docker meetup.md

Colorado Springs Docker Meetup 2/22/17

Orchestrating Least Privilege Docker Distributed Systems Summit

Majority of container orchestrators use the RAFT algorithm raft.github.io

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Mesos

• Why:
• Abstraction layer that allows you to treat many computers as a single target
• Provides fault tolerance infrastructure
• Supports more than docker containers

What do you need for Mesos:

• Mesos
• Zookeeper - provides the quorum (refer to this as service discovery)
• Marathon - scheduler
• Docker
• You can point a Hadoop scheduler to the Mesos Master

Largest customer: Twitter runs on it - 100K nodes

Kubernetes:

What you need:

• etcd
• Kubernetes
• Docker
• cAdvisor - for monitoring *Hardest part about it is the networking

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Swarm:

• Has automatic TLS with docker
• Seems like since Docker 1.12.1, Docker has caught up to k8s.
• No longer requires installling a separate key/value store
• Multi-container deployment called “stacks”
• Individual containers in a stack called a “service” (like compose)
• Stacks can be created via ‘docker stack’ command using
  • Distributed Application Bundle (DAB) file
  • (since Docker Engine 1.13) Compose file
• Individual services can be created via ‘docker service’ command
• Node failures now will reschedule containers to healthy nodes!
• Stack via DAB
  • works with 1.12.1 with swarm mode enabled
  • Most portable deployment configuration format
    • exposes random container ports as needed
    • doesn’t allow for creation of volumes
• Stack via compose file
  • works in docker engine 1.13+
    • use docker stack deploy —compose-file
    • will maintain configured exposed ports
    • will maintain configured volumes
• Compose File format Version 3
  • Works in Docker engine 1.13+
  • Adds deployment configurations to services
    • mode
      • global (one container per swarm mode)
      • replicated (specified number of containers)
    • replicas (number of containers to deploy in replicated mode)
    • placement (node/label constraints)
    • update_config (how containers get updated)
    • resources (limits/reservations on cpu/mem/etc/resources
    • restart_policy (condition, delay, max_attempts, window)

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Honorable mentions:

• Rancher
• Replicated (Triton) *SaaS application and run it on-prem is the value
• AWS (ECS, Elastic Beanstock)
• Pivotal Cloud Foundry

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Monitoring: Users - yoozers - A distributed fault injection system the containers are way to volatile to continually monitor with tools like nagios

• Prometheus was chosen
  • Pushgateway for VERY short lived workloads even as a little as a shell script
  • Scale, grabs 100,000’s of metrics per second put them into a csv.
  • Alertmanagers recommended to run two of them and send alerts to both of them at the same time
  • Contributing to Grafana as a data source endpoint
  • Technically came from Soundcloud (3 engineers from Google and went to soundcloud)
    • OpenSource re-invention of Borgmon
  • Pull scrape plain text page or key/value store
  • read values into memory
  • Evaluate rulesets vextor arithmetic
    • typically every 10 or 60 seconds starting all at once (some recommend every 5 seconds
    • send alerts
    • record to TSDB (InfluxDB, Graphite) however it doesn’t need one ( most popular one is graphite)
    • /metric html page and it will show you plain texts counters
  • Bad alerts
    • tell me when the file system is @ 90% full
  • Better alerts (what Prometheus does)
    • How long before the disk is full
      • Less than x hours of space based on current rate of change
  • cAdvisor (container Prometheus endpoint)
    • Container running
    • Container Metrics * CPU * Memory * Network in/out

****Compose has caught up a LOT since the last update. ****Your local syntax will be the same locally as it will in production or development environment if you are running docker swarm ****9/16 - 1.12 compared to k8s and swarm killed k8s in every category.