Multiple-Tango Host

Hi All

How to define multiple TANGO_HOST ?

Thanks and Regards
TCS-GMRT Team
Regards,
TCS_GMRT
Hi TCS-GMRT,

good question. TANGO_HOST refers to the hos:port address of the TANGO database where a device is defined. The concept of multiple TANGO_HOST means that you can communicate with devices from multiple TANGO_HOST databases in the same client. You do this by specifying the TANGO_HOST in the name of the device e.g. a client can talk to (i.e. create a Device Proxy) to the following devices //host1:port1/my/device/1 and //host2:port2/my/device/2. The client is then connected to multiple TANGO_HOSTs. If the TANGO_HOST is not specified then it the default TANGO_HOST is used.

This should be confused with a related concept namely the possibility to have multiple DataBaseds device servers serving the same TANGO_HOST i.e. database. Each DataBaseds listens on a different port and/or host but connects to the same TANGO database. The multiple addresses are then specified in the same TANGO_HOST. The client tries to connect to each address in sequence and connects to the first one that replies. NOTE this is NOT what we mean by multiple TANGO_HOST. This feature is used to improve reliability of a large TANGO control system.

I hope my explanation is clear!

Andy
Hello Andy

Thank you for the instant reply. Got you point.Just want to ask how to specify multiple addresses in TANGO_HOST variable ?
For example:
TANGO_HOST=localhost:10000, 10.29.214.325:10000

Should the multiple host in the TANGO_HOST variable be comma separated or space separated or anything else ? I am not clear about the method of the above problem.

Thanks and Regards
TCS-GMRT Team
Regards,
TCS_GMRT
Hello TCS_GMRT,

I've never used this feature but I've learned from the manual that it uses comma as separator:
http://www.esrf.eu/computing/cs/tango/tango_doc/kernel_doc/ds_prog/node10.html#SECTION0010110000000000000000

Cheers,
Zibi
Hi Zibi

Thanks a lot. Will try this feature and let u know.

Thanks and Regards
TCS-GMRT team
Regards,
TCS_GMRT
Here is the example from the ESRF:

TANGO_HOST=hostname:11000,hostname:10000

Where hostname is the name of the host where the database servers are running. In our case they are the same but they don't have to be.

Andy
 
Register or login to create to post a reply.