Persistent connectivity

You can enable a connection to persist for multiple requests across processes. When a connection is established, it is named, and subsequent requests can then specify this named connection. The connection is available to a request for reuse till it either expires based on the value specified in the <connection-ttl> element, or is terminated with a <terminate-on-exit> or a <terminate-connection> element.

The following adapters support persistent connectivity:

• SSH
• Kerberized SSH2
• Telnet
• SCP
• FTP
• SFTP
• PowerShell
• Session-based CLI adapters

The named connection is defined in an adapter request in the <target> block by using a <connection> block that contains a <name> tag and a <terminate-on-exit> tag. The <name> tag is required. The <terminate-on-exit> tag is optional, and its default value is false, maintaining the connection. The SSH, SCP, FTP, SFTP, and PowerShell adapters also contain a <connection-ttl> element that specifies the time (in seconds) for which a named connection should persist.

In the PowerShell adapter, you define a named connection by using the <connection-name> element. The <terminate-connection> element is optional.

The named connection is an optional function. If there is no <connection> block, the connection opens and closes in the request and must be reopened for each subsequent request of that target.

The following figure shows an XML sample of a named connection used with a dynamic target. This connection terminates on completion of the request.

XML sample of a named connection used in conjunction with a dynamic target

When using a named connection with a dynamic target, you must define the dynamic target completely in each request. You cannot reference it as a name attribute with the <target> in subsequent requests. Only targets defined in the adapter configuration can be referenced with a name attribute in an adapter request.

The following figure shows an XML sample of a named connection used in conjunction with a target name reference from the adapter configuration. In the absence of the <terminate-on-exit> element, this connection remains open on completion of the request.

XML sample of a named connection in conjunction with a target name reference

Each subsequent request that uses a named connection is configured in the same manner, with either a complete dynamic target or a target name reference to the adapter configuration that contains a <connection> block. The connection is reused if open, or reestablished if it has been closed.

The following figure shows an XML sample of a named connection used by the PowerShell adapter. To use named connection, <enable-psremoting> and <enable-psremoting-session> must be true.

XML sample of a named connection for a PowerShell adapter