DB2 Connect Quick Beginnings for Linux**
This section assumes that TCP/IP is functional on
the client and server workstations. See Software Requirements for the communication protocol requirements for your
platform. See Possible Client-to-Server Connectivity Scenarios for the supported communication protocols for your
particular client and server.
To set up TCP/IP communications on a DB2 client, perform the
following steps:
Step 1.
| Identify and record parameter values.
|
Step 2.
| Configure the client:
- Resolve the server's host address.
- Update the services file.
- Catalog a TCP/IP node.
- Catalog the database.
|
Step 3.
| Test the connection between the client and server.
|
|
Due to the characteristics of the TCP/IP protocol, TCP/IP may not be
immediately notified of the failure of a partner on another host. As a
result, a client application accessing a remote DB2 server using TCP/IP, or
the corresponding agent at the server, may sometimes appear to be hung.
DB2 uses the TCP/IP SO_KEEPALIVE socket option to detect when there has been a
failure and the TCP/IP connection has been broken.
If you are experiencing problems with your TCP/IP connection, refer to the
Troubleshooting Guide for information on how to adjust this parameter and other common TCP/IP
problems.
|
As you proceed through the configuration steps, complete the
Your Value column in the following table. You can fill in
some of the values before you start configuring this protocol.
Table 9. TCP/IP Values Required at the Client
| Parameter
| Description
| Sample Value
| Your Value
|
|
Host Name
- Hostname (hostname) or
- IP address (ip_address)
|
Use the hostname or ip_address of the remote server
workstation.
To resolve this parameter:
- Enter the hostname command at the server to obtain the
hostname.
- Contact your network administrator to obtain the ip_address or
enter the ping hostname command.
|
serverhost
or
9.21.15.235
|
|
|
Service Name
- Connection Service name (svcename) or
- Port number/Protocol (port_number/tcp)
|
Values required in the services file.
The Connection Service name (svcename) is an arbitrary name that
represents the Port number (port_number) on the client.
The port number for the client must be the same as the port number that the
svcename parameter maps to in the /etc/services file at
the server. (The svcename parameter is located in the database
manager configuration file on the server.) This value must not be in
use by any other applications, and must be unique within the
services file.
This value generally must be 1024 or higher.
Contact your database administrator for the values used to configure the
server or enter the db2 get dbm cfg command on the server.
|
db2cdb2inst1
50000/tcp
|
|
| Node name (node_name)
|
A local alias, or nickname, that describes the remote server (referred to
as a node) to which you are trying to connect. You can choose any name
you want; however, all node name values within your local node directory
must be unique.
| db2node
|
|
The following steps configure this protocol on the
client. Replace the sample values with your worksheet values.
|
If your network has a name server, or you are planning to directly specify
the IP address (ip_address) of the server, skip this step and proceed
to B. Update the Services File.
|
The client must know the address of the server with which it is attempting
to establish communications. If a name server does not exist on your
network, you may directly specify a hostname that maps to the IP address
(ip_address) of the server in the local hosts file.
The hosts file for your platform is located in the /etc
directory.
| If you plan to support a Linux client that uses Network Information
Services (NIS), and your network does not use a name server, you must update
the hosts file located on your NIS master server.
|
Edit the client's hosts file and add an entry for the
server's hostname. For example:
9.21.15.235 serverhost # host address for serverhost
where:
- 9.21.15.235
- is the ip_address of the remote DB2 server.
- serverhost
- is the remote DB2 server's hostname.
- #
- denotes the start of a comment that describes this entry
| If the server is not in the same domain as the client, you must provide a
fully qualified domain name such as
serverhost.vnet.ibm.com, where
vnet.ibm.com is the domain name.
|
|
If you plan to catalog a TCP/IP node using a port number
(port_number), skip this step and go to C. Catalog a TCP/IP Node.
|
Using a local text editor, add the Connection Service name and port number
to the client's services file for TCP/IP support.
The services file for your platform is located in the
/etc directory. For example:
db2cdb2inst1 50000/tcp # DB2 connection service port for remote server
where:
- db2cdb2inst1
- is an arbitrary unique connection service name in the client's
/etc/services file.
- 50000
- is the port number that the svcename maps to on the remote DB2
server. You must use the same port number on the DB2 client and the DB2
server.
- tcp
- is the communication protocol that you are using
- #
- denotes the start of a comment that describes this entry
The port number used on the client must match the port number used on the
server.
|
If you are planning on supporting a Linux client that uses Network
Information Services (NIS), you must update the services file
located on your NIS master server.
The file called services is located in the /etc
directory.
|
You must add an entry to the client's node directory
to describe the remote server node. This entry specifies the chosen
alias (node_name), the hostname or ip_address, and
the svcename or port_number that the client will use to
access the remote server.
To catalog a TCP/IP node, perform the following steps:
Step 1.
| Log on to the system with a valid DB2 user ID. For more
information, see Appendix D, Naming Rules.
| If you are adding a database to a system that has a DB2 Connect server
product installed, log on to this system as a user with System Administrative
(SYSADM) or System Controller (SYSCTRL) authority on the instance. For
more information, see Working with the System Administrative Group.
