Content Cache

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Overview

Deploy your own content distribution network (CDN).

Usage

To deploy the charm:

juju deploy cs:content-cache

Set juju config for the sites option as required. For example:

# Site with some public, some authenticated content, using another site
# with two IPs for authentication. In this case, 10.1.1.2 and 10.1.1.3
# would need to listen on 443 for auth.example1.com and process
# authentication requests. If set, cache-maxconn will set the maximum
# number of simultaneous connections to the nginx cache for this location,
# while backend-maxconn limits connections to the defined backends.
# If unset, both will default to 2048
example1.com:
  tls-cert-bundle-path: /var/lib/haproxy
  locations:
    '/':
      extra-config:
        - root /srv/example1.com/content/
        - autoindex on
    '/auth':
      modifier: '='
      backends:
        - 10.1.1.2:443
        - 10.1.1.3:443
      backend-check-path: /status
      backend-inter-time: '10s'
      backend-maxconn: 64
      backend-path: /auth-check/
      backend-tls: True
      cache-maxconn: 4096
      cache-validity: '200 401 1h'
      origin-headers:
        - Original-URI: $request_uri
        - Resource-Name: example1
      extra-config:
        - internal
        - proxy_cache_key $http_authorization
      site-name: auth.example1.com
    '/status':
      extra-config:
        - stub_status on
    '/private/content/':
      extra-config:
        - root /srv/example1.com/content/
        - autoindex on
        - auth_request /auth
      nagios-expect: 401 Unauthorized

To get metrics:

juju deploy cs:telegraf
juju add-relation telegraf:haproxy content-cache:haproxy-statistics

You can then query the telegraf endpoint to get HAProxy metrics from the content-cache charm.

To get cache hits metrics:

juju config content-cache enable_prometheus_metrics=true

This will expose the following metrics for each site configured:

# HELP nginx_cache_request_hit_total Number of cache hits per site
# TYPE nginx_cache_request_hit_total counter
nginx_cache_request_hit_total{host="myhost"} 10
# HELP nginx_cache_request_total Number of cache requests per site 
# TYPE nginx_cache_request_total counter                           
nginx_cache_request_total{host="myhost"} 20
# HELP nginx_http_request_total Number of HTTP requests per site
# TYPE nginx_http_request_total counter
nginx_http_request_total{host="myhost",status="200"} 110129
# HELP nginx_metric_errors_total Number of nginx-lua-prometheus errors
# TYPE nginx_metric_errors_total counter
nginx_metric_errors_total 0