Policy and Access Control: ArgoCD provides fine-grained RBAC (Role-Based Access Control) and a policy engine that allows you to control who can perform actions in the system. This is especially important in multi-team or multi-tenant Kubernetes environments.
- Open Source and Community-Driven: ArgoCD is open source and has an active community of contributors and users. This means you can benefit from a wide range of community-developed extensions, tools, and resources.
- Support for Multiple Environments: ArgoCD is suitable for managing applications in multiple environments, such as development, staging, and production. It allows you to easily promote application configurations across different clusters.
- While ArgoCD is a powerful CD tool for Kubernetes environments, the choice of CD tool should depend on your specific requirements, including the technology stack, deployment targets, and team preferences. Other CD tools like Jenkins, GitLab CI/CD, and Spinnaker have their own strengths and may be better suited for certain use cases.
12. How can you install ArgoCD on a Kubernetes cluster?
You can install ArgoCD using the kubectl or Helm, by applying YAML manifests or using tools like kustomize.
13. What is a “Repository” in ArgoCD, and how do you define one?
A repository in ArgoCD is a Git repository that contains the application definitions and manifests. You can define a repository in ArgoCD by specifying the repository URL, revision (branch/commit/tag), and path to the application manifests in the ArgoCD application YAML.
14. Explain the concept of “Application” in ArgoCD.
An Application in ArgoCD represents a Kubernetes application that you want to deploy. It includes information about the target cluster, the source repository, the sync policy, and the desired state defined in the Git repository.
15. What is the difference between “SyncPolicy” and “HealthStatus” in ArgoCD?
The SyncPolicy defines how and when an application is synchronized with its Git repository. HealthStatus, on the other hand, monitors the application’s health, checking if it’s in a healthy state on the cluster.
16. Explain the difference between ‘Automatic Sync’ and ‘Manual Sync’ in ArgoCD
Automatic Sync is a sync policy in which ArgoCD will automatically sync an application whenever changes are detected in the Git repository. Manual Sync requires a user to trigger the synchronization explicitly.
17. What is a “Custom Resource Definition (CRD)” in the context of ArgoCD?
ArgoCD extends Kubernetes by introducing custom resources such as AppProject and Repository. These CRDs allow you to define access control policies and specify repositories for your applications.
18. How does ArgoCD handle secrets and sensitive data in application manifests?
ArgoCD provides the option to encrypt sensitive data in the application manifests using the
argocd-secret tool. Secrets are stored securely in the target cluster and can be decrypted at runtime.
19. What are some best practices for securing an ArgoCD installation?
Best practices include enabling authentication, using Role-Based Access Control (RBAC), securing the ArgoCD API server, limiting who can modify sync policies, and regularly monitoring logs and audit trails.
20. Can you explain the process of rolling back an application to a previous state in ArgoCD?
To roll back an application, you need to modify the desired state in the Git repository to the version you want to roll back to, and then trigger a sync with the application. ArgoCD will ensure the application matches the desired state.
21. What are some alternatives to ArgoCD for GitOps in Kubernetes?
Alternatives include Flux, Jenkins X, and Tekton. Each of these tools has its own features and capabilities for GitOps-based continuous delivery.
ArgoCD Scenario Based Interview Questions
- What is an approx upper limit of number of clusters a single ArgoCD can connect and deploy before showing any issues.?
- How many apps can I create/deploy continuously using ArgoCD before showing any issue?
- How many max repositories can I configure in ArgoCD?
- ArgoCD uses Kubernetes etcd as its storage, can we externalize this to some other key-value pair storage?
In this article we have covered GitOps and ArgoCD Interview Questions and Answers | GitOps Interview Questions and Answers.