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Docker for developers - The big picture
The document discusses the evolution of software development methodologies towards microservices and containers, highlighting Docker as a popular container technology essential for modern deployments. It emphasizes the benefits of using containers, such as isolation, portability, and scalability, along with a brief overview of Docker's functionality and usage in development environments. Additionally, it underscores how .NET Core aligns with container philosophy, promoting a more efficient application development process.
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Docker for developers - The big picture
- 1. Docker containers The bigpicture
- 2. Brave new world UI Businesslogic Data access • Monoliths, our traditional approach in enterprise software • A black hole of technical debt • Layered • Regression • Rigid • Zero reusability I can go on, you get the gist…
- 3. Nice try, but… Softwaredevelopment methodologies Project management techniques They all have failed. However an engineering approach emerged scrum crystal xp lean adaptive pragmatic dsdm
- 4. Microservices & Containers arebecoming mainstream • Emerging engineering approach • The closest thing yet to ideal software components • Small, self-contained, critical- mission web components • Independently deployable Picture from: https://www.nginx.com/resources/library/app-dev-survey/
- 5. Go to marketneeds • We want to avoid deployment errors • We need a way to develop faster • We need a way to scale up our applications efficiently • We need rapid & continuous releases • REUSABILITY Picture from: https://www.nginx.com/resources/library/app-dev-survey/
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- 8. Containers • Standard unitof software deployment • Contains different code and dependencies • Each container can run an entire application • Container image is instantiated to run as a process, serving the application • Think of this analogy: Class vs object. • Offers • Isolation • Portability • Agility • Scalability
- 9. A container doesone thing and it does it in one process Container principle
- 10. What’s Docker? Most popularcontainer technology According to google trends: Super popular Steadily increasing (currently on peak)
- 11. Docker • Lightweight containerengine • Similar to aVM – can host apps & services • Supports Linux, CoreOS &Windows • Linux being the most popular • WindowsNano
- 12. Value for business *Accordingto https://www.docker.com/why-docker
- 13. Docker vsVMs • Farfewer resources • Easy to deploy • Fast start • Higher density More services in one h/w unit • Less cost • Same across deployments • Can go anywhere • OS is virtualized instead h/w https://docs.microsoft.com/en-us/dotnet/standard/microservices- architecture/container-docker-introduction/docker-defined
- 14. “ ” It works onmy machine Developers’ favorite phrase “It runs on Docker”
- 15. Terminology And many more… https://bit.ly/2rmKoLg •Registry • Service that provides access to a collection or related Docker images. • Orchestrator • Tool that simplifies management of clusters and Docker hosts, like Kubernetes • Images • Package with all dependencies needed to create a container. • Containers • Instance of a Docker image.
- 16. Docker containers, images& registry https://docs.microsoft.com/en-us/dotnet/standard/microservices- architecture/container-docker-introduction/docker-containers-images-registries
- 17. Benefits • One environmentfor the application to run • No more asking how it works in local or SIT and not in PROD • Easier to run containerized apps locally • Easier to test applications & run integration tests • Easier to use dependencies – Just use a Docker Image • Redis, SQL Server, Neo4J, Mongo… • External services
- 18. Dockerfile • docker build •Reads a Dockerfile • Creates a new image • Multi-stage build • Cleaner approach, smaller image size • ENTRYPOINT sets the commands that run when the container first runs.
- 19. Build image &run • docker build –t eshop/orders.api:latest –f Orders.API/Dockerfile . • Builds the image • docker run -d –p 8080:80 eshop/orders.api:latest • Runs the container on port 8080, mapping from port 80 inside the container • Runs a single container • What about multi-container applications? • docker-compose up • Ideal for development environments
- 20. Containerize applications inVisualStudio • Recommended to useVisual Studio to containerize applications when starting with Docker • Creates Dockerfiles • Creates Docker Compose files & overrides • Creates ignore files • Easy to Debug – Just F5 • Multiple applications start & debug with Docker Compose
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- 22. .NET Core &Containers • Cross-platform • Can target different OS compared to .NET Framework which requires Windows only • Microservices • .NET Core fits best the containers philosophy • Lightweight compared to .NET Framework • Container is lightweight also – Linux container size <Windows container size
- 23. Operating systems for .NETCore apps Docker can implicitly understand the target OS and download the appropriate container (Linux or Windows) https://docs.microsoft.com/en-us/dotnet/standard/microservices-architecture/net-core-net-framework- containers/net-container-os-targets
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- 25. Resources • https://docs.microsoft.com/en-us/dotnet/standard/microservices-architecture/ • https://www.pluralsight.com/courses/docker-containers-big-picture •https://www.pluralsight.com/courses/docker-getting-started • https://www.packtpub.com/virtualization-and-cloud/microservices-development- azure-java-video • https://www.nginx.com/resources/library/app-dev-survey/ • https://www.docker.com/ Disclaimer: Diagram images used are taken from Microsoft’s guide on microservices
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Editor's Notes
- #2 Some notes
- #4 Why so many errors in deployments? Why instruction books for deployments with steps? (Real world example) Why slow development? Why setting up so many dependencies, wasting time? (Real world example, 1 full day, 3 developers + 1 team lead/manager) Why CRQs? (Real world example)
- #14 Sidestory – server migration in BAML
- #19 Build a new stage, a small runtime-only base image Create /app directory in that image Expose port 80 Create a new stage with a larger image for building the application Create directory /src in the image Copy .csproj files Run dotnet restore Copy all directory tree for the solution to the /serc directory in the image Change current folder to Orders.API Build the project Then create a new stage, which publishes the artifacts from the .csproj Finally create a new stage, continuing from base and call it final Change current directory to /app Copy the /app directory from stage publish to the current directory Define the command to run when the container is started
- #21 Open Visual Studio, create a new ASP.NET Core Application or open an existing and containerize it
- #25 Create new solution Add a Web API application Add Docker support Run docker-compose up to compose all containers and their dependencies