What is Docker?#

Note: Docker is open-source, but it also offers commercial products and services for enterprise users.

Docker concepts#

1. Consistency: Docker ensures that your application runs the same way in every environment, from development to production.
2. Isolation: Containers are isolated from each other and the host system, improving security and reducing conflicts.
3. Portability: Docker containers can run on any system that supports Docker, regardless of the underlying infrastructure.
4. Efficiency: Containers share the host OS kernel, making them more lightweight than traditional virtual machines.
5. Scalability: Docker makes it easy to scale applications up or down quickly.
6. Version Control: Docker images can be versioned, allowing you to roll back to previous versions easily.

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Images and containers#

Containers and virtual machines#

• Unlike VMs( Virtual Machines ) that run on a Guest OS, using a hypervisor, Docker containers run directly on a host server (for Linux), using a Docker engine, making it faster and lightweight.
  
• Unlike VMs there is no need to preallocate the RAM. Hence docker containers utilize less RAM compared to VMs. So only the amount of RAM that is required is used.

Technology Used in Docker#

• namespaces: Docker uses namespaces to provide isolated workspace called containers. When a container is run, docker creates a set of namespaces for it, providing a layer of isolation. Each aspect of a container runs in a separate namespace and its access is limited to that namespace.
• cgroups( control groups ): croups are used to limit and isolate the resource usage( CPU, memory, Disk I/O, network etc ) of a collection of processes. cgroups allow Docker engine to share the available hardware resources to containers and optionally enforce limit and constraints.
• UnionFS( Union file systems ): are file systems that operate by creating layers, making them very lightweight and fast.It is used by Docker engine to provide the building blocks for containers.

Docker Architecture#

• Docker daemon: The background service running on the host that manages building, running, and distributing Docker containers.
• Docker client: The command-line tool that allows users to interact with the Docker daemon.
• Docker registries: Repositories that store Docker images. Docker Hub is a public registry that anyone can use.
• Docker objects: Images, containers, networks, volumes, plugins, and other objects.

Installing Docker#

• Windows
• Linux
• Mac

Docker Basics#

Docker CLI#

1. Check Docker version:

docker version

1. Display system-wide information:

docker info

Docker images#

1. List locally available images:

docker images

1. Pull an image from Docker Hub:

docker pull nginx:latest

Running your first container#

docker run -it ubuntu:latest /bin/bash

• docker run: Creates and starts a new container
• -it: Provides an interactive terminal
• ubuntu:latest: Specifies the image to use
• /bin/bash: Command to run inside the container

ls
cat /etc/os-release

Container lifecycle#

1. Create a container (without starting it):

docker create --name mycontainer ubuntu:latest

1. Start a container:

docker start mycontainer

1. Stop a running container:

docker stop mycontainer

1. docker restart mycontainer

docker restart mycontainer

1. Pause a running container:

docker pause mycontainer

1. Unpause a paused container:

docker unpause mycontainer

1. Remove a container:

docker rm mycontainer

Listing and inspecting containers#

1. List running containers:

docker ps

1. List all containers (including stopped ones):

docker ps -a

1. Inspect a container:

docker inspect mycontainer

1. View container logs:

docker logs mycontainer

Running containers in detached mode#

docker run -d --name mywebserver nginx

1. Working with Docker Images#

Anatomy of a Docker image#

Finding and pulling images#

1. Search for images on Docker Hub:

docker search nginx

1. Pull an image:

docker pull nginx:latest

Creating images#

1. Committing changes made in a container
2. Building from a Dockerfile (preferred method)

Committing changes#

1. Run a container and make some changes:

docker run -it ubuntu:latest /bin/bash
apt-get update
apt-get install -y nginx
exit

1. Commit the changes to a new image:

docker commit <container_id> my-nginx-image:v1

Building from a Dockerfile#

FROM ubuntu:latest
RUN apt-get update && apt-get install -y nginx
EXPOSE 80
CMD ["nginx", "-g", "daemon off;"]

docker build -t my-nginx-image:v2 .

Managing images#

1. List images:

docker images

1. Remove an image:

docker rmi my-nginx-image:v1

1. Tag an image:

docker tag my-nginx-image:v2 my-dockerhub-username/my-nginx-image:v2

1. Push an image to Docker Hub:

docker push my-dockerhub-username/my-nginx-image:v2

Image layers and caching#

docker history my-nginx-image:v2

1. Creating and Managing Docker Containers#

Running containers#

1. Run a container and automatically remove it when it exits:

docker run --rm ubuntu:latest echo "Hello, World!"

