Chef Infra Server Overview

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The Chef Infra Server acts as a hub for configuration data. The Chef Infra Server stores cookbooks, the policies that are applied to nodes, and metadata that describes each registered node that is being managed by Chef Infra Client. Nodes use Chef Infra Client to ask the Chef Infra Server for configuration details, such as recipes, templates, and file distributions. Chef Infra Client then does as much of the configuration work as possible on the nodes themselves (and not on the Chef Infra Server). This scalable approach distributes the configuration effort throughout the organization.

The front-end for the Chef Infra Server is written using Erlang, which is a programming language that first appeared in 1986, was open sourced in 1998, and is excellent with critical enterprise concerns like concurrency, fault-tolerance, and distributed environments. The Chef Infra Server can scale to the size of any enterprise and is sometimes referred to as Erchef.

Note

The Chef Infra Server can be configured via the /etc/opscode/chef-server.rb file. Whenever this file is modified, the chef-server-ctl reconfigure command must be run to apply the changes. See the Chef Infra Server settings guide for additional information.

Server Components

The following diagram shows the various components that are part of a Chef Infra Server deployment and how they relate to one another.

Diagram of Chef Infra Server deployment

Component	Description
Clients	The Chef Infra Server is accessed primarily by nodes that are under management by Chef, as Chef Infra Client runs occur. It is also accessed by individuals who maintain cookbooks and policy that is stored on the Chef Infra Server, typically from a workstation. And also by individual users with credentials to Chef Infra Server components, such as the Chef management console.
Load Balancer	Nginx is an open-source HTTP and reverse proxy server that is used as the front-end load balancer for the Chef Infra Server. All requests to the Chef Infra Server API are routed through Nginx.
Chef Manage	Chef Manage is the web interface for the Chef Infra Server, which uses the Chef Infra Server API for all communication to the Chef Infra Server.
Chef Infra Server	Erchef is a complete rewrite of the core API for the Chef Infra Server, which allows it to be faster and more scalable than previous versions. The API itself is still compatible with the original Ruby-based Chef Infra Server, which means that cookbooks and recipes that were authored for the Ruby-based Chef Infra Server will continue to work on the Erlang-based Chef Infra Server. Chef Infra Client is still written in Ruby. Note Even though the Chef Infra Server is authored in Erlang, writing code in Erlang is NOT a requirement for using Chef.
Bookshelf	Bookshelf is used to store cookbook content—files, templates, and so on—that have been uploaded to the Chef Infra Server as part of a cookbook version. Cookbook content is stored by content checksum. If two different cookbooks or different versions of the same cookbook include the same file or template, Bookshelf will store that file only once. The cookbook content managed by Bookshelf is stored in flat files and is separated from the Chef Infra Server and search index repositories. All cookbooks are stored in a dedicated repository.
Messages	chef-elasticsearch wraps Elastisearch and exposes its REST API for indexing and search. All messages are added to a dedicated search index repository.
PostgreSQL	PostgreSQL is the data storage repository for the Chef Infra Server.

External Cookbooks

The following diagram highlights the specific changes that occur when cookbooks are stored at an external location, such as Amazon Simple Storage Service (S3).

The following table describes the components that are different from the default configuration of the Chef Infra Server when cookbooks are stored at an external location:

Component	Description
Clients	The Chef Infra Server will provide signed URLs for cookbook requests made by the various clients (individual users, knife requests, and from the Chef Infra Client that is installed on nodes under management by Chef).
Load Balancer	The signed URLs for cookbooks are pointed here, and then routed to cookbook storage, as required.
Chef Infra Server	Erchef is a complete rewrite of the core API for the Chef Infra Server, which allows it to be faster and more scalable than previous versions. The API itself is still compatible with the original Ruby-based Chef Infra Server, which means that cookbooks and recipes that were authored for the Ruby-based Chef Infra Server will continue to work on the Erlang-based Chef Infra Server. Chef Infra Client is still written in Ruby. Note Even though the Chef Infra Server is authored in Erlang, writing code in Erlang is NOT a requirement for using Chef.
Amazon Simple Storage Service (S3)	Bookshelf is used to store cookbook content—files, templates, and so on—that have been uploaded to the Chef Infra Server as part of a cookbook version. Cookbook content is stored by content checksum. If two different cookbooks or different versions of the same cookbook include the same file or template, Bookshelf will store that file only once. The cookbook content managed by Bookshelf is stored in flat files and is separated from the Chef Infra Server and search index repositories. This represents external cookbooks storage at Amazon Simple Storage Service (S3).