This restriction is controlled by the catalog_noauth database
manager configuration parameter. For more information, refer to the
Administration Guide.
|
|
Step 2.
| Set up the instance environment and invoke the DB2 command line processor
by entering one of the following commands:
. INSTHOME/sqllib/db2profile (for Bash, Bourne or Korn shell)
source INSTHOME/sqllib/db2cshrc (for C shell)
where INSTHOME represents the home directory of the
instance.
|
Step 3.
| Catalog the node by entering the following commands:
db2 "catalog tcpip node node_name remote [hostname|ip_address]
server [svcename|port_number"
db2 terminate
For example, to catalog the remote server serverhost on the node
called db2node, using the service name db2cdb2inst1, enter
the following commands:
db2 "catalog tcpip node db2node remote serverhost server db2cdb2inst1"
db2 terminate
To catalog a remote server with the IP address
9.21.15.235 on the node called db2node,
using the port number 50000, enter the following:
db2 "catalog tcpip node db2node remote 9.21.15.235 server 50000"
db2 terminate
|
|
If you need to change values that were set with the catalog node
command, perform the following steps:
Step 1.
| Run the uncatalog node command in the command line processor as
follows:
db2 "uncatalog node node_name"
| Step 2.
| Recatalog the node with the values that you want to use.
|
|
Before a client application can access a remote database, the database must
be cataloged on the server node and on any client nodes that will connect to
it. When you create a database, it is automatically cataloged on the
server with the database alias (database_alias) the same as the
database name (database_name). The information in the database
directory, along with the information in the node directory, is used on the
client to establish a connection to the remote database.
To catalog a database on the client, perform the following steps:
Step 1.
| Log on to the system with a valid DB2 user ID. For more
information, see Appendix D, Naming Rules.
| If you are adding a database to a system that has a DB2 Connect server
product installed, log on to this system as a user with System Administrative
(SYSADM) or System Controller (SYSCTRL) authority on the instance. For
more information, see Working with the System Administrative Group.
This restriction is controlled by the catalog_noauth database
manager configuration parameter. For more information, refer to the
Administration Guide.
|
|
Step 2.
| Fill in the Your Value column in the following
worksheet.
Table 10. Worksheet: Parameter Values for Cataloging Databases
| Parameter
| Description
| Sample Value
| Your Value
|
| Database name (database_name)
| The database alias (database_alias) of the remote
database. When you create a database, it is automatically cataloged on
the server with the database alias (database_alias) the same as the
database name (database_name).
| sample
|
|
| Database alias (database_alias)
| An arbitrary local nickname for the remote database, on the
client. If you do not provide one, the default is the same as the
database name (database_name). This is the name that you use
when connecting to a database from a client.
| tor1
|
|
| Node name (node_name)
| The name of the node directory entry that describes where the database
resides. Use the same value for node name (node_name) that you
used to catalog the node in the previous step.
| db2node
|
|
|
Step 3.
| Set up the instance environment and invoke the DB2 command line processor
by entering one of the following commands:
. INSTHOME/sqllib/db2profile (for Bash, Bourne or Korn shell)
source INSTHOME/sqllib/db2cshrc (for C shell)
where INSTHOME represents the home directory of the
instance.
|
Step 4.
| Catalog the database by entering the following commands:
db2 "catalog database database_name as database_alias at node node_name"
db2 terminate
For example, to catalog a remote database called SAMPLE so that
it has the alias tor1, on the node db2node, enter the
following commands:
db2 "catalog database sample as tor1 at node db2node"
db2 terminate
| If you need to change values that were set with the catalog
database command, perform the following steps:
Step a.
| Enter the uncatalog database command as follows:
db2 "uncatalog database database_alias"
| Step b.
| Recatalog the database with the value that you want to use.
|
|
|
When you have finished configuring the client for
communications, perform the following steps to test the connection:
| You will need to connect to a remote database to test the
connection.
|
Step 1.
| Start the database manager by entering the db2start command on
the server (if it was not automatically started at boot time).
|
Step 2.
| Enter the following command to connect the client to the remote
database:
db2 "connect to database_alias user userid using password"
|
The values for userid and password must be valid for the
system on which they are authenticated. By default, authentication
takes place on the server for a DB2 server and on the host or AS/400 machine
for a DB2 Connect server.
Authentication for connecting to host databases is set while configuring
the DB2 Connect server. For more information, refer to the DB2 Connect User's Guide.
If the connection is successful, you will get a message showing the name of
the database to which you have connected. You are now able to retrieve
data from that database. For example, to retrieve a list of all the
table names listed in the system catalog table, enter the following
command:
"select tabname from syscat.tables"
When you are finished using the database connection, enter the db2
connect reset command to end the database connection.
| You are now ready to start using DB2. For more advanced topics,
refer to the Administration Guide and the Installation and Configuration Supplement.
|
If the connection fails, check the following
items:
At the server:
__ 1.
| The db2comm registry value includes the value
tcpip.
|
Check the settings for the db2comm registry value by entering the
db2set DB2COMM command. For more information, refer to the
Administration Guide.
|
|
__ 2.
| The services file was updated correctly.
|
__ 3.
| The service name (svcename) parameter was updated correctly in
the database manager configuration file.
|
__ 4.
| The database was created and cataloged properly.
|
__ 5.
| The database manager was stopped and started again (enter the
db2stop and db2start commands on the server).
|
|
If there are problems starting a protocol's connection managers, a
warning message appears and the error messages are logged in the
db2diag.log file. This file is located in the
INSTHOME/sqllib/db2dump directory, where INSTHOME
represents home directory of the instance owner.
For more information on the db2diag.log file, refer to
the Troubleshooting Guide.
|
At the client:
__ 1.
| If used, the services and hosts files were updated
correctly.
|
__ 2.
| The node was cataloged with the correct hostname (hostname) or IP
address (ip_address).
|
__ 3.
| The port number matches, or the service name maps to, the port number used
on the server.
|
__ 4.
| The node name (node_name) that was specified in the database
directory points to the correct entry in the node directory.
|
__ 5.
| The database was cataloged properly, using the server's
database alias (database_alias) that was cataloged when the database
was created on the server, as the database name (database_name) on
the client.
|
If the connection still fails after you verify these items, refer to the
Troubleshooting Guide.
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