1. Run a container with a custom name:

docker run --name my-custom-container ubuntu:latest

1. Run a container and publish a port:

docker run -p 8080:80 nginx

1. Run a container with environment variables:

docker run -e MY_VAR=my_value ubuntu:latest env

1. Run a container with a limited amount of memory:

docker run --memory=512m ubuntu:latest

Executing commands in running containers#

docker exec -it my-custom-container /bin/bash

Copying files between host and container#

1. From host to container:

docker cp ./myfile.txt my-custom-container:/path/in/container/

1. From container to host:

docker cp my-custom-container:/path/in/container/myfile.txt ./

Monitoring containers#

1. View container resource usage:

docker stats

1. View processes running in a container:

docker top my-custom-container

Container resource constraints#

1. Limit CPU:

docker run --cpus=0.5 ubuntu:latest

1. Set CPU shares (relative weight):

docker run --cpu-shares=512 ubuntu:latest

1. Limit memory and enable swapping:

docker run --memory=1g --memory-swap=2g ubuntu:latest

Updating containers#

1. Update container resources:

docker update --cpus=1 --memory=2g my-custom-container

1. Rename a container:

docker rename my-custom-container my-new-container-name

Container restart policies#

docker run --restart=always nginx

• no: Never restart (default)
• on-failure[:max-retries]: Restart only if the container exits with a non-zero status code
• always: Always restart the container regardless of the exit status
• unless-stopped: Always restart the container unless it was explicitly stopped

Attaching to and detaching from containers#

1. Attach to a running container:

docker attach my-custom-container

1. Detach from a container without stopping it: Press Ctrl-p followed by Ctrl-q.

1. Docker Networking#

Network drivers#

1. bridge: The default network driver. It’s used for standalone containers that need to communicate.
2. host: Removes network isolation between the container and the Docker host.
3. overlay: Used for connecting multiple Docker daemons together (used in Swarm mode).
4. macvlan: Allows you to assign a MAC address to a container, making it appear as a physical device on your network.
5. none: Disables all networking for a container.

Listing and inspecting networks#

1. List networks:

docker network ls

docker network inspect bridge

Creating custom networks#

docker network create --driver bridge my-custom-network

Connecting containers to networks#

1. Connect a running container to a network:

docker network connect my-custom-network my-container

1. Disconnect a container from a network:

docker network disconnect my-custom-network my-container

1. Run a new container and connect it to a network:

docker run --network my-custom-network nginx

Container DNS#

1. Create a network:

docker network create my-app-network

1. Run two containers on this network:

docker run -d --name web --network my-app-network nginx
docker run -d --name db --network my-app-network postgres

1. Now, the web container can communicate with the db container using the hostname db.

Port mapping#

docker run -p 8080:80 nginx

docker run -p 127.0.0.1:8080:80 nginx

Network troubleshooting#

1. Check container network settings:

docker inspect --format '{{json .NetworkSettings.Networks}}' my-container

1. Use the docker exec command to run network diagnostic tools inside a container:

docker exec -it my-container ping google.com
docker exec -it my-container netstat -tuln

1. Use the docker logs command to check for network-related issues:

docker logs my-container

1. If you suspect DNS issues, check the container’s DNS configuration:

docker exec -it my-container cat /etc/resolv.conf

Advanced networking topics#

1. Exposing containers: Use the --expose flag to expose ports without publishing them to the host:

docker run --expose 80 nginx

1. Link containers (Note: This is a legacy feature; use user-defined networks instead):

docker run --name db postgres
docker run --link db:database nginx

1. MacVLAN networks: Create a network that allows containers to appear as physical devices on your network:

docker network create -d macvlan \
  --subnet=192.168.1.0/24 \
  --gateway=192.168.1.1 \
  -o parent=eth0 my-macvlan-net

1. Docker Volumes and Data Management#

Types of data persistence in Docker#

1. Volumes: Managed by Docker and stored in a part of the host filesystem.
2. Bind mounts: File or directory on the host machine mounted into a container.
3. tmpfs mounts: Stored in the host system’s memory only.

