There are two types of services that need to be discovered and used by a client:
A firmware server that provides the latest firmware for a Sun Ray Client.
A session server that provides a Sun Ray display session to to any client.
These services are by default provided by the same server but may be separated. There are many ways to configure how these servers are discovered. This section describes using pre-defined DNS entries to enable clients to find the servers. For other discovery methods that may provide more granularity or flexibility, see the Alternate Network Configurations chapter in the Administration Guide.
The On-Screen Display (OSD) shows status during a client's server discoveries. For example, during DNS lookups, a status line in the OSD window shows the name being looked up and, if one is found, the IP address.
When you install the Sun Ray Software on a Sun Ray server or apply the latest maintenance update, the latest firmware for all supported Sun Ray Clients is also installed. Any Sun Ray server providing the latest firmware for Sun Ray Clients is considered a firmware server.
When a Sun Ray Client boots in a properly configured environment, it checks with a firmware server to determine if it needs a firmware update. A Sun Ray Client's firmware server is discovered in the following order:
Locally configured value (configured through Configuration GUI)
DHCP Sun Ray vendor option (FWSrvr)
Generic DHCP option 66 (TftpSrvr) (IP Address or DNS name)
DNS lookup of sunray-config-servers (if
mapped to multiple addresses, choose one randomly)
Each of these values are attempted in order until one succeeds. Although it is the last value attempted, the DNS lookup is the recommended firmware discovery configuration, as described below.
If the local configuration value is used and fails, none of the others are attempted. This prevents the overwriting of custom-configured firmware in a situation where the controlling firmware server happens to be temporarily unresponsive. See the Sun Ray Client Boot Process section in the Administration Guide for more details on how a Sun Ray Client finds its firmware server.
Once a firmware server is discovered by a Sun Ray Client, the
client retrieves a parameter file
(.parms) via TFTP. This file is used by
the client to determine if its currently installed firmware is
older than the firmware on the firmware server. If so, the
newer firmware is automatically downloaded and installed on
the client.
In the event of an error in the firmware download, error messages provide additional information that can be useful in diagnosing and correcting the problem. See Sun Ray Client Troubleshooting Icons chapter in the Administration Guide for details.
By default, a client's firmware uses the configuration
provided by the Sun Ray server's .parms
file, which provides a centralized mechanism to administer
firmware. However, you can enable the Configuration GUI on a
client, which enables users to modify a Sun Ray Client's
local configuration. See the Sun Ray Client
Firmware chapter in the Administration
Guide for details.
Once a client resolves whether it has the latest firmware installed, the next step in the boot process is to obtain a session from a Sun Ray server. As with discovering a firmware server, the client searches for a session server in the following order:
Locally configured value (configured through Configuration GUI)
Generic DHCP option 49 (IP Address or DNS name)
The servers= key in the client's
.parms file
DNS lookup of sunray-servers (if mapped
to multiple addresses, choose one randomly)
Each of these values are attempted in order until one succeeds. Although it is the last value attempted, the DNS lookup is the recommended session server discovery, as described below.
See the Sun Ray Client Boot Process section in the Administration Guide for more details on how a Sun Ray Client finds its session server.
Although there are multiple ways to configure server discovery, the recommended way is through DNS entries. If the Sun Ray DNS entries are defined appropriately for the Sun Ray Clients, no extra DHCP parameters are required by the Sun Ray Client except for basic network information. When DNS is used as the default server resolution, only the TFTP transport is available.
The DNS entries for Sun Ray server discovery are as follows:
sunray-config-servers for firmware
servers
sunray-servers for session servers
In both cases, if the DNS entry contains multiple server addresses, one is picked randomly. And, both entries should consist of several servers in your failover group for redundancy purposes.
A DNS client incorporated in a Sun Ray Client's firmware allows many values to be names rather than IP addresses. Most values can be either a name or an IP address. If a name is specified, the DNS lookup appends the DHCP (or GUI) provided domain name. Components or the domain name are stripped successively until the lookup succeeds or only two components are left. If none of those lookups succeed, the name is looked up by itself. If the name itself ends with a dot character ("."), the name is taken to be a rooted name, and it is looked up without domain name components appended.