CMSC389L

Microservices

"Any organization that designs a system  will inevitably produce a design whose structure is a copy of the organization's communication structure."

- Melvin Conway

Microservices vs. Monolith

Data Isolation

Microservices vs. Monolithic

Microservices Cons

• Avoid microservices until you need them
  • Just adds complexity
  • Distributed logging, distributed tracing, deployment automation, monitoring, learning curve, ...

[https://martinfowler.com/bliki/MicroservicePremium.html]

Microservices in Prod

etc.

Docker

What is Docker?

• Container creation tool
  • Containers = isolated processes
• Problems it solves:
  • ​Conflicting configurations, runtimes, dependencies...
  • "It works for me"
    • Unified development + production environments

Docker vs. VMs

Docker Concepts

Example Dockerfile

FROM ubuntu:12.10

MAINTAINER Ken Cochrane "kencochrane@gmail.com"

RUN apt-get -qq update
RUN apt-get install -y python-dev python-setuptools supervisor git-core

RUN easy_install pip
RUN pip install virtualenv
RUN pip install uwsgi

RUN virtualenv --no-site-packages /opt/ve/djdocker

ADD . /opt/apps/djdocker
ADD .docker/supervisor.conf /opt/supervisor.conf
ADD .docker/run.sh /usr/local/bin/run

RUN (cd /opt/apps/djdocker && git remote rm origin)
RUN (cd /opt/apps/djdocker && git remote add origin https://github.com/kencochrane/django-docker.git)
RUN /opt/ve/djdocker/bin/pip install -r /opt/apps/djdocker/requirements.txt
RUN (cd /opt/apps/djdocker && /opt/ve/djdocker/bin/python manage.py syncdb --noinput)
RUN (cd /opt/apps/djdocker && /opt/ve/djdocker/bin/python manage.py collectstatic --noinput)

EXPOSE 8000

CMD ["/bin/sh", "-e", "/usr/local/bin/run"]

Docker Registry

• "Github" for Docker images
  • K:V store

    • image_name:tag -> image

    • example:web:latest

• Run your own or use managed registry:
  • Docker Registry
  • AWS EC2 Container Registry (ECR)

    • 800593953112.dkr.ecr.us-east-1.amazonaws.com

Docker Concepts

Docker Demo

ECS

ECS at a High Level

• Cluster of EC2 instances
  • Often 1 for dev, 1 for staging, 1 for production...
  • Can mix-and-match EC2 instances

• Task Definition: Container Configuration
  • Specifies memory, CPU, image,  
• Services: Container Manager Configuration
  • Specifies desired count, auto-scaling, etc.

ECS at a High Level

Advanced ECS

• Transition Deployments:
  • New task definitions will incrementally swap out with the old task definitions
• Auto Scaling
  • via CloudWatch events

ECS Demo