The DShell Pattern (DevOpsDays London 2019)

Transcript

1. The DShell Pattern
   DevOps Days London, 2019
   

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2. David McKay
   ➔ Developer Advocate for
   InfluxData
   ➔ Kubernetes Release
   Team
   ➔ Tweets @rawkode
   ★ Scottish
   ★ Lover of esoteric
   programming languages
   ★ Likes symmetry
   

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3. BREAKING NEWS
   Some* developers don’t
   want to use Docker
   * No developer with macOS wants to use Docker
   

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4. Docker is useful
   Encapsulated
   Dependencies
   Documented Build
   Process
   Deployable
   

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5. 3 Components
   Dockerfile
   Docker
   Compose
   Makefile
   

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6. Dockerfile
   Make it work for all environments
   

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7. Dockerfile
   FROM elixir:1.9-alpine AS base
   FROM base AS development
   RUN apk add --update vim git make
   FROM base AS build
   RUN make compile
   FROM base AS production
   COPY --from=build … ...
   

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8. Docker Compose
   Make it as (more) painful as possible (than normal)
   

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9. dshell
   dshell:
   @docker-compose run \
   --rm \
   --service-ports \
   --user $UID \
   --use-aliases \
   --entrypoint=ash \
   myapp
   

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10. Encourage DShell
    Block Up
    service:
    myapp:
    entrypoint: sh
    command: echo
    Publish Service Ports
    --service-ports
    Override Entrypoint
    --entrypoint=ash
    

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11. UNPOPULAR OPINION
    DO NOT
    use compose syntax v3
    in dev
    

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12. Best Practice
    Use Depends On
    depends_on:
    mongodb:
    condition:
    service_healthy
    12-Factor
    env_file: .env
    env_file:
    - .env
    - .env.secret
    

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13. Makefile
    Unify Developers
    

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14. The Sausage
    .PHONY: dshell dclean up
    up: deps
    @mix run --no-halt
    compile: deps
    @mix compile
    

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15. up
    up:
    @npm run develop
    @mix test
    @FLASK_APP=hello flask run
    

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16. dclean!
    dclean:
    @docker-compose down --rmi=local -v
    

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17. Final API
    ❏ make dshell [host]
    ❏ make up [container]
    ❏ make test | deps | whatever [container]
    ❏ make dclean [host]
    

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18. Better Together
    We’re deploying Docker to production (I hope), so encourage (not
    force) it’s usage for local development; make it easy for people to
    dip their toe in.
    

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19. VSCode Remotes
    {
    "dockerComposeFile": [
    "../docker-compose.yml",
    ],
    "service": "node",
    }
    

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20. Thank You
    ➔ Follow me on Twitter (@rawkode)
    ➔ At the InfluxData booth
    (I’ve got badges and stickers)
    ➔ Come speak to me about InfluxDB, Cloud Native,
    Monitoring, Docker, or Kubernetes
    

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