Working with Docker volumes#

1. Create a volume:

docker volume create my-vol

1. List volumes:

docker volume ls

1. Inspect a volume:

docker volume inspect my-vol

1. Remove a volume:

docker volume rm my-vol

1. Run a container with a volume:

docker run -v my-vol:/app/data nginx

Bind mounts#

docker run -v /host/path:/container/path nginx

docker run --mount type=bind,source=/host/path,target=/container/path nginx

Read-only mounts#

docker run -v /host/path:/container/path:ro nginx

Sharing data between containers#

1. Using a named volume:

docker run -v shared-data:/app/data --name container1 nginx
docker run -v shared-data:/app/data --name container2 nginx

1. Using the --volumes-from flag:

docker run --name container1 -v /app/data nginx
docker run --volumes-from container1 --name container2 nginx

Data backup and restore#

1. Backup a volume:

docker run --rm -v my-vol:/source -v $(pwd):/backup ubuntu tar cvf /backup/backup.tar /source

1. Restore a volume:

docker run --rm -v my-vol:/target -v $(pwd):/backup ubuntu tar xvf /backup/backup.tar -C /target --strip-components=1

Volume drivers#

docker volume create --driver local \
    --opt type=nfs \
    --opt o=addr=192.168.1.1,rw \
    --opt device=:/path/to/dir \
    my-nfs-volume

1. Writing Dockerfiles#

Dockerfile basics#

FROM ubuntu:20.04
RUN apt-get update && apt-get install -y nginx
COPY ./my-nginx.conf /etc/nginx/nginx.conf
EXPOSE 80
CMD ["nginx", "-g", "daemon off;"]

1. FROM: Specifies the base image to use.
2. RUN: Executes commands in a new layer on top of the current image.
3. COPY: Copies files from the host into the image.
4. ADD: Similar to COPY, but can also handle remote URLs and automatically extract compressed files.
5. EXPOSE: Informs Docker that the container listens on specified network ports at runtime.
6. CMD: Provides defaults for an executing container.
7. ENTRYPOINT: Configures a container to run as an executable.

Best practices for writing Dockerfiles#

1. Use official base images when possible.
2. Minimize the number of layers by combining commands:

RUN apt-get update && \
    apt-get install -y \
    package1 \
    package2 \
    package3 && \
    rm -rf /var/lib/apt/lists/*

FROM golang:1.16 AS builder
WORKDIR /app
COPY . .
RUN go build -o myapp
FROM alpine:3.14
COPY --from=builder /app/myapp /usr/local/bin/myapp
CMD ["myapp"]

1. Set the WORKDIR to organize your commands:

WORKDIR /app
COPY . .

ENV APP_HOME /app
WORKDIR $APP_HOME

1. Use LABEL for metadata:

LABEL maintainer="your-email@example.com" \
      version="1.0" \
      description="This is my custom image"

Building images from Dockerfiles#

docker build -t my-image:v1 .

Dockerfile instructions in depth#

1. HEALTHCHECK: Tells Docker how to test if a container is still working:

HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
  CMD curl -f http://localhost/ || exit 1

ARG VERSION=latest
FROM ubuntu:${VERSION}

1. VOLUME: Creates a mount point and marks it as holding externally mounted volumes:

VOLUME /app/data

1. USER: Sets the user name or UID to use when running the image:

RUN groupadd -r mygroup && useradd -r -g mygroup myuser
USER myuser

Multi-stage builds#

# Build stage
FROM golang:1.16 AS builder
WORKDIR /app
COPY . .
RUN go mod download
RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o main .
# Final stage
FROM alpine:3.14
RUN apk --no-cache add ca-certificates
WORKDIR /root/
COPY --from=builder /app/main .
CMD ["./main"]

1. Docker Compose#

Docker Compose basics#

version: "3"
services:
  web:
    image: nginx:alpine
    ports:
      - "8000:80"
  db:
    image: postgres:12
    environment:
      POSTGRES_PASSWORD: example

Key concepts#

1. Services: Containers that make up your application.
2. Networks: How services communicate with each other.
3. Volumes: Where services store and share data.

