General Docker Troubleshooting, Best Practices & Where to Go From Here

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:
  

   docker rmi <img1-id> <img2-id> <img3-id> ..
  

• Execute system prune:
  

   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:
  

   docker stats <name/id>
  

• Provides real-time snapshots of your container's performance.

2.Inspecting Container Details:

• Explore detailed information in JSON format:
  

   docker inspect <container name/id>
  

  • For less detailed output:

    docker inspect <container name/id> | less
  

3.Viewing Running Processes:

   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:

    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.

References:

1. Docker Documentation. Docker system prune.
2. Docker Documentation. Manage data in containers.
3. Clair. Vulnerability Static Analysis for Containers.
4. Trivy. A Simple and Comprehensive Vulnerability Scanner for Containers.
5. Dagda. A tool to perform static analysis of known vulnerabilities, trojans, viruses, malware & other malicious threats in Docker images/containers.
6. Docker Compose Documentation. Overview of Docker Compose.
7. Kubernetes Documentation. Kubernetes Basics.
8. VMware. vCenter Server.
9. Rundeck Documentation. Introduction to Rundeck.