The Challenges of Container Configuration

The Challenges of Container Configuration

Talk from Craft 2016 all about configuration and containers

98234c645fe8c935edc0fec0186d28b8?s=128

Gareth Rushgrove

April 29, 2016
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  1. 1.

    (without introducing more risk) The Challenges of Container Configuration Puppet

    Gareth Rushgrove New capabilities and associated problems
  2. 9.

    (without introducing more risk) - Immutability and containers - Runtime

    vs build time - Who configures the orchestrator? Gareth Rushgrove
  3. 10.

    (without introducing more risk) Mainly Docker and Kubernetes examples, but

    should be generally applicable Gareth Rushgrove
  4. 13.

    (without introducing more risk) Gareth Rushgrove $ docker run -d

    ubuntu:16.04 /bin/sh \ -c "while true; do echo hello world; sleep 1; done"
  5. 18.

    (without introducing more risk) Gareth Rushgrove $ docker run --read-only

    -d ubuntu:16.04 /bin/sh \ -c "while true; do echo hello world; sleep 1; done"
  6. 19.

    (without introducing more risk) Gareth Rushgrove $ docker exec 379150b2cf05

    touch /tmp/surprise touch: cannot touch '/tmp/surprise': Read-only file syste
  7. 22.

    (without introducing more risk) Gareth Rushgrove 1 import logging 2

    from logging.handlers import RotatingFileHandler 3 4 from flask import Flask 5 6 app = Flask(__name__) 7 8 @app.route('/') 9 def home(): 10 app.logger.info('log request') 11 return "We'll never get to here" 12 13 if __name__ == '__main__': 14 handler = RotatingFileHandler('app.log', maxBytes=10000, backupCount 15 handler.setLevel(logging.INFO) 16 app.logger.addHandler(handler) 17 app.run(debug=True, host='0.0.0.0')
  8. 23.

    (without introducing more risk) Gareth Rushgrove 1 import logging 2

    from logging.handlers import RotatingFileHandler 3 4 from flask import Flask 5 6 app = Flask(__name__) 7 8 @app.route('/') 9 def home(): 10 app.logger.info('log request') 11 return "We'll never get to here" 12 13 if __name__ == '__main__': 14 handler = RotatingFileHandler('app.log', maxBytes=10000, backupCount 15 handler.setLevel(logging.INFO) 16 app.logger.addHandler(handler) 17 app.run(debug=True, host='0.0.0.0')
  9. 24.

    (without introducing more risk) Gareth Rushgrove $ docker run --read-only

    -p 5000:5000 garethr/flaskapp Traceback (most recent call last): File "app.py", line 14, in <module> handler = RotatingFileHandler('app.log', maxBytes=10000, backupCount=1) File "/usr/lib/python2.7/logging/handlers.py", line 117, in __init__ BaseRotatingHandler.__init__(self, filename, mode, encoding, delay) File "/usr/lib/python2.7/logging/handlers.py", line 64, in __init__ logging.FileHandler.__init__(self, filename, mode, encoding, delay) File "/usr/lib/python2.7/logging/__init__.py", line 913, in __init__ StreamHandler.__init__(self, self._open()) File "/usr/lib/python2.7/logging/__init__.py", line 943, in _open stream = open(self.baseFilename, self.mode) IOError: [Errno 30] Read-only file system: '/app/app.log'
  10. 26.

    (without introducing more risk) Gareth Rushgrove $ docker run --read-only

    --tmpfs /tmp \ -d ubuntu:16.04 /bin/sh \ -c "while true; do echo hello world; sleep 1; done"
  11. 31.

    (without introducing more risk) Remember Without technical controls you only

    have social guarantees of immutability Gareth Rushgrove
  12. 33.

    (without introducing more risk) Given an image - What machine

    built this image? - Are all the licenses compatible? - Who supports this image? - Does this image contain malware? Gareth Rushgrove
  13. 34.

    (without introducing more risk) Given a running container - Who

    built it? - How was it built? - What software does it contain? - Is the software up-to-date? Gareth Rushgrove
  14. 35.

    (without introducing more risk) Gareth Rushgrove FROM ubuntu:16.04 RUN apt-get

    update && \ apt-get install -y python-pip python-dev build-essent apt-get clean && \ rm -rf /var/lib/apt/lists/* RUN pip install flask COPY . /app WORKDIR /app ENTRYPOINT ["python"] CMD ["app.py"]
  15. 36.