Common Docker Compose commands#

1. Start services:

docker-compose up

1. Start services in detached mode:

docker-compose up -d

1. Stop services:

docker-compose down

1. View running services:

docker-compose ps

1. View logs:

docker-compose logs

1. Run a command in a service:

docker-compose exec web bash

Docker Compose file structure#

version: "3.8"
services:
  web:
    build: ./web
    ports:
      - "5000:5000"
    volumes:
      - ./web:/code
    environment:
      FLASK_ENV: development
    depends_on:
      - db
  db:
    image: postgres:12
    volumes:
      - postgres_data:/var/lib/postgresql/data
    environment:
      POSTGRES_PASSWORD: example
volumes:
  postgres_data:
networks:
  default:
    name: my_app_net

Advanced Docker Compose features#

1. Scaling services:

docker-compose up -d --scale web=3

1. Extending services:

version: "3.8"
services:
  web:
    extends:
      file: common-services.yml
      service: webapp
    environment:
      - DEBUG=1
  db:
    extends:
      file: common-services.yml
      service: database

1. Using profiles:

version: "3.9"
services:
  web:
    image: nginx:alpine
    profiles: ["frontend", "dev"]
  db:
    image: postgres:12
    profiles: ["backend", "dev"]

docker-compose --profile dev up

1. Health checks:

version: "3.8"
services:
  web:
    image: nginx:alpine
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost"]
      interval: 1m30s
      timeout: 10s
      retries: 3
      start_period: 40s

Docker Swarm#

Key concepts#

1. Node: A machine in the Swarm (can be a manager or a worker).
2. Service: The definition of tasks to execute on nodes.
3. Task: A Docker container and the commands to run inside it.

Setting up a Swarm#

1. Initialize a Swarm:

docker swarm init --advertise-addr <MANAGER-IP>

1. Join a worker node to the Swarm:

docker swarm join --token <TOKEN> <MANAGER-IP>:2377

1. List nodes in the Swarm:

docker node ls

Managing services in Swarm#

1. Create a service:

docker service create --name my_web nginx

1. List services:

docker service ls

1. Scale a service:

docker service scale my_web=5

1. Update a service:

docker service update --image nginx:1.19 my_web

docker service rm my_web

Deploying stacks with Docker Compose#

docker stack deploy -c docker-compose.yml my_stack

Swarm networking#

Swarm secrets#

1. Create a secret:

echo "my_secret_data" | docker secret create my_secret -

1. Use the secret in a service:

docker service create --name nginx --secret my_secret nginx

Rolling updates and rollbacks#

docker service update --update-parallelism 2 --update-delay 10s my_web

docker service update --rollback my_web

1. Docker Security Best Practices#

1. Keep Docker up to date#

1. Use official images#

1. Scan images for vulnerabilities#

docker scan my-image:latest

1. Limit container capabilities#

FROM ubuntu:20.04
RUN apt-get update && apt-get install -y nginx
RUN setcap cap_net_bind_service=+ep /usr/sbin/nginx
USER www-data

1. Use non-root users#

FROM ubuntu:20.04
RUN groupadd -r myuser && useradd -r -g myuser myuser
USER myuser

1. Use read-only file systems#

docker run --read-only ubuntu:20.04

1. Limit resources#

docker run --cpus=0.5 --memory=512m ubuntu:20.04

1. Use secrets management#

docker secret create my_secret my_secret.txt
docker service create --name nginx --secret my_secret nginx

1. Implement network segmentation#

docker network create - driver overlay - attachable my_secure_network
docker service create - name nginx - network my_secure_network nginx

10. Use security options

docker run --security-opt=no-new-privileges ubuntu:20.04

1. Implement logging and monitoring#

docker run --log-driver=syslog ubuntu:20.04

1. Use Docker Content Trust (DCT)#

export DOCKER_CONTENT_TRUST=1
docker pull nginx:latest

1. Regularly audit your Docker environment#

docker run -it --net host --pid host --userns host --cap-add audit_control \
    -e DOCKER_CONTENT_TRUST=$DOCKER_CONTENT_TRUST \
    -v /var/lib:/var/lib \
    -v /var/run/docker.sock:/var/run/docker.sock \
    -v /usr/lib/systemd:/usr/lib/systemd \
    -v /etc:/etc --label docker_bench_security \
    docker/docker-bench-security

1. Use multi-stage builds#

FROM golang:1.16 AS builder
WORKDIR /app
COPY . .
RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o main .
FROM alpine:3.14
RUN apk --no-cache add ca-certificates
COPY --from=builder /app/main .
USER nonroot
CMD ["./main"]

