Nginx options and variables

About Nginx

Applications deployed with Cloud 66 use Nginx as their web server, and its configuration is dependent on the resources of your server(s).

Boolean variables

To ensure correct boolean condition checks within your template, always explicitly compare the variable with true or false (even if you are checking for true).

Good syntax:

if passenger != true
if passenger != false
if passenger == true
if passenger == false

Bad syntax:

Bad: if passenger
Bad: if !passenger

Default Nginx configuration

The following table outlines the default configuration of Nginx.

Category	Attribute	Default value
General
	user	nginx
	worker_processes	Dynamically set based on instance size
	error_log	/var/deploy/[app_name]/web_head/shared/log/nginx_error.log
Events
	worker_connections	1024
HTTP
	gzip	on
	gzip_min_length	100
	gzip_proxied	expired no-cache no-store private auth
	gzip_types	text/plain application/xml text/css application/x-javascript text/javascript
	gzip_disable	"MSIE [1-6]\."
	passenger_root	[passenger location]
	passenger_ruby	[app ruby shell]
	passenger_ruby	nginx
	passenger_pool_idle_time	0
	passenger_max_pool_size	15
	ssl_session_cache	shared:SSL:10m
	ssl_session_timeout	10m
	underscores_in_headers	on
	default_type	application/octet-stream
	client_max_body_size	50m
	sendfile	on
	server_tokens	off
	keepalive_timeout	65
Server
	listen	80 default_server
	server_name	_ or SSL server name
	rails_env	[app environment]
	client_max_body_size	50m
	root	/var/deploy/[app name]/web_head/current/public
	passenger_enabled	on
	ssl_certificate_key	/etc/ssl/localcerts/[ssl cerificate file name].key
	ssl_certificate	/etc/ssl/localcerts/[ssl cerificate file name].crt

Nginx CustomConfig variables

The following variables are available for use in your Nginx CustomConfig.

Variable Name	Type	Description
allow_ssl	boolean	Is an SSL Certificate configured on the application?
app_name	string	Application name (lowercase)
blacklist	hash	List of IPs you are blacklisting
cors_all_origins	boolean	CORS allow all origins
cors_credentials	boolean	CORS allow credentials
cors_enabled	boolean	Is CORS enabled on the application?
cors_headers	string	CORS allowed custom headers
cors_methods	string	CORS Methods
cors_origin	string	CORS Origins string
cors_origins	array	List of CORS origins
deploy_to	string	Application path on the server
envars	hash	Hash of all environment variables on the application
environment	string	Application environment name (lowercase)
has_ha_proxy_load_balancer	boolean	Are you using a HAProxy load balancer?
letsencrypt_primary_address	string	Sets the address of the host that "owns" the Let's Encrypt certificate. Can then be used with the `proxy_pass` directive to serve SSL requests via other hosts.
load_balancer_address	string	Address of your load balancer
load_balancer_address	string	Address of your load balancer
maintenance_mode_active	boolean	Is the application in maintenance mode?
passenger	boolean	Is nginx running Passenger or a custom web server?
passenger_enterprise	boolean	Are you using Passenger enterprise?
passenger_location	string	Passenger location (Passenger only)
passenger_pool_max	integer	The maximum number of processes that Passenger will spawn. This value is derived from `passenger_process_memory` which can be set via the manifest file. See below for an explanation on how this is calculated.
passenger_supports_cgi_param	boolean	Does the current Passenger version support CGI param?
perfect_forward_secrecy	boolean	Is perfect forward secrecy enabled on the application?
red_http_to_https	boolean	Are you redirecting HTTP to HTTPS?
red_www	boolean	Are you redirecting traffic to www?
ruby_shell	string	/var/deploy/ruby_shell
server_address	string	Server address (IP or fqdn)
stack_supports_nginx_tcp_and_udp_reverse_proxy	boolean	Does your application support TCP and UDP reverse proxy?
supports_realip_module	boolean	Does your Nginx instance use the Real IP module?
supports_tcp_proxy	boolean	Does your NGINX version support TCP reverse proxy and load balancing?
supports_udp_proxy	boolean	Does your NGINX version support UDP reverse proxy and load balancing?
use_ruby_shell	boolean	Used internally
user_name	string	User name running the application process
websocket_support	boolean	Does this version of Nginx support websocket?
workers	integer	Number of CPU cores on the server

How passenger_pool_max is calculated

passenger_pool_max is a Cloud-66-specific variable that we use to dynamically set a value in Nginx for the native Passenger setting passenger_max_pool_size.