AWS Settings

Required Settings

To configure external cookbook storage using Amazon Simple Storage Service (S3) set the following configuration settings in the chef-server.rb file and run chef-server-ctl reconfigure:

Setting	Description
`bookshelf['access_key_id']`	The access key identifier. Default value: generated by default. Specifying this directly in the configuration file is discouraged. Please use `chef-server-ctl set-secret bookshelf access_key_id` from the Secrets Management commands.
`bookshelf['external_url']`	The full URL of the S3 bucket.
`bookshelf['secret_access_key']`	The secret key. Default value: generated by default. Specifying this directly in the configuration file is discouraged. Please use `chef-server-ctl set-secret bookshelf secret_access_key` from the Secrets Management commands.
`opscode_erchef['s3_bucket']`	The name of the Amazon Simple Storage Service (S3) bucket. Default value: `bookshelf`.
`bookshelf['vip']`	The virtual IP address or host name of the Amazon Simple Service (S3) API. Default value: `127.0.0.1`.

An example chef-server.rb configuration:

bookshelf['vip'] = 's3-external-1.amazonaws.com'
bookshelf['external_url'] = 'https://s3-external-1.amazonaws.com'
bookshelf['access_key_id'] = '<ACCESS_ID>'
bookshelf['secret_access_key'] = '<ACCESS_KEY>'
opscode_erchef['s3_bucket'] = '<BUCKET_NAME>'

Optional Settings

The following optional settings are also available and may require modification when using an external S3 provider:

Setting	Description
`opscode_erchef['nginx_bookshelf_caching']`	Whether Nginx is used to cache cookbooks. When `:on`, Nginx serves up the cached content instead of forwarding the request. Default value: `:off`.
`opscode_erchef['s3_parallel_ops_fanout']`	Default value: `20`.
`opscode_erchef['s3_parallel_ops_timeout']`	Default value: `5000`.
`opscode_erchef['s3_url_expiry_window_size']`	The frequency at which unique URLs are generated. This value may be a specific amount of time, i.e. `15m` (fifteen minutes) or a percentage of the value of `s3_url_ttl`, i.e. `10%`. Default value: `:off`.
`opscode_erchef['s3_url_ttl']`	The amount of time (in seconds) before connections to the server expire. If node bootstraps are timing out, increase this setting. Default value: `28800`.

External PostgreSQL

The following diagram highlights the specific changes that occur when PostgreSQL is configured and managed independently of the Chef Infra Server configuration.

The following table describes the components in an external PostgreSQL configuration that are different from the default configuration of the Chef Infra Server:

Component	Description
Chef Infra Server	The Chef Infra Server configuration file is updated to point to an independently configured set of servers for PostgreSQL.
PostgreSQL	PostgreSQL is the data storage repository for the Chef Infra Server. This represents the independently configured set of servers that are running PostgreSQL and are configured to act as the data store for the Chef Infra Server.

PostgreSQL Settings

Use the following configuration settings in the chef-server.rb file to configure external PostgreSQL for use with the Chef Infra Server:

postgresql['db_superuser']

Required when postgresql['external'] is set to true. The PostgreSQL user name. This user must be granted either the CREATE ROLE and CREATE DATABASE permissions in PostgreSQL or be granted SUPERUSER permission. This user must also have an entry in the host-based authentication configuration file used by PostgreSQL (traditionally named pg_hba.conf). Default value: 'superuser_userid'.

postgresql['db_superuser_password']

The password for the user specified by postgresql['db_superuser']. Required when postgresql['external'] is set to true.

The db_superuser_password can also be set using chef-server-ctl set-db-superuser-password from the Secrets Management commands.

postgresql['external']

Required. Set to true to run PostgreSQL external to the Chef Infra Server. Must be set once only on a new installation of the Chef Infra Server before the first chef-server-ctl reconfigure command is run. If this is set after a reconfigure or set to false, any reconfigure of the Chef Infra Server will return an error. Default value: false.

postgresql['port']

Optional when postgresql['external'] is set to true. The port on which the service is to listen. The port used by PostgreSQL if that port is not 5432. Default value: 5432.

postgresql['vip']

Required when postgresql['external'] is set to true. The virtual IP address. The host for this IP address must be online and reachable from the Chef Infra Server via the port specified by postgresql['port']. Set this value to the IP address or hostname for the machine on which external PostgreSQL is located when postgresql['external'] is set to true.