1. Implement proper access controls#

1. Advanced Docker Techniques#

1. Custom base images#

FROM scratch
ADD alpine-minirootfs-3.14.0-x86_64.tar.gz /
CMD ["/bin/sh"]

1. Dockerfile heredocs#

FROM ubuntu:20.04
RUN <<EOF
apt-get update
apt-get install -y nginx
rm -rf /var/lib/apt/lists/*
EOF

1. BuildKit features#

export DOCKER_BUILDKIT=1

# syntax=docker/dockerfile:1.2
FROM ubuntu:20.04
RUN --mount=type=cache,target=/var/cache/apt \
apt-get update && apt-get install -y nginx

1. Multi-arch builds#

docker buildx create --use
docker buildx build --platform linux/amd64,linux/arm64 -t myimage:latest .

1. Distroless images#

FROM golang:1.16 AS builder
WORKDIR /app
COPY . .
RUN CGO_ENABLED=0 go build -o main .
FROM gcr.io/distroless/static
COPY --from=builder /app/main /
CMD ["/main"]

1. Docker image squashing#

docker build --squash -t myimage:squashed .

1. Docker image slimming#

docker-slim build myimage:latest

1. Custom networks with specific drivers#

docker network create --driver macvlan \
  --subnet=192.168.1.0/24 \
  --gateway=192.168.1.1 \
  -o parent=eth0 my_macvlan_net

1. Docker plugins#

docker plugin install vieux/sshfs
docker volume create -d vieux/sshfs \
  -o sshcmd=user@host:/remote \
  -o password=password \
  sshvolume

1. Custom Docker commands#

mkdir -p ~/.docker/cli-plugins
cp ./my-custom-command ~/.docker/cli-plugins/docker-my-custom-command
chmod +x ~/.docker/cli-plugins/docker-my-custom-command

1. Docker context#

docker context create my-remote-docker --docker "host=ssh://user@remote-host"
docker context use my-remote-docker
docker ps  # This will now run on the remote host

1. Docker Compose extends#

version: "3.8"
services:
  web:
    extends:
      file: common-services.yml
      service: webapp
    environment:
      - DEBUG=1
  db:
    extends:
      file: common-services.yml
      service: database

1. Docker Compose anchors and aliases#

version: "3.8"
x-common-config: &common-config
  restart: always
  environment:
    - COMMON_VAR=value
services:
  web:
    <<: *common-config
    image: nginx:latest
  app:
    <<: *common-config
    image: my-app:latest

1. Docker in Production#

1. Container orchestration#

• Advanced scheduling and scaling
• Self-healing capabilities
• Rolling updates and rollbacks
• Service discovery and load balancing
• Configuration management

1. Monitoring and logging#

• Use tools like Prometheus and Grafana for monitoring
• Implement centralized logging with the ELK stack (Elasticsearch, Logstash, Kibana) or similar solutions
• Use Docker’s logging drivers to send logs to your centralized logging system:

docker run --log-driver=fluentd --log-opt fluentd-address=localhost:24224 my-app

1. CI/CD pipelines#

• Automatically build and test Docker images on each commit
• Use multi-stage builds to optimize your build process
• Implement vulnerability scanning in your pipeline
• Automate deployments to your orchestration platform

1. High availability#

• Use multiple replicas for each service
• Implement proper health checks
• Use rolling updates to minimize downtime during deployments
• Utilize load balancers to distribute traffic across containers

1. Persistent storage#

• Use volume drivers appropriate for your infrastructure (e.g., AWS EBS, GCE Persistent Disk)
• Implement proper backup and recovery strategies for your volumes
• Consider using stateless containers where possible to simplify scaling and management

1. Networking#

• Use overlay networks for multi-host networking
• Implement network policies to control traffic between services
• Use service discovery mechanisms provided by your orchestration platform

1. Security#

• Use a container-specific OS like CoreOS or RancherOS to reduce attack surface
• Implement strong access controls and authentication mechanisms
• Use network segmentation to isolate sensitive services
• Regularly update and patch your containers and host systems
• Implement runtime security monitoring

1. Resource management#

• Set appropriate resource limits for your containers
• Use resource quotas at the namespace level in Kubernetes
• Implement autoscaling based on resource usage or custom metrics

1. Image management#

• Use a private registry for production images
• Implement proper versioning for your images
• Use image scanning tools to detect vulnerabilities
• Implement policies to prevent the use of outdated or vulnerable images

