Nulecule: Packaging, Distributing
and Deploying Multi-Container
Applications the Cloud Way
ContainerCon North America 2016
Charlie Drage
Container Tools /
Project Atomic @ Red Hat
cdrage @
http://projectatomic.io
Wait, what’s
Project Atomic?
Lightweight OS designed with
the sole purpose of
deploying containerized
applications
Container tools such as the
Atomic CLI to deploy your
applications
GUI tools such as the
Cockpit Project to help
manage
What’s the current problem?
Multiple standards in
multi-container deployment
orchestrators (Kubernetes,
OpenShift, Docker Compose, Mesos,
Nomad, Dokku, Flynn, etc..)
Even though…
We’re slowly converging to a single
standard in the container front
(single image and runtime spec) via
the OCI (Open Container Initiative)
e.g. rkt + docker
https://www.opencontainers.org/
Nulecule &&
Atomic App
A simple way of deploying
multi-container applications to
provider-agnostic environments
Nulecule = specification
Atomic App = implementation
"Well, it all starts when a nulecule
comes out of its nest...” - Homer
Issues with container distribution /
orchestration
As awesome as container orchestration
tools are, (imo) they’ve got a high
learning curve.
What distribution, parameterization
methods?
How do I deploy a Kubernetes example
as simple as `docker run -p 80:80
nginx`?
Containers galore
Over 941 different
MariaDB containers on
Docker Hub
So many varieties and
yet only one that
people should use
* Last checked August
3rd 2016
How we help
Creating a multi-container application for say, ex. Ops to
deploy
Building a single image for deployment
Deploy and undeploy from multiple providers
Distributing parameterized apps
Composability to multiple orchestration providers
Atomic App is packaged into a single deployment container
Multi-container applications
Composability
Import and use an
official container into
your application
*Similar to “Docker
Compose”
Metadata
Most environment
variables require some
sort of change
Metadata and various
orchestrators
Metadata: No common way to
distribute metadata from ops
to devs and vice-versa.
Unable to provide
environment variables at
deployment time (have to
specify in an .env file)
Orchestrators: Multiple
deployment tools and file
formats
Creating your first
Nulecule file
It’s super easy! “Hello world”
Includes: specification,
composability, distribution,
parametrization, orchestrator
agnostic
--specversion: 0.0.2
id: helloapache-app
metadata:
name: Hello Apache App
appversion: 0.0.1
description: Atomic app for deploying a really basic Apache HTTP
server
location: docker.io/projectatomic/helloapache
params:
- name: provider
description: The specified default provider.
default: kubernetes
graph:
- name: helloapache-app
params:
- name: image
description: The webserver image
default: centos/httpd
- name: hostport
description: The host TCP port as the external endpoint
default: 80
artifacts:
docker:
- file://artifacts/docker/hello-apache-pod_run
kubernetes:
- file://artifacts/kubernetes/hello-apache-pod.json
marathon:
- file://artifacts/marathon/helloapache.json
Another spec?
Let’s build an
Etherpad example
with MariaDB
Identifier and
Specification
Version
Give the ID that will be used
for import into different
applications as well as the
current spec version
--specversion: "0.0.2"
id: etherpad-app
Metadata
Included metadata available for
scraping
metadata:
name: etherpad-app
appversion: 0.0.1
description: Etherpad demo
location: docker.io/user/etherpad-app
Params
Global parameters
params:
- name: provider
description: Default provider
default: kubernetes
Graph
The “bread and butter” of the
Nulecule file format. Define
application components and
dependencies.
graph:
- name: mariadb-centos7-atomicapp
...
- name: etherpad-app
...
Graph Source
Import an already pre-made
Nulecule application
graph:
- name: mariadb-centos7-atomicapp
source: docker://user/mariadb-atomicapp
...
Graph Params
Provide the correct values at
deployment time
graph:
...
- name: etherpad-app
params:
- name: image
description: Container image
default: centos/etherpad
- name: hostport
description: Host TCP Port
default: 9001
- name: db_user
description: Database User
- name: db_pass
description: Database Password
- name: db_name
description: Database Name
- name: db_host
description: Database hostname/IP
default: mariadb
- name: db_port
description: Database service port
default: 3306
Answers file
Graph parameters can be
pre-defined prior to deployment
instead of “answered”
[general]
provider = kubernetes
[etherpad-app]
db_user = foo
db_host = bar
...
Graph Artifacts
Metadata templates for
different orchestrators
graph:
...
- name: etherpad-app
params:
...
artifacts:
docker:
...
kubernetes:
- file://artifacts/kubernetes/etherpad-rc.yaml
- file://artifacts/kubernetes/etherpad-svc.yaml
openshift:
- inherit:
- kubernetes
Graph Params in
kubernetes/etherpad-rc.yaml
Dollar sign variable
replacement in each artifact
file
--apiVersion: v1
kind: ReplicationController
metadata:
name: etherpad
labels:
name: etherpad
spec:
replicas: 1
selector:
name: etherpad
template:
metadata:
labels:
name: etherpad
spec:
containers:
- name: etherpad
image: $image
ports:
- name: etherpad-server
containerPort: $hostport
env:
- name: DB_HOST
value: $db_host
- name: DB_DBID
value: $db_name
- name: DB_PASS
value: $db_pass
- name: DB_PORT
value: $db_port
- name: DB_USER
value: $db_user
Atomic App
Reference implementation of
Nulecule
Installer, manager,
container builder, single
command deployment
Create a Nulecule
application in one
container
Build your app on top of our
Atomic App base image
FROM projectatomic/atomicapp:0.6.1
MAINTAINER Red Hat, Inc. <[email protected]>
LABEL io.projectatomic.nulecule.providers="kubernetes" \
io.projectatomic.nulecule.specversion="0.0.2"
ADD /Nulecule /Dockerfile README.md /application-entity/
ADD /artifacts /application-entity/artifacts
DEMO
Learn more at
Project:
http://projectatomic.io
Github:
http://github.com/projectatomic/nulecule
http://github.com/projectatomic/atomicapp
IRC:
#nulecule @ freenode
Mailing list:
[email protected]
Charlie Drage, @cdrage, [email protected]