    (without introducing more risk) Gareth Rushgrove FROM ubuntu:16.04 RUN apt-get

    update && \ apt-get install -y python-pip python-dev build-essent apt-get clean && \ rm -rf /var/lib/apt/lists/* RUN pip install flask COPY . /app WORKDIR /app ENTRYPOINT ["python"] CMD ["app.py"] Where did this base image come from?
  16. 37.

    (without introducing more risk) Gareth Rushgrove FROM ubuntu:16.04 RUN apt-get

    update && \ apt-get install -y python-pip python-dev build-essent apt-get clean && \ rm -rf /var/lib/apt/lists/* RUN pip install flask COPY . /app WORKDIR /app ENTRYPOINT ["python"] CMD ["app.py"] What packages are installed? At what version? Where are those packages from?
  17. 38.

    (without introducing more risk) Gareth Rushgrove FROM ubuntu:16.04 RUN apt-get

    update && \ apt-get install -y python-pip python-dev build-essent apt-get clean && \ rm -rf /var/lib/apt/lists/* RUN pip install flask COPY . /app WORKDIR /app ENTRYPOINT ["python"] CMD ["app.py"] What version of flask is this?
  18. 39.

    (without introducing more risk) Gareth Rushgrove FROM ubuntu:16.04 RUN apt-get

    update && \ apt-get install -y python-pip python-dev build-essent apt-get clean && \ rm -rf /var/lib/apt/lists/* RUN pip install flask COPY . /app WORKDIR /app ENTRYPOINT ["python"] CMD ["app.py"] What was in this folder at build time?
  19. 44.

    (without introducing more risk) Gareth Rushgrove LABEL vendor="ACME\ Incorporated" \

    com.example.is-beta \ com.example.version="0.0.1-beta" \ com.example.release-date="2015-02-12"
  20. 45.

    (without introducing more risk) Gareth Rushgrove LABEL vendor="ACME\ Incorporated" \

    com.example.is-beta \ com.example.version="0.0.1-beta" \ com.example.release-date="2015-02-12" What time? What timezone?
  21. 46.

    (without introducing more risk) Gareth Rushgrove $ docker inspect -f

    "{{json .Config.Labels }}" \ 4fa6e0f0c678 | jq { "vendor": "ACME Incorporated", "com.example.is-beta": "", "com.example.version": "0.0.1-beta", "com.example.release-date": "2015-02-12" }
  22. 50.

    (without introducing more risk) Gareth Rushgrove $ docker inspect -f

    "{{json .Config.Labels }}" \ garethr/alpine \ | jq { "net.morethanseven.dockerfile": "/Dockerfile", }
  23. 51.

    (without introducing more risk) Gareth Rushgrove $ docker run -i

    -t garethr/alpine cat /Dockerfile FROM alpine LABEL net.morethanseven.dockerfile="/Dockerfile" RUN apk add --update bash && rm -rf /var/cache/apk/* COPY Dockerfile /
  24. 53.

    (without introducing more risk) Gareth Rushgrove $ docker inspect -f

    "{{json .Config.Labels }}" \ garethr/alpine \ | jq { "com.example.api.packages": "apk info -vv" }
  25. 54.

    (without introducing more risk) Gareth Rushgrove $ docker run -i

    -t garethr/alpine apk info -vv musl-1.1.11-r2 - the musl c library (libc) implementation busybox-1.23.2-r0 - Size optimized toolbox of many common UNIX alpine-baselayout-2.3.2-r0 - Alpine base dir structure and init openrc-0.15.1-r3 - OpenRC manages the services, startup and shu alpine-conf-3.2.1-r6 - Alpine configuration management scripts
  26. 57.

    (without introducing more risk) Schedulers/orchestrators abstract you from - Where

    individual containers run - Balancing due to new resources - Balancing due to failed resources Gareth Rushgrove
  27. 59.
  28. 60.

    (without introducing more risk) Gareth Rushgrove $ docker daemon \

    --label com.example.environment="production" \ --label com.example.storage="ssd"
  29. 61.

    (without introducing more risk) Gareth Rushgrove $ docker run -d

    -P \ -e constraint:storage==ssd --name db mysql
  30. 62.

    (without introducing more risk) Gareth Rushgrove 1 template: 2 metadata:

    3 labels: 4 app: guestbook 5 tier: frontend 6 spec: 7 containers: 8 - name: php-redis 9 image: gcr.io/google_samples/gb-frontend:v4 10 resources: 11 requests: 12 cpu: 100m 13 memory: 100Mi 14 env: 15 - name: GET_HOSTS_FROM 16 value: dns 17 # If your cluster config does not include a dns service, th 18 # instead access environment variables to find service host 19 # info, comment out the 'value: dns' line above, and uncomm
  31. 64.