1. Backup and disaster recovery#

• Regularly backup your data volumes
• Implement cross-region or cross-datacenter replication for critical data
• Document and regularly test your disaster recovery procedures

1. Performance optimization#

• Use performance monitoring tools to identify bottlenecks
• Optimize your Dockerfiles for smaller, more efficient images
• Use appropriate storage drivers for your workload
• Consider using caching mechanisms like Redis for frequently accessed data

1. Cost management#

• Use appropriate instance types for your workload
• Implement autoscaling to match resources with demand
• Use spot instances or preemptible VMs where appropriate
• Regularly review and optimize your resource usage

1. Documentation and runbooks#

• Document your architecture and deployment procedures
• Create runbooks for common operations and troubleshooting scenarios
• Keep your documentation up-to-date as your systems evolve

1. Troubleshooting and Debugging#

1. Checking container logs#

docker logs <container_id>

docker logs -f <container_id>

1. Inspecting containers#

docker inspect <container_id>

docker inspect --format '{{.State.Status}}' <container_id>

1. Executing commands in running containers#

docker exec -it <container_id> /bin/bash

1. Checking resource usage#

docker stats

1. Debugging network issues#

docker network inspect <network_name>

docker exec -it <container_id> ping google.com

1. Analyzing filesystem changes#

docker diff <container_id>

1. Debugging build issues#

docker build --progress=plain -t myimage .

1. Using Docker events#

docker events

1. Checking Docker daemon logs#

systemctl -u docker.service

1. Using debug mode#

dockerd -D

1. Debugging multi-container applications#

docker-compose logs
docker-compose ps
docker-compose top

1. Using third-party tools#

• Sysdig: For system-level visibility
• cAdvisor: For container resource usage and performance characteristics
• Weave Scope: For visualizing your Docker containers, images, and hosts

1. Debugging kernel issues#

dmesg | tail

1. Using Docker’s experimental features#

docker version -f '{{.Server.Experimental}}'

1. Debugging Docker Swarm#

docker node ls
docker service logs <service_name>
docker service ps <service_name>

Common issues and solutions#

1. Container won’t start

• Check logs: docker logs <container_id>
• Verify the image exists: docker images
• Check for port conflicts: docker port <container_id>

1. Container exits immediately

• Ensure the container has a running process: Check the CMD or ENTRYPOINT in the Dockerfile
• Use docker run -it to start the container interactively and investigate

1. Cannot connect to a container’s exposed port

• Verify the port mapping: docker port <container_id>
• Check if the application inside the container is binding to 0.0.0.0 instead of localhost

1. Out of disk space

• Remove unused containers, images, and volumes: docker system prune
• Increase the size of the Docker host’s filesystem

1. Container is running but not responding

• Check resource usage: docker stats <container_id>
• Inspect logs for any error messages: docker logs <container_id>

1. Network connectivity issues between containers

• Verify containers are on the same network: docker network inspect <network_name>
• Check for any network policies or firewall rules that might be blocking traffic

1. Docker Ecosystem and Tools#

1. Container Orchestration#

• Kubernetes: The de facto standard for container orchestration
• Docker Swarm: Docker’s native clustering and orchestration solution
• Nomad: A flexible workload orchestrator to deploy and manage containers and non-containerized applications

1. Container Registries#

• Docker Hub: Docker’s public container registry
• Amazon Elastic Container Registry (ECR): AWS’s fully-managed Docker container registry
• Google Container Registry: Google Cloud’s Docker image registry
• Azure Container Registry: Microsoft Azure’s container registry service
• Harbor: An open-source container registry project

1. Continuous Integration/Continuous Deployment (CI/CD)#

• Jenkins: An open-source automation server with Docker pipeline support
• GitLab CI/CD: GitLab’s built-in CI/CD system with excellent Docker support
• CircleCI: A CI/CD platform with first-class Docker support
• Travis CI: A hosted CI service that supports Docker-based builds
• GitHub Actions: GitHub’s automation platform with Docker support

1. Monitoring and Logging#

• Prometheus: An open-source monitoring and alerting toolkit
• Grafana: A popular open-source platform for monitoring and observability
• ELK Stack (Elasticsearch, Logstash, Kibana): A powerful logging and analytics suite
• Fluentd: An open-source data collector for unified logging layer
• cAdvisor: Analyzes resource usage and performance characteristics of running containers

