--- /dev/null
+THE NEW NODE MANAGER
+====================
+
+This is a very preliminary version of the new node manager. Currently
+it is set up to download slices.xml; however, not all of the
+implemented functionality is accessible via slices.xml.
+
+FILES
+=====
+
+accounts.py - Account management functionality generic between
+delegate accounts and VServers.
+
+api.py - XMLRPC interface to Node Manager functionality. Runs on port
+812, supports a Help() call with more information.
+
+bwcap.py - Sets the bandwidth cap via the bwlimit module. The bwlimit
+calls are commented out because they've been giving me a bunch of
+errors.
+
+config.py - Configuration parameters. You'll probably want to change
+SA_HOSTNAME to the PLC address.
+
+database.py - The dreaded NM database. The main class defined is a
+dict subclass, which both indexes and stores various records. These
+records include the sliver/delegate records, as well as the timestamp,
+node bw cap, and any other crap PLC wants to put there.
+
+delegate.py - Create and delete delegate accounts. These accounts
+have low space overhead (unlike a VServer) and serve to authenticate
+remote NM users.
+
+forward_api_calls.c - The forward_api_calls program proxies stdin to
+the Unix domain socket /tmp/node_mgr_api, letting Node Manager take
+advantage of ssh authentication. It is intended for use as a shell on
+a special delegate account.
+
+logger.py - This is a very basic logger.
+
+Makefile - For compiling forward_api_calls.
+
+nm.py - The main program.
+
+plc.py - Downloads and parses slices.xml, reads the node id file.
+
+README.txt - Duh.
+
+sliver.py - Handles all VServer functionality.
+
+ticket.py - Not used at the moment; contains a demonstration of
+xmlsec1.
+
+tools.py - Various convenience functions for functionality provided by
+Linux.
+
+RUNNING
+=======
+
+Change SA_HOSTNAME in config.py and run nm.py. No bootstrapping
+required.
+
+INTERNALS
+=========
+
+At the moment, the main thread loops forever, fetching slices.xml and
+updating the database. Other threads handle incoming API connections
+(each connection is handled by a separate thread) and the database
+dumper. There is also one thread per account, which supervises
+creation/deletion/resource initialization for that account. The other
+threads request operations by means of a queue.
+
+Other than the queues, the threads synchronize by acquiring a global
+database lock before reading/writing the database. The database
+itself is a collection of records, which are just Python dicts with
+certain required fields. The most important of these fields are
+'timestamp', 'expiry', and 'record_key'. 'record_key' serves to
+uniquely identify a particular record; the only naming conventions
+followed are that account records have record_key <account
+type>_<account name>; thus sliver princeton_sirius has record_key
+'sliver_princeton_sirius'.
+
+The two main features that will not be familiar from the old node
+manager are delegates and loans. Delegates, as described above, are
+lightweight accounts whose sole purpose is to proxy NM API calls from
+outside. The current code makes a delegate account 'del_snoop' that's
+allowed to spy on everyone's RSpec; you'll need to change the key in
+plc.py order to use it. Loans are resource transfers from one sliver
+to another; the format for loans is a list of triples: recipient
+sliver, resource type, amount. Thus for princeton_sirius to give 20%
+guaranteed CPU to princeton_eisentest, it would call
+
+api.SetLoans(['princeton_eisentest', 'nm_cpu_guaranteed_share', 200])
+
+provided, of course, that it has 200 guaranteed shares :)
+
+POSTSCRIPT
+==========
+
+The log file will come in a great deal of use when attempting to
+use/debug node manager; it lives at /var/log/pl_node_mgr.log. If you
+break the DB, you should kill the pickled copy, which lives at
+<config.py:DB_FILE>.
+
+I have been refactoring the code constantly in an attempt to keep the
+amount of glue to a minimum; unfortunately comments quickly grow stale
+in such an environment, and I have not yet made any attempt to comment
+reasonably. Until such time as I do, I'm on the hook for limited
+support of this thing. Please feel free to contact me at
+deisenst@cs.princeton.edu.
git://git.onelab.eu / nodemanager.git / blobdiff