General Docker Troubleshooting, Best Practices & Where to Go From Here
Tags: docker, kubernetes, tutorial, webdev
Published: 2024-01-19 13:00:00

## Tackling Common Issues: No Space and Sluggish Containers

Addressing common issues is crucial for maintaining a seamless Docker experience. Let's highlight the importance and break down each of the upcoming sections:

### No Space Issue:

**Image Cleanup:**
   - To remove unused images:
     ```bash
     docker rmi <img1-id> <img2-id> <img3-id> ..
     ```
   - Execute system prune:
     ```bash
     docker system prune
     ```
   - This command intelligently removes unnecessary data, including stopped containers and obsolete layers.

### Container Performance:

1.**Monitoring Container Stats:**
   - Use the `docker stats` command:
     ```bash
     docker stats <name/id>
     ```
   - Provides real-time snapshots of your container's performance.

2.**Inspecting Container Details:**
   - Explore detailed information in JSON format:
     ```bash
     docker inspect <container name/id>
     ```
    - For less detailed output: 
     ```bash
      docker inspect <container name/id> | less
     ```

3.**Viewing Running Processes:**
   ```bash
   docker top <container name/id>
   ```
   - Reveals running processes inside the container.

## Docker Best Practices

Adhering to best practices is paramount for ensuring security and stability within your Docker environment:

1. **Image Security:**
   - Use verified images for enhanced security.
   - Leverage Container Image Scanners like Clair, Trivy, and Dagda for unverified images.

2. **Avoid Using Latest:**
   - Specify image versions to maintain stability.

3. **User Privileges:**
   - Utilize non-root users within containers for increased security.

## Where to Go Next

### Docker Compose:

1. **Multi-Container Apps:**
   - Docker excels for single-application deployment.
   - For apps with multiple components, use Docker Compose to define containers and their relationships in a single Compose Manifest.

2. **Getting Started:**
   - Start containers with:
     ```bash
     docker-compose up
     ```

### Kubernetes:

1. **Scaling for Production:**
   - Docker eases single-system container deployment.
   - Kubernetes addresses challenges in managing hundreds of thousands of containers in production.

2. **Kubernetes Challenges:**
   - Overcoming difficulties in linking docker networks across hosts.
   - Managing containers across multiple hosts.
   - Lack of built-in solutions for container migration between hosts.
   - Production concerns like load balancing and securing traffic are challenging with Docker client alone.

3. **Container Orchestrations:**
   - Solutions like VMware’s vCenter and Rundeck utilize orchestrators for easy scaling, container movement, and traffic routing.

#### Planet-Scale Container Orchestrator - Kubernetes:
   - Kubernetes automates deployment, scaling, and management of containerized applications.
   - It's designed for distributed systems, running components across multiple machines.
   - Enables auto-scaling and URL-based traffic routing, making it a platform of platforms.

## Conclusion:

Navigating Docker troubleshooting, adopting best practices, and exploring advanced orchestration tools are essential steps in mastering containerization. Whether you choose Docker Compose for multi-container simplicity or venture into the vast landscape of Kubernetes, each path unlocks new possibilities for deploying and managing your applications.

![Containerization Evolution](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/ww8sh54qhgn6dzh5yuvm.png)

**References:**
1. Docker Documentation. [Docker system prune.](https://docs.docker.com/engine/reference/commandline/system_prune/)
2. Docker Documentation. [Manage data in containers.](https://docs.docker.com/storage/)
3. Clair. [Vulnerability Static Analysis for Containers.](https://github.com/quay/clair)
4. Trivy. [A Simple and Comprehensive Vulnerability Scanner for Containers.](https://github.com/aquasecurity/trivy)
5. Dagda. [A tool to perform static analysis of known vulnerabilities, trojans, viruses, malware & other malicious threats in Docker images/containers.](https://github.com/eliasgranderubio/dagda)
6. Docker Compose Documentation. [Overview of Docker Compose.](https://docs.docker.com/compose/)
7. Kubernetes Documentation. [Kubernetes Basics.](https://kubernetes.io/docs/tutorials/kubernetes-basics/)
8. VMware. [vCenter Server.](https://www.vmware.com/products/vcenter-server.html)
9. Rundeck Documentation. [Introduction to Rundeck.](https://docs.rundeck.com/docs/manual/introduction.html)