1. Security#

• Clair: Open source project for static analysis of vulnerabilities in Docker containers
• Anchore Engine: A service that analyzes Docker images and applies user-defined acceptance policies
• Trivy: A simple and comprehensive vulnerability scanner for containers
• Falco: Cloud-native runtime security project

1. Development Tools#

• Docker Compose: Defines and runs multi-container Docker applications
• Visual Studio Code with Docker extension: Provides IntelliSense for Dockerfiles and docker-compose.yml files
• Portainer: Web-based management UI for Docker environments
• Dive: A tool for exploring a Docker image, layer contents, and discovering ways to shrink the size of your Docker image

1. Networking#

• Weave Net: Creates a virtual network that connects Docker containers across multiple hosts
• Calico: An open-source networking and network security solution for containers
• Cilium: Provides and secures network connectivity between application containers

1. Storage#

• Rexray: Provides persistent storage for Docker containers
• Flocker: An open-source container data volume manager
• Longhorn: Cloud-native distributed block storage system for Kubernetes

1. Service Discovery#

• Consul: A service mesh solution providing service discovery, configuration, and segmentation functionality
• etcd: A distributed, reliable key-value store for the most critical data of a distributed system

1. Container Management Platforms#

• Rancher: An open-source platform for managing Docker in production
• OpenShift: Red Hat’s container application platform based on Kubernetes
• Docker Enterprise: Docker’s commercial platform for container-based application development

1. Serverless Frameworks for Containers#

• OpenFaaS: Serverless Functions Made Simple for Docker & Kubernetes
• Knative: Kubernetes-based platform to deploy and manage modern serverless workloads

1. Local Development Environments#

• Docker Desktop: An easy-to-install application for your Mac or Windows environment
• Minikube: Runs a single-node Kubernetes cluster inside a VM on your laptop

1. Image Building#

• BuildKit: Docker’s next-generation image building backend
• Kaniko: Build container images in Kubernetes without depending on a Docker daemon
• Buildah: A tool that facilitates building OCI container images

1. Configuration Management#

• confd: Manage local application configuration files using templates and data from etcd or consul
• envsubst: Substitutes environment variables in shell format strings

1. Testing#

• Test Kitchen: A test harness tool to execute your configured code on one or more platforms in isolation
• Container Structure Test: A framework to validate the structure of a container image

1. Conclusion and Next Steps#

Recap#

1. Introduction to Docker and its core concepts
2. Installing Docker on various platforms
3. Working with Docker images and containers
4. Docker networking and volumes
5. Writing Dockerfiles and building custom images
6. Using Docker Compose for multi-container applications
7. Docker Swarm for container orchestration
8. Security best practices for Docker
9. Advanced Docker techniques
10. Using Docker in production environments
11. Troubleshooting and debugging Docker containers
12. An overview of the Docker ecosystem and related tools

Next Steps#

1. Practice, practice, practice: The best way to become proficient with Docker is to use it regularly. Try to incorporate Docker into your development workflow and experiment with containerizing different types of applications.
2. Dive deeper into orchestration: While we covered Docker Swarm, consider learning Kubernetes, which has become the industry standard for container orchestration. The Kubernetes official documentation is a great place to start.
3. Explore cloud platforms: Learn how to use Docker with major cloud platforms like AWS, Google Cloud, or Azure. Each platform has its own container services that integrate well with Docker.
4. Contribute to open-source projects: Many Docker-related projects are open-source. Contributing to these projects can be a great way to learn more and give back to the community.
5. Stay updated: Docker and its ecosystem are evolving rapidly. Follow Docker blogs, attend conferences or webinars, and join Docker community forums to stay up-to-date with the latest developments.
6. Certification: Consider pursuing Docker certification, such as the Docker Certified Associate (DCA) exam, to validate your skills and knowledge.
7. Explore related technologies: Look into related technologies like serverless computing, service meshes, and GitOps to understand how they complement and extend container-based architectures.
8. Focus on security: Deepen your understanding of container security. Explore tools and best practices for securing containerized applications throughout the development lifecycle.
9. Learn about monitoring and observability: Dive deeper into monitoring and observability solutions for containerized environments. Understanding how to effectively monitor and troubleshoot containerized applications is crucial for production use.
10. Experiment with different application architectures: Try containerizing different types of applications, from monoliths to microservices, to understand the strengths and challenges of each approach.