Dockerizing Django projects

Pros and Cons of the different ways there are to turn a Django project into a Docker container.

Transcript

1. Dockerizing Django projects Roberto Rosario robertorosario.com
2. Who am I? robertorosario.com me@robertorosario.com Roberto Rosario
4. What is Docker?
5. Docker provides an integrated technology suite that enables development and IT operations teams to build, ship, and run distributed applications anywhere.
6. In human now.
7. Containers.
8. Lightweight virtualization. ie: No video hardware emulation.
9. Some devops now hate me.
10. Deploy everywhere.
11. Easy scalability.
12. Even auto scaling.
13. Deploying Django: Old school.
20. Deployed! Congratulations!
21. Your users have now quadrupled!
24. Server are old, let’s go virtual!
28. Different technology, same problem.
33. Django and Docker?
34. Configuration files.
35. First steps.
38. Classes Instances
39. More devops hate me now.
41. Dockerfile
42. An entire OS for just a part of the Django project?
43. Not to worry.
46. Your Django project
47. Your Django project
48. Your Django project image Your Django project
49. Base image = Base class Your image = Subclass
50. Pretty much every devops hate me at this point.
51. One size doesn’t fit all.
52. Monolithic
53. App Workers Web server
54. docker run --name postgres -e POSTGRES_DB=mayan -e POSTGRES_USER=mayan -e POSTGRES_PASSWORD=mysecretpassword -v /var/lib/postgresql/data -d postgres docker run --name redis -d redis docker run --name mayan-edms -p 80:80 --link postgres:postgres --link redis:redis -e POSTGRES_DB=mayan -e POSTGRES_USER=mayan -e POSTGRES_PASSWORD=mysecretpassword -v /usr/local/lib/python2.7/dist- packages/mayan/media -d mayanedms/monolithic
55. • Single download • Low entry barrier • Easiest to maintain • Big size download • Not good for scaling • Same VM/Server problem
56. Split
57. App Workers Web server
58. Split ~ Frontend + Backend
59. • Scale individually • Smaller download • Best approach for production • Harder to setup • Need documentation • Several DockerFiles
60. Mixed
61. Role Frontend Backend
63. • Single download • Can reuse configuration file templates • Single core repo • Bigger size download
64. Lean
65. Lean = Split without any 3rd party
66. App Workers Web server
67. • Smallest download • Hardest to configure • Might not scale best • Might violate port export concept
68. Django + uWSGI NGINX
69. Django + uWSGI NGINX TCP Port uwsgi_pass 127.0.0.1:3031; socket = 127.0.0.1:3031
70. Django + uWSGI NGINX socket = /tmp/uwsgi.sock uwsgi_pass unix:///tmp/uwsgi.sock; ?
71. Django + uWSGI NGINX socket = /tmp/uwsgi.sock uwsgi_pass unix:///tmp/uwsgi.sock; Volume?
72. • Need to include NGINX config
73. $ docker run --name some-nginx -v /some/nginx.conf:/etc/nginx/nginx.conf:ro -d nginx
74. environment: - NGINX_HOST=foobar.com - NGINX_PORT=80 command: /bin/bash -c "envsubst < /etc/nginx/conf.d/mysite.template > /etc/nginx/conf. d/default.conf && nginx -g 'daemon off;'"
75. Last approach
76. Kitchen sink
77. App Workers Database Web server Broker
78. • Single download • Lowest entry barrier • Biggest size download • Terrible for scaling • Same VM/Server problem • Support 3rd party software
80. Educational purposes only
81. Don’t use in production
82. EVER!
83. Kitchen sink will freeze your servers
84. Devops don’t like frozen servers
86. Don’t turn your devops into Gordon Ramsay
87. Post init actions
88. migrate & collectstatic
93. Service synchronization
94. $ docker run --name postgres -e POSTGRES_DB=mayan -e POSTGRES_USER=mayan -e POSTGRES_PASSWORD=mysecretpassword -v /var/lib/postgresql/data -d postgres $ docker run --name redis -d redis $ docker run --name mayan-edms -p 80:80 --link postgres:postgres --link redis:redis -e POSTGRES_DB=mayan -e POSTGRES_USER=mayan -e POSTGRES_PASSWORD=mysecretpassword -v /usr/local/lib/python2.7/dist- packages/mayan/media -d mayanedms/monolithic
95. Database connection error.
97. $ docker run --name postgres -e POSTGRES_DB=mayan -e POSTGRES_USER=mayan -e POSTGRES_PASSWORD=mysecretpassword -v /var/lib/postgresql/data -d postgres $ docker run --name redis -d redis $ docker run --name mayan-edms -p 80:80 --link postgres:postgres --link redis:redis -e POSTGRES_DB=mayan -e POSTGRES_USER=mayan -e POSTGRES_PASSWORD=mysecretpassword -v /usr/local/lib/python2.7/dist- packages/mayan/media -d mayanedms/monolithic
98. $ docker run --name postgres -e POSTGRES_DB=mayan -e POSTGRES_USER=mayan -e POSTGRES_PASSWORD=mysecretpassword -v /var/lib/postgresql/data -d postgres $ docker run --name redis -d redis $ docker run --name mayan-edms -p 80:80 --link postgres:postgres --link redis:redis -e POSTGRES_DB=mayan -e POSTGRES_USER=mayan -e POSTGRES_PASSWORD=mysecretpassword -v /usr/local/lib/python2.7/dist- packages/mayan/media -d mayanedms/monolithic until nc -z $POSTGRES_PORT_5432_TCP_ADDR $POSTGRES_PORT_5432_TCP_PORT; do echo "$(date) - waiting for postgres..." sleep 1 done
99. Service synchronization doesn’t belong in configuration files.
100. until nc -z $POSTGRES_PORT_5432_TCP_ADDR $POSTGRES_PORT_5432_TCP_PORT; do echo "$(date) - waiting for postgres..." sleep 1 done until nc -z $RABBITMQ_PORT_5672_TCP_ADDR $RABBITMQ_PORT_5672_TCP_PORT; do echo "$(date) - waiting for rabbitmq..." sleep 1 done
101. More problems.
102. • Not foolproof • Mute services • nc is not universal • API URL paths?
103. Solutions?
105. $ docker run -d --name mycontainer some-image-or-other $ docker run --link mycontainer:mycontainer aanand/wait waiting for TCP connection to 172.17.0.105:5432......ok
106. Interesting, but...
108. An entire container to run nc.
109. Cool solution, wrong problem.
112. It’s the container manager’s responsibility.
115. Kubernetes approach
117. Port, path, initial delay & timeout!
120. Docker upstream native approach needed
123. Templating
124. Docker images are static. Less reusable.
126. Docker containers are configured with environment variables.
128. uWSGI support environment variables. NGINX doesn’t.
129. Docker upstream native approach needed
132. “Thank you for using Docker” “But your fix is in another repository”
134. Options?
136. And then there is genius
139. Bonus
141. Can help with logs too
143. Demo time
144. Lessons learned?
150. Thank you!