1. Channel Finder operational experience at BNL
work by: Gabriele Carcassi, Robert Petkus, Guobao Shen, Kunal Shroff, Lingyun Yang,
written by: Gabriele Carcassi performed by: Kunal Shroff

2. Scripts to - populate properties - create lattice
ChannelFinder at BNL
channelfinder.nsls2.bnl.gov
IOCs
update daemon
/cf-update
NFS
Web proxy
Glassfish Web service
CSS
Scripts to - populate properties - create lattice
dependency
data flow

3. Getting channels from the IOCs
channelfinder.nsls2.bnl.gov
IOCs
/cf-update
NFS
dependency
data flow

4. Getting channels from the IOCs
channelfinder.nsls2.bnl.gov exports the directory /cf-update through NFS
Each IOC directly or indirectly has access to it
When the IOC boots, the startup script saves the output of a dbl command to a file
Filename format: hostname.iocname.dbl

5. Updating channel list channelfinder.nsls2.bnl.gov update daemon
/cf-update
Glassfish Web service
dependency
data flow

6. Updating channel list
Daemon monitors for changes in the /cf- update directory and updates channelfinder
Setup a script in /etc/init.d
Uses /usr/bin/inoticoming to monitor for changes in the directory
Uses CFUpdateIOC.py script coming with channel finder python client to perform the update
Ignores all the channels that ends in “_” (NSLS-II convention for “internal” channels)

7. Updating channel list Update process feels very fast
System has been very reliable
no problems so far

8. Glassfish setup channelfinder.nsls2.bnl.gov Glassfish Web service
dependency
data flow

9. Glassfish setup Running Glassfish 3.1
Single instance of Glassfish for multiple applications
Will be the same deployment server for our log service (collaboration with MSU)
Each application available as an alias
Top application changes according to the alias
– ChannelFinder
– log

10. Glassfish setup Glassfish runs as glassfish user
Glassfish redirects to PAM for authentication
This is supported only as root user
We had to make glassfish member of the shadow group and allow it to access /etc/shadow (for local accounts) and /etc/pam_ldap.conf (for ldap accounts)
Runs fine now

11. Glassfish setup In ldap created the following groups:
cf-admins, admins
cf-channels, users that adds/removes channels, currently only cf-update
cf-properties, users that can add properties, a couple of people in our group and physics group
cf-tags, users that can only add tags, more people in the physics group
aphla, accelerator physics high level application, to group tags/properties from that group

12. Glassfish setup Main problems Increase max file descriptors
OutOfMemory error
Used to hit it, now we don’t anymore
Quantum-bug: stopped appearing once we setup the infrastructure to debug it when it would happen again

13. Usage from high level physics
channelfinder.nsls2.bnl.gov
Glassfish Web service
Scripts to - populate properties - create lattice
dependency
data flow

14. Usage from high level physics
Our physics group adds properties/tags
From Linyun Yang (accelerator physics) talk:
From Channel Access to Channel Finder Service:
Channel Accesses in Python and Matlab are simple to use.
High level applications (HLA) deals with thousands of magnets, instruments and more channels.
Organized/structured channel information is necessary.
Channels linked to accelerator lattice and diagnostics are even better.
Searching instead of remembering is easier for HLA users.
A “dictionary” service can help HLA to manage the channels and build a lattice structure to which the AP is familiar. (they done simulation, analysis with it in the design).

15. device FM1G4C02A

16. Usage from high level physics
Physics group can re-create the lattice from the information in channel finder
By tags, different lattices can be built, and elements can be shared between them.
Sharing is important for injection, where LTD1 and LTD2 shares a lot of elements with LTB

17. CSS & ChannelFinder channelfinder.nsls2.bnl.gov Glassfish Web service
dependency
data flow

18. CSS & ChannelFinder
See next talk!