The Future?
Deploying micro-service based
node apps on coreos
Ken Perkins
Rackspace Developer Experience | @kenperkins
A look to the past
Microsoft shuts down zoom.it, and it needs a new home
Zoom.it?
- Multi-resolution imaging as a service
- 1.2 million images
- 1.2 billion image tiles
- All hosted on Azure
I got 5 million problems,
but node aint one
- top ~5k images resulted in
~4.2m image tiles to migrate
The monolith
Or how I used to solve this problem
Data migration problems
- Identifying what to migrate
- pause/resume
- auto retry
- capturing failed transfers
- statistics (i.e. items/sec, etc)
- ...
Microservices Definition
"The microservice architectural style [1] is an approach to developing a single application as a suite of small services, each running in its own process and communicating with lightweight mechanisms, often an HTTP resource API"
http://martinfowler.com/articles/microservices.html
What does that really mean?
Small, lightweight apps, designed to do a single task well
zoomhub-importer
- zh-populate
- zh-import-blobs
- zh-upload-dzis
- zh-stats
- redis*
But how do we now deploy, configure, and coordinate multiple apps?
Enter Docker
Docker is an open source project to pack, ship and run any application as a lightweight container
Dockerfile
FROM node:0.10
MAINTAINER Ken Perkins "ken.perkins@rackspace.com"
RUN npm install -g zoomhub-importer
CMD ["/usr/bin/node", "--version"]
CoreOS & CoreOS Clusters
warehouse-scale computing on top of a minimal, modern operating system
Etcd
A highly-available key value store for shared configuration and service discovery
Fleet
fleet ties together systemd and etcd into a distributed init system
Deploy Some Services
Redis, Populate, and Stats, plus the heavy lifters
app-redis.service
[Unit]
Description=App Redis
After=docker.service
Requires=docker.service
[Service]
EnvironmentFile=/etc/environment
TimeoutStartSec=0
Restart=always
ExecStartPre=-/usr/bin/docker kill %n
ExecStartPre=-/usr/bin/docker rm %n
ExecStartPre=/usr/bin/docker pull redis
ExecStart=/usr/bin/docker run --name %n -p ${COREOS_PRIVATE_IPV4}:6379:6379 redis:latest redis-server --requirepass foo-bar-biz-baz-buz
ExecStartPost=/bin/bash -c '\
while true; do \
/usr/bin/etcdctl set /services/app-redis ${COREOS_PRIVATE_IPV4}:6379 --ttl 10; \
sleep 5; \
done'
ExecStop=/usr/bin/etcdctl rm /services/app-redis
ExecStop=/usr/bin/docker stop %n
app-populate.service
[Unit]
Description=ZH Populate Service
Requires=docker.service
Requires=etcd.service
After=docker.service
After=etcd.service
[Service]
EnvironmentFile=/etc/environment
User=core
Restart=no
TimeoutStartSec=0
ExecStartPre=-/usr/bin/docker kill zh-populate
ExecStartPre=-/usr/bin/docker rm zh-populate
ExecStartPre=/usr/bin/docker pull kenperkins/zoomhub-importer
ExecStart=/usr/bin/docker run --name zh-populate \
-e RAX_USERNAME=zoomingservice \
-e RAX_PASSWORD=this-is-not-my-password \
-e RAX_REGION=IAD \
-e ZH_REDIS_PASSWORD=foo-bar-biz-baz-buz \
-e ZH_LOG_LEVEL=info \
kenperkins/zoomhub-importer /usr/bin/zh-populate-queue --useInternal --useEtcd
ExecStop=/usr/bin/docker stop zh-populate
app-stats.service
[Unit]
Description=ZH Stats Service
Requires=docker.service
Requires=etcd.service
After=docker.service
After=etcd.service
[Service]
EnvironmentFile=/etc/environment
User=core
Restart=always
TimeoutStartSec=0
ExecStartPre=-/usr/bin/docker kill zh-stats
ExecStartPre=-/usr/bin/docker rm zh-stats
ExecStartPre=/usr/bin/docker pull kenperkins/zoomhub-importer
ExecStart=/usr/bin/docker run --name zh-stats \
-e RAX_USERNAME=zoomingservice \
-e RAX_PASSWORD=this-is-not-my-password \
-e RAX_REGION=IAD \
-e ZH_REDIS_PASSWORD=foo-bar-biz-baz-buz \
-e ZH_LOG_LEVEL=info \
kenperkins/zoomhub-importer /usr/bin/zh-stats --useInternal --useEtcd
ExecStop=/usr/bin/docker stop zh-stats
app-importer@.service
[Unit]
Description=ZH Blob Importer Service
Requires=docker.service
Requires=etcd.service
After=docker.service
After=etcd.service
[Service]
EnvironmentFile=/etc/environment
User=core
Restart=always
TimeoutStartSec=0
ExecStartPre=-/usr/bin/docker kill %p-%i
ExecStartPre=-/usr/bin/docker rm %p-%i
ExecStartPre=/usr/bin/docker pull kenperkins/zoomhub-importer
ExecStart=/usr/bin/docker run --name %p-%i \
-e RAX_USERNAME=zoomingservice \
-e RAX_PASSWORD=this-is-not-my-password \
-e RAX_REGION=IAD \
-e ZH_REDIS_PASSWORD=foo-bar-biz-baz-buz \
-e ZH_LOG_LEVEL=info \
kenperkins/zoomhub-importer /usr/bin/zh-import-blobs --useInternal --useEtcd
ExecStop=/usr/bin/docker stop %p-%i
app-uploader@.service
[Unit]
Description=ZH DZI Uploader Service
Requires=docker.service
Requires=etcd.service
After=docker.service
After=etcd.service
[Service]
EnvironmentFile=/etc/environment
User=core
Restart=always
TimeoutStartSec=0
ExecStartPre=-/usr/bin/docker kill %p-%i
ExecStartPre=-/usr/bin/docker rm %p-%i
ExecStartPre=/usr/bin/docker pull kenperkins/zoomhub-importer
ExecStart=/usr/bin/docker run --name %p-%i \
-e RAX_USERNAME=zoomingservice \
-e RAX_PASSWORD=this-is-not-my-password \
-e RAX_REGION=IAD \
-e ZH_REDIS_PASSWORD=foo-bar-biz-baz-buz \
-e ZH_LOG_LEVEL=info \
kenperkins/zoomhub-importer /usr/bin/zh-upload-dzis --useInternal --useEtcd
ExecStop=/usr/bin/docker stop %p-%i
Demo + fleetctl
Schedule & Start the services
Not Covered
- Persistent Data Stores
- Load Balancing & HA
- Failover
- ...
Final Thoughts
- build small, simple services
- use coreos to scale horizontally
- experiment & learn!
Kickstarter. Seriously.
