6.2.4. Setting Broker and Supporting Service Parameters

When using the installation scripts, you can set a variety of parameters related to the broker and supporting services. The following table highlights some important parameters used during the installation of the respective components:

Table 6.4. Broker and Supporting Service Parameters

Parameter Description
domain This sets the network domain under which DNS entries for applications are placed.
hosts_domain If specified and host DNS is to be created, this domain is created and used for creating host DNS records; application records are still placed in the domain specified with the domain parameter.
hostname This is used to configure the host's actual host name. This value defaults to the value of the broker_hostname parameter if the broker component is being installed, otherwise named_hostname if installing named, activemq_hostname if installing activemq, or datastore_hostname if installing datastore.
broker_hostname This is used as a default for the hostname parameter when installing the broker component. It is also used both when configuring the broker and when configuring the node, so that the node can contact the broker's REST API for actions such as scaling applications up or down. It is also used when adding DNS records, if the named_entries parameter is not specified.
named_ip_addr This is used by every host to configure its primary name server. It defaults to the current IP address if installing the named component, otherwise it defaults to the broker_ip_addr parameter.
named_entries This specifies the host DNS entries to be created in comma-separated, colon-delimited hostname:ipaddress pairs, or can be set to none so that no DNS entries are created for hosts. The installation script defaults to creating entries only for other components being installed on the same host when the named component is installed.
bind_key This sets a key for updating BIND instead of generating one. If you are installing the broker component on a separate host from the named component, or are using an external DNS server, configure the BIND key so that the broker can update it. Any Base64-encoded value can be used, but ideally an HMAC-SHA256 key generated by dnssec-keygen should be used. For other key algorithms or sizes, ensure the bind_keyalgorithm and bind_keysize parameters are appropriately set as well.
valid_gear_sizes This is a comma-separated list of gear sizes that are valid for use in applications, and sets the VALID_GEAR_SIZES parameter in the /etc/openshift/broker.conf file.
default_gear_size This is the default gear size used when new gears are created, and sets the DEFAULT_GEAR_SIZE parameter in the /etc/openshift/broker.conf file.
default_gear_capabilities This is a comma-separated list of default gear sizes allowed on a new user account, and sets the DEFAULT_GEAR_CAPABILITIES parameter in the /etc/openshift/broker.conf file.
See the OpenShift Enterprise Administration Guide for more information on the VALID_GEAR_SIZES, DEFAULT_GEAR_SIZE, and DEFAULT_GEAR_CAPABILITIES parameters in the /etc/openshift/broker.conf file.
For example, the following command runs the openshift.sh script and sets various parameters for the broker and supporting services, using default values for all unspecified parameters:

Example 6.7. Setting Broker and Supporting Service Parameters Using openshift.sh

$ sudo sh openshift.sh install_components=broker,named,activemq,datastore domain=apps.example.com hosts_domain=hosts.example.com broker_hostname=broker.hosts.example.com named_entries=broker:192.168.0.1,activemq:192.168.0.1,node1:192.168.0.2 valid_gear_sizes=medium default_gear_size=medium default_gear_capabilities=medium