Optional Settings

The following optional settings are required when configuring external PostgreSQL on Microsoft Azure:

bookshelf['sql_connection_user']: The PostgreSQL user name in 'username@hostname' format (e.g. 'bookshelf@my_postgresql.postgres.database.azure.com'), where username would normally equal the value of bookshelf['sql_user'] (default: 'bookshelf'). This setting is required in an external Azure PostgreSQL database-as-a-service configuration. If set to nil, Chef Infra Server assumes that the database is not on Azure and the PostgreSQL connection will be made using the value specified in bookshelf['sql_user'] Default value: nil.
oc_bifrost['sql_connection_user']: The PostgreSQL user name in 'username@hostname' format (e.g. 'bifrost@my_postgresql.postgres.database.azure.com'), where username would normally equal the value of oc_bifrost['sql_user'] (default: 'bifrost'). This setting is required in an external Azure PostgreSQL database-as-a-service configuration. If set to nil, Chef Infra Server assumes that the database is not on Azure and the PostgreSQL connection will be made using the value specified in oc_bifrost['sql_user']. Default value: nil.
oc_id['sql_connection_user']: The PostgreSQL user name in 'username@hostname' format (e.g. 'oc_id@my_postgresql.postgres.database.azure.com'), where username would normally equal the value of oc_id['sql_user'] (default: 'od_id'). This setting is required in an external Azure PostgreSQL database-as-a-service configuration. If set to nil, Chef Infra Server assumes that the database is not on Azure and the PostgreSQL connection will be made using the value specified in oc_id['sql_user']. Default value: nil.
opscode_erchef['sql_connection_user']: The PostgreSQL user name in 'username@hostname' format (e.g. 'opscode_chef@my_postgresql.postgres.database.azure.com'), where username would normally equal the value of opscode-erchef['sql_user'] (default: 'opscode_chef'). This setting is required in an external Azure PostgreSQL database-as-a-service configuration. If set to nil, Chef Infra Server assumes that the database is not on Azure and the PostgreSQL connection will be made using the value specified in opscode_erchef['sql_user']. Default value: nil.
postgresql['db_connection_superuser']: The PostgreSQL superuser name in 'username@hostname' format (e.g. 'opscode_pgsql@my_postgresql.postgres.database.azure.com'), where username would normally equal the value of postgresql['db_superuser'] with any dashes replaced by underscores. This setting is required in an external Azure PostgreSQL database-as-a-service configuration. If set to nil, Chef Infra Server assumes that the database is not on Azure and the PostgreSQL connection will be made using the value specified in postgresql['db_superuser']. Default value: nil.

An example chef-server.rb configuration for External PostgreSQL on Microsoft Azure:

topology 'standalone'
postgresql['external'] = true
postgresql['vip'] = 'my_postgresql.postgres.database.azure.com'
postgresql['db_superuser'] = 'opscode_pgsql'
postgresql['db_superuser_password'] = 'My_postgres_password1!'
postgresql['db_connection_superuser'] = 'opscode_pgsql@my_postgresql.postgres.database.azure.com'
# postgresql['sslmode']='require' # required if 'Enforce SSL connection' is enabled on Azure PostgreSQL
bookshelf['sql_connection_user'] = 'bookshelf@my_postgresql.postgres.database.azure.com'
oc_bifrost['sql_connection_user'] = 'bifrost@my_postgresql.postgres.database.azure.com'
oc_id['sql_connection_user'] = 'oc_id@my_postgresql.postgres.database.azure.com'
opscode_erchef['sql_connection_user'] = 'opscode_chef@my_postgresql.postgres.database.azure.com'

Note

See the list of error messages that may be present when configuring the Chef Infra Server to use a remote PostgreSQL server.

Bookshelf Settings

In instances that require cookbooks to be stored within a SQL backend, such as in a high availability setup, you must set the storage_type to :sql:

bookshelf['storage_type'] = :sql

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