We calculate the value for passenger_pool_max as follows:

passenger_pool_max = ( server’s memory - reserved_server_memory ) / passenger_process_memory

…and this is rounded down to the nearest integer. So if your server has 4GB of free RAM and each process uses 600MB the your passenger_pool_max will be 6.

Nginx worker configuration

The following table specifies the number of workers configured for your Nginx based on the server resources (CPU cores) on each cloud.

Cloud provider	Instance type	Number of Workers
AWS
	t1.micro	1
	m1.small	1
	m1.medium	2
	m1.large	2
	m1.xlarge	4
	m3.medium	1
	m3.large	2
	m3.xlarge	4
	m3.2xlarge	8
	m2.xlarge	2
	m2.2xlarge	4
	m2.4xlarge	8
	c1.medium	2
	c1.xlarge	8
	c3.large	2
	c3.xlarge	4
	c3.2xlarge	8
	c3.4xlarge	16
	c3.8xlarge	32
	cc2.8xlarge	88
	i2.xlarge	4
	i2.2xlarge	8
	i2.4xlarge	16
	i2.8xlarge	32
	cr1.8xlarge	88
	hi1.4xlarge	35
	hs1.8xlarge	35
	cg1.4xlarge	33
	g2.2xlarge	8
DigitalOcean
	512MB - 1 CPU	1
	1GB - 1 CPU	1
	2GB - 2 CPU	2
	4GB - 2 CPU	2
	8GB - 4 CPU	4
	16GB - 8 CPU	8
	32GB - 12 CPU	12
	48GB - 16 CPU	16
	64GB - 20 CPU	20
	96GB - 24 CPU	24
GCE
	n1-standard-1	1
	n1-standard-2	2
	n1-standard-4	4
	n1-standard-8	8
	n1-standard-16	16
	n1-highmem-2	2
	n1-highmem-4	4
	n1-highmem-8	8
	n1-highmem-16	16
	n1-highcpu-2	2
	n1-highcpu-4	4
	n1-highcpu-8	8
	n1-highcpu-16	16
	f1-micro	1
	g1-small	1
Linode
	Linode 1GB	1
	Linode 2GB	2
	Linode 4GB	4
	Linode 8GB	6
	Linode 16GB	8
	Linode 32GB	12
	Linode 48GB	16
	Linode 64GB	20
	Linode 96GB	20
Microsoft Azure
	ExtraSmall	1
	Small	1
	Medium	2
	Large	4
	ExtraLarge	8
	A5	2
	A6	4
	A7	8
	A8	8
	A9	16
	STANDARD_D1	1
	STANDARD_D2	2
	STANDARD_D3	4
	STANDARD_D4	8
	STANDARD_D11	2
	STANDARD_D12	4
	STANDARD_D13	8
	STANDARD_D14	16
Rackspace
	512MB Standard Instance	1
	1GB Standard Instance	1
	2GB Standard Instance	2
	4GB Standard Instance	2
	8GB Standard Instance	4
	15GB Standard Instance	6
	30GB Standard Instance	8
	3.75 GB Compute v1	2
	7.5 GB Compute v1	4
	15 GB Compute v1	8
	30 GB Compute v1	16
	60 GB Compute v1	32
	1 GB General Purpose v1	1
	2 GB General Purpose v1	2
	4 GB General Purpose v1	4
	8 GB General Purpose v1	8
	15 GB I/O v1	4
	30 GB I/O v1	8
	60 GB I/O v1	16
	90 GB I/O v1	24
	120 GB I/O v1	32
	15 GB Memory v1	2
	30 GB Memory v1	4
	60 GB Memory v1	8
	120 GB Memory v1	16
	240 GB Memory v1	32
	1 GB Performance	2
	2 GB Performance	2
	4 GB Performance	4
	8 GB Performance	8
	15 GB Performance	4
	30 GB Performance	8
	60 GB Performance	16
	90 GB Performance	24
	120 GB Performance	32

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