    (without introducing more risk) Gareth Rushgrove $ docker daemon \

    --label com.example.environment="production" \ --label com.example.storage="ssd" Does this machine really have an SSD? What if someone swaps the drive?
  32. 66.

    (without introducing more risk) Gareth Rushgrove $ facter | head

    -n 20 architecture => x86_64 domain => local facterversion => 2.4.6 fqdn => Pro.local gid => staff hardwareisa => i386 hardwaremodel => x86_64 hostname => Pro id => garethr interfaces => lo0,gif0,stf0,en0,p2p0,awdl0,en1,en2,bridge0,vboxnet0,vboxnet1,v ipaddress => 192.168.0.5 ipaddress_en0 => 192.168.0.5
  33. 67.

    (without introducing more risk) Gareth Rushgrove $ facter -j os

    | jq { "os": { "name": "Darwin", "family": "Darwin", "release": { "major": "14", "minor": "5", "full": "14.5.0" } } }
  34. 68.

    (without introducing more risk) Gareth Rushgrove $ docker daemon \

    --label net.example.os=`facter operatingsystem` \ --label net.example.virtual=`facter is_virtual` \ --label net.example.kernel=`facter kernelversion` \ ...
  35. 72.

    (without introducing more risk) Gareth Rushgrove $ kubectl get pod

    mypod -o yaml \ | sed 's/\(image: myimage\):.*$/\1:v4/' \ | kubectl replace -f -
  36. 73.

    (without introducing more risk) Gareth Rushgrove $ docker network create

    bob c0a0f4538d259515813b771264688d37aaedb41098379a0d73ec0ca08 $ docker network create bob Error response from daemon: network with name bob already
  37. 76.

    The language to represent the data should be a simple,

    data-only format such as JSON or YAML, and programmatic modification of this data should be done in a real programming language Gareth Rushgrove Borg, Omega, and Kubernetes, ACM Queue, Volume 14, issue 1 http://queue.acm.org/detail.cfm?id=2898444 “
  38. 80.

    (without introducing more risk) Gareth Rushgrove $ cat test.jsonnet //

    Example jsonnet file { person1: { name: "Alice", welcome: "Hello " + self.name + "!", }, person2: self.person1 { name: "Bob" }, }
  39. 81.

    (without introducing more risk) Gareth Rushgrove $ jsonnet test.jsonnet |

    jq { "person1": { "name": "Alice", "welcome": "Hello Alice!" }, "person2": { "name": "Bob", "welcome": "Hello Bob!" } }
  40. 82.

    (without introducing more risk) Gareth Rushgrove $ jsonnet test.jsonnet |

    json2yaml --- person1: name: "Alice" welcome: "Hello Alice!" person2: name: "Bob" welcome: "Hello Bob!"
  41. 85.

    (without introducing more risk) Gareth Rushgrove kubernetes_pod { 'sample-pod': ensure

    => present, metadata => { namespace => 'default', }, spec => { containers => [{ name => 'container-name', image => 'nginx', }] }, }
  42. 86.

    (without introducing more risk) Gareth Rushgrove apiVersion: v1 kind: Pod

    metadata: namespace: default name: sample-pod spec: container: - image: nginx name: container-name
  43. 87.

    (without introducing more risk) Gareth Rushgrove controller_service_pair { 'redis-master': app

    => 'redis', role => 'master', tier => 'backend', port => 6379, }
  44. 88.

    (without introducing more risk) Gareth Rushgrove apiVersion: v1 kind: Service

    metadata: name: redis-master labels: app: redis tier: backend role: master spec: ports: # the port that this service should serve on - port: 6379 targetPort: 6379 selector: app: redis tier: backend role: master --- apiVersion: v1 kind: ReplicationController metadata: name: redis-master # these labels can be applied automatically # from the labels in the pod template if not set labels: app: redis role: master tier: backend spec: # this replicas value is default # modify it according to your case replicas: 1 # selector can be applied automatically # from the labels in the pod template if not set # selector: # app: guestbook # role: master # tier: backend
  45. 91.

    (without introducing more risk) The difference between how you think

    something works and how it actually works risks hard-to-debug production issues Gareth Rushgrove
  46. 95.

    (without introducing more risk) - Identification - Control - Status

    accounting - Verification Gareth Rushgrove Military Handbook Configuration Management Guidance MIL-HDBK-61B
  47. 96.