An IceGrid node is a process that activates, monitors, and deactivates registered server processes. You can run any number of nodes in a domain, but typically there is one node per host. A node must be running on each host on which servers are activated automatically, and nodes cannot run without an IceGrid registry.
The IceGrid node server is implemented by the icegridnode executable. If you wish to run a registry and node in one process, icegridnode is the executable you must use.
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Command Line Options for icegridnode
The node supports the following command-line options:
Usage: icegridnode [options]
Options:
-h, --help Show this message.
-v, --version Display the Ice version.
--nowarn Don't print any security warnings.
--readonly Start the collocated master registry in
read-only mode.
--initdb-from-replica <replica>
Initialize the collocated registry database from the
given replica.
--deploy DESCRIPTOR [TARGET1 [TARGET2 ...]]
Add or update descriptor in file DESCRIPTOR,
with optional targets.
If you are running the node with a collocated registry, the --readonly option prevents any updates to the registry's database; it also prevents slaves from synchronizing their databases with this master. This option is useful when you need to verify that the master registry's database is correct after promoting a slave to become the new master. The --initdb-from-replica option, added in Ice 3.5.1, allows you to initialize the database from another registry replica. This option is useful when you need to start a new master with the contents of a slave database.
The --deploy option allows an application to be deployed automatically as the node process starts, which can be especially useful during testing. The command expects the name of the XML deployment file, and optionally allows the names of the individual targets within the file to be specified.
Additional command line options are supported, including those that allow the node to run as a Windows service or Unix daemon, and Ice includes a utility to help you install an IceGrid node as a Windows service.
Configuring Node Endpoints
The IceGrid node's endpoints are defined by the IceGrid.Node.Endpoints property and must be accessible to the registry. It is not necessary to use a fixed port because each node contacts the registry at startup to provide its current endpoint information.
Node Security Considerations
It is important that you give careful consideration to the permissions of the account under which the node runs. If the servers that the node will activate have no special access requirements, and all of the servers can use the same account, it is recommended that you do not run the node under an account with system privileges, such as the root account on Unix or the Administrator account on Windows.
Configuring a Data Directory for the Node
The node requires an empty directory that it can use to store server files. The pathname of this directory is supplied by the configuration property IceGrid.Node.Data. To clear a node's state, first ensure the server is not currently running, then remove all of the files in its data directory and restart the server.
The node's data directory may also contain files and subdirectories used by your application's servers, such as configuration files and Freeze database environments. Before destroying the contents of the node's data directory, make sure that all servers are stopped and any important files are backed up.
When running a collocated node and registry server, we recommend using separate directories for the registry and node data directories.
Node Configuration Example
A minimal node configuration is shown in the following example:
IceGrid.Node.Endpoints=tcp IceGrid.Node.Name=Node1 IceGrid.Node.Data=/opt/ripper/node Ice.Default.Locator=IceGrid/Locator:tcp -p 4061
The value of the IceGrid.Node.Name property must match that of a deployed node known by the registry.
The Ice.Default.Locator property is used by the node to contact the registry. The value is a proxy that contains the registry's client endpoints. (You can avoid the need to define Ice.Default.Locator by using IceLocatorDiscovery.)
If you wish to run a collocated registry and node server, enable the property IceGrid.Node.CollocateRegistry and include the registry's configuration properties.
The remaining configuration properties are discussed in IceGrid.*.