Container Scheduling Without the Hype: Why Bother? DevOpsDays Boise 2018 Tyler Langlois Software Engineer, Elastic

$ whois tylerjl ● Infrastructure/software/devops-y things @ Elastic ● Lots of recent work on dynamic/containerized environments Come talk to me about Arm SBCs (or if you want to yell about the Elastic Puppet modules) ____________________ < angry at computers > -------------------- \ ^__^ \ (oo)\_______ (__)\ )\/\ ||----w | || ||

Who is This For? ● Why care about container schedulers? ● What can they offer operations and development? ● Real-world achievements made possible by these solutions (or, new ideas for current practitioners)

Where We’ve Been ??? /var/log/? tcp:localhost:??? statsd? prometheus? graphite? ... Dependent: ● Libraries ● Packages ● Runtime ● Distro ● etc.

Where We Can Go ??? /var/log/? tcp:localhost:??? statsd? prometheus? graphite? ... Dependent: ● Libraries ● Packages ● Runtime ● Distro ● etc. Let’s talk about: ● Runtime ● Monitoring ● Persistence ● Services

Runtime (Traditional) ● Without containers ○ Don’t even - dependencies are separate from code, messy ● With just containers ○ Where are you running them? Cloud instances? ○ How are you scheduling and running them?

Runtime --- image: org/app:1.0 env: FOO: bar count: 3 ● Nodes are cattle ● Contract w/consumers is clear: ○ Build instructions ○ Runtime instructions FROM python:3 COPY app.py app.py CMD python app.py

Runtime --- image: org/app:1.0 env: FOO: bar count: 3 ● Nodes are cattle ● Contract w/consumers is clear: ○ Build instructions ○ Runtime instructions FROM python:3 COPY app.py app.py CMD python app.py ● Deployments are always the same bits - repeatability ● Updates are hands-off for both dev and ops - rolling container upgrades ● Application changes async from backend (container build instructions)

Monitoring (Traditional) Logs ● Format? Path? ● Opt-in ● Accessibility? Metrics ● System metrics != app metrics ● Scrape from app? Alerts ● Metrics are good; deployment statistics as well?

Monitoring stdout stderr

Monitoring stdout stderr ● Zero-config for generic logs/metrics out of the box ● Easily build custom tools atop this data for out of the box alerting as well ● Logs/metrics become self-service with appropriate visualization solutions

Persistence (Traditional) ● Shared mass storage (ceph, gluster) in traditional setups ● Dynamically attached storage in the case of cloud environments (EBS) ● Works, but: ○ What ties them together, provisions them, migrates them, backs up? big ol’ data ?

Persistence --- volume: size: 50G ● Like runtime definitions, the underlying impl. Isn’t a concern ● Carve off a hunk of storage as needed ● Scheduling is happening all the time, storage follows big ol’ data

Persistence --- volume: size: 50G ● Like runtime definitions, the underlying impl. Isn’t a concern ● Carve off a hunk of storage as needed ● Scheduling is happening all the time, storage follows big ol’ data ● Nobody cares where or what the persistence base is, we just have space now ● Infra can develop tools to enhance storage for everyone (automated backups, snapshotting, etc.) ● Backend-agnostic - GCP, AWS, Azure, etc.

Services (Traditional) ● Both internal and external: ○ Spin up an app, add it to a pool of servers ○ Health checks sometimes ○ Typically, the “expose this” process very loosely coupled with “provision this”

● Tie service endpoints to groups of containers and let the router/proxy handle it for you Services pods

● Load balancers become a by-product of naturally selecting endpoints from a pool of healthy endpoints Services pods

Services (+MORE) Traefik/Envoy/Fabio are solving neat problems: ● Automatic Let’s Encrypt TLS ● Automatic Host/app name routing ● Networking ACLs

Better Processes Runtime Monitoring Persistence Services ● Contracts are clear - no one needs to learn another team’s tools if they don’t want to ● Improvements and iteration are completely unblocked on either side ● Infra tooling becomes immediately useful for everyone on the platform

Thank you! github.com/tylerjl irc/twitter: leothrix tjll.net Additional Information: ● Google for: ○ Kubernetes ○ Nomad ○ Mesos ○ Traefik ○ Envoy Let’s talk about monitoring/metrics at the Elastic booth