bootstrapping containers with confd
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The document discusses using confd to configure container configuration files at runtime. Confd uses templates and data sources like environment variables to render configuration files locally. It provides an example of using confd to generate an Nginx configuration file from templates and environment variables. The document argues that confd provides a simple way to configure files when bootstrapping containers compared to other methods like data volumes or external systems that add more complexity.
![Confd example
confd Nginx config
/etc/confd/conf.d/nginx.conf.toml
[template]
src = "proxy.conf.tmpl”
dest = "/etc/nginx/conf.d/proxy.conf”](https://image.slidesharecdn.com/devopsmeetup-bootstrappingcontainerswithconfd-150917115121-lva1-app6892/85/bootstrapping-containers-with-confd-24-320.jpg)
bootstrapping containers with confd
- 1. Bootstrapping containers with confd Michael Richardson @m_richo
- 3. Common methods for configuring containers
- 4. Common methods for configuring containers 1. Environment variables 2. Data volumes 3. External Systems
- 6. 1. Environment variables docker run -d --hostname my-rabbit --name some-rabbit -e RABBITMQ_DEFAULT_USER=user -e RABBITMQ_DEFAULT_PASS=password -e RABBITMQ_DEFAULT_VHOST=my_vhost rabbitmq:3-management
- 7. 1. Environment variables docker run -d --hostname my-rabbit --name some-rabbit -e RABBITMQ_DEFAULT_USER=user -e RABBITMQ_DEFAULT_PASS=password -e RABBITMQ_DEFAULT_VHOST=my_vhost rabbitmq:3-management
- 8. 1. Environment variables • super easy to set • Most applications are configured by config files rather than env vars.
- 10. 2. Data volumes docker run -d --name some-nginx -v /some/nginx.conf:/etc/nginx/nginx.conf:ro nginx
- 11. 2. Data volumes docker run -d --name some-nginx -v /some/nginx.conf:/etc/nginx/nginx.conf:ro nginx
- 12. 2. Data volumes • easily pass any configuration files from docker host to containers. • Doesn’t scale too well
- 15. 3. External Systems • Strong feature list and benefits • More complexity
- 16. What do I want?
- 17. What do I want? Simple method to set config files when bootstrapping containers
- 18. What do I want? Simple method to set config files when bootstrapping containers
- 19. Say hi to confd
- 20. confd Uses templates and data to render local configuration files. https://github.com/kelseyhightower/confd
- 21. confd Source of data • etcd • consul • dynamodb • Redis • Zookeeper • environment variables
- 22. confd Source of data • etcd • consul • dynamodb • Redis • Zookeeper • environment variables
- 23. Confd example confd Nginx template /etc/confd/templates/nginx.conf.tmpl server { server_name {{ getenv "proxy_domain" }}; location / { proxy_pass http://{{ getenv "backend_host" }}; proxy_redirect off; } }
- 24. Confd example confd Nginx config /etc/confd/conf.d/nginx.conf.toml [template] src = "proxy.conf.tmpl” dest = "/etc/nginx/conf.d/proxy.conf”
- 25. Confd example $ export proxy_domain=mydomain $ export backend_host=www.mricho.com $ /usr/local/bin/confd -onetime -backend env $ cat /etc/nginx/conf.d/proxy.conf server { server_name mydomain; location / { proxy_pass http://www.mricho.com; proxy_redirect off; proxy_set_header Host $host; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; } }
- 26. Confd example $ export proxy_domain=mydomain $ export backend_host=www.mricho.com $ /usr/local/bin/confd -onetime -backend env $ cat /etc/nginx/conf.d/proxy.conf server { server_name mydomain; location / { proxy_pass http://www.mricho.com; proxy_redirect off; proxy_set_header Host $host; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; } }
- 27. Confd appied to containers
- 28. Confd appied to containers 1. Install confd binary to docker images (Dockerfile) 2. Add confd templates and config to docker images (Dockerfile) 3. Create a bootstrap script for your container at runtime
- 29. Confd appied to containers 1. Install confd binary to docker images (Dockerfile) 2. Add confd templates and config to docker images (Dockerfile) 3. Create a bootstrap script for your container at runtime #!/bin/bash set -e export proxy_domain=${proxy_domain:-$HOSTNAME} test $backend_host /usr/local/bin/confd -onetime -backend env echo "Starting Nginx” exec /usr/sbin/nginx -c /etc/nginx/nginx.conf
- 30. Confd appied to containers 1. Install confd binary to docker images (Dockerfile) 2. Add confd templates and config to docker images (Dockerfile) 3. Create a bootstrap script for your container at runtime 4. Run a container docker run -it -p 80:80 -e proxy_domain=mydomain -e backend_host=www.mricho.com confd-test
- 32. More than ‘strings’ upstream backend_hosts { {{ $nodes := split (getenv "app_servers") ":" }}{{range $nodes}} server {{.}};{{end}} } app_servers="myapp01.local:myapp02.local:myapp03.local:myapp04.local" upstream backend_hosts { server myapp01.local; server myapp02.local; server myapp03.local; server myapp04.local; }
- 33. confd Configure container config files at runtime with environment variables